The fetal inflammatory response syndrome: the origins of a concept, pathophysiology, diagnosis, and obstetrical implications

The fetus can deploy a local or systemic inflammatory response when exposed to microorganisms or, alternatively, to non-infection-related stimuli (e.g., danger signals or alarmins). The term "Fetal Inflammatory Response Syndrome" (FIRS) was coined to describe a condition characterized by evidence of a systemic inflammatory response, frequently a result of the activation of the innate limb of the immune response. FIRS can be diagnosed by an increased concentration of umbilical cord plasma or serum acute phase reactants such as C-reactive protein or cytokines (e.g., interleukin-6). Pathologic evidence of a systemic fetal inflammatory response indicates the presence of funisitis or chorionic vasculitis. FIRS was first described in patients at risk for intraamniotic infection who presented preterm labor with intact membranes or preterm prelabor rupture of the membranes. However, FIRS can also be observed in patients with sterile intra-amniotic inflammation, alloimmunization (e.g., Rh disease), and active autoimmune disorders. Neonates born with FIRS have a higher rate of complications, such as early-onset neonatal sepsis, intraventricular hemorrhage, periventricular leukomalacia, and death, than those born without FIRS. Survivors are at risk for long-term sequelae that may include bronchopulmonary dysplasia, neurodevelopmental disorders, such as cerebral palsy, retinopathy of prematurity, and sensorineuronal hearing loss. Experimental FIRS can be induced by intra-amniotic administration of bacteria, microbial products (such as endotoxin), or inflammatory cytokines (such as interleukin-1), and animal models have provided important insights about the mechanisms responsible for multiple organ involvement and dysfunction. A systemic fetal inflammatory response is thought to be adaptive, but, on occasion, may become dysregulated whereby a fetal cytokine storm ensues and can lead to multiple organ dysfunction and even fetal death if delivery does not occur ("rescued by birth"). Thus, the onset of preterm labor in this context can be considered to have survival value. The evidence so far suggests that FIRS may compound the effects of immaturity and neonatal inflammation, thus increasing the risk of neonatal complications and long-term morbidity. Modulation of a dysregulated fetal inflammatory response by the administration of antimicrobial agents, anti-inflammatory agents, or cell-based therapy holds promise to reduce infant morbidity and mortality.

The biological basis and prevention of preterm birth

The time of birth is a critical determinant of perinatal and long-term outcomes. Preterm birth is still the first cause of infant mortality and morbidity; unfortunately, rates of preterm birth remain high in both high- and low-resource countries, ranging from 5% to 18%. Preterm parturition is a syndrome, which can be induced by various factors such as infection, cervical pathology, uterine overdistension, progesterone deficiency, vascular alterations (utero-placental ischemia, decidual hemorrhage), maternal and fetal stress, allograft reaction, allergic phenomena, and probably other several unknown factors. These various etiologies can lead to the pathological activation of a common pathway of decidua/fetal membranes, which causes uterine contractility, cervical ripening, and rupture of membranes. Moreover, the mechanisms responsible for these processes have been identified, which involve receptors, chemokines, and inflammatory cytokines. It is very important to understand the cellular and biochemical pathways responsible for preterm labor to identify, treat, and prevent negative outcome in a timely manner. Clinicians and researchers play a key role in improving biochemical knowledge on preterm delivery, identifying risk factors, and shaping interventions that can address this complex syndrome.

The prevalence of vaginal microorganisms in pregnant women with preterm labor and preterm birth

Background

To investigate the risk factors for vaginal infections and antimicrobial susceptibilities of vaginal microorganisms among women who experienced preterm birth (PTB), we compared the prevalence of vaginal microorganisms between women who experienced preterm labor (PTL) without preterm delivery and spontaneous PTB.

Methods

Vaginal swab specimens from 126 pregnant women who experienced PTL were tested for group B streptococcus (GBS), Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Chlamydia trachomatis, Trichomonas vaginalis, Neisseria gonorrhoeae, Treponema pallidum, herpes simplex virus (HSV) I and II, and bacterial vaginosis. A control group of 91 pregnant women was tested for GBS. Antimicrobial susceptibility tests were performed for GBS, M. hominis, and U. urealyticum.

