Intrapartum rupture of the unscarred uterus.

OBJECTIVE: To examine risk factors and maternal and neonatal outcomes in ten cases of intrapartum rupture of the unscarred uterus.

METHODS: Uterine ruptures in women without previous cesarean deliveries were identified from an ongoing log for a 12-year period beginning January 1, 1983. Detailed information was obtained by review of hospital records.

RESULTS: From January 1, 1983, through December 31, 1994, we identified 13 uterine ruptures in women without previous cesarean deliveries. Three resulted from motor vehicle accidents and were excluded from analysis. Ten occurred during labor and are the subjects of our report. The incidence of intrapartum rupture of an unscarred uterus was 1 in 16,849 deliveries. Associated factors included oxytocin use (four cases), prostaglandin use (three cases), use of vacuum or forceps (three cases), grand multiparity (two cases), and malpresentation (two cases). Intervention was prompted by fetal heart rate decelerations in seven cases and by severe hemorrhage in three. Uterine rupture was associated with acute abdominal pain in six cases, maternal tachycardia in five, and severe hypotension in two. Neonatal outcomes were normal in nine cases. There were no maternal or perinatal deaths.

CONCLUSION: Intrapartum rupture of the unscarred uterus is a rare obstetric emergency. Maternal and perinatal outcomes are optimized by awareness of risk factors, recognition of clinical signs and symptoms, and prompt surgical intervention.