Elective Induction of Labor Following Prior Cesarean Delivery.

Abstract

Following the ARRIVE trial, induction of labor at 39 weeks has increased in the United States. The risk of uterine rupture and optimal timing of elective induction in those patients with a prior cesarean delivery is not well described, and they were not included in the original trial. We aim to determine the risk of uterine rupture in those patients undergoing elective induction of labor with prior cesarean delivery. This was a retrospective cohort of participants with prior cesarean delivery from 1996 to 2000. Participants were included if they had ≤ 2 prior cesareans. Participants were excluded if they had a history of an unknown prior incision, a classical incision, gestational age < 39 weeks, any diabetes, chronic hypertension, twin gestation, collagen or vascular disease, or HIV. Those undergoing expectant management were compared to those undergoing elective induction with no medical or obstetrical indications for delivery. Analysis was performed at three gestational age groups: 39 weeks, 40 weeks, and 41 weeks. The primary outcomes were uterine rupture, rates of successful vaginal delivery, and a composite major morbidity risk. Multivariable logistic regression was performed. At 39 weeks, 618 (10.3%) elective inductions were compared to 5365 (89.7%) undergoing expectant management; uterine rupture occurred more frequently (13 patients (2.1%) vs. 49 patients (0.9%); aOR, 2.5; 95% CI, 1.3 - 4.6) with fewer successful VBAC (66.8% vs. 75%; aOR, 0.6; 95% CI, 0.5 - 0.7). The risk of uterine rupture was similar between groups at 40 (5 patients (0.8%) vs. 21 patients (1.2%); P=0.387) and 41 weeks (7 patients (1.4%) vs. 2 patients (0.8%); P=0.448). Patients undergoing elective induction of labor with a prior cesarean scar had an increased risk of uterine rupture when compared to expectant management at 39 weeks, with fewer successful VBAC.