Morbidity and mortality among very-low-birth-weight infants born to mothers with clinical chorioamnionitis

Impact of maternal infection on outcomes in extremely preterm infants

BACKGROUND

Infants born less than 29 weeks, or extremely preterm (EPT), experience increased morbidity and mortality. We hypothesized that exposure to maternal infection might contribute to neurodevelopmental impairment (NDI) or death at 2 years of age.

METHODS

We conducted a retrospective cohort study of EPT infants from January 2010 to December 2020. Maternal data extracted included maternal infections, classified as extrauterine or intrauterine. Placental pathologic and infant data were extracted. The primary outcome was NDI or death at 2 years of age.

RESULTS

548 EPT infants were born to 496 pregnant people: 379 (69%) were not exposed to any documented maternal infection prenatally, 124 (23%) to extrauterine infection, and 45 (8%) to intrauterine infection. Neither diagnosis of maternal extrauterine nor intrauterine infection was associated with NDI or death at 2 years of age (p > 0.05). Acute histologic chorioamnionitis was associated with NDI or death at 2 years of age (p = 0.033).

CONCLUSIONS

Maternal infection was not associated with NDI or death at 2 years of age in EPT infants. However, acute histologic chorioamnionitis was associated with this outcome. Further work should investigate the differential influence of infection and immune response with this pathology as relates to outcomes in EPT infants.

IMPACT

Maternal infection was not associated with neurodevelopmental impairment (NDI) or death at 2 years of age in extremely preterm (EPT) infants. This is reassuring support that mechanisms at the maternal-fetal interface largely protect the EPT infant. However, pathologic findings of acute histologic chorioamnionitis were associated with NDI and death at 2 years of age. Further work should investigate the differential influence of infection and immune response with acute histologic chorioamnionitis on pathology as relates to outcomes in EPT infants.

Chorioamnionitis, Cesarean Deliveries, and Racial Disparities in the USA

BACKGROUND

Studies showed disparities in management and outcomes of African American when compared to Caucasian population. The presence of chorioamnionitis may affect the decision to have a cesarean delivery (CD); however, it is not known if such a decision is affected by the mothers' race/ethnicity.

OBJECTIVE

To assess the interaction between African American race/ethnicity and CD in women with chorioamnionitis.

METHODS

Utilizing the National Inpatient Sample dataset, we examined the association of CD with chorioamnionitis in the overall population and within Caucasian and African American. Logistic regression models were used to control for confounders.

RESULTS

The study included 6,648,883 women who delivered 6,925,920 infants. The prevalence of chorioamnionitis was 0.78 and 1.1 in Caucasian and African American, respectively. CD with and without chorioamnionitis was 41.2% and 32.4%, respectively (aOR 1.46 (1.43-1.49), p < 0.001), in Caucasian population and 45.0% and 36.6% in African American population aOR 1.42 (1.37-1.47), p < 0.001. African American population had significantly higher CD after controlling for chorioamnionitis and other confounding variables (aOR of 1.18 (1.17-1.18), p < 0.001).

CONCLUSION

Chorioamnionitis is associated with increased rate of CD. Ethnic disparities exist in CD rates regardless of the chorioamnionitis status. Such findings warrant further investigation to explore factors associated with this discrepancy.

Risk Factors for Periventricular Leukomalacia in Preterm Infants: A Systematic Review, Meta-analysis, and GRADE-Based Assessment of Certainty of Evidence

BACKGROUND

We analyzed the certainty of evidence (CoE) for risk factors of periventricular leukomalacia (PVL) in preterm neonates, a common morbidity of prematurity.

METHODS

Medline, CENTRAL, Embase, and CINAHL were searched. Cohort and case-control studies and randomised randomized controlled trials were included. Data extraction was performed in duplicate. A random random-effects meta-analysis was utilizedused. CoE was evaluated as per Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.

