Single- versus double-layer uterine incision closure and uterine rupture

Objective. To evaluate whether closure of the uterine incision with one or two layers changes uterine rupture or vaginal birth after cesarean section (VBAC) success rates. Methods. Subjects with one previous cesarean section by documented transverse uterine incision that attempted VBAC were identified. Exclusion criteria included lack of documentation of the type of closure of the previous uterine incision, multiple gestation, more than one previous cesarean section, and previous scar other than low transverse. Uterine rupture and VBAC success rates were compared between those with single-layer and double-layer uterine closure. Time interval between deliveries, birth weight, body mass index (BMI), and history of previous VBAC were evaluated as possible confounders. Results. Of 948 subjects identified, 913 had double-layer closure and 35 had single-layer closure. The uterine rupture rate was significantly higher in the single-layer closure group (8.6% vs. 1.3%, p=0.015). This finding persisted when controlling for previous VBAC, induction, birth weight >4000g, delivery interval > 19 months, and BMI >29 (OR 8.01, 95% CI 1.96-32.79). There was no difference in VBAC success rate (74.3% vs. 77%, p=0.685). Conclusion. Single-layer uterine closure may be more likely to result in uterine rupture.