- Models to predict successful trial of labor after cesarean (TOLAC) may underpredict success.
- Consider validation of models for specific populations prior to their use in counseling patients.
Why this matters
- Counseling patients about the decision for TOLAC vs elective repeat cesarean delivery (CD) often includes individual estimates of success based on vaginal birth after cesarean (VBAC) models.
- With predicted successful vaginal delivery
- Rate of successful VBAC was 75%.
- Women with successful VBAC were more likely to:
- be Hispanic: 37.1%;
- have a normal BMI: 38.3%; and/or
- have a prior vaginal delivery: 54%.
- Predictive models (Grobman and Metz) were most accurate when predicted probabilities of successful VBAC were >60%.
- The models underpredicted success when predicted probability
- Births following successful and unsuccessful TOLAC between 2013 and 2016 at 1 US institution were identified from an electronic database (n=404).
- Predictive performance was compared among 3 models and to the actual VBAC rate.
- Funding: None.
- Data do not include women who elected not to pursue TOLAC.