A trial of labor after cesarean (TOLAC) is being offered to a woman with one previous low transverse cesarean for fetal malpresentation. She is now at 39 weeks with a favorable cervix (Bishop score 8) and an estimated fetal weight of 3.6 kg. Her uterine rupture risk for TOLAC in this scenario is approximately:

• A 3-5%, which is prohibitively high and necessitates repeat cesarean
• B <0.1%, equivalent to the risk of uterine rupture in unscarred uterus
• C 1.5-2%, significantly higher if labor is induced with oxytocin versus spontaneous labor
• D 0.5-0.9%, with successful vaginal birth after cesarean (VBAC) rate approximately 60-80% ✓

Explanation

Uterine rupture risk with one prior low transverse cesarean and TOLAC is approximately 0.5-0.9% (some studies cite 0.7%) — much lower than previously feared. Overall VBAC success rate is 60-80% in appropriately selected candidates, and successful VBAC has lower overall morbidity than repeat cesarean. Factors increasing success: prior vaginal delivery, spontaneous labor onset, favorable cervix, non-recurrent indication. Uterine rupture risk increases with induction (particularly misoprostol is contraindicated) but oxytocin augmentation carries only modestly higher risk (1.1-1.4%). The 3-5% risk applies to prior classical uterine incision, where TOLAC is contraindicated.

Reference: Williams Obstetrics, 26th ed.

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Written and medically reviewed by the StethoPrep medical team.