BackgroundHemoperitoneum resulting from a rupture of an unscarred uterus is a rare condition. Uterine rupture in patients without evident risk factors is associated with non-specific signs and symptoms that can delay the diagnosis. This is a report of spontaneous rupture of posterior wall of the uterus in the second trimester of pregnancy presented as intra-abdominal bleeding.Case presentationHere, we report the case of a 31-year-old Caucasian multiparous female (gravida 3, para 1) who had a sudden onset of abdominal pain at 28 weeks of gestation. The patient had no history of caesarean section. Exploratory laparotomy was performed due to deterioration of the patient’s clinical condition, and ultrasound results were suspicious for hemoperitoneum. Uterine rupture in the posterior wall with active bleeding from the defect was confirmed. A caesarean section was performed, and a live female infant weighing 1000 g, with an Apgar score of three, was delivered. A hysterectomy was performed during the caesarean section.ConclusionDiagnostic difficulties arise from the rarity of the disease, a nonspecific clinical picture and the absence of the main risk factors. Uterine rupture should be considered in the differential diagnosis of hemoperitoneum in patients with an unscarred uterus.