VBAC Eligibility Calculator

American College of Obstetricians and Gynecologists. Vaginal Birth After Cesarean Delivery. ACOG Practice Bulletin No. 205. Obstet Gynecol. 2019;133(2):e110–e127. — Primary clinical guideline defining TOLAC eligibility criteria and contraindications.
Grobman WA, Lai Y, Landon MB, et al. Development of a nomogram for prediction of vaginal birth after cesarean delivery. Obstet Gynecol. 2007;109(4):806–812. — The MFMU nomogram for VBAC success prediction. Antepartum model (without cervical data) used here.
Landon MB, Hauth JC, Leveno KJ, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004;351(25):2581–2589. — Large MFMU study quantifying uterine rupture risk and maternal/neonatal outcomes by labor type.
Guise JM, Eden K, Emeis C, et al. Vaginal birth after cesarean: new insights. Evid Rep Technol Assess (Full Rep). 2010;191:1–397. — AHRQ systematic review of TOLAC safety outcomes.

Step 1 — Uterine Surgical History

Prior Uterine Incision Type

The type of prior uterine incision is the most critical determinant of TOLAC eligibility. This refers to the uterine incision, not the skin incision.

Low-transverse uterine incision (LTCS)

Most common type. Uterine rupture risk with TOLAC: approximately 0.5–0.9% (Landon et al., NEJM 2004)

Unknown uterine incision type — records not available

ACOG: unknown incision type is not an absolute contraindication; individualize based on clinical circumstances

Low-vertical uterine incision

May extend into the upper segment; ACOG does not consider this an absolute contraindication, but success rates are lower

Classical (upper segment) or T-shaped uterine incision

Contraindication to TOLAC — uterine rupture risk 4–9%; ACOG PB 205

Prior uterine rupture

Absolute contraindication to TOLAC (ACOG PB 205)

Prior transfundal uterine surgery (myomectomy entering cavity, etc.)

Contraindication to TOLAC depending on extent of surgery

Number of Prior Cesarean Deliveries

One prior cesarean delivery

Two prior cesarean deliveries

ACOG: may be offered TOLAC if prior low-transverse incision; limited data; success and rupture rates similar to 1 prior CD in select patients

Three or more prior cesarean deliveries

Insufficient data to support TOLAC; ACOG does not recommend

Step 2 — Contraindications to TOLAC

Select any that apply. These are additional conditions that may preclude TOLAC.

Placenta previa or other condition precluding vaginal delivery

Surgeon not immediately available to perform emergency cesarean delivery at this facility

Anesthesia services not immediately available at this facility

None of the above — no additional contraindications