Intraamniotic infection and the onset of labor in preterm premature rupture of the membranes

Clinical chorioamnionitis at term: definition, pathogenesis, microbiology, diagnosis, and treatment

Clinical chorioamnionitis, the most common infection-related diagnosis in labor and delivery units, is an antecedent of puerperal infection and neonatal sepsis. The condition is suspected when intrapartum fever is associated with two other maternal and fetal signs of local or systemic inflammation (eg, maternal tachycardia, uterine tenderness, maternal leukocytosis, malodorous vaginal discharge or amniotic fluid, and fetal tachycardia). Clinical chorioamnionitis is a syndrome caused by intraamniotic infection, sterile intraamniotic inflammation (inflammation without bacteria), or systemic maternal inflammation induced by epidural analgesia. In cases of uncertainty, a definitive diagnosis can be made by analyzing amniotic fluid with methods to detect bacteria (Gram stain, culture, or microbial nucleic acid) and inflammation (white blood cell count, glucose concentration, interleukin-6, interleukin-8, matrix metalloproteinase-8). The most common microorganisms are Ureaplasma species, and polymicrobial infections occur in 70% of cases. The fetal attack rate is low, and the rate of positive neonatal blood cultures ranges between 0.2% and 4%. Intrapartum antibiotic administration is the standard treatment to reduce neonatal sepsis. Treatment with ampicillin and gentamicin have been recommended by professional societies, although other antibiotic regimens, eg, cephalosporins, have been used. Given the importance of Ureaplasma species as a cause of intraamniotic infection, consideration needs to be given to the administration of antimicrobial agents effective against these microorganisms such as azithromycin or clarithromycin. We have used the combination of ceftriaxone, clarithromycin, and metronidazole, which has been shown to eradicate intraamniotic infection with microbiologic studies. Routine testing of neonates born to affected mothers for genital mycoplasmas could improve the detection of neonatal sepsis. Clinical chorioamnionitis is associated with decreased uterine activity, failure to progress in labor, and postpartum hemorrhage; however, clinical chorioamnionitis by itself is not an indication for cesarean delivery. Oxytocin is often administered for labor augmentation, and it is prudent to have uterotonic agents at hand to manage postpartum hemorrhage. Infants born to mothers with clinical chorioamnionitis near term are at risk for early-onset neonatal sepsis and for long-term disability such as cerebral palsy. A frontier is the noninvasive assessment of amniotic fluid to diagnose intraamniotic inflammation with a transcervical amniotic fluid collector and a rapid bedside test for IL-8 for patients with ruptured membranes. This approach promises to improve diagnostic accuracy and to provide a basis for antimicrobial administration.

Evaluation of the fetal myocardial performance ındex and Epicardial fat thickness in pregnant women with preterm prelabor rupture of membranes

OBJECTIVE

To assess the epicardial fat thickness (EFT) and modified myocardial performance index (Mod-MPI) measurements in fetuses at pregnant women with preterm prelabor rupture of membranes (pPROM) and compare them to healthy pregnant women's fetuses.

METHODS

Forty patients who presented to our clinic at 24-36 + 6 gestational weeks and were diagnosed with pPROM were included in the patient group. During the same period, 40 healthy pregnant women at similar gestational weeks were randomly selected as the control group.

RESULTS

The pPROM and control groups were similar in terms of demographics. In the pPROM group, EFT, Mod-MPI, and isovolumetric contraction(ICT) and relaxation times(IRT) were significantly higher and ejection time (ET) was significantly lower compared to the control group. In addition, Mod-MPI z-scores, IRT z-scores, ICT z-scores were significantly higher and ET z-scores was significantly lower in the pPROM. According to the ROC analysis, the optimal cutoff value of EFT was calculated as 1.55 mm, with 68% sensitivity and 71% specificity (AUC: 0.718, 95% CI: 0.550-0.786, p = .018) for predicting NICU requirement and the optimal cutoff value of EFT was calculated as 1.55 mm with 72% sensitivity and 73% specificity (AUC: 0.726, 95% CI: 0.556-0.896, p = .015) for predicting medication use in the pPROM group.

CONCLUSION

This study revealed differences in the EFT and Mod-MPI measurements of the fetuses of pregnant women with pPROM. Considering that EFT is an important energy source for the myocardium, as well as an endocrine structure in which inflammatory and anti-inflammatory markers are secreted, it is recommended to be evaluated in inflammatory conditions such as pPROM.

Antibiotic administration reduced intra-amniotic inflammation 7 days after preterm premature rupture of the membranes with intra-amniotic infection

OBJECTIVE

Intra-amniotic infections increase the risk of preterm delivery and short- and long-term fetal morbidity; however, no consensus exists on the choice of antimicrobial agents as treatment for these infections. We aimed to examine the efficacy of intravenous administration of sulbactam/ampicillin (SBT/ABPC) and azithromycin (AZM) for intra-amniotic infection in patients with preterm premature rupture of membranes (PPROM).

METHODS

This study followed a single-centered retrospective cohort design. We compared changes in interleukin 6 (IL-6) levels and the load of Ureaplasma species DNA in the amniotic fluid between singleton pregnancy patients with intra-amniotic infection (Group A) and without either intra-amniotic inflammation (IAI) or microbial invasion of the amniotic cavity (MIAC) (Group B) who developed PPROM between week 22, day 0 and week 33, day 6 of gestation and maintained pregnancy for ≥7 d after diagnosis (August 2014 to April 2020). Patients in Group A were treated with SBT/ABPC and AZM, whereas those in Group B were treated with ABPC and AZM or clarithromycin.

RESULTS

Thirty-one patients with IAI and 48 patients without either IAI or MIAC at diagnosis of PPROM underwent pregnancy/delivery management at our hospital. Following the study population selection, we evaluated six patients in Group A and 13 patients in Group B. Amniotic fluid IL-6 concentrations at the initial amniocentesis were high, ranging from 11.7 ng/mL to 139.2 ng/mL, indicating a state of severe IAI in all six patients in Group A. In five of the six patients in Group A, the amniotic fluid cultures during the first amniocentesis included Ureaplasma species only. In both groups, the amniotic fluid IL-6 concentration at the follow-up amniocentesis was lower than that at the initial amniocentesis (Group A: follow-up median 3.06 ng/mL [quartiles, 1.75-6.74], initial median 30.53 ng/mL [quartiles, 15.60-67.07], p＝.03; Group B: follow-up median 0.40 ng/mL [quartiles, 0.18-0.69], initial median 0.96 ng/mL [quartiles, 0.65-1.42], p＝.005); Group A showed a greater decrease than Group B (p < .001). No difference was found between the microbial loads of Ureaplasma species DNA in the initial and follow-up amniocentesis (p = .13).

CONCLUSIONS

In patients with PPROM and intra-amniotic infection, IL-6 levels in the amniotic fluid decreased significantly from before antimicrobial administration to day 7. This decrease is thought to be mainly due to the effects of intravenous AZM. The efficacy of AZM in patients with PPROM needs to be further confirmed via randomized controlled studies in the future.

Antibiotic treatment of women with isolated intrapartum fever vs clinical chorioamnionitis: maternal and neonatal outcomes

BACKGROUND

Clinical chorioamnionitis refers to the presence of maternal fever (≥38°C) and at least 2 clinical signs: (1) maternal tachycardia (>100 bpm), (2) fetal tachycardia (>160 bpm), (3) maternal leukocytosis >15,000/mm2, (4) purulent vaginal discharge, and (5) uterine tenderness. Few data exist to guide the appropriate management of women with isolated intrapartum fever in the absence of other clinical signs suggesting chorioamnionitis.

OBJECTIVE

This study compared maternal and neonatal infectious outcomes and microbiological outcomes between women with isolated intrapartum fever and women with clinical chorioamnionitis.

STUDY DESIGN

This 10-year retrospective study included all the laboring women at our institution, at ≥34 weeks of gestation, with a singleton pregnancy and body temperature of ≥38.0°C, with or without other evidences of infection. According to our department protocol, women with isolated intrapartum fever received intravenous ampicillin, whereas women with clinical chorioamnionitis received intravenous ampicillin plus gentamicin. The primary outcome was puerperal endometritis, compared between women with isolated intrapartum fever (treated with ampicillin) and women with clinical chorioamnionitis (treated with ampicillin plus gentamicin). The secondary maternal outcomes consisted of (1) maternal clinical outcomes, such as cesarean delivery, surgical site infection, postpartum hemorrhage, and postpartum length of stay, and (2) microbiological studies, including positive chorioamniotic membrane swabs and blood culture. Among the secondary neonatal outcomes were early-onset sepsis, neonatal intensive care unit admission, and length of stay. Of note, 2 multivariate logistic regression models were created. A model aimed to predict puerperal endometritis controlled for gestational age of >41 weeks, diabetes mellitus, obesity, positive group B streptococcus status, rupture of membrane ≥18 hours, meconium staining, positive chorioamniotic membrane swabs, cesarean delivery, and empiric postdelivery antibiotic administration. A model aimed to predict neonatal early-onset sepsis controlled for gestational age of 34 to 37 weeks, positive group B streptococcus status, rupture of membrane ≥18 hours, and positive chorioamniotic membrane swabs.

RESULTS

Overall, 458 women met the inclusion criteria. Compared with women with clinical chorioamnionitis (n=231), women with isolated intrapartum fever (n=227) had higher rates of puerperal endometritis (3.9% vs 8.8%; P=.03), early-onset sepsis (0.4% vs 4.4%; P=.005), positive chorioamniotic membrane swabs (46.3% vs 63.9%; P<.001), and ampicillin-resistant Escherichia coli (35.5% vs 48.9%; P=.033). The rate of group B streptococcus-positive chorioamniotic membrane swabs was similar between the groups. In a subanalysis of women with negative or unknown group B streptococcus status, the puerperal endometritis and neonatal early-onset sepsis rates were higher among women with isolated intrapartum fever than women with suspected chorioamnionitis (8.7% vs 3.3% [P=.041] and 4.1% vs 0% [P<.001], respectively). In 2 multivariate analysis models, among women with isolated intrapartum fever treated with ampicillin compared with those with clinical chorioamnionitis treated with ampicillin and gentamicin, the odds ratio of antibiotic treatment of endometritis was 2.65 (95% confidence interval, 1.06-6.62; P=.036), and the odds ratio of neonatal early-onset sepsis was 8.33 (95% confidence interval, 1.04-60.60; P=.045).

CONCLUSION

Women with intrapartum fever, with or without other signs of infection, were at increased risk of maternal and neonatal complications. The use of ampicillin as a sole agent in isolated intrapartum fever might promote ampicillin-resistant E coli growth in the chorioamniotic membranes and consequently lead to puerperal endometritis and early-onset sepsis. In this context, a broad-range antibiotic should be considered.

Residual amniotic fluid volume predicts the sealing of preterm prelabor rupture of fetal membranes in the pre- and periviable period

OBJECTIVE

Preterm prelabor rupture of fetal membranes (pPROM) is a leading cause of preterm birth. When pPROM occurs around the pre- and periviable period, the perinatal outcome is unfavorable. However, there have been a few cases in which the leakage of amniotic fluid ceases and the ruptured fetal membranes are spontaneously sealed.

MATERIALS AND METHODS

The prognosis of 38 cases of pPROM at less than 27 weeks of gestation in Kyoto University Hospital were studied. The clinical factors related to the sealing of fetal membranes were investigated.

RESULTS

Spontaneous sealing was confirmed in five patients (13%), and sealing occurred within 14 days of pPROM. Women in the no sealing group delivered at 26.3 ± 0.5 weeks of gestation, whereas women in the sealing group delivered at term at 38.8 ± 0.4 weeks (p < 0.0001). The maximum vertical pocket (MVP) of amniotic fluid at the time of pPROM diagnosis was 2.2 ± 0.3 cm in the no sealing group and 3.8 ± 0.5 cm in the sealing group (p = 0.043). All cases of sealing occurred when the MVP at diagnosis was more than 2 cm, and there were no cases of sealing if the MVP at diagnosis was less than 2 cm. In addition, the value of C-reactive protein at ROM was less than 0.4 mg/dL in all cases in the sealing group.