Results

The overall detection rates for each microorganism were: U. urealyticum, 62.7%; M. hominis, 12.7%; GBS, 7.9%; C. trachomatis, 2.4%; and HSV type II, 0.8%. The colonization rate of GBS in control group was 17.6%. The prevalence of GBS, M. hominis, and U. urealyticum in PTL without preterm delivery and spontaneous PTB were 3.8% and 8.7% (relative risk [RR], 2.26), 3.8% and 17.3% (RR, 4.52), and 53.8% and 60.9% (RR, 1.13), respectively, showing no significant difference between the 2 groups. The detection rate of M. hominis by PCR was higher than that by culture method (11.1% vs. 4.0%, P=0.010). The detection rates of U. urealyticum by PCR and culture method were 16.7% and 57.1%, respectively.

Conclusions

There was no significant difference in the prevalence of GBS, M. hominis, and U. urealyticum between the spontaneous PTB and PTL without preterm delivery groups.

A critical role of interleukin-1 in preterm labor

Preterm birth (PTB) is a leading cause of neonatal mortality and morbidity worldwide, and represents a heavy economic and social burden. Despite its broad etiology, PTB has been firmly linked to inflammatory processes. Pro-inflammatory cytokines are produced in gestational tissues in response to stressors and can prematurely induce uterine activation, which precedes the onset of preterm labor. Of all cytokines implicated, interleukin (IL)-1 has been largely studied, revealing a central role in preterm labor. However, currently approved IL-1-targeting therapies have failed to show expected efficacy in pre-clinical studies of preterm labor. Herein, we (a) summarize animal and human studies in which IL-1 or IL-1-targeting therapeutics are implicated with preterm labor, (b) focus on novel IL-1-targeting therapies and diagnostic tests, and (c) develop the case for commercialization and translation means to hasten their development.

Modeling hormonal and inflammatory contributions to preterm and term labor using uterine temporal transcriptomics

BACKGROUND

Preterm birth is now recognized as the primary cause of infant mortality worldwide. Interplay between hormonal and inflammatory signaling in the uterus modulates the onset of contractions; however, the relative contribution of each remains unclear. In this study we aimed to characterize temporal transcriptome changes in the uterus preceding term labor and preterm labor (PTL) induced by progesterone withdrawal or inflammation in the mouse and compare these findings with human data.

METHODS

Myometrium was collected at multiple time points during gestation and labor from three murine models of parturition: (1) term gestation; (2) PTL induced by RU486; and (3) PTL induced by lipopolysaccharide (LPS). RNA was extracted and cDNA libraries were prepared and sequenced using the Illumina HiSeq 2000 system. Resulting RNA-Seq data were analyzed using multivariate modeling approaches as well as pathway and causal network analyses and compared against human myometrial transcriptome data.

RESULTS

We identified a core set of temporal myometrial gene changes associated with term labor and PTL in the mouse induced by either inflammation or progesterone withdrawal. Progesterone withdrawal initiated labor without inflammatory gene activation, yet LPS activation of uterine inflammation was sufficient to override the repressive effects of progesterone and induce a laboring phenotype. Comparison of human and mouse uterine transcriptomic datasets revealed that human labor more closely resembles inflammation-induced PTL in the mouse.

CONCLUSIONS

Labor in the mouse can be achieved through inflammatory gene activation yet these changes are not a requisite for labor itself. Human labor more closely resembles LPS-induced PTL in the mouse, supporting an essential role for inflammatory mediators in human "functional progesterone withdrawal." This improved understanding of inflammatory and progesterone influence on the uterine transcriptome has important implications for the development of PTL prevention strategies.

Plasma inflammatory and immune proteins as predictors of intra-amniotic infection and spontaneous preterm delivery in women with preterm labor: a retrospective study

Background

We investigated whether various inflammatory and immune proteins in plasma predict intra-amniotic infection and imminent preterm delivery in women with preterm labor and compared their predictive ability with that of amniotic fluid (AF) interleukin (IL)-6 and serum C-reactive protein (CRP).

Methods

This retrospective cohort study included 173 consecutive women with preterm labor who underwent amniocentesis for diagnosis of infection and/or inflammation in the AF. The AF was cultured, and assayed for IL-6. CRP levels and cervical length by transvaginal ultrasound were measured at the time of amniocentesis. The stored maternal plasma was assayed for IL-6, matrix metalloproteinase (MMP)-9, and complements C3a and C5a using ELISA kits. The primary and secondary outcome criteria were positive AF cultures and spontaneous preterm delivery (SPTD) within 48 h, respectively. Univariate, multivariate, and receiver operating characteristic analysis were used for the statistical analysis.

