A woman with two previous lower-segment cesarean sections requests a trial of labour (TOLAC). She has a spontaneous onset of labour at 39 weeks. Which finding during labour is the most specific early warning of uterine rupture?
- A Sudden cessation of contractions
- B Prolonged fetal heart rate deceleration (sinusoidal or prolonged bradycardia) ✓
- C Haematuria
- D Scar tenderness between contractions
Correct answer: B. Prolonged fetal heart rate deceleration (sinusoidal or prolonged bradycardia)
Explanation
The most common and earliest fetal sign of uterine rupture is an abnormal fetal heart rate pattern — particularly a prolonged bradycardia or sudden late decelerations — occurring in up to 70% of rupture cases before other signs appear. Sudden loss of contractions, haematuria, and scar tenderness are later or less specific signs. Maternal hemodynamic instability and vaginal bleeding may occur but are not the earliest indicators. CTG abnormality in a TOLAC should prompt immediate evaluation for rupture.
Reference: Williams Obstetrics, 26th ed.
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Written and medically reviewed by the StethoPrep medical team.