Vaginal birth after caesarean delivery: does maternal age affect safety and success?

To estimate maternal age effects on the rates of vaginal birth after caesarean delivery (VBAC), the related maternal complications and patient election to attempt VBAC, we conducted a secondary analysis of a retrospective cohort study of women who were offered VBAC from 1996 to 2000 in 17 community and university hospitals. We used bivariable and multivariable analyses to assess the association between maternal age and the study outcomes. A total of 25 005 patients were included, of whom 13 706 (54.81%) elected to attempt VBAC. After controlling for several confounding variables, using ages 21-34 years as the referent group, women aged 15-20 years were 27% less likely to have a failed VBAC attempt (OR = 0.73 [0.62, 0.87], P < 0.001). Analysing maternal age as a dichotomous variable, women who were of advanced maternal age (>or=35 years) were more likely to experience an unsuccessful trial of labour (OR = 1.14 [1.03, 1.25], P = 0.009). In addition, women >or=35 years of age had 39% more risk of experiencing one of the VBAC-related operative complications (OR = 1.39 [1.02, 1.89], P = 0.039). As women increase in age, they are less likely to attempt VBAC and more likely to have an unsuccessful labour trial. While teenage patients do not appear to be at increased risk for VBAC-related complications, patients of advanced maternal age do show an increase in composite VBAC-related operative complication rates.