CONCLUSION

The residual volume of sterile amniotic fluid at the onset of pPROM may predict the possibility of fetal membrane sealing.

Myo-inositol: a potential prophylaxis against premature onset of labour and preterm birth

The incidence of preterm birth (PTB), delivery before 37 completed weeks of gestation, is rising in most countries. Several recent small clinical trials of myo-inositol supplementation in pregnancy, which were primarily aimed at preventing gestational diabetes, have suggested an effect on reducing the incidence of PTB as a secondary outcome, highlighting the potential role of myo-inositol as a preventive agent. However, the underlying molecular mechanisms by which myo-inositol might be able to do so remain unknown; these may occur through directly influencing the onset and progress of labour, or by suppressing stimuli that trigger or promote labour. This paper presents hypotheses outlining the potential role of uteroplacental myo-inositol in human parturition and explains possible underlying molecular mechanisms by which myo-inositol might modulate the uteroplacental environment and inhibit preterm labour onset. We suggest that a physiological decline in uteroplacental inositol levels to a critical threshold with advancing gestation, in concert with an increasingly pro-inflammatory uteroplacental environment, permits spontaneous membrane rupture and labour onset. A higher uteroplacental inositol level, potentially promoted by maternal myo-inositol supplementation, might affect lipid metabolism, eicosanoid production and secretion of pro-inflammatory chemocytokines that overall dampen the pro-labour uteroplacental environment responsible for labour onset and progress, thus reducing the risk of PTB. Understanding how and when inositol may act to reduce PTB risk would facilitate the design of future clinical trials of maternal myo-inositol supplementation and definitively address the efficacy of myo-inositol prophylaxis against PTB.

Evaluation of Midkine levels in pregnant women with preterm premature rupture of membranes: A cohort study from a tertiary hospital

OBJECTIVE

To assess midkine (MK) levels in pregnant women with preterm premature rupture of membranes (PPROM) and compare them to healthy pregnant women. We also assessed the performance of the maternal serum MK level in predicting neonatal intensive care unit (NICU) requirement in the PPROM group.

METHODS

Forty pregnant women who presented to our clinic at 24-37 gestational weeks and were diagnosed with PPROM were included in the study group. During the same period, 40 healthy pregnant women at similar gestational weeks were randomly selected as the control group. Clinical characteristics, inflammatory markers, and serum MK levels were compared between the groups. The same parameters were then compared between the PPROM cases with and without NICU requirement. Finally, the receiver operating characteristic (ROC) analysis was performed to assess the predictive value of MK for NICU requirement.

RESULTS

The PPROM and control groups were similar in terms of demographics. The MK level of the pregnant woman with PPROM was significantly higher than that of the controls. No statistically significant difference was found between the MK levels of the cases with and without NICU requirement in the PPROM group. In the ROC analysis, the optimal cut-off value of was found to be 0.287, at which it had 63 % sensitivity and 65 % specificity (area under the curve(AUC): 0.78, 95 % confidence interval(CI): 0.683-0.881, p < 0.001) for the prediction of NICU requirement in cases with PPROM. In the same analysis performed for the prediction of PPROM, when the optimal cut-off value was taken as 0.298, MK had 56 % sensitivity and 60 % specificity (AUC: 0.65, 95 % CI: 0.522-0.770, p = 0.037).

CONCLUSION

Serum MK seems to be associated with complicated inflammatory processes leading to PPROM, and this novel marker has the potential to predict NICU requirement in PPROM cases.

Is there a placental microbiota? A critical review and re-analysis of published placental microbiota datasets

The existence of a placental microbiota is debated. The human placenta has historically been considered sterile and microbial colonization was associated with adverse pregnancy outcomes. Yet, recent DNA sequencing investigations reported a microbiota in typical human term placentas. However, this detected microbiota could represent background DNA or delivery-associated contamination. Using fifteen publicly available 16S rRNA gene datasets, existing data were uniformly re-analyzed with DADA2 to maximize comparability. While Amplicon Sequence Variants (ASVs) identified as Lactobacillus, a typical vaginal bacterium, were highly abundant and prevalent across studies, this prevalence disappeared after applying likely  DNA contaminant removal to placentas from term cesarean deliveries. A six-study sub-analysis targeting the 16S rRNA gene V4 hypervariable region demonstrated that bacterial profiles of placental samples and technical controls share principal bacterial ASVs and that placental samples clustered primarily by study origin and mode of delivery. Contemporary DNA-based evidence does not support the existence of a placental microbiota.ImportanceEarly-gestational microbial influences on human development are unclear. By applying DNA sequencing technologies to placental tissue, bacterial DNA signals were observed, leading some to conclude that a live bacterial placental microbiome exists in typical term pregnancy. However, the low-biomass nature of the proposed microbiome and high sensitivity of current DNA sequencing technologies indicate that the signal may alternatively derive from environmental or delivery-associated bacterial DNA contamination. Here we address these alternatives with a re-analysis of 16S rRNA gene sequencing data from 15 publicly available placental datasets. After identical DADA2 pipeline processing of the raw data, subanalyses were performed to control for mode of delivery and environmental DNA contamination. Both environment and mode of delivery profoundly influenced the bacterial DNA signal from term-delivered placentas. Aside from these contamination-associated signals, consistency was lacking across studies. Thus, placentas delivered at term are unlikely to be the original source of observed bacterial DNA signals.

Role of cervical sliding sign in predicting preterm delivery in pregnancies complicated with preterm premature rupture of membranes

OBJECTIVE

To investigate the effect of cervical sliding sign (CSS) to predict preterm delivery in patients with premature rupture of membranes.

METHODS

This prospective cohort study included 88 pregnant women between 24^0/7 and 36^6/7  weeks of gestation who were complicated with preterm premature rupture of membranes (PPROM) between June 2020 and January 2022. We measured the cervical length (CL) and applied pressure to the anterior fornix of the cervix with the transvaginal probe to investigate the CSS, which is defined as the sliding of the anterior lip of the cervix on the posterior lip.

RESULTS

The time between PPROM and delivery was significantly shorter in the CSS+ group (P < 0.001). Receiver operating characteristic curve analysis was performed for CSS with regard to predicting delivery within 7 days following PPROM (area under the curve, 0.749 [95% confidence interval, 0.642-0.857], P < 0.001). On logistic regression analysis, CL <25 mm increased the predictive accuracy of delivery within 7 days following PPROM 1.91-fold, and CSS increased the predictive accuracy of delivery within 7 days following PPROM 10.71-fold.

CONCLUSION

CSS is an effective sonographic marker in predicting preterm delivery and provides better information of oncoming preterm delivery in patients with PPROM than CL measurement.

Preterm Birth: An Overview

Birth order has a significant impact on perinatal and long-term outcomes. Preterm birth rates, ranging from 5% to 18%, are regrettably still high in industrialized and developing countries, making them the main contributor to infant mortality and morbidity. Infection, cervical pathology, uterine overdistension, progesterone deficiency, stress on the mother and fetus, allograft reaction, allergic phenomena, and likely more unknown factors are just a few of the causes of preterm birth syndrome. These several causes may improperly stimulate the usual pathway between the decidua and the fetal membranes, resulting in cervical ripening, membrane rupture, and uterine contractility. Some of the mechanisms underpinning these actions include receptors, chemokines, and inflammatory cytokines. For early identification, treatment, and avoidance of negative consequences, it is essential to understand the cellular and metabolic mechanisms that cause preterm labor. Clinicians and researchers are crucial to improving our knowledge of the biochemistry of preterm delivery, identifying risk factors, and creating treatments for this challenging condition. Intrauterine growth restriction and pre-eclampsia or eclampsia are frequent causes of suspected preterm births. "Spontaneous preterm births" occur after preterm labor that develops without warning with an early membrane rupture. It is thought that the condition that may cause these births may have several causes, such as uterine overdistension, vascular disease, infection, or inflammation. Unplanned preterm births have several reasons, including the black race, periodontal disease, low mother body mass index (BMI), and previous preterm births. A short cervical length and a high cervical-vaginal fetal fibronectin concentration are the two best signs of premature birth.

Directive clinique no 430 : Diagnostic et prise en charge de la rupture prématurée des membranes avant terme

OBJECTIF

Fournir des directives claires et concises pour le diagnostic et la prise en charge de la rupture prématurée des membranes avant terme (RPMAT).

POPULATION CIBLE

Toute patiente manifestant une rupture prématurée des membranes avant 37 semaines d'aménorrhée. BéNéFICES, RISQUES ET COûTS: La présente directive clinique vise à fournir les premières recommandations générales canadiennes sur la prise en charge de la rupture des membranes avant terme. Elle repose sur un examen complet et à jour des données probantes sur le diagnostic de la rupture et sur la prise en charge, le bon moment et les modes d'accouchement. DONNéES PROBANTES: Des recherches ont été effectuées dans PubMed-Medline et Cochrane en 2021 en utilisant les termes suivants : preterm premature rupture of membranes, PPROM, chorioamnionitis, Nitrazine test, ferning, commercial tests, PAMG-1, IGFBP-1 test, ultrasonography, PPROM/antenatal corticosteroids, PPROM/Magnesium sulphate, PPROM/antibiotic treatment, PPROM/tocolysis, PPROM/preterm labour, PPROM/neonatal outcomes, PPROM/mortality, PPROM/outpatient/inpatient, PPROM/cerclage, previable PPROM. Les articles retenus sont des essais cliniques randomisés, des méta-analyses, des revues systématiques, des directives cliniques et des études observationnelles. D'autres publications pertinentes ont été sélectionnées à partir des notices bibliographiques de ces articles. Seuls les articles en anglais ont été examinés. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Voir l'annexe A (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et faibles). PROFESSIONNELS CONCERNéS: Tous les fournisseurs de soins de santé prénatale ou périnatale. DÉCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Guideline No. 430: Diagnosis and management of preterm prelabour rupture of membranes

OBJECTIVE

To provide clear and concise guidelines for the diagnosis and management of preterm prelabour rupture of membranes (PPROM) TARGET POPULATION: All patients with PPROM <37 weeks gestation BENEFITS, HARMS, AND COSTS: This guideline aims to provide the first Canadian general guideline on the management of preterm membrane rupture. It includes a comprehensive and up-to-date review of the evidence on the diagnosis, management, timing and method of delivery.

EVIDENCE

The following search terms were entered into PubMed/Medline and Cochrane in 2021: preterm premature rupture of membranes, PPROM, chorioamnionitis, Nitrazine test, ferning, commercial tests, placental alpha microglobulin-1 (PAMG-1) test, insulin-like growth factor-binding protein-1 (IGFBP-1) test, ultrasonography, PPROM/antenatal corticosteroids, PPROM/Magnesium sulphate, PPROM/ antibiotic treatment, PPROM/tocolysis, PPROM/preterm labour, PPROM/Neonatal outcomes, PPROM/mortality, PPROM/outpatient/inpatient, PPROM/cerclage, previable PPROM. Articles included were randomized controlled trials, meta-analyses, systematic reviews, guidelines, and observational studies. Additional publications were identified from the bibliographies of these articles. Only English-language articles were reviewed.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

All prenatal and perinatal health care providers.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Fetal macrophages assist in the repair of ruptured amnion through the induction of epithelial-mesenchymal transition

The premature rupture of the amniotic sac, a condition referred to as a preterm prelabor rupture of membranes (pPROM), is a leading cause of preterm birth. In some cases, these ruptured membranes heal spontaneously. Here, we investigated repair mechanisms of the amnion, a layer of epithelial cells in the amniotic sac closest to the embryo. Macrophages migrated to and resided at rupture sites in both human and mouse amnion. A process called epithelial-mesenchymal transition (EMT), in which epithelial cells acquire a mesenchymal phenotype and which is implicated in tissue repair, was observed at rupture sites. In dams bearing macrophage-depleted fetuses, the repair of amnion ruptures was compromised, and EMT was rarely detected at rupture sites. The migration of cultured amnion epithelial cells in wound healing assays was mediated by EMT through transforming growth factor-β (TGF-β)-Smad signaling. These findings suggest that fetal macrophages are crucial in amnion repair because of their ability to induce EMT in amnion epithelial cells.