Results

In bivariate analyses, elevated plasma IL-6 level was significantly associated with intra-amniotic infection and imminent preterm delivery, whereas elevated plasma levels of MMP-9, C3a, and C5a were not associated with these two outcomes. On multivariate analyses, an elevated plasma IL-6 level was significantly associated with intra-amniotic infection and imminent preterm delivery after adjusting for confounders, including high serum CRP levels and short cervical length. In predicting intra-amniotic infection, the area under the curve (AUC) was significantly lower for plasma IL-6 than for AF IL-6 but was similar to that for serum CRP. Differences in the AUCs between plasma IL-6, AF IL-6, and serum CRP were not statistically significant in predicting imminent preterm delivery.

Conclusions

Maternal plasma IL-6 independently predicts intra-amniotic infection in women with preterm labor; however, it has worse diagnostic performance than that of AF IL-6 and similar performance to that of serum CRP. To predict imminent preterm delivery, plasma IL-6 had an overall diagnostic performance similar to that of AF IL-6 and serum CRP. Plasma MMP-9, C3a, and C5a levels could not predict intra-amniotic infection or imminent preterm delivery.

Pregnancy in Adolescence: Is It an Obstetrical Risk?

STUDY OBJECTIVE

Adolescent pregnancy is an important public health problem worldwide. It is associated with increased risk of maternal and fetal complications. We aimed to investigate whether adolescent pregnancies have an increased risk for perinatal complications. We focused primarily on the relationship between adolescent pregnancy and preterm delivery. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: We used records of 38,646 women who gave birth at our hospital, between January 2008 and December 2009. Five hundred eighty-two randomly selected pregnant adolescents and 2,920 healthy parity and body mass index matched pregnant women 20-34 years of age were included the study. Perinatal outcomes were compared between the groups.

RESULTS

The mean gestational ages of the adolescent and control groups at the first prenatal visit were 11.2 (range, 8-31) and 8.5 (range, 7-28) weeks, respectively (P < .001). The risks of preterm delivery (odds ratio, 2.46; 95% confidence interval, 1.80-3.37; P < .001) and preeclampsia (odds ratio, 2.14; 95% confidence interval, 1.30-3.51; P = .002) were significantly greater among the adolescent mothers. In both groups, the most frequent reason was spontaneous preterm delivery.

CONCLUSION

As shown in this study, pregnant adolescents present to hospitals for prenatal care at a much more advanced gestational age compared with adults. At the time they present to the hospital, and particularly in the first trimester, they must be advised to undergo an ultrasound scan to determine the gestational age. As such, it would be reasonable to increase the frequency of examinations after the second trimester, because of the increased risk of preterm labor and preterm birth.

Progesterone and preterm birth

Progestogens (vaginal progesterone and intramuscular 17-hydroxyprogesterone acetate) are widely recommended for women at high risk of preterm birth. Typical regimens include 17-hydroxyprogesterone caproate (250 mg intramuscularly weekly), starting at 16-20 gestational weeks until 36 weeks or delivery for women with a singleton gestation and a history of spontaneous preterm birth, or vaginal progesterone (90-mg vaginal gel or 200-mg micronized vaginal soft capsules) for women with a short cervix (typically ≤25 mm). Although some randomized trials support this approach, neither of the largest trials (PROLONG for 17-hydroxyprogesterone acetate or OPPTIMUM for vaginal progesterone) demonstrated efficacy. There are almost no data on long-term effects, and none that shows benefit beyond the neonatal period. Although some analyses suggest the cost-effectiveness of the approach, a cervical length screening program followed by progesterone for those with a short cervix will reduce preterm birth rates by less than 0.5%. The present review assesses evidence on the efficacy, likely impact, and long-term effects of implementing the recommendations for progestogens in full. Clinicians and pregnant women can look forward to resolution of the conflicting views on efficacy once the Patient-Centered Outcomes Research Initiative (PCORI)-funded individual patient data meta-analysis is published.

Brucellosis in pregnancy: clinical aspects and obstetric outcomes

OBJECTIVE

Brucellosis is a zoonosis with high morbidity in humans. This disease has gained interest recently due to its re-emergence and potential for weaponization. Pregnant women with this disease can develop severe complications. Its association with adverse obstetric outcomes is not clearly understood. The objective of this study was to describe the obstetric outcomes of brucellosis in pregnancy.

