A pregnant woman with acute abdomen.

Background: Acute abdomen in pregnancy is challenging. The presentation of symptoms and available diagnostic tools are directed and complicated by the pregnancy. A rare cause of acute abdomen in pregnancy requiring immediate intervention is presented.

Case Presentation: A primiparous woman with 34 weeks of uncomplicated pregnancy presented with acute onset of abdominal pain, no signs of labour or vaginal bleeding, blood pressure 127/100, and pulse 90. No fetal distress was indicated by cardiotocography or abdominal ultrasound, while large amounts of intra-abdominal free fluid were identified. The clinical examination revealed free intra-abdominal fluid, which combined with the intense pain prompted an emergency caesarean section on vital indication with removal of intra-abdominal blood, immediate delivery, and manual compression of the aorta. No signs of placental abruption or rupture of the uterine wall were identified. The bleeding, originating from a spontaneous rupture of the left uterine vein, was halted by vessel ligation. Although haemodynamically stable, the woman's estimated blood loss was 4700 millilitres. The child remained for ten days in the NICU owing to prematurity.

Interpretation: A total of 100 case reports of acute spontaneous haemoperitoneum during pregnancy have been published. The underlying pathophysiology is undetermined, but possible risk factors include nulliparity, endometriosis causing extrauterine bleeding, and varicose veins. The condition requires immediate intervention, as morbidity and mortality rates for mother and fetus are high.