Mode of delivery at periviable gestational ages: impact on subsequent reproductive outcomes.

AIM: The aim of this study was to assess the risk of subsequent delivery complications after extremely preterm deliveries by initial (index) pregnancy mode of delivery (MOD): cesarean (CD) versus vaginal (VD). METHODS: This is a retrospective, longitudinal cohort study using Washington State birth certificate data and International Classification of Diseases, Ninth Revision codes, 1989-2008, identifying women with deliveries 20-26 weeks' gestation and linked subsequent deliveries. Index MOD was considered as a predictor of adverse subsequent maternal and neonatal outcomes, using t-test, χ(2)-test or Fisher's exact test, and regression analysis. RESULTS: Of 2472 women with periviable delivery and subsequent birth, index CD (n=386) and index VD (n=2086) showed similar risks of composite morbidity (16.1% vs. 15.4%, P=0.76) and subsequent hemorrhage (9.6% vs. 11.1%, P=0.39). Women with index CD were more likely than index VD to experience uterine rupture (1.8% vs. 0.1%, P<0.001), to deliver earlier (35.9 vs. 36.9 weeks, P<0.001), and to have lower birth weight (2736 vs. 3014 g, P<0.001) subsequently. Neonatal hospital charges and lengths of stay were also higher after index CD. CONCLUSIONS: MOD at extreme prematurity did not impact subsequent maternal hemorrhage or overall morbidity. However, CD was associated with substantial uterine rupture risk despite evidence of practice to avoid labor (lower birth weight and earlier delivery) in the subsequent pregnancy.

Serious and life-threatening pregnancy-related infections: opportunities to reduce the global burden.

Michael Gravett and colleagues review the burden of pregnancy-related infections, especially in low- and middle-income countries, and offer suggestions for a more effective intervention strategy.

Parallel detection of lactobacillus and bacterial vaginosis-associated bacterial DNA in the chorioamnion and vagina of pregnant women at term.

BACKGROUND: The majority of early preterm births are associated with intrauterine infections, which are thought to occur when microbes traffic into the uterus from the lower genital tract and seed the placenta. Bacterial vaginosis (BV) is associated with heterogeneous bacterial communities in the vagina and is linked to preterm birth. The extent to which trafficking into the uterus of normal and BV-associated vaginal bacteria occurs is unknown. The study objective was to characterize in parallel the distribution and quantities of bacteria in the vagina, uterus, and placental compartments. METHODS: Pregnant women at term (≥37 weeks) presenting for delivery were recruited prospectively. Swabs were collected in parallel from the vagina, chorioamnion. Choriodecidual swabs were collected if a cesarean section was performed. Samples were analyzed by culture, broad-range 16S rRNA gene PCR, and bacterial species-specific quantitative PCR (qPCR) for DNA from Lactobacillus and a panel of BV-associated bacteria. Results were correlated with placental histopathology. RESULTS: Of the 23 women enrolled, 15 were delivered by cesarean section (N = 10 without labor; N = 5 in labor) and eight were delivered vaginally. BV was diagnosed in two women not in labor. Placental histopathology identified chorioamnionitis or funisitis in six cases [1/10 (10%) not in labor; 5/13 (38%) in labor]. Among non-laboring women, broad-range 16S qPCR detected bacteria in the chorioamnion and the choriodecidua (4/10; 40%). Among laboring women, Lactobacillus species were frequently detected in the chorioamnion by qPCR (4/13; 31%). In one case, mild chorioamnionitis was associated with qPCR detection of similar microbes in the chorioamnion and vagina (e.g. Leptotrichia/Sneathia, Megasphaera), along a quantitative gradient. CONCLUSIONS: Microbial trafficking of lactobacilli and fastidious bacteria into the chorioamniotic membranes and choriodecidua occurs at term in normal pregnancies. In one case, we demonstrated a quantitative gradient between multiple bacterial species in the lower genital tract and placenta. Not all bacterial colonization is associated with placental inflammation and clinical sequelae. Further studies of the role of placental colonization with Lactobacillus in normal pregnancy and fastidious bacteria in chorioamnionitis may improve prevention and treatment approaches for preterm labor.

