Incidence of uterine rupture among women with mu ̈llerian duct anomalies who attempt vaginal birth after cesarean delivery

Objective: The purpose of this study was to determine and compare the incidences of uterine rupture among women with and without müllerian duct anomalies who were attempting vaginal birth after cesarean delivery. Study Design: There were 1813 attempts at vaginal birth after cesarean delivery between 1992 and 1997 at the Foothills Hospital in Calgary, Alberta, Canada. Of the patients 25 had known müllerian duct anomalies and 1788 did not. The records of these 1813 women were reviewed with respect to uterine rupture, other complications, mode of delivery, and characteristics of the trial of labor. Comparisons were made with the Fisher exact test. Results: The rates of uterine rupture were 8% (2/25) in the group with müllerian duct anomalies and 0.61% (11/1788) in the group without müllerian duct anomalies (P = .013). The cesarean delivery rates were 20% (5/25) and 25.1% (448/1788), respectively. All cesarean deliveries among women with müllerian duct anomalies were performed urgently in response to severe fetal heart rate abnormalities. The rates of fetal heart rate abnormalities necessitating immediate delivery (60% vs 14.1%, P = .013), operative vaginal delivery (40% vs 19.6%, P = .02), and cord prolapse (8% vs 0.45%, P = .0076) were significantly greater in the group with müllerian duct anomalies. Conclusions: Vaginal delivery is common among women with müllerian duct anomalies who attempt vaginal birth after cesarean delivery, but the rates of uterine rupture and other complications are high. (Am J Obstet Gynecol 1999;181:877-81.)