Critical window for the association between prenatal environmental tobacco smoke exposure and preterm birth

Although environmental tobacco smoke (ETS) exposure is considered to be a severe public health problem and a modifiable risk factor for preterm birth (PTB), we still lack a comprehensive understanding of the PTB risk associated with trimester-specific prenatal ETS exposure. This study aimed to examine the accumulation of risk across trimester ETS exposure and the critical window of the association between maternal ETS exposure during pregnancy and PTB. A total of 63,038 mother-child pairs were involved in the analysis of the 2017 survey of Longhua Child Cohort Study. Information about socio-demographic characteristics, prenatal ETS exposure, and birth outcomes were collected using a self-report questionnaire. A series of logistic regression models were employed to assess the associations between prenatal ETS exposure and PTB. We found that maternal ETS exposure during pregnancy significantly increased the risk of PTB and this association increased with both the average level of daily ETS exposure and the number of trimesters of ETS exposure. Moreover, mothers who were initially exposed to ETS in the 1st trimester of pregnancy had significant higher risk of PTB (OR = 1.34, 95% CI: 1.25-1.44). Furthermore, mothers exposed to ETS in the 1st trimester only (OR = 1.26, 95%CI: 1.04-1.50), in both 1st and 2nd trimester (OR = 1.35, 95%CI: 1.08-1.67) and throughout pregnancy (OR = 1.35, 95%CI: 1.24-1.46) experienced a significantly high risk of PTB. Prenatal maternal ETS exposure during only the 2nd trimester also resulted in a high risk of PTB with marginal significance (OR = 1.33, 95% CI:0.78-2.13). To conclude, the 1st and early 2nd trimester might be the critical window for prenatal ETS exposure causing PTB.

Estimated time to emergence of secondary intra-amniotic infection or inflammation since the onset of the preterm premature rupture of membranes

OBJECTIVE

Prematurity is the most important prognostic factor for infants born following preterm premature rupture of membranes (PPROM). Therefore, when PPROM occurs between 22 and 33 weeks of gestation, prolonging pregnancy is recommended. Determination of management strategies requires screening for the presence of intra-amniotic infection or inflammation at the time of PPROM diagnosis. If intra-amniotic infection/inflammation is not detected, it is important to monitor the patient to diagnose any new infection/inflammation. We examined the period from PPROM to secondary intra-amniotic infection/inflammation and associated factors.

MATERIALS AND METHODS

This retrospective study was conducted at a single facility. We examined 26 patients who experienced PPROM between 26 and 33 weeks of gestation and were negative for intra-amniotic infection/inflammation at the time of diagnosis and underwent serial amniocentesis. Antibiotic therapy comprising ampicillin, amoxicillin, and clarithromycin for 7 days was started after the first amniocentesis. The period from PPROM to secondary intra-amniotic infection/inflammation was analyzed using a Kaplan-Meier survival curve. The onset of intra-amniotic infection/inflammation was considered as the time at which amniotic fluid bacterial culture results became positive, the time when amniotic fluid Interleukin (IL)-6 increased beyond 2.6 ng/mL, or the day of delivery if histological chorioamnionitis was observed in the delivered placenta. Patients were treated as censored if no intra-amniotic infection/inflammation could be confirmed in the amniotic fluid and delivered placenta.

RESULTS

The median time from PPROM to secondary intra-amniotic infection/inflammation was 18 days. Six patients developed intra-amniotic infection/inflammation, while 13 patients without intra-amniotic infections/inflammation delivered fewer than 7 days after PPROM. No confounding factors at the time of PPROM diagnosis were associated with the time from PPROM until secondary intra-amniotic infection/inflammation.

CONCLUSIONS

The time between PPROM and onset of secondary intra-amniotic infection/inflammation appears prolonged. Treatments other than antimicrobial agents may need to be added to prolong pregnancy.

Clarithromycin prevents preterm birth and neonatal mortality by dampening alarmin-induced maternal–fetal inflammation in mice

Background

One of every four preterm neonates is born to a woman with sterile intra-amniotic inflammation (inflammatory process induced by alarmins); yet, this clinical condition still lacks treatment. Herein, we utilized an established murine model of sterile intra-amniotic inflammation induced by the alarmin high-mobility group box-1 (HMGB1) to evaluate whether treatment with clarithromycin prevents preterm birth and adverse neonatal outcomes by dampening maternal and fetal inflammatory responses.

Methods

Pregnant mice were intra-amniotically injected with HMGB1 under ultrasound guidance and treated with clarithromycin or vehicle control, and pregnancy and neonatal outcomes were recorded (n = 15 dams each). Additionally, amniotic fluid, placenta, uterine decidua, cervix, and fetal tissues were collected prior to preterm birth for determination of the inflammatory status (n = 7–8 dams each).

Results

Clarithromycin extended the gestational length, reduced the rate of preterm birth, and improved neonatal mortality induced by HMGB1. Clarithromycin prevented preterm birth by interfering with the common cascade of parturition as evidenced by dysregulated expression of contractility-associated proteins and inflammatory mediators in the intra-uterine tissues. Notably, clarithromycin improved neonatal survival by dampening inflammation in the placenta as well as in the fetal lung, intestine, liver, and spleen.

Conclusions

Clarithromycin prevents preterm birth and improves neonatal survival in an animal model of sterile intra-amniotic inflammation, demonstrating the potential utility of this macrolide for treating women with this clinical condition, which currently lacks a therapeutic intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04764-2.

Erythromycin vs azithromycin for treatment of preterm prelabor rupture of membranes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to estimate the effect of erythromycin vs azithromycin on the duration of latency and the rate of clinical chorioamnionitis in women with preterm prelabor rupture of membranes by performing a systematic review and meta-analysis of the existing literature.

DATA SOURCES

From inception to October 2021, we explored MEDLINE, Scopus, Embase, CINAHL, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials.

STUDY ELIGIBILITY CRITERIA

Studies comparing the duration of latency and the rate of clinical chorioamnionitis between women with preterm prelabor rupture of membranes who were treated with erythromycin and those who were treated with azithromycin at the time of diagnosis were included.

METHODS

Here, 2 reviewers separately ascertained studies, obtained data, and gauged study quality. The mean length of latency and the rate of clinical chorioamnionitis were compared and mean differences and odds ratios with 95% confidence intervals were estimated.

RESULTS

A total of 5 studies with 1289 women were identified. The mean length of latency in women with preterm prelabor rupture of membranes was similar between individuals treated with erythromycin and those treated with azithromycin: 6.6 days vs 6.7 days (mean difference, 0.07 days; 95% confidence interval, -0.45 to 0.60; I², 0%). The median point prevalence rates of clinical chorioamnionitis were 25% (95% confidence interval, 12-32) in women treated with erythromycin and 14% (95% confidence interval, 9-24) in women treated with azithromycin. The overall clinical chorioamnionitis rate in women treated with azithromycin was lower than women treated with erythromycin (pooled odds ratio, 0.53; 95% confidence interval, 0.39-0.71; I², 0%).

CONCLUSION

The administration of azithromycin in women with preterm prelabor rupture of membranes was associated with a similar latency period but a lower rate of clinical chorioamnionitis than the administration of erythromycin.

Respiratory responses to hypoxia during rest and exercise in individuals born pre-term: a state-of-the-art review

The pre-term birth survival rate has increased considerably in recent decades, and research investigating the long-term effects of premature birth is growing. Moreover, altitude sojourns are increasing in popularity and are often accompanied by various levels of physical activity. Individuals born pre-term appear to exhibit altered acute ventilatory responses to hypoxia, potentially predisposing them to high-altitude illness. These impairments are likely due to the use of perinatal hyperoxia stunting the maturation of carotid body chemoreceptors, but may also be attributed to limited lung diffusion capacity and/or gas exchange inefficiency. Aerobic exercise capacity also appears to be reduced in this population. This may relate to the aforementioned respiratory impairments, or could be due to physiological limitations in pulmonary blood flow or at the exercising muscle (e.g. mitochondrial efficiency). However, surprisingly, the debilitative effects of exercise when performed at altitude do not seem to be exacerbated by premature birth. In fact, it is reasonable to speculate that pre-term birth could protect against the consequences of exercise combined with hypoxia. The mechanisms that underlie this assertion might relate to differences in oxidative stress responses or in cardiopulmonary morphology in pre-term individuals, compared to their full-term counterparts. Further research is required to elucidate the independent effects of neonatal treatment, sex differences and chronic lung disease, and to establish causality in some of the proposed mechanisms that could underlie the differences discussed throughout this review. A more in-depth understanding of the acclimatisation responses to chronic altitude exposures would also help to inform appropriate interventions in this clinical population.

Individualized treatment of preterm premature rupture of membranes to prolong the latency period, reduce the rate of preterm birth, and improve neonatal outcomes

BACKGROUND

Preterm premature rupture of membranes complicates approximately 3% of pregnancies. Currently, in the absence of chorioamnionitis or placental abruption, expectant management, including antenatal steroids for lung maturation and prophylactic antibiotic treatment, is recommended. The benefits of individualized management have not been adequately explored.

OBJECTIVE

This study aimed to compare the impact of 2 different management strategies of preterm premature rupture of membranes in 2 tertiary obstetrical centers on latency of >7 days, latency to birth, chorioamnionitis, funisitis, and short-term adverse maternal and neonatal outcomes.

STUDY DESIGN

This was a multicenter retrospective study of women with singleton pregnancies with preterm premature rupture of membranes from 23 0/7 to 33 6/7 weeks of gestation between 2014 and 2018 and undelivered within 24 hours after hospital admission managed at Sunnybrook Health Sciences Center, Toronto, Canada (standard management group), and BCNatal (Hospital Clínic of Barcelona and Hospital Sant Joan de Déu Barcelona), Barcelona, Spain (individualized management group), following local protocols. The standard management group received similar management for all patients, which included a standard antibiotic regimen and routine maternal and fetal surveillance, whereas the individualized management group received personalized management on the basis of amniocentesis at hospital admission (if possible), to rule out microbial invasion of the amniotic cavity and targeted treatment. The exclusion criteria were cervical dilatation >2 cm, active labor, contraindications to expectant management (acute chorioamnionitis, placental abruption, or abnormal fetal tracing), and major fetal anomalies. The primary outcome was latency of >7 days, and the secondary outcomes included latency to birth, chorioamnionitis, and short-term adverse maternal and neonatal outcomes. Statistical comparisons between groups were conducted with propensity score weighting.

RESULTS

A total of 513 pregnancies with preterm premature rupture of membranes were included in this study: 324 patients received standard management, and 189 patients received individualized management, wherein amniocentesis was performed in 112 cases (59.3%). After propensity score weighting, patients receiving individualized management had a higher latency of >7 days (76.0% vs 41.6%; P<.001) and latency to birth (18.1±14.7 vs 9.7±9.7 days; P<.001). Although a higher rate of clinical chorioamnionitis was suspected in the individualized management group than the standard group (34.5% vs 22.0%; P<.01), there was no difference between the groups in terms of histologic chorioamnionitis (67.2% vs 73.4%; P=.16), funisitis (57.6% vs 58.1%; P=.92), or composite infectious maternal outcomes (9.1% vs 7.9%; P=.64). Prolonged latency in the individualized management group was associated with a significant reduction of preterm birth at <32 weeks of gestation (72.1% vs 90.5%; P<.001), neonatal intensive care unit admission (75.6% vs 83.0%; P=.046), and neonatal respiratory support at 28 days of life (16.1% vs 26.1%; P<.01) compared with that in the standard management group. Moreover, prolonged latency was not associated with neonatal severe morbidity at discharge (survival without severe morbidity, 80.4% vs 73.5%; P=.09).