METHODS

Cases of pregnant women with active brucellosis seen at the Hospital Nacional Cayetano Heredia from 1970 to 2012 were reviewed. Diagnostic criteria were a positive agglutination test and/or positive blood/bone marrow culture. Presentation and outcomes data were collected. The Chi-square test was used for nominal variables. A p-value of <0.05 indicated significance.

RESULTS

One hundred and one cases were included; 27.7% had a threatened abortion/preterm labor, 12.8% experienced spontaneous abortion, 13.9% preterm delivery, 8.1% fetal death, and 1.1% congenital malformations. There was one maternal death secondary to severe sepsis. After delivery, neonatal death occurred in 8.1%, low birth weight in 14.5%, and congenital brucellosis in 6.4%. The most common treatment was aminoglycosides plus rifampicin (42.2% of cases). Complication rates decreased if treatment was started within 2 weeks of presentation (p < 0.001).

CONCLUSIONS

This is the largest series of brucellosis in pregnancy reported in the literature. Brucella presents adverse obstetric outcomes including fetal and maternal/neonatal death. Cases with unexplained spontaneous abortion should be investigated for brucellosis. Prompt treatment is paramount to decrease the devastating outcomes.

Patient satisfaction and psychological well-being after internet-based cognitive behavioral stress management (IB-CBSM) for women with preterm labor: A randomized controlled trial

OBJECTIVE AND METHODS

Despite its value for the management of psychological burden, little is known about the efficacy of and patient satisfaction with internet-based cognitive behavioral stress management (IB-CBSM) for women with preterm labor. The present study sets out to analyze stress/anxiety reduction, patient satisfaction and patient's working alliance in a group of 58 women with preterm labor participating in an online psychological stress management project. As part of the project, women were randomly assigned to online stress management or a control condition.

RESULTS

Levels of stress and anxiety decreased significantly in both conditions from pre- to post-treatment measure. Participants in IB-CBSM reported significant higher working alliance inventory (WAI) scores in the task and goal subscale (p<.001; p<.05) than women in the control condition. In Addition the IB-CBSM group showed significant correlations of the WAI subscale task and goal and the stress/anxiety outcome. Regarding patient satisfaction, women in the IB-CBSM reported significantly higher satisfaction scores (p<.001) than women in the control condition. WAI explained nearly 40% of the variance in patient satisfaction. Furthermore, WAI mediates, at least in part, the relationship between group condition and patient satisfaction.

CONCLUSION

The current analysis indicated that participants in IB-CBSM had higher WAI scores and were more satisfied with the program. In addition only the IB-CBSM group showed significant correlations of the WAI with the stress/anxiety reduction outcome. Based on these findings, it can be presumed that measures of agreement with working alliance parameters, especially task and goal components, are substantially important for more effective and satisfactory therapeutic interventions.

Predictors of preterm birth

Cervical length (CL) measured by transvaginal ultrasound examination (TVUE) best identifies the risk for preterm birth (PTB). It identifies women at risk who can benefit from corticosteroids or in utero transfer. Early screening improves effectiveness of tocolysis. It reduces iatrogenicity and cost. In preterm premature rupture of membranes (PPROM), CL is devoid of infectious risk and predicts duration of the latency phase but not the risk of perinatal sepsis. Asymptomatic women at risk should be screened at a 2-week interval starting from 16 to 18 weeks, up to 24 weeks. CLs <10th centile are at risk of PTB, especially with decrease in CL after 16 weeks. Repeat ultrasound improves predictive values. Stable CL calls for term delivery. Funneling does not improve predictivity of CL. In twin pregnancies, CL reduces unnecessary interventions. In symptomatic women, fetal fibronectin performs less than CL. Its combination with inconclusive CL has not emerged productive through randomized controlled trials (RCTs), and studies with homogeneous management for preterm labor (PTL) suggest that up to 15% of unjustified hospitalizations and treatment could be avoided.

Late prematurity: a systematic review

OBJECTIVE

this study aimed to review the literature regarding late preterm births (34 weeks to 36 weeks and 6 days of gestation) in its several aspects.

SOURCES

the MEDLINE, LILACS, and Cochrane Library databases were searched, and the references of the articles retrieved were also used, with no limit of time.

