Differing Prevalence and Diversity of Bacterial Species in Fetal Membranes from Very Preterm and Term Labor

Background

Intrauterine infection may play a role in preterm delivery due to spontaneous preterm labor (PTL) and preterm prolonged rupture of membranes (PPROM). Because bacteria previously associated with preterm delivery are often difficult to culture, a molecular biology approach was used to identify bacterial DNA in placenta and fetal membranes.

Methodology/Principal findings

We used broad-range 16S rDNA PCR and species-specific, real-time assays to amplify bacterial DNA from fetal membranes and placenta. 74 women were recruited to the following groups: PPROM <32 weeks (n = 26; 11 caesarean); PTL with intact membranes <32 weeks (n = 19; all vaginal birth); indicated preterm delivery <32 weeks (n = 8; all caesarean); term (n = 21; 11 caesarean). 50% (5/10) of term vaginal deliveries were positive for bacterial DNA. However, little spread was observed through tissues and species diversity was restricted. Minimal bacteria were detected in term elective section or indicated preterm deliveries. Bacterial prevalence was significantly increased in samples from PTL with intact membranes [89% (17/19) versus 50% (5/10) in term vaginal delivery p = 0.03] and PPROM (CS) [55% (6/11) versus 0% (0/11) in term elective CS, p = 0.01]. In addition, bacterial spread and diversity was greater in the preterm groups with 68% (13/19) PTL group having 3 or more positive samples and over 60% (12/19) showing two or more bacterial species (versus 20% (2/10) in term vaginal deliveries). Blood monocytes from women with PTL with intact membranes and PPROM who were 16S bacterial positive showed greater level of immune paresis (p = 0.03). A positive PCR result was associated with histological chorioamnionitis in preterm deliveries.

Conclusion/Significance

Bacteria are found in both preterm and term fetal membranes. A greater spread and diversity of bacterial species were found in tissues of women who had very preterm births. It is unclear to what extent the greater bacterial prevalence observed in all vaginal delivery groups reflects bacterial contamination or colonization of membranes during labor. Bacteria positive preterm tissues are associated with histological chorioamnionitis and a pronounced maternal immune paresis.     

The Citrus Flavone Nobiletin Reduces Pro-Inflammatory and Pro-Labour Mediators in Fetal Membranes and Myometrium: Implications for Preterm Birth

Spontaneous preterm birth is the leading cause of infant death and of neurological disabilities in survivors. A significant proportion of spontaneous preterm births are associated with infection. Infection activates inflammation which induces a cascade of events that leads to myometrial contractions and rupture of fetal membranes. In non-gestational tissues, the citrus flavone nobiletin has been shown to exert potent anti-inflammatory properties. Thus, in this study, we sought to determine the effect of nobiletin on pro-inflammatory mediators in human fetal membranes and myometrium. Human fetal membranes and myometrium were treated with bacterial endotoxin lipopolysaccharide (LPS) in the absence or presence of nobiletin. In addition, the effect of nobiletin in fetal membranes taken from spontaneous preterm deliveries with and without infection (i.e. histological chorioamnionitis) was also examined. In human fetal membranes and myometrium, nobiletin significantly decreased LPS-stimulated expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8) and MMP-9 expression and pro-MMP-9 secretion. Additionally, nobiletin significantly decreased COX-2 expression and subsequent prostaglandin (PG) E₂ production. Notably, nobiletin was also able to reduce the expression and production of pro-inflammatory cytokines and MMP-9 in fetal membranes taken from women after spontaneous preterm birth. In conclusion, our study demonstrates that nobiletin can reduce infection-induced pro-inflammatory mediators in human fetal membranes and myometrium. These in vitro studies further support the increasing volume and quality of evidence that high fruit and vegetable intake in pregnancy is associated with a decreased risk of adverse pregnancy outcomes.     