CONCLUSION

Individualized management of preterm premature rupture of membranes may prolong pregnancy and reduce preterm birth at <32 weeks of gestation, the need for neonatal support, and neonatal intensive care unit admissions, without an increase in histologic chorioamnionitis, funisitis, neonatal infection-related morbidity, and short-term adverse maternal and neonatal outcomes.

Bacteria in the amniotic fluid without inflammation: early colonization vs. contamination

OBJECTIVES

Intra-amniotic infection, defined by the presence of microorganisms in the amniotic cavity, is often accompanied by intra-amniotic inflammation. Occasionally, laboratories report the growth of bacteria or the presence of microbial nucleic acids in amniotic fluid in the absence of intra-amniotic inflammation. This study was conducted to determine the clinical significance of the presence of bacteria in amniotic fluid samples in the absence of intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study included 360 patients with preterm labor and intact membranes who underwent transabdominal amniocentesis for evaluation of the microbial state of the amniotic cavity as well as intra-amniotic inflammation. Cultivation techniques were used to isolate microorganisms, and broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was utilized to detect the nucleic acids of bacteria, viruses, and fungi.

RESULTS

Patients whose amniotic fluid samples evinced microorganisms but did not indicate inflammation had a similar perinatal outcome to those without microorganisms or inflammation [amniocentesis-to-delivery interval (p=0.31), spontaneous preterm birth before 34 weeks (p=0.83), acute placental inflammatory lesions (p=1), and composite neonatal morbidity (p=0.8)].

CONCLUSIONS

The isolation of microorganisms from a sample of amniotic fluid in the absence of intra-amniotic inflammation is indicative of a benign condition, which most likely represents contamination of the specimen during the collection procedure or laboratory processing rather than early colonization or infection.

Birth weight and intra-amniotic inflammatory and infection-related complications in pregnancies with preterm prelabor rupture of membranes: a retrospective cohort study

OBJECTIVE

To assess the association between the birth weight of newborns and microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation in pregnancies with preterm prelabor rupture of membranes.

METHODS

A total of 528 pregnancies with preterm prelabor rupture of membranes were included in this retrospective cohort study. Transabdominal amniocentesis to determine the presence of MIAC (through culturing and molecular biology methods) and intra-amniotic inflammation (according to amniotic fluid interleukin-6 level) was performed as part of standard clinical management. Based on the presence of MIAC and/or intra-amniotic inflammation, the participants were divided into four subgroups: with intra-amniotic infection (presence of both), with sterile IAI (intra-amniotic inflammation alone), with colonization (MIAC alone), and with negative amniotic fluid (absence of both). Birth weights of newborns are expressed as percentiles derived from INTERGROWTH-21st standards for (i) newborn birth weight and (ii) estimated fetal weight.

RESULTS

No differences in birth weights, expressed as percentiles derived from newborn weight standards (infection: median 52; sterile: median 54; colonization: median 50; negative amniotic fluid: median 51; p = .93) and estimated fetal weight standards (infection: median 47; sterile: median 51; colonization: median 47; negative amniotic fluid: median 53; p = .48) were found among the four subgroups. No differences in percentiles (derived from both standards) were found in the subset of participants who delivered within 72 h after rupture of membranes (newborn weight standard, p = .99; estimated fetal weight standard, p = .81).

CONCLUSIONS

No association was identified between the birth weight of newborns and the presence of intra-amniotic inflammatory and infection-related complications in pregnancies with preterm prelabor rupture of membranes.

Disorders of placental villous maturation are present in one-third of cases with spontaneous preterm labor

OBJECTIVES

Spontaneous preterm labor is an obstetrical syndrome accounting for approximately 65-70% of preterm births, the latter being the most frequent cause of neonatal death and the second most frequent cause of death in children less than five years of age worldwide. The purpose of this study was to determine and compare to uncomplicated pregnancies (1) the frequency of placental disorders of villous maturation in spontaneous preterm labor; (2) the frequency of other placental morphologic characteristics associated with the preterm labor syndrome; and (3) the distribution of these lesions according to gestational age at delivery and their severity.

METHODS

A case-control study of singleton pregnant women was conducted that included (1) uncomplicated pregnancies (controls, n=944) and (2) pregnancies with spontaneous preterm labor (cases, n=438). All placentas underwent histopathologic examination. Patients with chronic maternal diseases (e.g., chronic hypertension, diabetes mellitus, renal disease, thyroid disease, asthma, autoimmune disease, and coagulopathies), fetal malformations, chromosomal abnormalities, multifetal gestation, preeclampsia, eclampsia, preterm prelabor rupture of the fetal membranes, gestational hypertension, gestational diabetes mellitus, and HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome were excluded from the study.

RESULTS

Compared to the controls, the most prevalent placental lesions among the cases were the disorders of villous maturation (31.8% [106/333] including delayed villous maturation 18.6% [62/333] vs. 1.4% [6/442], q<0.0001, prevalence ratio 13.7; and accelerated villous maturation 13.2% [44/333] vs. 0% [0/442], q<0.001). Other lesions in decreasing order of prevalence included hypercapillarized villi (15.6% [68/435] vs. 3.5% [33/938], q<0.001, prevalence ratio 4.4); nucleated red blood cells (1.1% [5/437] vs. 0% [0/938], q<0.01); chronic inflammatory lesions (47.9% [210/438] vs. 29.9% [282/944], q<0.0001, prevalence ratio 1.6); fetal inflammatory response (30.1% [132/438] vs. 23.2% [219/944], q<0.05, prevalence ratio 1.3); maternal inflammatory response (45.5% [195/438] vs. 36.1% [341/944], q<0.01, prevalence ratio 1.2); and maternal vascular malperfusion (44.5% [195/438] vs. 35.7% [337/944], q<0.01, prevalence ratio 1.2). Accelerated villous maturation did not show gestational age-dependent association with any other placental lesion while delayed villous maturation showed a gestational age-dependent association with acute placental inflammation (q-value=0.005).

CONCLUSIONS

Disorders of villous maturation are present in nearly one-third of the cases of spontaneous preterm labor.

PRG2 and AQPEP are misexpressed in fetal membranes in placenta previa and percreta†

The obstetrical conditions placenta accreta spectrum (PAS) and placenta previa are a significant source of pregnancy-associated morbidity and mortality, yet the specific molecular and cellular underpinnings of these conditions are not known. In this study, we identified misregulated gene expression patterns in tissues from placenta previa and percreta (the most extreme form of PAS) compared with control cases. By comparing this gene set with existing placental single-cell and bulk RNA-Seq datasets, we show that the upregulated genes predominantly mark extravillous trophoblasts. We performed immunofluorescence on several candidate molecules and found that PRG2 and AQPEP protein levels are upregulated in both the fetal membranes and the placental disk in both conditions. While this increased AQPEP expression remains restricted to trophoblasts, PRG2 is mislocalized and is found throughout the fetal membranes. Using a larger patient cohort with a diverse set of gestationally aged-matched controls, we validated PRG2 as a marker for both previa and PAS and AQPEP as a marker for only previa in the fetal membranes. Our findings suggest that the extraembryonic tissues surrounding the conceptus, including both the fetal membranes and the placental disk, harbor a signature of previa and PAS that is characteristic of EVTs and that may reflect increased trophoblast invasiveness.

Clinical chorioamnionitis at term X: microbiology, clinical signs, placental pathology, and neonatal bacteremia - implications for clinical care

OBJECTIVES

Clinical chorioamnionitis at term is considered the most common infection-related diagnosis in labor and delivery units worldwide. The syndrome affects 5-12% of all term pregnancies and is a leading cause of maternal morbidity and mortality as well as neonatal death and sepsis. The objectives of this study were to determine the (1) amniotic fluid microbiology using cultivation and molecular microbiologic techniques; (2) diagnostic accuracy of the clinical criteria used to identify patients with intra-amniotic infection; (3) relationship between acute inflammatory lesions of the placenta (maternal and fetal inflammatory responses) and amniotic fluid microbiology and inflammatory markers; and (4) frequency of neonatal bacteremia.

METHODS

This retrospective cross-sectional study included 43 women with the diagnosis of clinical chorioamnionitis at term. The presence of microorganisms in the amniotic cavity was determined through the analysis of amniotic fluid samples by cultivation for aerobes, anaerobes, and genital mycoplasmas. A broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry was also used to detect bacteria, select viruses, and fungi. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin-6 (IL-6) concentration ≥2.6 ng/mL.

RESULTS

(1) Intra-amniotic infection (defined as the combination of microorganisms detected in amniotic fluid and an elevated IL-6 concentration) was present in 63% (27/43) of cases; (2) the most common microorganisms found in the amniotic fluid samples were Ureaplasma species, followed by Gardnerella vaginalis; (3) sterile intra-amniotic inflammation (elevated IL-6 in amniotic fluid but without detectable microorganisms) was present in 5% (2/43) of cases; (4) 26% of patients with the diagnosis of clinical chorioamnionitis had no evidence of intra-amniotic infection or intra-amniotic inflammation; (5) intra-amniotic infection was more common when the membranes were ruptured than when they were intact (78% [21/27] vs. 38% [6/16]; p=0.01); (6) the traditional criteria for the diagnosis of clinical chorioamnionitis had poor diagnostic performance in identifying proven intra-amniotic infection (overall accuracy, 40-58%); (7) neonatal bacteremia was diagnosed in 4.9% (2/41) of cases; and (8) a fetal inflammatory response defined as the presence of severe acute funisitis was observed in 33% (9/27) of cases.

CONCLUSIONS

Clinical chorioamnionitis at term, a syndrome that can result from intra-amniotic infection, was diagnosed in approximately 63% of cases and sterile intra-amniotic inflammation in 5% of cases. However, a substantial number of patients had no evidence of intra-amniotic infection or intra-amniotic inflammation. Evidence of the fetal inflammatory response syndrome was frequently present, but microorganisms were detected in only 4.9% of cases based on cultures of aerobic and anaerobic bacteria in neonatal blood.

Maternal serum procalcitonin levels in prediction of chorioamnionitis in women with preterm premature rupture of membranes

INTRODUCTION

Chorioamnionitis is one of the most important maternal complications in the expectant management of patients with preterm premature rupture of membranes (PPROM). Procalcitonin (proCT), the precursor of the hormone calcitonin, is used to differentiate bacterial infections from non-bacterial ones. The objective of the study was to determine the efficacy of maternal serum procalcitonin levels in the early prediction of chorioamnionitis in women with PPROM.

MATERIAL AND METHODS

The study was conducted in 76 pregnant women hospitalized due to PPROM at the maternal-fetal medicine unit of a tertiary center in Istanbul. Patients were followed up with white blood cell (WBC), C-reactive protein (CRP) and proCT levels every 2 days. The values of investigated parameters were recorded at the diagnosis of PPROM and at the time of delivery. The maximum values during the follow-up period were also recorded.

RESULTS

Out of the 76 patients with PPROM, 15 (19.73%) developed clinical chorioamnionitis. No significant difference could be detected in the gravidity, parity, duration of hospitalization and gestational week at diagnosis between those patients who developed clinical chorioamnionitis and those who did not. The WBC at the time of hospital admittance and before delivery, and CRP levels before delivery were statistically higher in the chorioamnionitis group (p < 0.05). No difference in the proCT levels could be detected either at the time of hospital admittance or before delivery between the two groups.

CONCLUSIONS

Maternal proCT was not found to be predictive of chorioamnionitis. However, since there are reports in the literature that contradict these results, further studies are warranted to determine the true efficacy of proCT in the prediction of clinical chorioamnionitis.

Pretransplant ascites and encephalopathy and their influence on survival and liver graft rejection in alcoholic cirrhosis disease

INTRODUCTION

The Child-Pugh and model for end-stage liver disease (MELD) scores are widely used to predict the outcomes of liver transplant (LT). Both have similar prognostic values in most cases, although their benefits might differ in some specific conditions. The aim of our study was to analyze the influence of pre-transplant ascites and encephalopathy in post-transplant liver rejection development and survival in alcohol cirrhosis (AC) patients undergoing LT to determine the usefulness of the Child-Pugh score for the assessment of prognosis in such patients.