DATA SYNTHESIS

numerous studies showed a recent increase in late preterm births. In all series, late preterm comprised the majority of preterm births. Studies including millions of births showed a strong association between late preterm birth and neonatal mortality. A higher mortality in childhood and among young adults was also observed. Many studies found an association with several neonatal complications, and also with long-term disorders and sequelae: breastfeeding problems, cerebral palsy, asthma in childhood, poor school performance, schizophrenia, and young adult diabetes. Some authors propose strategies to reduce late preterm birth, or to improve neonatal outcome: use of antenatal corticosteroids, changes in some of the guidelines for early delivery in high-risk pregnancies, and changes in neonatal care for this group.

CONCLUSIONS

numerous studies show greater mortality and morbidity in late preterm infants compared with term infants, in addition to long-term disorders. More recent studies evaluated strategies to improve the outcomes of these neonates. Further studies on these strategies are needed.

Association of Chlamydia trachomatis infections with preterm delivery; a systematic review and meta-analysis

Background

Premature birth is a primary cause of infant mortality and its etiology varies in different countries. Chlamydia trachomatis (CT) is a common infectious agent transmitted through sexual contact. The purpose of this study is to investigate the connection between CT infections and preterm birth by meta-analysis.

Methods

All articles published in literature databases including Google Scholar, PubMed, ISI (Web of Science), Biological Abs, IranMedex, SID, and Scopus were investigated. Twenty-four relevant articles, authored betweenm 1998–2014 were analyzed through a random effects model. Heterogeneity of the studies was evaluated by I² index. The relationship between years of data collection, sample size, and CT infections with preterm delivery prevalence was examined by meta-regression. Data were analyzed with R and STATA [Ver. 12].

Results

The overall prevalence of CT infections leading to preterm deliveries was estimated to be 0.13% (CI 95%: 0.11–0.16). The prevalence of CT infections leading to preterm deliveries were calculated based on the study method including PCR [0.06 (CI 95%: 0.04–0.09)], serology [0.23 (CI 95%: 0.10–0.35)] and culture [0.17 (CI 95%: 0.10–0.24)]. Analysis indicates that women with chlamydia infections were 2.28 more likely to deliver pre-term in comparison with those who were not infected. It can be concluded that chlamydia infections increase the risks of preterm delivery, OR = 2.28 (95% CI:1.64–3.16).

Conclusions

In regard to the results in numerous studies performed on different continents, this meta- analysis showed a clear association between preterm delivery and prior CT colonization.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1868-0) contains supplementary material, which is available to authorized users.

Impact of microbial invasion of amniotic cavity and the type of microorganisms on short-term neonatal outcome in women with preterm labor and intact membranes

INTRODUCTION

The objective of this study was to evaluate the impact of microbial invasion of the amniotic cavity and the type of microorganisms on pregnancy and short-term neonatal outcomes in women with preterm labor.

MATERIAL AND METHODS

Prospective observational cohort study including women with preterm labor from 22.0 to 36.0 weeks. Microbial invasion of the amniotic cavity was defined based on amniotic fluid aerobic/anaerobic/mycoplasma cultures, and intra-amniotic inflammation on amniotic fluid interleukin-6 levels. Demographic data and pregnancy outcomes were compared among women exposed to microbial invasion of the amniotic cavity by Ureaplasma spp., women with microbial invasion of the amniotic cavity by other microorganisms, and a No-microbial invasion of the amniotic cavity/No-intra-amniotic inflammation group. The short-term neonatal outcome was evaluated in women delivering after 24.0 weeks.

RESULTS

We included 228 women with preterm labor. Microbial invasion of the amniotic cavity occurred in 35% (80/228), 28% (22/80) being caused by Ureaplasma spp. Gestational age at admission and at delivery were significantly earlier and the rate of delivery at <24.0 weeks' gestation and of women who further developed clinical chorioamnionitis were significantly higher in women with microbial invasion of the amniotic cavity by microorganisms other than Ureaplasma spp. However, after 24 weeks, regardless of the microorganisms isolated, the short-term neonatal outcome was similar between women exposed to microbial invasion of the amniotic cavity and the No-microbial invasion of the amniotic cavity/No-intra-amniotic inflammation group when gestational age was considered.

CONCLUSIONS

Microbial invasion of the amniotic cavity by microorganisms other than Ureaplasma spp. was associated with earlier gestational age at admission and at delivery, and a higher rate of preterm delivery <24.0 weeks and of women who developed clinical chorioamnionitis. However, we did not find differences in the short-term neonatal outcome between women exposed to microbial invasion of the amniotic cavity and the no-microbial invasion of the amniotic cavity/no-intra-amniotic inflammation group delivering after 24.0 weeks' gestation when adjusted by gestational age at delivery.