RESULTS

One hundred eighty-six studies evaluating 95 risk factors for PVL were included. Of the 2,509,507 neonates assessed, 16,569 were diagnosed with PVL. Intraventricular hemorrhage [adjusted odds ratio: 3.22 (2.52-4.12)] had moderate CoE for its association with PVL. Other factors such as hypocarbia, chorioamnionitis, PPROM >48 hour, multifetal pregnancy reduction, antenatal indomethacin, lack of antenatal steroids, perinatal asphyxia, ventilation, shock/hypotension, patent ductus arteriosus requiring surgical ligation, late-onset circulatory collapse, sepsis, necrotizing enterocolitis, and neonatal surgery showed significant association with PVL after adjustment for confounders (CoE: very low to low). Amongst the risk factors associated with mother placental fetal (MPF) triad, there was paucity of literature related to genetic predisposition and defective placentation. Sensitivity analysis revealed that the strength of association between invasive ventilation and PVL decreased over time (P < 0.01), suggesting progress in ventilation strategies. Limited studies had evaluated diffuse PVL.

CONCLUSION

Despite decades of research, our findings indicate that the CoE is low to very low for most of the commonly attributed risk factors of PVL. Future studies should evaluate genetic predisposition and defective placentation in the MPF triad contributing to PVL. Studies evaluating exclusively diffuse PVL are warranted.

Clinical chorioamnionitis and histologic placental inflammation: association with early-neonatal sepsis

OBJECTIVE

Chorioamnionitis and fetal inflammatory response syndrome (FIRS) are significant risk factors for early onset sepsis (EOS). Recently, the use "Intrauterine Inflammation or Infection or both" or triple I has been proposed, classifying cases into an isolated maternal fever, suspected triple I, or confirmed chorioamnionitis. Evidence suggests that the association between suspected chorioamnionitis and confirmed histological chorioamnionitis (HCA) is not consistent, as well as the impact of HCA on the development of EOS.We aimed to evaluate the association between suspected chorioamnionitis and HCA, the impact of HCA on EOS, and the effect of antepartum antibiotic prophylaxis on EOS.

METHODS

We retrospectively reviewed the medical records of all infants admitted to our institution, between 2017 and 2018, with a diagnosis of chorioamnionitis. We recorded the clinical evidence of chorioamnionitis, the histologic report of the placenta, the maternal and neonatal data, the neonatal inflammatory markers including C-reactive protein (CRP), and the incidence of EOS. The impact of antepartum antibiotic prophylaxis on the infants' CRP and EOS was calculated, and the logistic regression model was performed to estimate the association of confirmed HCA with EOS, while controlling for FIRS stage, gestation age, birth weight, maternal fever, foul-smelling amniotic fluid, and prolonged rupture of membranes.

RESULTS

During the study period, a total of 266 infants were identified; 81 (30%) infants had a confirmed HCA (HCA-present cases), and 185 (70%) infants were diagnosed with suspected triple I (HCA-absent cases). Antepartum antibiotics had been commenced in a significantly higher proportion in HCA-present cases (46%) in comparison to 14% of HCA-absent cases (p < .001). HCA-present infants were of significantly lower gestation (31.6 ± 4weeks versus 33.3 ± 4weeks, p = .004), and birth weight (1826 ± 840 g versus 2092 ± 849 g, p = .019), they had a significantly higher rate of clinical symptoms (31% versus 6%, p < .001), and a higher CRP at birth and 24 h (1.4 ± 1.5 mg/dL versus 0.3 ± 0.2 mg/dL, p < .001, and 2.1 ± 2.3 mg/dL versus 0.4 ± 0.6 mg/dL, p < .001, respectively). All HCA-present cases had evidence of FIRS; 43% were stage I, 25% stage II, and 32% were FIRS stage III. A significantly higher proportion of HCA-present infants were diagnosed with EOS (46% as compared to 6%, p < .001). The antepartum antibiotic administration was related to a significantly lower CRP at birth and 24 h only in HCA-present cases, albeit not with any reduction ιn EOS incidence. HCA was significantly associated with EOS (RR 3.18, 95% CI 2.81-5.18, p < .001). After adjusting for perinatal factors, the presence of HCA (OR 7.89, 95% CI 1.19-23.34, p = .032) and an advanced FIRS stage (OR 10.35, 95% CI 4.23-25.32, p < .001) were significantly associated with EOS.