MATERIAL AND METHODS

Two hundred and eighty-one AC patients, classified according to viral infections and pre-transplant complications, were analyzed. Acute (AR) and chronic (CR) liver rejections and Child-Pugh, MELD and albumin-bilirubin (ALBI) scores were studied in all cases.

RESULTS

Similar AC rejection percentages were observed in ascites or encephalopathy groups (18.5% and 16.5%, p = 0.735), although a higher but not statistically significant AC rate was observed in patients with grade III ascites (p = 0.777) and with grade II encephalopathy (p = 0.089). Chronic rejection was only developed by 9.1% of AC patients, regardless of the presence of ascites (6.2%) or encephalopathy (5.5%). The presence of ascites and encephalopathy complications did not seem to influence post-transplant survival. Neither the Child-Pugh nor the ALBI score can be considered the best for predicting patient survival in the short or long term.

CONCLUSIONS

Ascites and encephalopathy do not seem to influence AC or CR in patient survival, regardless of the presence of viral infections, so in our study neither the Child-Pugh nor ALBI score seems to be the best score to predict the outcomes of these patients.

Management of clinical chorioamnionitis: an evidence-based approach

This review aimed to examine the existing evidence about interventions proposed for the treatment of clinical chorioamnionitis, with the goal of developing an evidence-based contemporary approach for the management of this condition. Most trials that assessed the use of antibiotics in clinical chorioamnionitis included patients with a gestational age of ≥34 weeks and in labor. The first-line antimicrobial regimen for the treatment of clinical chorioamnionitis is ampicillin combined with gentamicin, which should be initiated during the intrapartum period. In the event of a cesarean delivery, patients should receive clindamycin at the time of umbilical cord clamping. The administration of additional antibiotic therapy does not appear to be necessary after vaginal or cesarean delivery. However, if postdelivery antibiotics are prescribed, there is support for the administration of an additional dose. Patients can receive antipyretic agents, mainly acetaminophen, even though there is no clear evidence of their benefits. Current evidence suggests that the administration of antenatal corticosteroids for fetal lung maturation and of magnesium sulfate for fetal neuroprotection to patients with clinical chorioamnionitis between 24 0/7 and 33 6/7 weeks of gestation, and possibly between 23 0/7 and 23 6/7 weeks of gestation, has an overall beneficial effect on the infant. However, delivery should not be delayed to complete the full course of corticosteroids and magnesium sulfate. Once the diagnosis of clinical chorioamnionitis has been established, delivery should be considered, regardless of the gestational age. Vaginal delivery is the safer option and cesarean delivery should be reserved for standard obstetrical indications. The time interval between the diagnosis of clinical chorioamnionitis and delivery is not related to most adverse maternal and neonatal outcomes. Patients may require a higher dose of oxytocin to achieve adequate uterine activity or greater uterine activity to effect a given change in cervical dilation. The benefit of using continuous electronic fetal heart rate monitoring in these patients is unclear. We identified the following promising interventions for the management of clinical chorioamnionitis: (1) an antibiotic regimen including ceftriaxone, clarithromycin, and metronidazole that provides coverage against the most commonly identified microorganisms in patients with clinical chorioamnionitis; (2) vaginal cleansing with antiseptic solutions before cesarean delivery with the aim of decreasing the risk of endometritis and, possibly, postoperative wound infection; and (3) antenatal administration of N-acetylcysteine, an antioxidant and antiinflammatory agent, to reduce neonatal morbidity and mortality. Well-powered randomized controlled trials are needed to assess these interventions in patients with clinical chorioamnionitis.

Tocolysis compared with no tocolysis in women with threatened preterm birth and ruptured membranes: A propensity score analysis

INTRODUCTION

In women with preterm ruptured membranes and contractions, the administration of tocolysis is controversial. This study compares tocolysis with no tocolysis in women with threatened preterm birth and ruptured membranes.

OBJECTIVE

To compare tocolysis with no tocolysis in women with threatened preterm birth and ruptured membranes.

STUDY DESIGN

Data from the APOSTEL III RCT was combined with data from the National Maternity Hospital, Dublin. In the APOSTEL III trial, women with threatened preterm birth were randomized to atosiban or nifedipine. Patient data from Ireland were obtained from a cohort of women with threatened preterm birth with ruptured membranes. The Irish women received no tocolytic treatment. Only women with ruptured membranes and contractions were selected. We studied women with singleton or twin pregnancies and a gestational age between 25⁺⁰ and 33⁺⁶ weeks. Propensity score matching was performed to create comparable groups. Primary outcome was a composite adverse neonatal outcome. Secondary outcomes were individual components of the primary outcome, as well as neonatal intensive care unit (NICU) admission, gestational age at delivery, prolongation of pregnancy and mode of delivery.

RESULTS

153 women from the Apostel III trial were compared with 51 eligible women of the Irish cohort. We could match 46 women who received tocolysis and 46 women who received no tocolysis. All women had ruptured membranes. Maternal age, BMI, parity and gestational age at study entry were comparable between the groups after matching. There were no statistically significant differences in neonatal composite outcome (9.6 % in the tocolysis group versus 18 % in the control group, OR 0.46, 95 % CI 0.13-1.63). We found a lower incidence of NICU admission in the tocolysis group (63 %) than in the control group (94 %; OR 0.11, 95 % CI 0.03-0.41), which could be explained by differences in national admission policies. There were no statistically significant differences between tocolysis and no tocolysis in any of the other outcomes including sepsis, gestational age at delivery and time to delivery.

CONCLUSION

In this propensity score analysis of women with threatened preterm birth and ruptured membranes, tocolytic therapy did not alter composite adverse neonatal outcome or time to delivery.

In utero inflammatory challenge induces an early activation of the hepatic innate immune response in late gestation fetal sheep

Chorioamnionitis is associated with inflammatory end-organ damage in the fetus. Tissues in direct contact with amniotic fluid drive a pro-inflammatory response and contribute to this injury. However, due to a lack of direct contact with the amniotic fluid, the liver contribution to this response has not been fully characterized. Given its role as an immunologic organ, we hypothesized that the fetal liver would demonstrate an early innate immune response to an in utero inflammatory challenge. Fetal sheep (131 ± 1 d gestation) demonstrated metabolic acidosis and high cortisol and norepinephrine values within 5 h of exposure to intra-amniotic LPS. Likewise, expression of pro-inflammatory cytokines increased significantly at 1 and 5 h of exposure. This was associated with NF-κB activation, by inhibitory protein IκBα degradation, and nuclear translocation of NF-κB subunits (p65/p50). Corroborating these findings, LPS exposure significantly increased pro-inflammatory innate immune gene expression in fetal sheep hepatic macrophages in vitro. Thus, an in utero inflammatory challenge induces an early hepatic innate immune response with systemic metabolic and stress responses. Within the fetal liver, hepatic macrophages respond robustly to LPS exposure. Our results demonstrate that the fetal hepatic innate immune response must be considered when developing therapeutic approaches to attenuate end-organ injury associated with in utero inflammation.

A new rapid bedside test to diagnose and monitor intraamniotic inflammation in preterm PROM using transcervically collected fluid

BACKGROUND

Microbial invasion of the amniotic cavity, a clinical condition present in approximately 50% of patients with preterm prelabor rupture of membranes, is often associated with intraamniotic inflammation, a risk factor for a short admission-to-delivery interval, early preterm delivery, and neonatal complications. We previously developed a transcervical amniotic fluid collector, the device that allows the collection of fluid noninvasively from the cervical canal when membrane rupture occurs.

OBJECTIVE

This study was designed to determine whether rapid analysis of an interleukin-8 concentration in fluid obtained noninvasively by the transcervical amniotic fluid collector can be used to assess the risk of intraamniotic inflammation. We also compared the diagnostic performance of this point-of-care test for interleukin-8 in transcervically obtained fluid to that of a white blood cell count determined in amniotic fluid retrieved by transabdominal amniocentesis.

STUDY DESIGN

This prospective cohort study was conducted between October 2011 and April 2017. Fluid was retrieved through both transabdominal amniocentesis and the use of a transcervical amniotic fluid collector within 24 hours of amniocentesis in patients with a singleton pregnancy and preterm prelabor rupture of the membranes (16-35 weeks of gestation). Amniotic fluid obtained via amniocentesis was cultured for aerobic and anaerobic bacteria and genital mycoplasmas; a white blood cell count was also measured in amniotic fluid. Intraamniotic infection was diagnosed when microorganisms were identified by the cultivation of amniotic fluid. Intraamniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration (>23 ng/mL) assayed by enzyme-linked immunosorbent assay. Interleukin-8 in cervical fluid obtained by the collector was measured by the point-of-care test that used a test strip and scanner based on the fluorescence immunochromatographic analysis in 2019. The diagnostic indices, predictive values, and likelihood ratios of the 2 different tests were calculated.

RESULTS

First, interleukin-8 concentration ≥9.5 ng/mL in cervical fluid, determined by the point-of-care test, was at the knee of the receiver operating characteristic curve analysis and had a sensitivity of 98% (56/57; 95% confidence interval, 91-99.96%), specificity of 74% (40/54; 95% confidence interval, 60-85%), positive predictive value of 80% (56/70; 95% confidence interval, 72-86%), negative predictive value of 98% (40/41; 95% confidence interval, 85-99.6%), positive likelihood ratio of 3.79 (95% confidence interval, 2.41-5.96), and negative likelihood ratio of 0.02 (95% confidence interval, 0.003-0.17) in the identification of intraamniotic inflammation; a concentration of matrix metalloproteinase-8 >23 ng/mL by enzyme-linked immunosorbent assay had a prevalence of 51% (57/111). Second, a cervical fluid interleukin-8 concentration ≥9.5 ng/mL had significantly higher sensitivity than a transabdominally obtained amniotic fluid white blood cell count (≥19 cells/mm³) in the identification of intraamniotic inflammation (sensitivity: 98% [95% confidence interval, 91-99.96%] vs 84% [95% confidence interval, 72-93%]; P<.05; specificity: 74% [95% confidence interval, 60-85%] vs 76% [95% confidence interval, 62-87%); positive and negative predictive values: 80% [95% confidence interval, 72-86%] and 98% [95% confidence interval, 85-99.6%] vs 79% [95% confidence interval, 69-86%] and 82% [95% confidence interval, 71-89%]) and in the identification of intraamniotic inflammation/infection (gold standard: positive culture for bacteria or a matrix metalloproteinase-8 >23 ng/mL; sensitivity: 91% [95% confidence interval, 82-97%] vs 75% [95% confidence interval, 63-85%]; P<.05).

CONCLUSION

The point-of-care test was predictive of intraamniotic inflammation, based on the determination of interleukin-8 in fluid retrieved by a transcervical amniotic fluid collector. Therefore, the analysis of cervically obtained fluid by such point-of-care test may be used to noninvasively monitor intraamniotic inflammation in patients with preterm prelabor rupture of membranes.

Antibiotic administration reduces the rate of intraamniotic inflammation in preterm prelabor rupture of the membranes

BACKGROUND

Preterm prelabor rupture of the membranes (PPROM) is frequently complicated by intraamniotic inflammatory processes such as intraamniotic infection and sterile intraamniotic inflammation. Antibiotic therapy is recommended to patients with PPROM to prolong the interval between this complication and delivery (latency period), reduce the risk of clinical chorioamnionitis, and improve neonatal outcome. However, there is a lack of information regarding whether the administration of antibiotics can reduce the intensity of the intraamniotic inflammatory response or eradicate microorganisms in patients with PPROM.

OBJECTIVE

The first aim of the study was to determine whether antimicrobial agents can reduce the magnitude of the intraamniotic inflammatory response in patients with PPROM by assessing the concentrations of interleukin-6 in amniotic fluid before and after antibiotic treatment. The second aim was to determine whether treatment with intravenous clarithromycin changes the microbial load of Ureaplasma spp DNA in amniotic fluid.

