Spontaneous rupture of an unscarred gravid uterus in a primigravid woman at 32 weeks of gestation.

Uterine rupture usually occurs in a scarred uterus, especially secondary to prior cesarean section. Antepartum uterine rupture in an unscarred uterus is extremely rare. We report a case of spontaneous rupture of an unscarred gravid uterus at 32 weeks of gestation in a primigravid woman. Ultrasonography and magnetic resonance imaging showed a bulging cystic lesion communicating with the intrauterine cavity. Operative findings during emergent cesarean section revealed uterine perforation in the right cornual area and a prolapsed, nonbleeding amniotic sac. The left cornual area was also focally thin. An arcuate uterus was suspected based on follow-up hysterosalpingography. Antepartum uterine rupture tends to occur in the uterine cornual area. In this case, Mullerian duct anomalies may have been associated with focal myometrial defects.