CONCLUSIONS

Amongst infants with suspected chorioamnionitis, the diagnosis is partially supported by histological confirmation, and that is more prominent in pregnancies of a lower gestation. The presence of HCA and an advanced FIRS stage predispose to an increased risk of EOS after adjusting for other perinatal and neonatal factors. The antepartum prophylaxis against intra-amniotic infection was related to a significantly lower CRP in HCA-present cases.

Chorioamnionitis and Risk for Maternal and Neonatal Sepsis: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the risk of maternal and neonatal sepsis associated with chorioamnionitis.

DATA SOURCES

PubMed, BIOSIS, and ClinicalTrials.gov databases were systematically searched for full-text articles in English from inception until May 11, 2020.

METHODS OF STUDY SELECTION

We screened 1,251 studies. Randomized controlled trials, case-control, or cohort studies quantifying a relationship between chorioamnionitis and sepsis in mothers (postpartum) or neonates born at greater than 22 weeks of gestation were eligible. Studies were grouped for meta-analyses according to exposures of histologic or clinical chorioamnionitis and outcomes of maternal or neonatal sepsis.

TABULATION, INTEGRATION, AND RESULTS

One hundred three studies were included, and 55 met criteria for meta-analysis (39 studies of preterm neonates, 10 studies of general populations of preterm and term neonates, and six studies of late preterm and term neonates). Study details and quantitative data were abstracted. Random-effects models were used to generate pooled odds ratios (ORs); most studies only reported unadjusted results. Histologic chorioamnionitis was associated with confirmed and any early-onset neonatal sepsis (unadjusted pooled ORs 4.42 [95% CI 2.68-7.29] and 5.88 [95% CI 3.68-9.41], respectively). Clinical chorioamnionitis was also associated with confirmed and any early-onset neonatal sepsis (unadjusted pooled ORs 6.82 [95% CI 4.93-9.45] and 3.90 [95% CI 2.74-5.55], respectively). Additionally, histologic and clinical chorioamnionitis were each associated with higher odds of late-onset sepsis in preterm neonates. Confirmed sepsis incidence was 7% (early-onset) and 22% (late-onset) for histologic and 6% (early-onset) and 26% (late-onset) for clinical chorioamnionitis-exposed neonates. Three studies evaluated chorioamnionitis and maternal sepsis and were inconclusive.

CONCLUSION

Both histologic and clinical chorioamnionitis were associated with early- and late-onset sepsis in neonates. Overall, our findings support current guidelines for preventative neonatal care. There was insufficient evidence to determine the association between chorioamnionitis and maternal sepsis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42020156812.

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.

Histologic chorioamnionitis and risk of neurodevelopmental impairment at age 10 years among extremely preterm infants born before 28 weeks of gestation

BACKGROUND

Extremely preterm infants whose placenta had histologic evidence of chorioamnionitis have early brain dysfunction, but little is known about neurologic development at 10 years of age.

OBJECTIVE

We investigated the association between histologic chorioamnionitis and neurodevelopmental impairment at 10 years among children born <28 weeks' gestation (extremely preterm).

STUDY DESIGN

The multicenter Extremely Low Gestational Age Newborns study enrolled extremely preterm newborns from 2002 to 2004 at 14 hospitals in the United States. Chorioamnionitis was defined by histologic stage (early, moderate, and advanced) and grade (mild/moderate and severe) of chorionic plate and umbilical cord inflammation. The children were examined for cerebral palsy at 2 years and for autism spectrum disorder, cognitive impairment (intelligence quotient >2 standard deviations below the mean), and epilepsy at the age of 10 years by blinded evaluators using validated measures. Multivariable logistic regression with generalized estimating equations was used.