STUDY DESIGN

A retrospective cohort study included patients who had (1) a singleton gestation, (2) PPROM between 24+0 and 33+6 weeks, (3) a transabdominal amniocentesis at the time of admission, and (4) intravenous antibiotic treatment (clarithromycin for patients with intraamniotic inflammation and benzylpenicillin/clindamycin in the cases of allergy in patients without intraamniotic inflammation) for 7 days. Follow-up amniocenteses (7th day after admission) were performed in the subset of patients with a latency period lasting longer than 7 days. Concentrations of interleukin-6 were measured in the samples of amniotic fluid with a bedside test, and the presence of microbial invasion of the amniotic cavity was assessed with culture and molecular microbiological methods. Intraamniotic inflammation was defined as a bedside interleukin-6 concentration ≥745 pg/mL in the samples of amniotic fluid. Intraamniotic infection was defined as the presence of both microbial invasion of the amniotic cavity and intraamniotic inflammation; sterile intraamniotic inflammation was defined as the presence of intraamniotic inflammation without microbial invasion of the amniotic cavity.

RESULTS

A total of 270 patients with PPROM were included in this study: 207 patients delivered within 7 days and 63 patients delivered after 7 days of admission. Of the 63 patients who delivered after 7 days following the initial amniocentesis, 40 underwent a follow-up amniocentesis. Patients with intraamniotic infection (n = 7) and sterile intraamniotic inflammation (n = 7) were treated with intravenous clarithromycin. Patients without either microbial invasion of the amniotic cavity or intraamniotic inflammation (n = 26) were treated with benzylpenicillin or clindamycin. Treatment with clarithromycin decreased the interleukin-6 concentration in amniotic fluid at the follow-up amniocentesis compared to the initial amniocentesis in patients with intraamniotic infection (follow-up: median, 295 pg/mL, interquartile range [IQR], 72-673 vs initial: median, 2973 pg/mL, IQR, 1750-6296; P = .02) and in those with sterile intraamniotic inflammation (follow-up: median, 221 pg/mL, IQR 118-366 pg/mL vs initial: median, 1446 pg/mL, IQR, 1300-2941; P = .02). Samples of amniotic fluid with Ureaplasma spp DNA had a lower microbial load at the time of follow-up amniocentesis compared to the initial amniocentesis (follow-up: median, 1.8 × 104 copies DNA/mL, 2.9 × 104 to 6.7 × 108 vs initial: median, 4.7 × 107 copies DNA/mL, interquartile range, 2.9 × 103 to 3.6 × 107; P = .03).

CONCLUSION

Intravenous therapy with clarithromycin was associated with a reduction in the intensity of the intraamniotic inflammatory response in patients with PPROM with either intraamniotic infection or sterile intraamniotic inflammation. Moreover, treatment with clarithromycin was related to a reduction in the load of Ureaplasma spp DNA in the amniotic fluid of patients with PPROM <34 weeks of gestation.

Healing Mechanism of Ruptured Fetal Membrane

Preterm premature rupture of membranes (pPROM) typically leads to spontaneous preterm birth within several days. In a few rare cases, however, amniotic fluid leakage ceases, amniotic fluid volume is restored, and pregnancy continues until term. Amnion, the collagen-rich layer that forms the load-bearing structure of the fetal membrane, has regenerative capacity and has been used clinically to aid in the healing of various wounds including burns, diabetic ulcers, and corneal injuries. In the healing process of ruptured fetal membranes, amnion epithelial cells seem to play a major role with assistance from innate immunity. In a mouse model of sterile pPROM, macrophages are recruited to the injured site. Well-organized and localized inflammatory responses cause epithelial mesenchymal transition of amnion epithelial cells which accelerates cell migration and healing of the amnion. Research on amnion regeneration is expected to provide insight into potential treatment strategies for pPROM.

Microbial burden and inflammasome activation in amniotic fluid of patients with preterm prelabor rupture of membranes

Background Intra-amniotic inflammation, which is associated with adverse pregnancy outcomes, can occur in the presence or absence of detectable microorganisms, and involves activation of the inflammasome. Intra-amniotic inflammasome activation has been reported in clinical chorioamnionitis at term and preterm labor with intact membranes, but it has not yet been investigated in women with preterm prelabor rupture of membranes (preterm PROM) in the presence/absence of detectable microorganisms. The aim of this study was to determine whether, among women with preterm PROM, there is an association between detectable microorganisms in amniotic fluid and intra-amniotic inflammation, and whether intra-amniotic inflammasome activation correlates with microbial burden. Methods Amniotic fluids from 59 cases of preterm PROM were examined for the presence/absence of microorganisms through culture and 16S ribosomal RNA (rRNA) gene quantitative real-time polymerase chain reaction (qPCR), and concentrations of interleukin-6 (IL-6) and ASC [apoptosis-associated spec-like protein containing a caspase recruitment domain (CARD)], an indicator of inflammasome activation, were determined. Results qPCR identified more microbe-positive amniotic fluids than culture. Greater than 50% of patients with a negative culture and high IL-6 concentration in amniotic fluid yielded a positive qPCR signal. ASC concentrations were greatest in patients with high qPCR signals and elevated IL-6 concentrations in amniotic fluid (i.e. intra-amniotic infection). ASC concentrations tended to increase in patients without detectable microorganisms but yet with elevated IL-6 concentrations (i.e. sterile intra-amniotic inflammation) compared to those without intra-amniotic inflammation. Conclusion qPCR is a valuable complement to microbiological culture for the detection of microorganisms in the amniotic cavity in women with preterm PROM, and microbial burden is associated with the severity of intra-amniotic inflammatory response, including inflammasome activation.

Retrospective study of the recurrence risk of preterm birth in Japan

Background: A history of preterm birth is a risk factor for preterm birth in a future pregnancy, and there are some reports of prevention methods, such as the administration of progesterone. However, the rate of recurrence of preterm birth in Japan has not been clarified, and there is no data for judging whether these preventive methods are effective.Objective: To clarify the risk of recurrence of preterm birth and preterm prelabor rupture of membranes (pPROM) in Japan.Materials and methods: A retrospective study was conducted using the perinatal registration database of the Japan Obstetrics and Gynecology Society for the Perinatal Center from 2014 to 2016. There were 704,418 subjects, of which 190,990 were excluded those with unknown maternal information, those under the age of 20 years, those with perinatal disease related to preterm birth, and first-time mothers.Results: Logistic model unavailable and multivariate analysis were performed. An analysis of the preterm birth history indicated the risk of preterm birth in the current pregnancy, and the odds ratio for preterm birth recurrence once, twice, and three times or more was 3.3, 6.6, and 7.8, respectively. As a secondary analysis, we analyzed whether the history of pPROM is a risk factor of recurrence of pPROM and found a significant association with an odds ratio of 3.4.Conclusion: Having a preterm birth history increases the risk of recurrence of preterm birth, and the risk of recurrent preterm birth increases as the number of preterm births increases. Although this report is intended for high-risk pregnancies wherein the rate of preterm birth is high, as previously reported, our data indicate that in Japan, preterm birth is a risk factor of recurrent preterm birth.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

Evidence that intra-amniotic infections are often the result of an ascending invasion - a molecular microbiological study

Background Microbial invasion of the amniotic cavity resulting in intra-amniotic infection is associated with obstetrical complications such as preterm labor with intact or ruptured membranes, cervical insufficiency, as well as clinical and histological chorioamnionitis. The most widely accepted pathway for intra-amniotic infection is the ascension of microorganisms from the lower genital tract. However, hematogenous dissemination of microorganisms from the oral cavity or intestine, retrograde seeding from the peritoneal cavity through the fallopian tubes, and introduction through invasive medical procedures have also been suggested as potential pathways for intra-amniotic infection. The primary reason that an ascending pathway is viewed as most common is that the microorganisms most often detected in the amniotic fluid are those that are typical inhabitants of the vagina. However, thus far, no studies have shown that microorganisms in the amniotic cavity are simultaneously present in the vagina of the woman from which they were isolated. The objective of the study was to determine the frequency with which microorganisms isolated from women with intra-amniotic infection are also present in the lower genital tract. Methods This was a cross-sectional study of women with intra-amniotic infection with intact membranes. Intra-amniotic infection was defined as a positive culture and elevated concentrations of interleukin-6 (IL-6) (>2.6 ng/mL) in amniotic fluid and/or acute histologic chorioamnionitis and funisitis. Microorganisms isolated from bacterial cultures of amniotic fluid were taxonomically identified through matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and 16S ribosomal RNA (rRNA) gene sequencing. Vaginal swabs were obtained at the time of amniocentesis for the identification of microorganisms in the lower genital tract. The overall bacterial profiles of amniotic fluids and vaginal swabs were characterized through 16S rRNA gene sequencing. The bacterial profiles of vaginal swabs were interrogated for the presence of bacteria cultured from amniotic fluid and for the presence of prominent (>1% average relative abundance) operational taxonomic units (OTUs) within the overall 16S rRNA gene bacterial profiles of amniotic fluid. Results (1) A total of 75% (6/8) of women had bacteria cultured from their amniotic fluid that are typical residents of the vaginal ecosystem. (2) A total of 62.5% (5/8) of women with bacteria cultured from their amniotic fluid also had these bacteria present in their vagina. (3) The microorganisms cultured from amniotic fluid and also detected in the vagina were Ureaplasma urealyticum, Escherichia coli, and Streptococcus agalactiae. (4) 16S rRNA gene sequencing revealed that the amniotic fluid of women with intra-amniotic infection had bacterial profiles dominated by Sneathia, Ureaplasma, Prevotella, Lactobacillus, Escherichia, Gardnerella, Peptostreptococcus, Peptoniphilus, and Streptococcus, many of which had not been cultured from the amniotic fluid samples. (5) Seventy percent (7/10) of the prominent (>1% average relative abundance) OTUs found in amniotic fluid were also prominent in the vagina. Conclusion The majority of women with intra-amniotic infection had bacteria cultured from their amniotic fluid that were typical vaginal commensals, and these bacteria were detected within the vagina at the time of amniocentesis. Molecular microbiological interrogation of amniotic fluid from women with intra-amniotic infection revealed that the bacterial profiles of amniotic fluid were largely consistent with those of the vagina. These findings indicate that ascension from the lower genital tract is the primary pathway for intra-amniotic infection.

Infection-mediated preterm birth: Bacterial origins and avenues for intervention

Preterm birth (PTB) is globally the leading cause of death and disability in children under five years of age. Intra-amniotic infection is well recognised as a major cause of PTB. Importantly, it is the most common cause of extreme PTB (birth prior to 28 weeks gestation), which is frequently associated with a wide range of serious neonatal morbidities. Recent developments in next generation sequencing technologies, combined with many years of culture-based microbiological data have allowed us to gain a deeper understanding of the pathogenesis of infection-mediated PTB. In particular, studies have revealed numerous potential routes to intra-amniotic infection beyond the classically described ascending vaginal route. Currently, antibiotic therapy is standard treatment for suspected or confirmed intra-amniotic infection, although its use in this context has had mixed success due to problems ranging from inappropriate antibiotic selection in relation to the target organism/s, to poor transplacental drug passage. In this review, we will draw together evidence from animal models and human studies to characterise pathways to intra-amniotic infection. We will then thoroughly outline current therapeutic protocols for cases of intra-amniotic infection and suggest potential new avenues for treatment.

