VBAC Candidacy Check

A TOLAC — a trial of labor after cesarean — is the attempt: planning to labor and aim for a vaginal birth after a previous cesarean. A VBAC — vaginal birth after cesarean — is the outcome, when that trial of labor succeeds and you give birth vaginally. So everyone who has a VBAC first had a TOLAC, but a TOLAC can also end in a repeat cesarean if labor doesn't go as hoped, and that's a normal, planned-for possibility rather than a failure. This tool reads how good a candidate you may be for a planned TOLAC; whether to attempt one is a decision you make with your obstetric provider.

According to ACOG, most people with one prior low-transverse cesarean are candidates for a trial of labor and should be counseled about it. The factors that most raise the chance of success are a previous vaginal birth — above all a previous successful VBAC — and a prior cesarean done for a reason unlikely to repeat, such as a breech baby or placenta previa. Going into labor on your own also helps. Two prior cesareans, a prior cesarean for labor that stalled, needing an induction, a higher BMI, older age, and a short gap since the last birth each nudge the odds down without ruling a VBAC out. Overall, roughly 60 to 80 percent of appropriately selected people with one prior cesarean who attempt a TOLAC give birth vaginally — that's a general figure, not your personal number.

A trial of labor is generally advised against — and a planned repeat cesarean recommended instead — when the risk of the uterine scar giving way in labor is too high. ACOG lists a prior classical or high-vertical (or T- or J-shaped) uterine incision, a previous uterine rupture, and prior surgery that cut through the full thickness of the upper uterus (such as some myomectomies) as situations where a VBAC is not recommended. An unknown incision type is not itself a contraindication unless a classical incision is strongly suspected. If any of those hard factors apply, this tool always tells you so — and points you toward a conversation about a planned repeat cesarean.

The main serious risk of a trial of labor is uterine rupture, where the previous scar gives way. For someone with one prior low-transverse cesarean, ACOG puts that risk at well under 1 percent — roughly 0.5 to 0.9 percent. It's uncommon, but it is a genuine emergency for both parent and baby, which is why a TOLAC should take place in a facility able to perform an emergency cesarean quickly if it's needed. For most appropriate candidates the overall risk of a planned VBAC is comparable to a planned repeat cesarean, with a different mix of risks and benefits on each side. This is exactly the trade-off to weigh with your provider — not something a tool can settle for you.

No — and it deliberately doesn't try to. A personal percentage comes from a validated statistical model, the MFMU (NICHD) VBAC calculator, which your clinician uses with your full details; its 2021 revision removed race and ethnicity from the estimate. This tool doesn't reproduce that model or invent a number. Instead it gives an honest, qualitative read — a good candidate, an individualized decision, or generally not recommended — based on the factors ACOG describes. Use it to understand where you likely stand and to have a faster, better-informed conversation, then ask your provider to run the MFMU calculator with you for a personalized estimate.

Yes. This tool runs entirely in your browser. Your answers are weighed on your own device and are never sent to a server, saved, or shared — close the tab and they're gone. It's general educational information based on published ACOG guidance; it can't examine you, run your personal numbers, or replace a conversation with your obstetric provider.