RESULTS

Among 805 placentas, 43% (347/805) had histologic chorioamnionitis by moderate or advanced maternal stage, 36% (286/805) by severe maternal grade, 18% (132/737) by moderate or advanced fetal stage, and 1% (10/737) by severe fetal grade. The frequencies of impairments were 11% (88/767) for cerebral palsy, 7% (56/773) for autism spectrum disorder, 15% (120/788) for cognitive impairment, and 7% (52/763) for epilepsy. After adjustment for maternal age, body mass index, race, insurance status, maternal education, tobacco use, infant sex, and multiple gestations, the adjusted odds ratio for the association between histologic chorioamnionitis and cerebral palsy years was increased with advanced maternal stage (adjusted odds ratio, 2.5; 95% confidence interval, 1.6-3.9), severe maternal grade (adjusted odds ratio, 2.0; 95% confidence interval, 1.2-3.4), moderate fetal stage (adjusted odds ratio, 2.20; 95% confidence interval, 2.1-2.2), and mild or moderate fetal grade (adjusted odds ratio, 1.5; 95% confidence interval, 1.0-2.2). Similarly, the adjusted odds ratio for the association between histologic chorioamnionitis and epilepsy was increased with advanced maternal stage (adjusted odds ratio, 1.5; 95% confidence interval, 1.3-1.6) and severe fetal grade (adjusted odds ratio, 5.9; 95% confidence interval, 1.9-17.8). In addition, the adjusted odds ratio for the association between histologic chorioamnionitis and autism spectrum disorder was increased with mild or moderate fetal grade (adjusted odds ratio, 1.7; 95% confidence interval, 1.0-2.9). Histologic chorioamnionitis was not associated with cognitive impairment. These findings held after adjustment for gestational age at delivery. In contrast to histologic chorioamnionitis, a clinical diagnosis of chorioamnionitis was not associated with neurodevelopmental impairment.

CONCLUSION

Histologic chorioamnionitis may be associated with some forms of neurodevelopmental impairment at 10 years of life among infants born <28 weeks' gestation.

Cytokine profiles of umbilical cord blood mononuclear cells upon in vitro stimulation with lipopolysaccharides of different vaginal gram-negative bacteria

Inflammatory immune responses induced by lipopolysaccharides (LPS) of gram-negative bacteria play an important role in the pathogenesis of preterm labor and delivery, and in neonatal disorders. To better characterize LPS-induced inflammatory response, we determined the cytokine profile of umbilical cord blood mononuclear cells (UBMC) stimulated with LPS of seven vaginal gram-negative bacteria commonly found in pregnant women with preterm labor and preterm rupture of membrane. UBMC from ten newborns of healthy volunteer mothers were stimulated with purified LPS of Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter calcoaceticus, Citrobacter freundii, and Pseudomonas aeruginosa. UBMC supernatants were tested for the presence of secreted pro-inflammatory cytokines (IL-6, IL-1β, TNF), anti-inflammatory cytokine (IL-10), TH₁-type cytokines (IL-12, IFN-γ), and chemokines (IL-8, MIP-1α, MIP-1β, MCP-1) by Luminex technology. The ten cytokines were differentially induced by the LPS variants. LPS of E. coli and E. aerogenes showed the strongest stimulatory activity and P. aeruginosa the lowest. Interestingly, the ability of UBMC to respond to LPS varied greatly among donors, suggesting a strong individual heterogeneity in LPS-triggered inflammatory response.

Chorioamnionitis exposure remodels the unique histone modification landscape of neonatal monocytes and alters the expression of immune pathway genes

Chorioamnionitis is an intrauterine infection involving inflammation of the chorion, amnion, and placenta. It leads to a fetal systemic inflammatory response that can alter the transcription of neonatal immune genes. We have previously shown that neonatal monocytes gain the activating histone tail modification H3K4me3 at promoter sites of immunologically important genes as development progresses from preterm neonate to adult. In this study, we applied ChIP-seq and RNA-seq to evaluate the impact of chorioamnionitis on the neonatal monocyte H3K4me3 histone modification landscape over the course of fetal and neonatal immune system development. Chorioamnionitis exposure in neonatal monocytes resulted in a net increase in total monocyte H3K4me3, primarily in introns and intergenic regions. Immune gene expression was decreased in chorioamnionitis-exposed monocytes, with the majority of enriched transcripts falling into pathways that are not linked to the immune system. Over half of all neonatal monocyte H3K4me3 peaks, independent of their location, were associated with active gene transcription. Overall, chorioamnionitis exposure resulted in the global remodeling of the neonatal monocyte H3K4me3 landscape and changes in the expression of known immune genes. These changes resulted in a less robust inflammatory response upon exposure to a secondary challenge, which may explain why chorioamnionitis-exposed neonates have an increased risk of sepsis. DATABASE: ChIP-seq data for U30/O30/Term: GEO GSE81957 ChIP-seq data for U30C/O30C/TermC: GEO GSE111873 RNA-seq data for U/L/CU/CL: GEO GSE111927.

