A 32-year-old woman with one previous lower segment cesarean section (LSCS) presents at 39 weeks for counselling about trial of labour after cesarean (TOLAC). The factor that MOST significantly reduces the likelihood of successful vaginal birth after cesarean (VBAC) is:

• A Maternal obesity (BMI > 30)
• B Previous cesarean for failure to progress at full dilatation
• C Inter-delivery interval of 18 months
• D Recurrence of the original indication for cesarean (e.g., cephalopelvic disproportion) ✓

Explanation

The most significant predictor of failed TOLAC is recurrence of the original indication, particularly cephalopelvic disproportion or arrest disorders. When the indication was a non-recurring reason (e.g., fetal malpresentation, cord prolapse), VBAC success rates are higher (70–80%). Obesity reduces success rates modestly (to ~55–65%). An inter-delivery interval < 18 months is a risk factor for uterine rupture rather than VBAC failure per se. Previous cesarean for second-stage arrest is particularly associated with failed VBAC.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.