Maternal serum proinflammatory cytokines in preterm labor with intact membranes: neonatal outcome and histological associations

Our aim was to compare maternal serum concentrations of interleukin(IL)-1alpha IL-1beta, IL-6 and IL-8 in pregnancies complicated by preterm labor (PTL), with the levels in healthy controls at comparable gestational age, and to determine if these assays have any value in the prediction of early-onset neonatal infection or histological chorioamnionitis. The study population consisted of 65 women with new-onset PTL, and 31 healthy controls. Maternal serum concentrations of IL-6 (8.40 versus 3.30 pg/mL; p = 0.002) and IL-1beta (2.20 versus 0.50 pg/mL; p = 0.003) were significantly higher in patients with PTL as compared to healthy pregnant women. The IL-1beta concentration (13.60 versus 1.20 pg/mL; p = 0.02) was significantly higher in the serum of mothers whose babies developed early-onset infections, than in mothers of newborns that were healthy. However, its predictive value, and the value of the other cytokines studied, was poor. In addition, IL-1beta levels (28.79 versus 5.19 pg/mL; p = 0.001) were significantly higher in patients with histological chorionamnionitis, than in those without the condition,. The cut-off value of >or= 14 pg/mL predicted inflammatory changes with a sensitivity of 80%, specificity of 86%, PPV of 80% and NPV of 86%. IL-1beta seems to be of moderate value in the prediction of histological chorioamnionitis.     

IL-6 trans-signaling system in intra-amniotic inflammation, preterm birth, and preterm premature rupture of the membranes

Classic IL-6 signaling is conditioned by the transmembrane receptor (IL-6R) and homodimerization of gp130. During trans-signaling, IL-6 binds to soluble IL-6R (sIL-6R), enabling activation of cells expressing solely gp130. Soluble gp130 (sgp130) selectively inhibits IL-6 trans-signaling. To characterize amniotic fluid (AF) IL-6 trans-signaling molecules (IL-6, sIL-6R, sgp130) in normal gestations and pregnancies complicated by intra-amniotic inflammation (IAI), we studied 301 women during second trimester (n = 39), third trimester (n = 40), and preterm labor with intact (n = 131, 85 negative IAI and 46 positive IAI) or preterm premature rupture of membranes (PPROM; n = 91, 61 negative IAI and 30 positive IAI). ELISA, Western blotting, and real-time RT-PCR were used to investigate AF, placenta, and amniochorion for protein and mRNA expression of sIL-6R, sgp130, IL-6R, and gp130. Tissues were immunostained for IL-6R, gp130, CD15(+) (polymorphonuclear), and CD3(+) (T cell) inflammatory cells. The ability of sIL-6R and sgp130 to modulate basal and LPS-stimulated release of amniochorion matrix metalloprotease-9 was tested ex vivo. We showed that in physiologic gestations, AF sgp130 decreases toward term. AF IL-6 and sIL-6R were increased in IAI, whereas sgp130 was decreased in PPROM. Our results suggested that fetal membranes are the probable source of AF sIL-6R and sgp130. Immunohistochemistry and RT-PCR revealed increased IL-6R and decreased gp130 expression in amniochorion of women with IAI. Ex vivo, sIL-6R and LPS augmented amniochorion matrix metalloprotease-9 release, whereas sgp130 opposed this effect. We conclude that IL-6 trans-signaling molecules are physiologic constituents of the AF regulated by gestational age and inflammation. PPROM likely involves functional loss of sgp130.     

