Rethinking the VBAC Calculator: Observed vs Predicted VBAC Outcomes

The tools we use to counsel patients aren't always keeping pace with reality. In this episode, midwife-researcher Ann Ledbetter joins us to discuss her study, Observed versus Predicted Vaginal Birth After Cesarean for Patients of a Community Health Center, published in the Journal of Midwifery & Women's Health.Ann shares findings from 507 labors after cesarean at a Milwaukee community health center serving a predominantly Latina population. The numbers challenge assumptions baked into the widely used VBAC calculator. Her team found actual VBAC success rates outpaced predictions across the board, with the calculator proving especially inaccurate for patients with higher BMIs and no prior vaginal birth.We dig into what these findings mean for clinical counseling, the risks of discouraging TOLAC based on probability scores alone, and why Ann believes the conversation needs to shift from "fixing the calculator" to examining hospital-level practices driving cesarean variability. She also makes the case for continued midwifery support as a driver of improved VBAC rates, and outlines the research she'd like to see next.A thoughtful, data-driven conversation about equity, autonomy, and trusting birthing people's bodies.Articles:Considering Labor After Cesarean in a Woman with Class 3 Obesity - Ledbetter - 2020 - Journal of Midwifery & Women's Health - Wiley Online LibraryObserved Versus Predicted Vaginal Birth After Cesarean for Patients of a Community Health Center - Ledbetter - 2025 - Journal of Midwifery & Women's Health - Wiley Online LibraryAnn's Substack: A Moderate Midwife | Ann Ledbetter | SubstackAnn is featured on Emily Oster's newsletter Parent DataVBAC: Risks, Benefits, & How to Prepare