What's the harm? Risks and benefits of evolving rule-out sepsis practices

Asymptomatic term and late-preterm newborns with risk factors for early onset sepsis commonly undergo laboratory evaluation and receive empiric antibiotic therapy. Some have challenged the rationale for current "rule-out sepsis" practices, arguing that they lead to unnecessary overtreatment and healthcare costs. A series of recent clinical studies has explored scheduled serial observations as an alternative to laboratory testing and empiric antibiotics for asymptomatic newborns with historical risk factors for sepsis. These studies have shared the conclusion that serial observation is safe and cost-effective for well-appearing term and late-preterm babies, but they are also somewhat speculative because culture-proven early onset sepsis is an extremely low prevalence diagnosis. Here, we review the evolving consensus of optimal rule-out sepsis practices. We examine chorioamnionitis as an example of a problematic risk factor that has contributed to the controversy surrounding this topic. We also discuss how introduction of online sepsis risk calculators has allowed more precise delineation of a patient's chances of developing culture-proven infection. Finally, we analyze existing data from published studies to estimate the number needed to harm (NNH) when an observation-based strategy is used instead of a risk-based approach. We conclude that, if harm is defined as death or serious sepsis complications such as hemodynamic instability or neurologic injury, the NNH is 1610, compared to an NNH of 7 and 2.9 for IV infiltrates and delayed breastfeeding, respectively-two common and potentially consequential complications of NICU admission for a rule-out sepsis. We believe that the differential between risk of serious harm from observing a well-appearing term or late-preterm newborn with risk factors for sepsis and the risk of less significant but common NICU complications argues in favor of the ongoing trend toward less aggressive management of newborns with sepsis risks.

Comparison between leukocyte esterase activity and histopathological examination in identifying chorioamnionitis

Objective

To compare the sensitivity and specificity of leukocyte esterase activity (LEA) to histopathological examination in diagnosing chorioamnionitis.

Methods

We compared the diagnostic tests performed at Dr. Mohammad Hoesin Hospital, Palembang, Indonesia, from September 2015 to April 2016. Ninety-one pregnant women were included in the study. The LEA and histopathological examination were carried out with neonatal sepsis the main outcome. Data were analyzed using the SPSS version 21.0 and MedCalc statistics.

Results

Chorioamnionitis was detected in 54 (77.1%) patients with a gestational age ≥37 weeks and in 16 (22.9%) patients with a gestational age <37 weeks. The duration of membrane rupture was significantly associated with chorioamnionitis (P = 0.001 and P = 0.011). Neonatal sepsis was also significantly associated with chorioamnionitis in both groups (P = 0.014 and P = 0.036). A LEA value with the cut-off point >0.5 was able to significantly predict chorioamnionitis with 98.6% sensitivity and 95.2% specificity, providing better accuracy in diagnosing chorioamnionitis in the preterm pregnancy group.

Conclusion

LEA had a very good predictive value for chorioamnionitis with better accuracy in diagnosing chorioamnionitis in preterm pregnancy.

Infections following surgical patent ductus arteriosus ligation in very-low-birthweight neonates

BACKGROUND

Very-low-birthweight (VLBW) neonates (<1500g) comprise approximately 1% of liveborn infants in Poland. Patent ductus arteriosus (PDA) is a common complication of prematurity. This study aimed to determine how many VLBW neonates treated in the participating units needed surgical correction of PDA, and to evaluate the incidence of various types of postoperative infections and their microbiology.

METHODS

Observational study in five neonatology departments by the Polish Neonatology Surveillance Network, involving 2039 VLBW newborns of whom 103 (5.1%) required surgical PDA ligation. Continuous infection surveillance was conducted between 2009 and 2013; infections were defined based on Gastmeier's criteria.

RESULTS

PDA surgery was required significantly more frequently in infants from multiple pregnancies, and where labour was complicated by amnionitis. Surgical PDA correction was performed, on average, at 19 days of life. The incidence of infection was 48.5% (N = 50), and the most common infections were bloodstream infection (26.2%) and pneumonia (22.3%). A correlation was observed between the day on which the procedure was performed and the time of infection: the earlier the neonate underwent PDA surgery, the earlier the infection manifested (P = 0.032). A high CRIB score and chorioamnionitis contributed significantly to the presence of infection.