Alloreactive fetal T cells promote uterine contractility in preterm labor via IFN-γ and TNF-α

Healthy pregnancy is the most successful form of graft tolerance, whereas preterm labor (PTL) may represent a breakdown in maternal-fetal tolerance. Although maternal immune responses have been implicated in pregnancy complications, fetal immune responses against maternal antigens are often not considered. To examine the fetal immune system in the relevant clinical setting, we analyzed maternal and cord blood in patients with PTL and healthy term controls. We report here that the cord blood of preterm infants has higher amounts of inflammatory cytokines and a greater activation of dendritic cells. Moreover, preterm cord blood is characterized by the presence of a population of central memory cells with a type 1 T helper phenotype, which is absent in term infants, and an increase in maternal microchimerism. T cells from preterm infants mount a robust proliferative, proinflammatory response to maternal antigens compared to term infants yet fail to respond to third-party antigens. Furthermore, we show that T cells from preterm infants stimulate uterine myometrial contractility through interferon-γ and tumor necrosis factor-α. In parallel, we found that adoptive transfer of activated T cells directly into mouse fetuses resulted in pregnancy loss. Our findings indicate that fetal inflammation and rejection of maternal antigens can contribute to the signaling cascade that promotes uterine contractility and that aberrant fetal immune responses should be considered in the pathogenesis of PTL.

Antibiotic administration can eradicate intra-amniotic infection or intra-amniotic inflammation in a subset of patients with preterm labor and intact membranes

BACKGROUND

Intra-amniotic infection is present in 10% of patients with an episode of preterm labor, and is a risk factor for impending preterm delivery and neonatal morbidity/mortality. Intra-amniotic inflammation is often associated with intra-amniotic infection, but is sometimes present in the absence of detectable microorganisms. Antibiotic treatment of intra-amniotic infection has traditionally been considered to be ineffective. Intra-amniotic inflammation without microorganisms has a prognosis similar to that of intra-amniotic infection.

OBJECTIVE

To determine whether antibiotics can eradicate intra-amniotic infection or intra-amniotic inflammation in a subset of patients with preterm labor and intact membranes.

MATERIALS AND METHODS

The study population consisted of women who met the following criteria: 1) singleton gestation between 20 and 34 weeks; 2) preterm labor and intact membranes; 3) transabdominal amniocentesis performed for the evaluation of the microbiologic/inflammatory status of the amniotic cavity; 4) intra-amniotic infection and/or intra-amniotic inflammation; and 5) received antibiotic treatment that consisted of ceftriaxone, clarithromycin, and metronidazole. Follow-up amniocentesis was performed in a subset of patients. Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and polymerase chain reaction was performed for Ureaplasma spp. Intra-amniotic infection was defined as a positive amniotic fluid culture or positive polymerase chain reaction, and intra-amniotic inflammation was suspected when there was an elevated amniotic fluid white blood cell count or a positive result of a rapid test for matrix metalloproteinase-8. For this study, the final diagnosis of intra-amniotic inflammation was made by measuring the interleukin-6 concentration in stored amniotic fluid (>2.6 ng/mL). These results were not available to managing clinicians. Treatment success was defined as eradication of intra-amniotic infection and/or intra-amniotic inflammation or delivery ≥37 weeks.

RESULTS

Of 62 patients with intra-amniotic infection and/or intra-amniotic inflammation, 50 received the antibiotic regimen. Of those patients, 29 were undelivered for ≥7 days and 19 underwent a follow-up amniocentesis. Microorganisms were identified by culture or polymerase chain reaction of amniotic fluid obtained at admission in 21% of patients (4/19) who had a follow-up amniocentesis, and were eradicated in 3 of the 4 patients. Resolution of intra-amniotic infection/inflammation was confirmed in 79% of patients (15/19), and 1 other patient delivered at term, although resolution of intra-amniotic inflammation could not be confirmed after a follow-up amniocentesis. Thus, resolution of intra-amniotic inflammation/infection or term delivery (treatment success) occurred in 84% of patients (16/19) who had a follow-up amniocentesis. Treatment success occurred in 32% of patients (16/50) with intra-amniotic infection/inflammation who received antibiotics. The median amniocentesis-to-delivery interval was significantly longer among women who received the combination of antibiotics than among those who did not (11.4 days vs 3.1 days: P = .04).

CONCLUSION

Eradication of intra-amniotic infection/inflammation after treatment with antibiotics was confirmed in 79% of patients with preterm labor, intact membranes, and intra-amniotic infection/inflammation who had a follow-up amniocentesis. Treatment success occurred in 84% of patients who underwent a follow-up amniocentesis and in 32% of women who received the antibiotic regimen.

Evidence that antibiotic administration is effective in the treatment of a subset of patients with intra-amniotic infection/inflammation presenting with cervical insufficiency

BACKGROUND

Cervical insufficiency is a risk factor for spontaneous midtrimester abortion or early preterm birth. Intra-amniotic infection has been reported in 8-52% of such patients and intra-amniotic inflammation in 81%. Some professional organizations have recommended perioperative antibiotic treatment when emergency cervical cerclage is performed. The use of prophylactic antibiotics is predicated largely on the basis that they reduce the rate of complications during the course of vaginal surgery. However, it is possible that antibiotic administration can also eradicate intra-amniotic infection/inflammation and improve pregnancy outcome.

OBJECTIVE

To describe the outcome of antibiotic treatment in patients with cervical insufficiency and intra-amniotic infection/inflammation.

STUDY DESIGN

The study population consisted of 22 women who met the following criteria: (1) singleton pregnancy; (2) painless cervical dilatation of >1 cm between 16.0 and 27.9 weeks of gestation; (3) intact membranes and absence of uterine contractions; (4) transabdominal amniocentesis performed for the evaluation of the microbiologic and inflammatory status of the amniotic cavity; (5) presence of intra-amniotic infection/inflammation; and (6) antibiotic treatment (regimen consisted of ceftriaxone, clarithromycin, and metronidazole). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and polymerase chain reaction for Ureaplasma spp. was performed. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms or a positive polymerase chain reaction for Ureaplasma spp., and intra-amniotic inflammation was suspected when there was an elevated amniotic fluid white blood cell count (≥19 cells/mm³) or a positive rapid test for metalloproteinase-8 (sensitivity 10 ng/mL). For the purpose of this study, the "gold standard" for diagnosis of intra-amniotic inflammation was an elevated interleukin-6 concentration (>2.6 ng/mL) using an enzyme-linked immunosorbent assay. The results of amniotic fluid interleukin-6 were not available to managing clinicians. Follow-up amniocentesis was routinely offered to monitor the microbiologic and inflammatory status of the amniotic cavity and fetal lung maturity. Treatment success was defined as resolution of intra-amniotic infection/inflammation or delivery ≥34 weeks of gestation.

RESULTS

Of 22 patients with cervical insufficiency and intra-amniotic infection/inflammation, 3 (14%) had microorganisms in the amniotic fluid. Of the 22 patients, 6 (27%) delivered within 1 week of amniocentesis and the remaining 16 (73%) delivered more than 1 week after the diagnostic procedure. Among these, 12 had a repeat amniocentesis to assess the microbial and inflammatory status of the amniotic cavity; in 75% (9/12), there was objective evidence of resolution of intra-amniotic inflammation or intra-amniotic infection demonstrated by analysis of amniotic fluid at the time of the repeat amniocentesis. Of the 4 patients who did not have a follow-up amniocentesis, all delivered ≥34 weeks, 2 of them at term; thus, treatment success occurred in 59% (13/22) of cases.

CONCLUSION

In patients with cervical insufficiency and intra-amniotic infection/inflammation, administration of antibiotics (ceftriaxone, clarithromycin, and metronidazole) was followed by resolution of the intra-amniotic inflammatory process or intra-amniotic infection in 75% of patients and was associated with treatment success in about 60% of cases.

Azithromycin vs erythromycin for the management of preterm premature rupture of membranes

BACKGROUND

Preterm premature rupture of membranes complicates 2-3% of pregnancies. Many institutions have advocated for the use of azithromycin instead of erythromycin. This is secondary to national shortages of erythromycin, ease of administration, better side effect profile, and decreased cost of azithromycin as compared with erythromycin.

OBJECTIVE

The objective of the study was to evaluate whether there are differences in the latency from preterm premature rupture of membranes to delivery in patients treated with different dosing regimens of azithromycin vs erythromycin.

STUDY DESIGN

This is a multicenter, retrospective cohort of women with singleton pregnancies with confirmed rupture of membranes between 23⁰ and 33⁶ weeks from January 2010 to June 2015. Patients were excluded if there was a contraindication to expectant management of preterm premature rupture of membranes. Patients received 1 of 4 antibiotic regimens: (1) azithromycin 1000 mg per os once (azithromycin 1 day group); (2) azithromycin 500 mg per os once, followed by azithromycin 250 mg per os daily for 4 days (azithromycin 5 day group); (3) azithromycin 500 mg intravenously for 2 days, followed by azithromycin 500 mg per os daily for 5 days (azithromycin 7 day group); or (4) erythromycin intravenously for 2 days followed by erythromycin per os for 5 days (erythromycin group). The choice of macrolide was based on institutional policy and/or availability of antibiotics at the time of admission. In addition, all patients received ampicillin intravenously for 2 days followed by amoxicillin per os for 5 days. Primary outcome was latency from diagnosis of rupture of membranes to delivery. Secondary outcomes included clinical and histopathological chorioamnionitis and neonatal outcomes.

RESULTS

Four hundred fifty-three patients who met inclusion criteria were identified. Seventy-eight patients received azithromycin for 1 day, 191 patients received azithromycin for 5 days, 52 patients received azithromycin for 7 days, and 132 patients received erythromycin. Women who received the 5 day regimen were younger and less likely to be non-African American, have hypertension, have sexually transmitted infection, or experienced substance abuse. There was no statistical difference in median latency time of azithromycin 1 day (4.9 days, 95% confidence interval, 3.3-6.4), azithromycin 5 days (5.0, 95% confidence interval, 3.9-6.1), or azithromycin 7 days (4.9 days, 95% confidence interval, 2.8-7.0) when compared with erythromycin (5.1 days, 95% confidence interval, 3.9-6.4) after adjusting for demographic variables (P = .99). Clinical chorioamnionitis was not different between groups in the adjusted model. Respiratory distress syndrome was increased in the azithromycin 5 day group vs azithromycin 1 day vs erythromycin (44% vs. 29% and 29%, P = .005, respectively).

CONCLUSION

There was no difference in latency to delivery, incidence of chorioamnionitis, or neonatal outcomes when comparing different dosing regimens of the azithromycin with erythromycin, with the exception of respiratory distress syndrome being more common in the 5 day azithromycin group. Azithromycin could be considered as an alternative to erythromycin in the expectant management of preterm premature rupture of membranes if erythromycin is unavailable or contraindicated. There appears to be no additional benefit to an extended course of azithromycin beyond the single-day dosing, but final recommendations on dosing strategies should rely on clinical trials.

Blood Microbial Communities During Pregnancy Are Associated With Preterm Birth

Microbial infection of the placenta, amniotic fluid, vaginal canal, and oral cavity is known to significantly contribute to preterm birth (PTB). Although microbes can be translocated into the blood, little is known regarding the blood microbiota during pregnancy. To assess changes in the microbiome during pregnancy, blood samples were obtained 2 or 3 times during pregnancy from a cohort of 45 pregnant women enrolled between 2008 and 2010. To analyze the association with PTB, we conducted a case-control study involving 41 pregnant women upon admission for preterm labor and rupture of membrane (20 with term delivery; 21 with PTB). Bacterial diversity was assessed in number and composition between the first, second, and third trimesters in term delivered women according to 16S rRNA gene amplicon sequencing, and data were analyzed using Quantitative Insight Into Microbial Ecology (QIIME). Taxonomy was assigned using the GreenGenes 8.15.13 database. Dominant microorganisms at the phylum level in all pregnant women were identified as Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. However, the number and composition of bacteria in women with PTB differed from that in women with term delivery. Firmicutes and Bacteroidetes were more abundant in women with PTB than in women with term delivery, while Proteobacteria was less prevalent in women with PTB. At the genus level, Bacteroides, Lactobacillus, Sphingomonas, Fastidiosipila, Weissella, and Butyricicoccus were enriched in PTB samples. These observational results suggest that several taxa in the maternal blood microbiome are associated with PTB. Further studies are needed to confirm the composition of the blood microbiota in women with PTB. Additionally, the mechanism by which pathogenic microbes in maternal blood cause infection and PTB requires further analysis.