High Mobility Group-Box 1 (HMGB1) levels are increased in amniotic fluid of women with intra-amniotic inflammation-determined preterm birth,and the source may be the damaged fetal membranes

BackgroundHigh Mobility Group Box-1 (HMGB1) is considered a prototype alarmin molecule. Upon its extracellular release, HMGB1 engages pattern recognition receptors and the Receptor for Advanced Glycation End-products (RAGE) followed by an outpouring of inflammatory cytokines, including interleukin (IL)-6.MethodsWe assayed the amniotic fluid (AF) levels of HMGB1 and IL-6 in 255 women that either had a normal pregnancy outcome or delivered preterm. Immunohistochemistry on fetal membranes was used for cellular localization and validation of immunoassay findings. HMGB1 also was analyzed in amniochorion tissue explants subjected to endotoxin.ResultsAF HMGB1 levels are not gestational age regulated but are increased in women with intra-amniotic inflammation and preterm birth. The likely source is the damaged amniochorion, as demonstrated by immunohistochemistry and explant experiments.ConclusionsOur research supports a role for HMGB1 in the inflammatory response leading to preterm birth. As a delayed phase cytokine, in utero exposure to elevated AF HMGB1 levels may have an impact on the newborn beyond the time of birth.     

Interleukin-8 release from human gestational tissue explants: effects of gestation, labor, and chorioamnionitis.

Interleukin-8 (IL-8) is a chemotactic cytokine that has been implicated in the process of human parturition, including the processes of cervical ripening and rupture of fetal membranes. In this study, the in vitro release of IL-8 from human amnion, choriodecidua, and placenta tissues obtained before and after spontaneous labor onset both at term and preterm, was assessed. The effect of chorioamnionitis on IL-8 release was also established. All tissue explants examined released IL-8; however, IL-8 release from choriodecidual explants was significantly (p < 0.02) greater than that observed from amnion and placenta. Furthermore, choriodecidual IL-8 release was significantly (p < 0.001) greater from term tissues (850 +/- 134.4 ng/mg DNA, n = 18) than from preterm tissues (458 +/- 68.8 ng/mg DNA, n = 17). Spontaneous onset of labor, irrespective of the eventual mode of delivery, was not associated with any significant changes in IL-8 release from human gestational tissues compared to not-in-labor tissues, both at term and preterm. IL-8 release from gestational tissues was not significantly different in the absence or presence of chorioamnionitis. These data are in contrast to the previously reported stimulatory effects of bacterial endotoxin on IL-8 release from human gestational tissues. The data are consistent, however, with the suggestion that IL-8 release is an early event in chorioamnionitis that precedes the appearance of clinically overt symptoms.     

Cervical Microbiota in Women with Preterm Prelabor Rupture of Membranes

ObjectiveTo analyze the cervical microbiota in women with preterm prelabor rupture of membranes (PPROM) by pyrosequencing and to document associations between cervical microbiota, cervical inflammatory response, microbial invasion of the amniotic cavity (MIAC), histological chorioamnionitis, and intraamniotic infection (IAI).ResultsFour bacterial community state types [CST I (Lactobacillus crispatus dominated), CST III (Lactobacillus iners dominated), CST IV-A (non-Lactobacillus bacteria dominated), and CST IV-B (Gardnerella vaginalis and Sneathia sanguinegens dominated)] were observed in the cervical microbiota of women with PPROM. Cervical fluid IL-6 concentrations differed between CSTs (CST I = 145 pg/mL, CST III = 166 pg/mL, CST IV-A = 420 pg/mL, and CST IV-B = 322 pg/mL; p = 0.004). There were also differences in the rates of MIAC, of both MIAC and histological chorioamnionitis, and of IAI among CSTs. No difference in the rate of histological chorioamnionitis was found among CSTs.ConclusionsThe cervical microbiota in PPROM women in this study was characterized by four CSTs. The presence of non-Lactobacillus CSTs was associated with a strong cervical inflammatory response and higher rates of MIAC, both MIAC and histological chorioamnionitis, and IAI representing a PPROM subtype with pronounced inflammation. CST I represents the dominant type of PPROM with a low rate of MIAC, IAI, and the combination of MIAC and histological chorioamnionitis.     