CONCLUSION

The later the PDA surgery was performed, the later the infection occurred. The incidence of infection after correction of PDA among VLBW neonates was comparable with the incidence of infection among all hospitalized VLBW neonates.

Clinical chorioamnionitis at term VIII: a rapid MMP-8 test for the identification of intra-amniotic inflammation

OBJECTIVE

Clinical chorioamnionitis is the most common infection/inflammatory process diagnosed in labor and delivery units worldwide. The condition is a syndrome that can be caused by (1) intra-amniotic infection, (2) intra-amniotic inflammation without demonstrable microorganisms (i.e. sterile intra-amniotic inflammation), and (3) maternal systemic inflammation that is not associated with intra-amniotic inflammation. The presence of intra-amniotic inflammation is a risk factor for adverse maternal and neonatal outcomes in a broad range of obstetrical syndromes that includes clinical chorioamnionitis at term. Although the diagnosis of intra-amniotic infection has relied on culture results, such information is not immediately available for patient management. Therefore, the diagnosis of intra-amniotic inflammation could be helpful as a proxy for intra-amniotic infection, while results of microbiologic studies are pending. A rapid test is now available for the diagnosis of intra-amniotic inflammation, based on the determination of neutrophil collagenase or matrix metalloproteinase-8 (MMP-8). The objectives of this study were (1) to evaluate the diagnostic indices of a rapid MMP-8 test for the identification of intra-amniotic inflammation/infection in patients with the diagnosis of clinical chorioamnionitis at term, and (2) to compare the diagnostic performance of a rapid MMP-8 test to that of a conventional enzyme-linked immunosorbent assay (ELISA) interleukin (IL)-6 test for patients with clinical chorioamnionitis at term.

MATERIALS AND METHODS

A retrospective cohort study was conducted. A transabdominal amniocentesis was performed in patients with clinical chorioamnionitis at term (n=44). Amniotic fluid was analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital Mycoplasmas) and broad-range polymerase chain reaction (PCR) coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). Amniotic fluid IL-6 concentrations were determined by ELISA, and rapid MMP-8 results were determined by Yoon's MMP-8 Check®. Intra-amniotic inflammation was defined as an elevated amniotic fluid IL-6 concentration ≥2.6 ng/mL, and intra-amniotic infection was diagnosed by the presence of microorganisms in the amniotic fluid accompanied by intra-amniotic inflammation. The diagnostic indices of Yoon's MMP-8 Check® for the identification of intra-amniotic inflammation were calculated. In order to objectively compare Yoon's MMP-8 Check® with the ELISA IL-6 test for the identification of intra-amniotic inflammation, we used an amniotic fluid white blood cell (WBC) count ≥50 cells/mm3 to define intra-amniotic inflammation.

RESULTS

(1) A positive rapid MMP-8 test had a sensitivity of 82.4% (28/34), specificity of 90% (9/10), positive predictive value of 96.6% (28/29), negative predictive value of 60% (9/15), positive likelihood ratio 8.2 (95% CI 1.3-53.2), and negative likelihood ratio 0.2 (95% CI 0.1-0.4) for the identification of intra-amniotic inflammation (prevalence 77.3%); (2) a positive rapid MMP-8 test had a sensitivity of 91.7% (22/24), specificity of 65% (13/20), positive predictive value of 75.9% (22/29), negative predictive value of 86.7% (13/15), positive likelihood ratio of 2.6 (95% CI 1.4-4.8), and negative likelihood ratio of 0.1 (95% CI 0.03-0.5) for the identification of intra-amniotic infection; (3) the rapid MMP-8 test had a significantly higher specificity than the ELISA IL-6 test in the identification of intra-amniotic inflammation as determined by an amniotic fluid WBC count ≥50 cells/mm3. The sensitivity and accuracy of the rapid MMP-8 test were comparable to those of the ELISA IL-6 test; and (4) importantly, the rapid MMP-8 test had 100% sensitivity and 100% negative predictive value in the identification of neonates affected with fetal inflammatory response syndrome (FIRS).

