376: Cervical ripening balloon with and without oxytocin for cervical ripening in multiparas: A randomized controlled trial

Abstract

To determine if induction of labor with simultaneous use of oxytocin and a cervical ripening balloon (CRB), compared with sequential use, increases the likelihood of delivery within 24 hours in multiparous women. We performed a randomized controlled trial between November 2014 and June 2017. Eligible participants were multiparous women with a vertex presenting, non-anomalous singleton gestation ≥ 34 weeks undergoing induction of labor. Women were excluded for admission cervical examination > 2cm, ruptured membranes, chorioamnionitis or systemic infection, abruption, low-lying placenta, > 1 prior cesarean delivery, or contraindication to vaginal delivery. Patients were randomly allocated to either the simultaneous (CRB with oxytocin) or sequential (oxytocin after CRB expulsion) group. Per protocol, amniotomy was performed upon CRB expulsion. The primary outcome was delivery within 24 hours of CRB placement. Secondary outcomes included induction to delivery interval, time to CRB expulsion, mode of delivery, and adverse maternal or neonatal outcomes. The study was powered to evaluate a 20% increase in the primary outcome from 55% in the sequential group (β=0.2, α=0.05). 180 patients were randomized (90 simultaneous, 90 sequential). Baseline demographic and obstetric characteristics were similar between study groups, including initial cervical dilation and maternal body mass index. Women in the simultaneous group were significantly more likely to deliver within 24 hours of CRB placement compared to the sequential group (87.8% vs 73.3%, p=0.02). Simultaneous administration of CRB and oxytocin also resulted in a significantly shorter induction to delivery interval and greater cervical dilation at CRB expulsion (Table). There were no differences in mode of delivery, chorioamnionitis, or adverse maternal or neonatal outcomes. In multiparous women, simultaneous use of CRB and oxytocin results in an increased frequency of delivery within 24 hours and a shorter induction to delivery interval.