Alison G. Cahill, Methodius G. Tuuli, Anthony O. Odibo
Obstetrical & Gynecological Survey
The rate of uterine rupture and other complications is relatively low in women with a history of 2 prior cesareans who attempt vaginal birth (VBAC). Outcome data for women who have had more than 2 previous cesareans are limited, largely because prior studies often combined women with a history of more than 2 cesareans into 1 group and also had small sample sizes. It is possible that the risk of morbidity among women with more than 2 prior cesareans who attempt VBAC may be less than presumed, especially in women with a high likelihood of success. The aim of this retrospective cohort study was to compare the rate of success and risk of maternal morbidity among women with a history of 3 or more prior cesareans, who attempt VBAC with that of women who had repeat cesarean after 1 or 2 prior cesareans. The study was performed at 17 centers in the Northeast United States between 1996 and 2000. The study population was 25,005 women with at least 1 prior cesarean delivery. Univariate analysis was performed, and stratified analyses were used to adjust for potential confounding variables. The primary study outcome measures were a composite of maternal morbidity, defined as the occurrence of any one of the following: symptomatic uterine rupture, bladder or bowel injury, or uterine artery laceration. Secondary outcomes included VBAC success, the individual components of the composite outcome, and the presence of transfusion and fever. Of the 25,005 women, 860 (3.4%) had 3 or more prior cesareans; 89 (10.3%) of these attempted VBAC, and 771 (89.7%) had an elective repeat cesarean. No cases of composite maternal morbidity were found among the 89 women who attempted VBAC. Univariate analysis showed that women who attempted VBAC after 3 or more prior cesareans had a similar likelihood of success as women who attempted VBAC after 1 prior cesarean (79.8% vs. 75.5%). After adjusting for previous vaginal delivery, induction use of oxytocin, and diabetes, the similarity remained; the adjusted odds ratio was 1.4, with a 95% confidence interval of 0.81 to 2.41, P = 0.22. These findings indicate that there is no higher risk of maternal morbidity or failed VBAC attempt among women who attempt VBAC after 3 or more prior cesarean deliveries compared with women who attempt VBAC after 1 prior cesarean, as well as those having had 2 prior cesareans. These data are consistent with other studies and suggest that the current recommendations for VBAC attempts in women with more than 1 prior cesarean should be re-evaluated.