CONCLUSION

The rapid diagnosis of intra-amniotic inflammation is possible by analysis of amniotic fluid using a point-of-care test for MMP-8. Patients with a positive test are at risk of delivering a neonate affected with systemic inflammation, a risk factor for adverse neonatal outcome.

Chorioamnionitis: time for a new approach

PURPOSE OF REVIEW

The association between maternal chorioamnionitis and early-onset sepsis in the newborn has long been recognized, and established guidelines recommend treating all exposed infants with broad-spectrum antibiotics until infection can be ruled out. However, recent data suggest that close observation of well appearing term and late-preterm newborns may be a preferable alternative. The present review addresses the evidence in favor of newly proposed changes to the diagnosis and management of women and newborns following a maternal diagnosis of chorioamnionitis. Potential implications of these new practice guidelines will also be discussed.

RECENT FINDINGS

A panel of experts assembled in 2015 to provide updated, evidence-based guidelines for the diagnosis and management of women and newborns following a maternal diagnosis of chorioamnionitis. Revised terminology and diagnostic criteria were proposed as well as changes in the management of newborns of mothers with suspected intrauterine infection, most notably a recommendation to observe (rather than treat) well appearing term and late-preterm newborns.

SUMMARY

A management strategy consisting of close observation of well appearing term and late-preterm infants exposed to suspected intrauterine infection is preferable to empiric antimicrobial therapy. Large prospective epidemiologic studies will be needed to ascertain the impact of these new practice guidelines on the outcomes of infants exposed to intrauterine infection and/or inflammation. Improved precision in the clinical diagnosis of intrauterine infection should improve both the quality and reproducibility of data generated from future studies.

Comparison of amniotic fluid matrix metalloproteinase-8 and cathelicidin in the diagnosis of intra-amniotic infection

OBJECTIVE

To evaluate the association of amniotic fluid (AF) matrix metalloproteinase-8 (MMP-8) and cathelicidin concentrations with microbial invasion of the amniotic cavity (MIAC) in pregnancies with preterm prelabor rupture of the membranes or intact membranes.

STUDY DESIGN

Amniocentesis was performed in 54 singleton pregnancies between 22⁺⁰ and 34⁺² gestational weeks with suspected intra-amniotic infection. AF-MMP-8 was analysed by immunoassay and AF-cathelicidin by commercial ELISA. Standard biochemical methods, molecular microbiology and culture techniques were used.

RESULTS

MIAC was present in 18 (33%) women. The cutoff value for the diagnosis of MIAC was 41.5 ng ml^-1 for AF-MMP-8, and 11.6 ng ml^-1 for AF-cathelicidin. With these cutoff values AF-MMP-8 had a sensitivity of 100%, specificity of 69%, positive predictive value of 62% and negative predictive value of 100% for MIAC. The corresponding values for AF-cathelicidin were 89, 81, 70 and 94%.

CONCLUSION

The performance of AF-cathelicidin in the prediction of MIAC is comparable to AF-MMP-8.

Amniotic fluid rapid biomarkers are associated with intra-amniotic infection in preterm pregnancies regardless of the membrane status

OBJECTIVE

The objective of this study was to evaluate the association of amniotic fluid lactate dehydrogenase and glucose concentrations with microbial invasion of amniotic cavity and histologic chorioamnionitis before 37 pregnancy weeks in women with or without preterm premature rupture of membranes.

STUDY DESIGN

Amniocentesis was performed on 70 women with suspected intra-amniotic infection. Standard biochemical methods, molecular microbiology and culture techniques were used. Histopathological examination of the placenta was performed.

RESULTS

Thirty (48%) women had microbial invasion of the amniotic cavity (MIAC), 53 (76%) women had histological chorioamnionitis and 28 women had both. The cutoff values for MIAC and histological chorioamnionitis were 429 IU l(-1) for lactate dehydrogenase and 0.7 mmol l(-1) for glucose. Both end points occurred equally often regardless of the membrane status.

CONCLUSION

Increased amniotic fluid lactate dehydrogenase and decreased glucose were associated with MIAC and histological chorioamnionitis. However, test performance was of limited value.

Clinical chorioamnionitis at term IV: the maternal plasma cytokine profile

INTRODUCTION

Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentration: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that a fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response.

