Spontaneous Rupture of the Unscarred Uterus: A Review of the Literature

Uterine rupture is defined as a nonsurgical disruption of all layers of the uterus. Most ruptures occur in the presence of a scar, usually secondary to a previous cesarean delivery. Rupture of an unscarred uterus is rare and is associated with severe maternal and neonatal outcomes.

To outline the literature on potential predisposing factors, clinical findings, and maternal and fetal outcomes of a rupture of an unscarred uterus.

PubMed was searched for the phrases "uterine rupture," "unscarred," and "spontaneous." Individual case reports, retrospective case series, and review articles in English between 1983 and 2020 were included.

We found 84 case reports in 79 articles. The mean maternal age was 29.3 (SD, 5.7) years; 38 women (45.2%) were nulliparous. Uterine rupture occurred in 37% of the women at term; in 9.9%, the gestational age was ≤12 weeks. The most common clinical presentations were abdominal pain (77.4%), signs of hypovolemic shock (36.9%), fetal distress (31%), and vaginal bleeding (22.6%). The most common risk factors were the use of uterotonic drugs for induction or augmentation of labor and a prior curettage procedure. The most frequently ruptured site was the body of the uterus. Hysterectomy managed 36.9% of the ruptures. Four women died (4.8%). Perinatal mortality was 50.6%. Perinatal death was higher in developing than developed countries.

Although rare, spontaneous rupture of the unscarred uterus has serious consequences to the mother and the fetus and should be included in the differential diagnosis of acute abdomen in pregnancy.