胎盘组织学绒毛膜羊膜炎与未足月胎膜早破后早产儿脑损伤关系

目的:研究胎盘组织学绒毛膜羊膜炎与未足月胎膜早破后早产儿出现脑损伤的相关性。方法:选取我院妇产科2017年1月至2019年12月收治的因胎膜早破生产的未足月早产儿80例,根据是否存在绒毛膜羊膜炎分为观察组(绒毛膜羊膜炎)和对照组(无绒毛膜羊膜炎),每组40例,患儿于胎龄40 w时行颅脑核磁共振检查(Magnetic Resonance Examination,MRI),对比两组脑室周围白质软化(periventricular leukomalacia,PVL)阳性率,且采用新生儿20项行为神经评分量表(neonatal behavior neurological assessment,NBNA)评价两组患儿神经行为,然后在纠正胎龄3、6个月时对两组患儿进行智能发育指数(mental developmentalindex,MDI)及心理运动发育指数(psychomotor development index,PDI)测定并对比。结果:观察组PVL阳性率为27.5%,高于对照组的10.0%(P<0.05);观察组纠正胎龄40 w NBNA得分为(31.02±3.51)分,对照组为(35.21±4.02)分,差异具有统计学意义(P<0.05);胎龄3个月,MDI得分在观察组与对照组间差异无具有统计学意义(P>0.05),但其PDI得分低于对照组(P<0.05);胎龄6个月,观察组MDI及PDI得分均低于对照组(P<0.05)。结论:绒毛膜羊膜炎与未足月胎膜早破后早产儿的脑部损伤情况具有一定相关性,可以作为预测早产儿脑损伤程度的一项指标。     

Cytokine release from placental endothelial cells, a process associated with preterm labour in the absence of intrauterine infection

There is currently a great deal of interest in the role that cytokines may play in the processes mediating preterm as well as normal term labour. In case of preterm delivery a cause-effect relationship between infection, uncontrollable preterm labour, and increased uterine cytokine concentrations is widely accepted, but there is considerable information that increased uterine cytokine release is also a condition in normal term labour and preterm labour not due to infection. Thereby, the exact cellular sources of cytokine production have not yet been identified. In the present study, the authors used immunohistochemical analysis to localize interleukin 1beta (IL-1beta) interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) immunoreactivity within trophoblastic villi and fetal membranes. In the absence of chorioamnionitis, uncontrollable preterm labour, and also normal term labour was associated with strong immunoreactivity for IL-1beta and IL-6 in the endothelial cells within trophoblastic villi. In contrast, preterm delivery accompanied by histologically confirmed chorioamnionitis, was not associated with increased expression of cytokine antigens within endothelial cells of the fetal vascular system, but strong cytokine activity was found in polymorphonuclear cells infiltrating the amniochorionic membranes. Therefore, the data suggest two well-defined subgroups among patients delivering preterm. Thereby, increased uterine cytokine concentrations may be realized in both groups, but the cellular sources of cytokine production may be different.     

Acute Histologic Chorioamnionitis Is a Risk Factor for Adverse Neonatal Outcome in Late Preterm Birth after Preterm Premature Rupture of Membranes

Background

The objective of this study was to determine whether acute histologic chorioamnionitis is associated with adverse neonatal outcomes in late preterm infants who were born after preterm PROM.

Methodology/Principal Findings

The relationship between the presence of acute histologic chorioamnionitis and adverse neonatal outcome was examined in patients with preterm PROM who delivered singleton preterm newborns between 34 weeks and 36 6/7 weeks of gestation. Nonparametric statistics were used for data analysis. The frequency of acute histologic chorioamnionitis was 24% in patients with preterm PROM who delivered preterm newborns between 34 weeks and 36 6/7 weeks of gestation. Newborns born to mothers with histologic chorioamnionitis had significantly higher rates of adverse neonatal outcome (74% vs 51%; p<0.005) than those without histologic chorioamnionitis. This relationship remained significant after adjustment for gestational age at preterm PROM, gestational age at delivery, and exposure to antenatal corticosteroids.