CONCLUSIONS

1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis.

Clinical chorioamnionitis at term V: umbilical cord plasma cytokine profile in the context of a systemic maternal inflammatory response

OBJECTIVE

Microbial invasion of the fetus due to intra-amniotic infection can lead to a systemic inflammatory response characterized by elevated concentrations of cytokines in the umbilical cord plasma/serum. Clinical chorioamnionitis represents the maternal syndrome often associated with intra-amniotic infection, although other causes of this syndrome have been recently described. The objective of this study was to characterize the umbilical cord plasma cytokine profile in neonates born to mothers with clinical chorioamnionitis at term, according to the presence or absence of bacteria and/or intra-amniotic inflammation.

MATERIALS AND METHODS

A cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=38; cases) and those with spontaneous term labor without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) and amniotic fluid interleukin (IL)-6 concentration into three groups: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. A fetal inflammatory response syndrome (FIRS) was defined as an umbilical cord plasma IL-6 concentration >11 pg/mL. The umbilical cord plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) Neonates born to mothers with clinical chorioamnionitis at term (considered in toto) had significantly higher median umbilical cord plasma concentrations of IL-6, IL-12p70, IL-16, IL-13, IL-4, IL-10 and IL-8, but significantly lower interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF)-α concentrations than neonates born to mothers with spontaneous term labor without clinical chorioamnionitis; 2) neonates born to mothers with clinical chorioamnionitis at term but without intra-amniotic inflammation had higher concentrations of IL-6, IL-12p70, IL-13, IL-4, IL-5, and IL-8, but lower IFN-γ, than neonates not exposed to clinical chorioamnionitis, suggesting that maternal fever in the absence of intra-amniotic inflammation leads to a change in the fetal cytokine network; 3) there were significant, positive correlations between maternal and umbilical cord plasma IL-6 and IL-8 concentrations (IL-6: Spearman correlation=0.53; P<0.001; IL-8: Spearman correlation=0.42; P<0.001), consistent with placental transfer of cytokines; 4) an elevated fetal plasma IL-6 (>11 pg/mL), the diagnostic criterion for FIRS, was present in 21% of cases (8/38), and all these neonates were born to mothers with proven intra-amniotic infection; and 5) FIRS was associated with a high concentration of umbilical cord plasma IL-8, IL-10 and monocyte chemoattractant protein (MCP)-1.

CONCLUSIONS

Neonates born to mothers with clinical chorioamnionitis at term had higher concentrations of umbilical cord plasma cytokines than those born to mothers without clinical chorioamnionitis. Even neonates exposed to clinical chorioamnionitis but not to intra-amniotic inflammation had elevated concentrations of multiple cytokines, suggesting that intrapartum fever alters the fetal immune response.

Reappraisal of guidelines for management of neonates with suspected early-onset sepsis

Since 1992, professional societies or public health agencies in the United States^– and elsewhere^– have issued several generations of recommendations for prevention or management of early-onset neonatal sepsis (EOS). Despite those efforts, recommendations remain inconsistent, clarifications are necessary, local adaptations are common, and compliance rates are low. We postulate that lack of consensus, especially regarding postnatal management of the neonate, is largely a result of two sets of factors. First, obstetrical prevention strategies have substantially reduced incidence of EOS, potentially changing the utility of predictive strategies based on risk factors. Second, recent data better delineate relationships among risk factors, clinical signs, and EOS, suggesting that risk predictors may have different utilities in different groups. The purpose of this commentary is to explore these questions and to suggest new approaches to management of newborns who may be at risk for EOS.

Current management and long-term outcomes following chorioamnionitis

Chorioamnionitis is the process of active infection within the amniotic cavity that induces an inflammatory response. A wide variety of pathologic organisms can cause chorioamnionitis. Prompt diagnosis and timely treatment with broad-spectrum antibiotics can help avert the significant short-term and long-term consequences that may result. This review aims to summarize the up-to-date diagnosis criteria, treatment protocols, and long-term sequelae of missed diagnoses or poorly treated disease. It also calls for future studies that aim to better understand the mechanism of disease and to develop better detection and intervention methods to prevent the significant associated morbidity.