Folic acid supplementation in early pregnancy and the risk of preeclampsia, small for gestational age offspring and preterm delivery

OBJECTIVE

To assess whether folic acid intake during the first trimester of pregnancy is related to pregnancy outcomes preeclampsia, low birth weight or preterm birth.

STUDY DESIGN

Prospective cohort study of 3647 women who were followed from the first trimester of pregnancy. Detailed information on quantity of folic acid intake before and during the first three months of pregnancy was recorded. Pregnancy outcome data were abstracted from obstetric records.

RESULTS

Lean mothers who used folic acid supplementation the month before pregnancy had a 40% reduced risk of developing preeclampsia. The adjusted odds ratio (OR) with 95% confidence intervals (95%CI) for preeclampsia in lean mothers (BMI<25) who used folic acid supplements the month before pregnancy was 0.6 (95% CI 0.4-1.0). Obese mothers who used folic acid supplementation in the first trimester had an increased, but not statistically significant risk for preterm birth (adjusted OR 1.9 with 95% CI 0.9-4.0). There were no significant associations between folic acid supplementation and low birth weight.

CONCLUSION

Our study supports a possible protective effect of folate intake in early pregnancy on preeclampsia in lean mothers. There was no support for any beneficial effect of folic acid use on preterm birth or low birth weight, and we found no evidence of any harmful effects of folate use for the outcomes included in our study.

Predictive value of pregnancy-associated plasma protein-A (PAPP-A) and free beta-hCG on fetal growth restriction: results of a prospective study

PURPOSE

Low levels of plasmatic pregnancy-associated plasma protein-A (PAPP-A) and high levels of free-beta human chorionic gonadotropin (beta-hCG) could influence the outcome of pregnancy. The objective of this study is to assess the correlation between PAPP-A and free beta-hCG and birth weight.

MATERIALS AND METHODS

Prospective follow-up study performed on 3332 patients in the first trimester of pregnancy who were subjected to a screening test focused on evaluation of fetal aneuploidy (SCA-TEST). The values of PAPP-A and free beta-hCG were both analyzed as raw values and subsequently converted to a multiple of the median (MoM). Statistical analysis was performed using SPSS version 17.0.1 (SPSS Inc., Chicago, USA).

RESULTS

The incidence of "small for gestational age" in patients with PAPP-A MoM <1st and <5th ‰ was statistically significant (12 and 9.8 %; p < 0.0001). Also statistically significant data have been highlighted about free beta MoM > 95th ‰ (7 %; p = 0.03). The values of PAPP-A MoM > 99th ‰ are significantly correlated with an increased risk of "large for gestational age" (16.7 %; p < 0.0001).

CONCLUSION

Our study demonstrates that specific values of PAPP-A and free beta-hCG could identify the risk of low or high birth weight since the first trimester of pregnancy.

The frequency and clinical significance of intra-amniotic inflammation defined as an elevated amniotic fluid matrix metalloproteinase-8 in patients with preterm labor and low amniotic fluid white blood cell counts

Objective

To determine the frequency and clinical significance of intra-amniotic inflammation (IAI) defined as an elevated amniotic fluid (AF) matrix metalloproteinase-8 (MMP-8) concentration in patients with preterm labor and intact membranes (PTL) and low AF white blood cell (WBC) counts.

Methods

Adverse pregnancy outcomes were compared according to the presence or absence of IAI in 220 singleton gestations who underwent amniocentesis due to PTL (gestational age<35.7 weeks) and had low AF WBC counts (<19 cells/mm³). Adverse pregnancy outcomes included preterm birth within 5 days of amniocentesis, acute histologic chorioamnionitis (acute-HCA) and positive AF culture. IAI was defined as an elevated AF MMP-8 concentration (≥23 ng/mL).

Results

IAI was present in 19% of study population. Adverse pregnancy outcomes were significantly more frequent in patients with IAI than in those without IAI (preterm birth within 5 days of amniocentesis, 88% vs. 41%; acute-HCA, 47% vs. 11%; positive AF culture, 10% vs. 2%; each for P<0.05). Patients with IAI had a significantly shorter median amniocentesis-to-delivery interval than those without IAI (7.8 hours [0.01-3,307.3 hours] vs. 310.3 hours [0.01-2,973.8 hours]; P<0.001 from survival analysis). Multiple logistic regression analysis demonstrated that only an IAI (odds ratio, 3.3; 95% confidence interval, 1.5-7.3; P<0.005) retained a statistical significance in the prediction of acute-HCA after other confounding variables were adjusted.

