Early Versus Late Amniotomy During Induction of Labor in Obese Gravida [37I]

Abstract

INTRODUCTION: The purpose of this study is to compare early (≤4 cm) versus late (>4cm) amniotomy in obese women undergoing induction of labor and the effect on mode of delivery. METHODS: This is a secondary analysis of a retrospective cohort study that obtained IRB approval to investigate induction and augmentation of labor and BMI. Obese women undergoing induction of labor, with term, vertex, singleton pregnancies, with amniotomy as an intervention from 2012 to 2017 were included. Our primary outcome was mode of delivery. Secondary outcomes included length of labor, maximum dose of oxytocin required, adverse neonatal and maternal outcomes. Comparisons were made between those with early amniotomy at cervical exam ≤4 cm, and late amniotomy with cervical exam >4cm. RESULTS: The sub-analysis included 286 women. There was no difference in cesarean delivery rates between early and late amniotomy (21% vs. 12.7%, P=.075). Early amniotomy was associated with longer time from amniotomy to delivery (6.6 hours vs. 3.7 hours, P <.001). Early amniotomy was not associated with a statistically significant reduction in time to vaginal delivery, or vaginal delivery <24 hours from initiation of induction. Early amniotomy was associated with higher maximum dose of oxytocin. There was no statistically significant difference in hemorrhage, chorioamnionitis, NICU admissions or APGAR scores <7 at 1 minute. CONCLUSION: In an obese population, early amniotomy was not associated with an increase in cesarean delivery or increases in maternal or neonatal complications, but it did not appear to be associated with shorter labor course.