Vaginal birth after cesarean delivery (VBAC) failure is associated with perinatal morbidity. The ability to predict VBAC failure in subgroups of high-risk women is important. Our objectives were: (1) to estimate if women with pregestational diabetes (PDM) who attempt VBAC are at increased risk of failure, and (2) to identify clinical characteristics of PDM women associated with failure. We performed a retrospective cohort study of women eligible for VBAC, delivered between 1995 and 1999 at 17 hospitals to study maternal history/outcomes and neonatal outcomes ascertained through chart abstraction. Women with gestational diabetes were excluded. Student t test was used to compare continuous characteristics. Chi-square/Fisher exact tests were used to compare categorical variables. Multivariable logistic regression analysis was used to control for confounders. Of all eligible women (23,601), 37% of diabetics (n=127) and 56% of nondiabetics (n=12968) attempted VBAC. The VBAC failure rate for PDM was 38% versus 24% for nondiabetic women (p<0.001). The risk of failure for PDM patients was increased after controlling for confounders (adjusted odds ratio 1.61, 95% confidence interval 1.06 to 2.51; p=0.038). PDM is independently associated with VBAC failure. The success rate for women with PDM who attempted VBAC (62%) is at the lower end of the general published VBAC success rate range.
- Cesarean section