Conclusion

Approximately one-fifth of patients with PTL and low AF WBC counts have an evidence of IAI and are at risk for impending preterm delivery and acute-HCA when AF MMP-8 concentration is used.

The determinant role of IL-6 in the establishment of inflammation leading to spontaneous preterm birth

Preterm birth (PTB) and its consequences are a major public health concern as preterm delivery is the main cause of mortality and morbidity at birth. There are many causes of PTB, but inflammation is undeniably associated with the process of premature childbirth and fetal injury. At present, treatments clinically available mostly involve attempt to arrest contractions (tocolytics) but do not directly address upstream maternal inflammation on development of the fetus. One of the possible solutions may lie in the modulation of inflammatory mediators. Of the many pro-inflammatory cytokines involved in the induction of PTB, IL-6 stands out for its pleiotropic effects and its involvement in both acute and chronic inflammation. Here, we provide a detailed review of the effects of IL-6 on the timing of childbirth, its occurrence during PTB and its indissociable roles with associated fetal tissue damage.

A comparison of risk factors for breech presentation in preterm and term labor: a nationwide, population-based case-control study

PURPOSE

To determine if the common risks for breech presentation at term labor are also eligible in preterm labor.

METHODS

A Finnish cross-sectional study included 737,788 singleton births (24-42 gestational weeks) during 2004-2014. A multivariable logistic regression analysis was used to calculate the risks of breech presentation.

RESULTS

The incidence of breech presentation at delivery decreased from 23.5% in pregnancy weeks 24-27 to 2.5% in term pregnancies. In gestational weeks 24-27, preterm premature rupture of membranes was associated with breech presentation. In 28-31 gestational weeks, breech presentation was associated with maternal pre-eclampsia/hypertension, preterm premature rupture of membranes, and fetal birth weight below the tenth percentile. In gestational weeks 32-36, the risks were advanced maternal age, nulliparity, previous cesarean section, preterm premature rupture of membranes, oligohydramnios, birth weight below the tenth percentile, female sex, and congenital anomaly. In term pregnancies, breech presentation was associated with advanced maternal age, nulliparity, maternal hypothyroidism, pre-gestational diabetes, placenta praevia, premature rupture of membranes, oligohydramnios, congenital anomaly, female sex, and birth weight below the tenth percentile.

CONCLUSION

Breech presentation in preterm labor is associated with obstetric risk factors compared to cephalic presentation. These risks decrease linearly with the gestational age. In moderate to late preterm delivery, breech presentation is a high-risk state and some obstetric risk factors are yet visible in early preterm delivery. Breech presentation in extremely preterm deliveries has, with the exception of preterm premature rupture of membranes, similar clinical risk profiles as in cephalic presentation.

Beta3 adrenergic receptor stimulation in human macrophages inhibits NADPHoxidase activity and induces catalase expression via PPARγ activation

The beta3 adrenergic receptor (β3-AR) stimulation plays a protective role against preterm labor by blocking myometrial contraction, cytokine production, remodeling and apoptosis. We previously demonstrated that macrophage-induced ROS production in the myometrium was a key element leading to the induction of all these labor-associated features. We thus aimed to investigate if the β3-AR could be expressed in human macrophages and could trigger its protective role in the myometrium by directly inhibiting ROS production. Using lipopolysaccharide (LPS)-stimulated myometrial samples and cell co-culture experiments, we demonstrated that β3-AR stimulation inhibits the activation of the NADPH oxidase, leading to the subsequent inhibition of ROS production by macrophages. This antioxidant effect was associated with a potent anti-inflammatory response in macrophages. Furthermore, we observed that β3-AR leads to the expression of catalase not only in macrophages but also in myometrial cells, thereby preventing the transactivation of myometrial cells by hydrogen peroxide. Pharmacological experiments allowed us to demonstrate that these effects were driven by an Erk1/2-mediated activation of the antioxidant transcription factor PPARγ. These results suggest that β3-AR protective effects in the myometrium could be due to its dual antioxidant properties. Further, the effects observed in a macrophage could highlight new applications in chronic inflammatory diseases.

