The Role of Uterine Closure in the Risk of Uterine Rupture

A potentially modifiable risk factor for uterine rupture during labor is the uterine closure technique. There is no consensus at present on the most appropriate uterine closure, in part because previous studies examining the relationship between the technique used for closure and subsequent pregnancy outcome have been small and greatly underpowered. Two decades ago, the 2-layer technique was the most common and popular procedure for uterine closure. In the 1990s, single-layer closure gained popularity with obstetricians because of its shorter operative time and need for fewer hemostatic sutures, and presently this technique is commonly used. A retrospective study published in 2002 comparing the single- and 2-layer techniques reported that single-layer closure was associated with a 4-fold increased risk of subsequent uterine rupture in women undergoing a trial of labor after a previous cesarean. This multicenter, case-control study was designed to compare the independent contribution of a number of risk factors for uterine rupture in 2 groups of women who had a prior single low-transverse cesarean delivery; the study group was comprised of women who experienced complete uterine rupture during a trial of labor and the control group was comprised of women without uterine rupture during labor. Risk variables examined included maternal age, gestational age at delivery, prior vaginal delivery, maternal diabetes, interdelivery interval, induction of labor, cervical maturation, oxytocin or prostaglandin use, birth weight, prior method of uterine closure, and type of suture material. Univariable and multivariable conditional logistic regression analysis was conducted to estimate the effect of each variable on the risk of uterine rupture. The primary independent variable examined was type of closure (single or double layer or unknown). There were 96 cases of uterine rupture and 288 controls selected for analysis. Adverse outcomes occurred in 29% (28/96) of the neonates. The rate of single-layer closure was higher in the case group than in the controls (cases: 36%, 35/96, vs. controls: 20%, 58/288, P < 0.05). Multivariable analysis showed that single-layer closure (adjusted odds ratio [aOR], 2.69; 95% confidence interval [CI], 1.37-5.28) and birth weight more than 3500 gm (aOR, 2.03; 95% CI, 1.21-3.38) were associated with increased rates of uterine rupture, whereas previous vaginal birth was a protective factor (aOR, 0.47; 95% CI, 0.24-0.93, all 3 comparisons: P < 0.05). Single-layer closure was the only significant variable related to uterine rupture with adverse neonatal outcome (aOR, 2.89; 95% CI, 1.01-8.27). These findings indicate that prior single-layer closure has more than twice the risk of uterine rupture than double-layer closure, and suggest that the single-layer technique should be avoided in women who may choose future vaginal birth after cesarean delivery.