Conclusions/Significance

The presence of acute histologic chorioamnionitis is associated with adverse neonatal outcome in late preterm infants born to mothers with preterm PROM.     

Short fetal leukocyte telomere length and preterm prelabor rupture of the membranes

Background

Rupture of the fetal membranes is a common harbinger of imminent labor and delivery. Telomere shortening is a surrogate for oxidative stress (OS) and senescence. Fetal leukocyte and placental membrane DNA telomere lengths were evaluated to determine their association with preterm prelabor rupture of the membranes (pPROM) or spontaneous preterm births with intact membranes (PTB), compared to term birth.

Methods

Telomere lengths were quantified in cord blood leukocytes (n = 133) from three major groups: 1) pPROM (n = 28), 2) PTB (n = 69) and 3) uncomplicated full term births (controls, n = 35), using real-time quantitative PCR. Placental membrane specimens (n = 18) were used to correlate fetal leukocyte and placental telomere lengths. Telomere length differences among the groups were analyzed by ANOVA. Pearson correlation coefficients determined relationships between leukocyte and placental membrane telomere lengths.

Results

In pregnancies with intact membranes, fetal leukocyte telomere length was inversely proportional to gestational age. The mean telomere length decreased as gestation progressed, with the shortest at term. pPROM had telomere lengths (9962±3124 bp) that were significantly shorter than gestational age-matched PTB (11546±4348 bp, p = 0.04), but comparable to term births (9011±2497 bp, p = 0.31). Secondary analyses revealed no effects of race (African American vs. Caucasian) or intraamniotic infection on telomere length. A strong Pearson''s correlation was noted between fetal leukocyte and placental membrane telomere lengths (ρ = 0.77; p<0.01).

Conclusions

Fetal leukocyte telomere length is reduced in pPROM compared to PTB but is similar to term births. pPROM represents a placental membrane disease likely mediated by OS-induced senescence.     

The association between early membrane rupture, latency, clinical chorioamnionitis, neonatal infection, and adverse perinatal outcomes in twin pregnancies complicated by preterm prelabour rupture of membranes.

The objective of this study was to evaluate associations between adverse outcomes in twin pregnancies and preterm prelabour rupture of membranes (PPROM). A chart review of 246 consecutive twin pregnancies with confirmed PPROM was conducted. Regression analysis (beta [natural log of the odds ratio] and odds ratio [OR]) was performed to identify independent predictors. Two hundred and forty-six twin pregnancies, 492 liveborns, and 20 neonatal deaths. Mean (SD) PPROM gestational age (GA): 31.3 (3.8) wk; delivery GA: 32.0 (3.3) wk. PPROM < 30 wk was associated with increased parity (OR: 2.66), and log (admission leukocyte count) (OR: 9.99). Shortened latency was associated with PPROM GA (beta = -0.17) and chorioamnionitis (beta = 0.95). Neonatal sepsis was predicted by lower delivery GA (OR: 2.04). Adverse perinatal outcomes were protected against by older GA at PPROM (OR 0.53) and shortened latency (OR 0.73). It was concluded that increased leukocytosis and parity implies an infectious aetiology in earlier PPROM. Increased risk for neonatal sepsis at earlier delivery GA is consistent with gestation-dependent fetal immunocompetence. Early PPROM and long latencies were associated with increased adverse perinatal outcomes.     

