Elective induction of labor following prior cesarean delivery

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 women with a prior cesarean delivery is not well described, and they were not included in the ARRIVE trial. We aimed to estimate the risk of uterine rupture in those women undergoing elective induction of labor with a prior cesarean delivery. This was a retrospective cohort of women with a prior cesarean delivery from 1996 to 2000. Women were included if they had ≤ 2 prior cesareans. Women 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 outcome was uterine rupture. Secondary outcomes included vaginal delivery and a composite major morbidity. Comparisons were made using Student’s t-test or χ2 test as appropriate. At 39 weeks, 618 (10.3%) elective inductions were compared to 5365 (89.7%) undergoing expectant management; uterine rupture occurred more frequently (2.1% vs. 0.9%; P=0.006) with fewer successful VBAC (66.8% vs. 75%; P< 0.001). The risk of uterine rupture was similar between groups at 40 (0.8% vs. 1.2%; P=0.387) and 41 weeks (1.4% vs. 0.8%; P=0.448). Among elective inductions, the risk of rupture or major morbidity was not significantly different by timing, although 39 weeks was associated with more vaginal deliveries. Women 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. However, when induction is compared across all age groups, the risk of a major maternal morbidity is not increased.View Large Image Figure ViewerDownload Hi-res image Download (PPT)