Lower respiratory tract disorder hospitalizations among children born via elective early-term delivery.

OBJECTIVE: We evaluated the hypothesis that elective early-term delivery increases the risk of childhood lower respiratory tract disorder hospitalization. METHODS: Children born via early-term elective inductions were compared to full- or late-term elective inductions in a retrospective cohort study using Washington State birth certificate and hospital discharge data. Outcomes were the odds of lower respiratory disorder hospitalization before age five and cause specific odds ratios for asthma, bronchiolitis, bronchitis, and pneumonia. In addition, a subgroup analysis excluding infants with perinatal complications was conducted. RESULTS: Electively induced early-term children were at significantly increased risk of hospitalization before age five for lower respiratory disorders compared to similar full- or late-term children (adjusted OR: 1.31, 95% CI: 1.11-1.55). Bronchiolitis was the only cause-specific outcome with a statistically significant increase in odds of hospitalization, though comparable increases were found for the less common diagnoses of asthma (adjusted OR: 1.39, 95% CI: 0.93-2.08) and pneumonia (adjusted OR: 1.27, 95% CI: 0.99-1.64). Excluding infants with perinatal complications did not alter the results. CONCLUSIONS: There was an association between electively induced early-term delivery and hospitalization for lower respiratory tract disorders before age five. This reinforces policies discouraging elective early-term delivery.

Uterine rupture risk after periviable cesarean delivery.

OBJECTIVE: To investigate the risk of uterine rupture in women with prior periviable cesarean delivery and prior term cesarean delivery independent of initial incision type. METHODS: We conducted a retrospective longitudinal cohort study using Washington state birth certificate data and hospital discharge records, identifying primary cesarean deliveries performed at 20-26 weeks and 37-41 weeks of gestation with subsequent delivery between 1989 and 2008. We compared subsequent uterine rupture risk in the two groups considering both primary incision type and subsequent labor induction and augmentation. RESULTS: We identified 456 women with index periviable cesarean delivery and 10,505 women with index term cesarean delivery. Women with index periviable cesarean delivery were younger, more frequently of nonwhite race, more likely to smoke, and more likely to have hypertension. Women in the periviable group had more index classical incisions (42% compared with 1%, P<.001) and fewer subsequent inductions and augmentations (8% compared with 16%, P<.001). Uterine rupture in the subsequent pregnancy occurred more frequently among women in the index periviable group than those in the index term group (8/456 [1.8%] compared with 38/10,505 [0.4%], odds ratio [OR] 4.9, 95% confidence interval [CI] 2.3-10.6). This relationship persisted among women with a low transverse incision (4/228 [1.8%] compared with 36/9,558 [0.4%], OR 4.7, 95% CI 1.7-13.4). CONCLUSION: Cesarean delivery at periviability compared with term is associated with an increased risk for uterine rupture in a subsequent pregnancy, even after low transverse incision. These data support judicious use of cesarean delivery at periviable gestational ages and inform subsequent counseling. LEVEL OF EVIDENCE: II.

Synergy and interactions among biological pathways leading to preterm premature rupture of membranes.

Preterm premature rupture of membranes (PPROM) occurs in 1% to 2% of births. Impact of PPROM is greatest in low- and middle-income countries where prematurity-related deaths are most common. Recent investigations identify cytokine and matrix metalloproteinase activation, oxidative stress, and apoptosis as primary pathways to PPROM. These biological processes are initiated by heterogeneous etiologies including infection/inflammation, placental bleeding, uterine overdistention, and genetic polymorphisms. We hypothesize that pathways to PPROM overlap and act synergistically to weaken membranes. We focus our discussion on membrane composition and strength, pathways linking risk factors to membrane weakening, and future research directions to reduce the global burden of PPROM.