Elective Induction of Labor following Prior Cesarean Delivery.

OBJECTIVE

Following the release of A Randomized Trial of Induction versus Expectant Management (ARRIVE) trial, the 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 aimed to determine the risk of uterine rupture in those patients undergoing elective induction of labor with prior cesarean delivery.

STUDY DESIGN

This was a retrospective cohort of participants with prior cesarean delivery from 1996 to 2000. Participants were included if they had two or more 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 with 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.

RESULTS

At 39 weeks, 618 (10.3%) elective inductions were compared with 5,365 (89.7%) undergoing expectant management; uterine rupture occurred more frequently (13 patients [2.1%] vs. 49 patients [0.9%]; adjusted odds ratio [aOR], 2.5; 95% confidence interval, 1.3-4.6) with fewer successful vaginal birth after cesarean [VBAC; 66.8 vs. 75%; aOR, 0.6; 95% confidence interval, 0.5-0.7]. The risk of uterine rupture was similar between groups at 40 weeks (5 patients [0.8%] vs. 21 patients [1.2%];  = 0.387) and 41 weeks (7 patients [1.4%] vs. 2 patients (0.8%);  = 0.448).

CONCLUSION

Patients undergoing elective induction of labor with a prior cesarean scar had an increased risk of uterine rupture when compared with expectant management at 39 weeks, with fewer successful VBAC.

KEY POINTS

· TOLAC elective induction at 39 weeks has an increased risk of uterine rupture.. · TOLAC elective induction at 39 weeks has a less successful chance of vaginal delivery.. · Awaiting spontaneous labor in this cohort does not increase the risk of uterine rupture..