未足月胎膜早破合并绒毛膜羊膜炎孕妇血清淀粉样蛋白A、血小板激活因子水平的表达及临床意义

目的:检测未足月胎膜早破合并绒毛膜羊膜炎(HCA)孕妇血清淀粉样蛋白A(SAA)、血小板激活因子(PAF)水平,并探讨其临床意义。方法:选择从2013年7月到2017年7月,在我院接受治疗的165例胎膜早破孕产妇作为研究对象。165例患者中,未足月胎膜早破者80例(未足月胎膜早破组),足月胎膜早破者85例(足月胎膜早破组),再根据是否合并HCA分为合并HCA胎膜早破组43例和未合并HCA胎膜早破组122例。另选取同期在我院体检的80例健康孕产妇志愿者作为正常组,对比各组血清SAA和PAF水平,分析合并与未合并HCA胎膜早破组的妊娠结局,利用受试者工作特征(ROC)曲线分析血清SAA和PAF对未足月胎膜早破是否合并HCA的诊断价值。结果:未足月胎膜早破组及足月胎膜早破组的血清SAA和PAF水平均明显高于正常组,且未足月胎膜早破组又高于足月胎膜早破组,差异有统计学意义(P0.05)。未足月胎膜早破组80例患者中HCA发生率为35.00%(28/80),明显高于足月胎膜早破组的17.65%(15/85),差异有统计学意义(P0.05)。合并HCA胎膜早破组的血清SAA和PAF水平均明显高于未合并HCA胎膜早破组,差异有统计学意义(P0.05)。合并HCA的未足月胎膜早破患者血清SAA和PAF水平高于未合并HCA的未足月胎膜早破患者(P0.05)。合并HCA的胎膜早破组的产后大出血、剖宫产以及新生儿肺炎的发生率均明显高于未合并HCA胎膜早破组,差异有统计学意义(P0.05)。根据ROC曲线分析可知,血清SAA和PAF对未足月胎膜早破是否合并HCA的诊断价值较高。结论:血清SAA、PAF水平在未足月胎膜早破合并HCA孕妇中明显升高,二者对此种合并症具有较高的诊断价值。临床诊疗过程中可将SAA及PAF纳入到指标监测体系中,从而为临床治疗提供指导。     

Prediction of preterm delivery by second trimester inflammatory biomarkers in the amniotic fluid

ObjectiveTo search for a correlation between mid-pregnancy altered levels of inflammatory markers and preterm delivery.MethodsA prospective cohort series included 39 patients undergoing amniocentesis one additional milliliter of amniotic fluid (AF) was stored for later dosage of interleukin-6 (Il-6), matrix metalloproteinase-9 (MMP-9), glucose and C-reactive protein (CRP). Maternal serum CRP and glucose levels were also obtained. Exclusion criteria were multiple pregnancies, chorioamnionitis, group B streptococcus colonization, bacterial vaginosis and cases with proven aneuploidy. We searched for correlation between AF and plasmatic markers and also for a difference between patients with term and preterm delivery.Results33 participants were eligible and one third had preterm delivery. Levels of the plasmatic biomarkers did not correlate with the AF biomarkers except for plasmatic glucose and AF IL-6 levels (r = 0.350; p = 0.016). The levels of all AF biomarkers did not differ significantly between the pre-term and the term groups (p > 0.05). The optimal screening cutoffs for identifying pregnancies at risk were different than the ones initially indicated.ConclusionMid-pregnancy amniotic fluid biomarker levels do not correlate with preterm delivery. Plasma CRP is not correlated with these markers. Cutoff levels suggested are sparse and heterogeneous. Larger studies are needed before advising routine measurement of these markers.     

Preterm or Not – An Evaluation of Estimates of Gestational Age in a Cohort of Women from Rural Papua New Guinea

