188: Factors associated with successful trial of labor after cesarean delivery


      The objective of this study was to analyze factors and temporal trends associated with successful vaginal delivery for women undergoing trial of labor after cesarean delivery (TOLAC).

      Study Design

      This population-based study of U.S. natality records from 2005-2013 evaluated whether women undergoing TOLAC for live-born, non-anomalous, cephalic, singleton gestations from >37 to <42 weeks gestational age had a successful vaginal delivery or underwent repeat cesarean. Women with more than one prior cesarean delivery were excluded. The primary outcome was successful vaginal delivery. Obstetric, medical, and demographic characteristics associated with vaginal delivery were analyzed. Multivariable log linear regression models were developed to determine factors associated with vaginal delivery.


      Of 323,904 women attempting TOLAC included in the analysis, 229,479 (70.8%) successfully achieved vaginal delivery. White women were more likely to be successful than black women ( 73.8% vs 66.1%, p<0.01), as were women with prior vaginal delivery (84.0% compared to 60.4% in women without a prior vaginal delivery, p<0.01). Preexisting diabetes, chronic hypertension, and gestational hypertension/preeclampsia were associated with significantly lower rates of success (55.9%, 62.4%, and 63.1%, respectively). These factors retained significance in the adjusted model. Women undergoing labor induction had a similar rate of success compared to women with spontaneous labor (71.5% versus 70.7%, respectively). No significant temporal trends were noted.


      This contemporary data supports that TOLAC success is associated with specific medical, obstetric, and demographic factors. These findings support the use of TOLAC success prediction algorithms in provider counseling and patient decision making in balancing risks and benefits of undergoing TOLAC versus scheduled repeat cesarean delivery.