The diagnostic performance of the beta-glucan assay in the detection of intra-amniotic infection with Candida species

INTRODUCTION

A bioassay based on the detection of beta-glucan, a constituent of the cell wall of fungi, has been successfully used to diagnose fungal infections in a variety of biological fluids but not yet in the amniotic fluid.

OBJECTIVE

To determine the diagnostic performance of a beta-glucan bioassay in the detection of Candida species in the amniotic fluid of women who either did or did not have an intrauterine contraceptive device (IUD) in place during an episode of spontaneous preterm parturition.

METHODS

The study population comprised women who had a singleton pregnancy without congenital or chromosomal abnormalities, who experienced preterm labor or preterm prelabor rupture of the fetal membranes, and who underwent a transabdominal amniocentesis for clinical indications. Samples of amniotic fluid were cultured for aerobic and anaerobic bacteria, genital mycoplasmas, and Candida species, and assayed for beta-glucan, using the (1→3)-beta-d-glucan-specific Limulus amebocyte lysate test (beta-glucan assay) in all cases. Amniotic fluid interleukin (IL)-6 assay results were also available for all cases. The beta-glucan assay takes about 1 hour to run: a concentration >80 pg/mL was considered positive for fungi. Sterile intra-amniotic inflammation of the amniotic cavity was defined by the presence of an amniotic fluid IL-6 concentration ≥2.6 ng/mL and a negative amniotic fluid culture.

RESULTS

(1) One hundred ninety-seven (197) women met the study criteria, of whom 58 (29.4%) had an IUD in place; (2) 20 (10.2%) women had a culture of proven intra-amniotic Candida species-related infection, 19 of whom had a positive beta-glucan assay [sensitivity, 95% (19/20; 95% confidence interval (CI): 75.1-99.9%)]; and (3) the specificity of the beta-glucan assay was 75.1% [133/177; 95% CI: 68.1-99.9%]. It was affected by the presence of nonfungal intra-amniotic infections and an IUD, but not by the presence of sterile intra-amniotic inflammation, and there was a significant interaction between the presence of an IUD and nonfungal intra-amniotic infections (estimated for the interaction effect = 2.1923, p value =.026). The assay's specificity was reduced when nonfungal intra-amniotic infections were diagnosed but only in women who did not have an IUD. Among women without an IUD, the assay's specificity was 91.4% (117/128); it was 93% (106/114) for those without intra-amniotic infection, and 78.6% (11/14) for those with a nonfungal intra-amniotic infection; the difference was not significant (p = .09). Among women with an IUD, the assay's specificity was 32.7% (16/49); 42.9% (9/21) for those with a nonfungal intra-amniotic infection; and 25% (7/28) for those without intra-amniotic infection; and the difference was significant (p = .03).

CONCLUSIONS

The beta-glucan assay is a sensitive, rapid, point-of-care test used to diagnose intra-amniotic Candida species-related infection, and it has a high specificity in pregnant women who did not have an IUD in place.

Does the human placenta delivered at term have a microbiota? Results of cultivation, quantitative real-time PCR, 16S rRNA gene sequencing, and metagenomics

BACKGROUND

The human placenta has been traditionally viewed as sterile, and microbial invasion of this organ has been associated with adverse pregnancy outcomes. Yet, recent studies that utilized sequencing techniques reported that the human placenta at term contains a unique microbiota. These conclusions are largely based on the results derived from the sequencing of placental samples. However, such an approach carries the risk of capturing background-contaminating DNA (from DNA extraction kits, polymerase chain reaction reagents, and laboratory environments) when low microbial biomass samples are studied.

OBJECTIVE

To determine whether the human placenta delivered at term in patients without labor who undergo cesarean delivery harbors a resident microbiota ("the assemblage of microorganisms present in a defined niche or environment").

STUDY DESIGN

This cross-sectional study included placentas from 29 women who had a cesarean delivery without labor at term. The study also included technical controls to account for potential background-contaminating DNA, inclusive in DNA extraction kits, polymerase chain reaction reagents, and laboratory environments. Bacterial profiles of placental tissues and background technical controls were characterized and compared with the use of bacterial culture, quantitative real-time polymerase chain reaction, 16S ribosomal RNA gene sequencing, and metagenomic surveys.

RESULTS

(1) Twenty-eight of 29 placental tissues had a negative culture for microorganisms. The microorganisms retrieved by culture from the remaining sample were likely contaminants because corresponding 16S ribosomal RNA genes were not detected in the same sample. (2) Quantitative real-time polymerase chain reaction did not indicate greater abundances of bacterial 16S ribosomal RNA genes in placental tissues than in technical controls. Therefore, there was no evidence of the presence of microorganisms above background contamination from reagents in the placentas. (3) 16S ribosomal RNA gene sequencing did not reveal consistent differences in the composition or structure of bacterial profiles between placental samples and background technical controls. (4) Most of the bacterial sequences obtained from metagenomic surveys of placental tissues were from cyanobacteria, aquatic bacteria, or plant pathogens, which are microbes unlikely to populate the human placenta. Coprobacillus, which constituted 30.5% of the bacterial sequences obtained through metagenomic sequencing of placental samples, was not identified in any of the 16S ribosomal RNA gene surveys of these samples. These observations cast doubt as to whether this organism is really present in the placenta of patients at term not in labor.

CONCLUSION

With the use of multiple modes of microbiologic inquiry, a resident microbiota could not be identified in human placentas delivered at term from women without labor. A consistently significant difference in the abundance and/or presence of a microbiota between placental tissue and background technical controls could not be found. All cultures of placental tissue, except 1, did not yield bacteria. Incorporating technical controls for potential sources of background-contaminating DNA for studies of low microbial biomass samples, such as the placenta, is necessary to derive reliable conclusions.

Classification of Preterm Birth With Placental Correlates

Premature birth lacks a widely accepted classification that unites features of the clinical presentation with placental pathology. To further explore associations between the clinical categories of preterm birth and placental histology, 109 infants with gestational age <34 weeks and birth weight <2000 g were selected and, based on electronic records, were classified into preterm birth categories of preterm labor, prelabor premature rupture of membranes, preeclampsia, indicated preterm birth for maternal factors (other than preeclampsia), indicated preterm birth for fetal factors, and the clinical diagnosis of abruption. Corresponding placentas were analyzed for gross and microscopic variables, with findings grouped into categories of amniotic fluid infection, lymphocytic inflammation, maternal vascular malperfusion, and fetal vascular malperfusion. Placental features of maternal vascular malperfusion were pervasive in all preterm birth categories and were commonly associated with amniotic fluid infection and lymphocytic inflammation. Features of maternal vascular malperfusion were significantly associated with preterm birth due to preeclampsia, and amniotic fluid infection was highly associated with prelabor preterm rupture of membranes. Findings of lymphocytic inflammation were significantly increased in cases of abruption. Laminar decidual necrosis was present in all cases of abruption. Placentas from multiple gestations had significantly less histologic findings compared to singletons. Given that 75% of placentas demonstrated at least 1 feature of maternal vascular malperfusion despite different clinical presentations, seemingly different pathologies such as ascending amniotic fluid infection or lymphocytic inflammation may be mechanistically related to processes established early in pregnancy. The concept of "uterine ischemia" may be too simplistic to account for all of the changes attributed to maternal vascular malperfusion in the preterm placenta.

Urinary vanadium concentration in relation to premature rupture of membranes: A birth cohort study

Heavy metal exposure has been indicated to be linked with reproductive and developmental toxicity. However, human studies on the association between heavy metal exposure and premature rupture of membranes (PROM) are limited. Thus, we aimed to evaluate the associations between urinary metal concentrations in pregnant women and the risk of PROM. The study was conducted among 7290 pregnant women from an ongoing cohort study in China. Levels of urinary metals were determined using an inductively coupled plasma-mass spectrometry and adjusted by creatinine concentration (μg/g creatinine). Adjusted odds ratios (OR) and 95% confidence intervals (CI) for PROM and preterm PROM were estimated using logistic regression models. Among 12 urinary metals detected, vanadium (V) have shown stable positive associations with PROM and preterm PROM. With one unit increase in natural logarithmically transformed urinary V concentration, adjusted OR of 1.57 (95% CI: 1.47, 1.66) for PROM was observed. Compared with the lowest tertile of urinary V, we also observed positive associations between V levels and PROM (for the medium tertile, adjusted OR = 1.66, 95% CI: 1.34, 2.05; for the highest tertile, adjusted OR = 3.75, 95% CI: 3.09, 4.54). In addition, higher adjusted ORs for preterm PROM were observed (for the highest tertile, adjusted OR = 8.14, 95% CI: 4.55, 14.55). Further stratified analysis suggested the associations were more pronounced among women delivering male infants than those with female infants. Our present epidemiological study indicated that pregnant women exposure to higher level of V might lead to an increased risk of PROM.

[Diagnosis and management of intra-uterine infection: CNGOF Preterm Premature Rupture of Membranes Guidelines]

OBJECTIVE

To determine the diagnosis criteria and management of intra-uterine inflammation or infection (Triple I, III).

METHODS

PubMed and Cochrane Central databases search.

RESULTS

III is defined as an infection of the fetal membranes, and/or other components like the decidua, fetus, amniotic fluid or placenta. This word should be preferred to the word chorioamnionitis that is less precise (Professional consensus). III clinical signs exhibit poor limited sensibility and specificity (EL3). The diagnosis of III is retained in case of maternal fever (defined by a body temperature≥38°C) with no alternative cause identified and at least 2 signs among the following: fetal tachycardia>160 bpm for 10min or longer, uterine pain of labor, purulent fluid from the cervical canal (Professional consensus). Maternal hyperleukocytosis>20 giga/L in the absence of corticosteroids treatment or increased plasmatic C-reactive protein also argue for III, despite their limited sensibility and specificity (EL3). III requires prompt delivery (Grade A). III is not by itself an indication for cesarean delivery (Professional consensus). Antibiotic treatment should cover Streptococcus agalactiae and Escherichia coli. Antibiotics should be started immediately and maintained all over delivery, to reduce neonatal and maternal morbidity (Grade B). Treatment should rely on a combination of betalactamin and aminoglycoside (Grade B). After vaginal delivery, one single dose of antibiotic is required. Antibiotic duration should be longer in case of bacteremia. Longer duration could be considered in case of persistent fever or of cesarean delivery (Professional consensus).

[Epidemiology, risk factors and child prognosis: CNGOF Preterm Premature Rupture of Membranes Guidelines]

OBJECTIVES

To synthetize the available evidence regarding the incidence and risk factors of preterm premature rupture of membranes (PPROM). To describe the evolution of pregnancy, neonatal outcomes and the prognosis of infants born in a context of PPROM, according to the existence of an associated intrauterine infection and to the latency duration.

METHOD

Consultation of the Medline database, from 1980 to February 2018.

RESULTS

PPROM before 37 and before 34 weeks' gestation occur in 2-3% and <1% of pregnancies, respectively (LE2). Although many risk factors are identified, few are modifiable, and the vast majority of patients have no risk factors (LE2). Consequently, individual prediction of the risk of PPROM and primary prevention measures have not been shown to be effective and are not recommended in clinical practice (Grade B). Most women give birth within the week following PPROM (LE2). The main complications of PPROM are prematurity, intrauterine infection and obstetric and maternal complications (LE2). Latency duration and the frequency of complications decrease with increasing gestational age at PPROM (LE2). Neonatal prognosis is largely conditioned by gestational age at birth, with no apparent over-risk of poor outcomes linked to PPROM compared to other causes of preterm birth (LE2). In contrast, intrauterine infection is associated with an increased risk of in utero fetal death (LE3), necrotizing enterocolitis (LE1) and early-onset sepsis (LE2). The association of intrauterine infection with neurological morbidity remains controversial. Prolongation of latency, from gestational age at PPROM, is beneficial for the child (LE2).

CONCLUSION

PPROM is a major cause of prematurity and short- and long-term mortality and morbidity. Antenatal care is an important issue for obstetric and pediatric teams, aiming to reduce complications and adverse consequences for both mother and child.