BackgroundKnowledge of accurate gestational age is required for comprehensive pregnancy care and is an essential component of research evaluating causes of preterm birth. In industrialised countries gestational age is determined with the help of fetal biometry in early pregnancy. Lack of ultrasound and late presentation to antenatal clinic limits this practice in low-resource settings. Instead, clinical estimators of gestational age are used, but their accuracy remains a matter of debate.MethodsIn a cohort of 688 singleton pregnancies from rural Papua New Guinea, delivery gestational age was calculated from Ballard score, last menstrual period, symphysis-pubis fundal height at first visit and quickening as well as mid- and late pregnancy fetal biometry. Published models using sequential fundal height measurements and corrected last menstrual period to estimate gestational age were also tested. Novel linear models that combined clinical measurements for gestational age estimation were developed. Predictions were compared with the reference early pregnancy ultrasound (<25 gestational weeks) using correlation, regression and Bland-Altman analyses and ranked for their capability to predict preterm birth using the harmonic mean of recall and precision (F-measure).ResultsAverage bias between reference ultrasound and clinical methods ranged from 0–11 days (95% confidence levels: 14–42 days). Preterm birth was best predicted by mid-pregnancy ultrasound (F-measure: 0.72), and neuromuscular Ballard score provided the least reliable preterm birth prediction (F-measure: 0.17). The best clinical methods to predict gestational age and preterm birth were last menstrual period and fundal height (F-measures 0.35). A linear model combining both measures improved prediction of preterm birth (F-measure: 0.58).ConclusionsEstimation of gestational age without ultrasound is prone to significant error. In the absence of ultrasound facilities, last menstrual period and fundal height are among the more reliable clinical measures. This study underlines the importance of strengthening ultrasound facilities and developing novel ways to estimate gestational age.     

Newborns of Preeclamptic Women Show Evidence of Sex-Specific Disparity in Fetal Growth

BackgroundEvidence suggests that in response to in utero insults, male versus female infants have greater disadvantages in pregnancy outcome. In addition, there is a growing body of evidence suggesting that there is a sex-specific fetal response to maternal disease during pregnancy. We considered that a sex-specific relationship may exist between preeclampsia and reduced fetal growth.ObjectiveWe investigated if the relationship between preeclampsia and fetal growth was modified by fetal sex.MethodsWe limited the study population to singleton pregnancies of black and white normotensive and preeeclamptic women enrolled in the Collaborative Perinatal Project (1959–1965). The patients were offspring of 516 preeclamptic and 8801 normotensive women. After adjustment for confounders, interaction terms between preeclamptic status and fetal sex were evaluated to determine if the influence of preeclampsia on fetal growth varied with fetal sex. Separate linear and logistic regression models were then fitted for males and females to report the estimate of the relationship between preeclampsia and fetal growth by fetal sex. The results were stratified by preterm status (<37 vs ≥37 completed weeks of gestation). The mean head and chest circumferences, birthweight, ponderal index, and frequency of small for gestational age were examined. A 2-sided P value of <0.05 was considered statistically significant.ResultsThe results were stratified by preterm status. Male preterm offspring of preeclamptic mothers had greater reductions in chest circumference, head circumference, and birthweight than preterm female offspring of preeclamptic women (P = 0.01, P = 0.02, and P = 0.05, respectively, for interaction). Female versus male preterm offspring exposed to preeclampsia were less susceptible to being small for gestational age (synergy index 0.38; 95% CI, 0.00–0.84). The influence of preeclampsia on the growth of term offspring was more modest, and the influence of sex was opposite that in preterm infants. Compared with term offspring of normotensive women, the reduction in mean ponderal index was greater for female versus term male offspring of preeclamptic women (P = 0.02, interaction).ConclusionFetal growth was more impaired among male versus female preterm infants born to preeclamptic women. Our study underlined the importance of incorporating sex differences in the study of biological mechanisms for immediate- and long-term consequences of suboptimal fetal growth.     

Maternal glucocorticoids increase endotoxin-induced lung inflammation in preterm lambs

Antenatal betamethasone (Beta) is widely used in women with asymptomatic chorioamnionitis at risk for preterm delivery, but its effects on fetal inflammation are unstudied. Groups of ewes at 109 +/- 1 days of gestation received the following treatments: intra-amniotic (IA) saline (control), 0.5 mg/kg intramuscular Beta, 10 mg IA endotoxin (Endo), and Beta + 2 h later Endo (Beta + Endo). Beta suppressed Endo-induced lung inflammation at 1 day. However, compared with Endo 5 days after treatment, Beta + Endo lambs had increased alveolar neutrophils, proinflammatory cytokine mRNA expression, and serum amyloid A3 (SAA3) mRNA expression. IL-1beta mRNA expression was localized to the inflammatory cells, whereas SAA3 mRNA expression was induced in the bronchial epithelium and the inflammatory cells. Compared with Endo, Beta + Endo lambs had increased lung inflammation but equivalent lung volumes 15 days after treatment. The late increase in inflammation in the Beta + Endo animals suggests that glucocorticoids impair the ability of the preterm lung to downregulate Endo-induced inflammation after fetal clearance of the glucocorticoids. These results have implications for lung inflammation and bronchopulmonary dysplasia in preterm infants exposed to chorioamnionitis and maternal glucocorticoids.     

