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, x(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.