Direct and Vicarious Racial Discrimination at Three Life Stages and Preterm Labor: Results from the African American Women's Heart & Health Study

INTRODUCTION

Health disparities research has demonstrated a negative relationship between racial discrimination and African American women's maternal health outcomes. Yet, the relationship between racial discrimination and preterm labor, a key measure of maternal health, remains understudied. This study sought to examine the associations between preterm labor and direct and vicarious racial discrimination among African American women at three life stages: childhood, adolescence, and adulthood.

METHODS

Logistic regression methods were used to analyze cross-sectional data from the African American Women's Heart & Health Study (AAWHHS; N = 173). The AAWHHS includes detailed maternal health information on a community sample of African American women residing in the San Francisco Bay Area.

RESULTS

Findings indicated each unit increase in adolescent direct racial discrimination was associated with a 48% increase in the odds of preterm labor (OR: 1.480, 95% CI 1.002-2.187, p < 0.05) and each unit increase in childhood vicarious racial discrimination was associated with a 45% increase in the odds of preterm labor (OR: 1.453, 95% CI 1.010-2.092, p < 0.05) after adjusting for number of pregnancies and socioeconomic variables.

DISCUSSION

This study provides evidence of an association between life-stage racial discrimination and preterm labor risk among African American women, underscoring a need to consider how both directly and vicariously experienced racial discrimination at different developmental periods impact racial disparities in birth outcomes.

The role of visfatin (PBEF/Nampt) in pregnancy complications

Visfatin (PBEF/Nampt) is an adipocytokine that exerts pleiotropic effects within the human body, particularly affecting its metabolism and immunity. Visfatin was originally identified as being secreted by peripheral blood lymphocytes acting as a pre-B-cell colony-enhancing factor (PBEF). However, it was subsequently reported to be expressed in almost every tissue of the human body, with visceral fat deposits being the main source of visfatin. In addition to its secreted form, visfatin may also be found intracellularly where it functions as a nicotinamide phosphoribosyltransferase (Nampt). Visfatin maternal plasma concentrations increase during pregnancy, suggesting its important role in this complicated process. Alterations in visfatin level also take place in patients during pregnancy complications. This review focuses on the ones that most commonly occur in connection with visfatin: preterm labor, pre-eclampsia and gestational diabetes mellitus. The review aims to provide a better understanding of the role of visfatin during pregnancy and the causes of its alteration in maternal plasma, highlighting the potential use of visfatin as a diagnostic marker of pregnancy complications in the future.

Runt-related transcription factor 1 (RUNX1) deficiency attenuates inflammation-induced pro-inflammatory and pro-labour mediators in myometrium

Identifying new targets that regulate myometrial activation are required to develop effective treatments to stop preterm labor. Inflammation, which can be induced by sterile or infective insults, plays a role in initiating and maintaining uterine contractions. Several high throughput transcription screening studies have identified an upregulation of runt-related transcription factor 1 (RUNX1) mRNA expression in myometrium with labor. The role of RUNX1 in labor, however, is not known. We report increased RUNX1 during late gestation which was further augmented in labor, suggesting that RUNX1 may be involved in the transition of the myometrium from a quiescent into a contractile state in preparation for labor. By inhibiting the expression of RUNX1, we have established that RUNX1 induces the expression of pro-inflammatory cytokines, chemokines, adhesion molecules, contraction-associated proteins OXR and PTGFR, the uterotonic PGF_2α, and the ECM remodelling enzyme MMP9. Targeting RUNX1 may be a novel approach to prevent preterm labor.

Neonatal outcomes of late preterm and early term birth

OBJECTIVE

To compare neonatal deaths and complications in infants born at 34-36 weeks and six days (late preterm: LPT) with those born at term (37-41 weeks and six days); to compare deaths of early term (37-38 weeks) versus late term (39-41 weeks and six days) infants; to search for any temporal trend in LPT rate.

STUDY DESIGN

A retrospective cohort study of live births was conducted in the Campinas State University, Brazil, from January 2004 to December 2010. Multiple pregnancies, malformations and congenital diseases were excluded. Control for confounders was performed. The level of significance was set at p<0.05.

RESULTS

After exclusions, there were 17,988 births (1653 late preterm and 16,345 term infants). A higher mortality in LPT versus term was observed, with an adjusted odds ratio (OR) of 5.29 (p<0.0001). Most complications were significantly associated with LPT births. There was a significant increase in LPT rate throughout the study period, but no significant trend in the rate of medically indicated deliveries. A higher mortality was observed in early term versus late term infants, with adjusted OR: 2.43 (p=0.038).

CONCLUSION

LPT and early term infants have a significantly higher risk of death.