Intra-amniotic inflammatory response in subgroups of women with preterm prelabor rupture of the membranes

Background

To evaluate the influence of microbial invasion of the amniotic cavity (MIAC) and histological chorioamnionitis (HCA) on the magnitude of intra-amniotic inflammatory response in preterm prelabor rupture of membranes (PPROM).

Methodology/Principal Finding

A prospective cohort study was performed in 107 women with PPROM between 23.0 and 36.6 weeks of gestational age. Twenty-six proteins were assayed by multiple immunoassay in amniotic fluid. The policy for PPROM in Czech Republic is active, and 90% of the women were delivered within 96 hours of membrane rupture. Histopathological placental findings were evaluated based on the Salafia classification. Data were analyzed in four subgroups of population according to the presence of MIAC and/or HCA. Results were stratified by gestational age at PPROM (< or ≥34.0 weeks). The rates of MIAC and HCA were 44% and 57%, respectively. Regardless of gestational age at PPROM, intra-amniotic inflammatory response was higher when MIAC and HCA were both present. There were no differences in the intra-amniotic inflammatory response between women with MIAC or HCA alone and women without infection.

Conclusion

A higher intra-amniotic inflammatory response was identified when both HCA and MIAC were detected.     

Differences in late fetal death rates in association with determinants of small for gestational age fetuses: population based cohort study

Objective: To examine differences in late fetal death rates in association with determinants of small for gestational age fetuses. Design: Population based cohort study. Subjects: 1 026 249 pregnancies without congenital malformations. Setting: Sweden 1983-92. Main outcome measure: Late fetal death rate. Results: Depending on underlying determinants late fetal death rates were greatly increased in extremely small for gestational age fetuses (range 16 to 45 per 1000) compared with non-small for gestational age fetuses (1.4 to 4.6). In extremely small for gestational age fetuses late fetal death rates were increased from 31 per 1000 in mothers aged less than 35 years to 45 per 1000 in older mothers, and from 22 per 1000 in women <155 cm in height to 33 per 1000 in women ⩾175 cm tall. Late fetal death rates were also higher in extremely small for gestational age fetuses in singleton compared with twin pregnancies and in non-hypertensive pregnancies compared with pregnancies complicated by severe pre-eclampsia or other hypertensive disorders. Slightly higher late fetal death rates were observed in nulliparous compared with parous women and in non-smokers compared with smokers.Conclusions: Although the risk of late fetal death is greatly increased in fetuses that are extremely small for gestational age the risk is strongly modified by underlying determinants—for example, there is a lower risk of late fetal death in a small for gestational age fetus if the mother is of short stature, has a twin pregnancy, or has hypertension.

Key messages

• Small for gestational age fetuses are at increased risk of late fetal death regardless of the underlying determinants
• The effect of birthweight ratio on risk of late fetal death is modified by underlying determinants, except maternal age
• Regardless of birthweight ratio the rates of late fetal death are higher among women aged 35 years or older compared with younger women
• In pregnancies of extremely small for gestational age fetuses lower rates of late fetal death are associated with a maternal age of less than 35 years, short maternal stature, multiple births, and hypertensive disorders
• In pregnancies with non-malformed fetuses late fetal death rates are increased in smokers, in multiple births, and in women with severe pre-eclampsia.