Conservative management of a spontaneous retroperitoneal hematoma in the third trimester: a rare case report

Spontaneous retroperitoneal hematoma during pregnancy is an extremely rare clinical event. Although not categorized as a primary obstetric emergency, it poses significant challenges in clinical diagnosis and management. A 30-year-old patient at 33 + 5 weeks of gestation presented with acute abdominal and low back pain. Imaging revealed a large, multiloculated cystic mass posterior to the cervix with internal hemorrhagic signals, which was initially misdiagnosed as a hemorrhagic ovarian cyst. Under ultrasound guidance, culdocentesis was performed, draining 85 mL of non-clotting blood, leading to subsequent symptom relief. Serial follow-up demonstrated overall gradual shrinkage of the mass, with a transient postoperative increase at one week, followed by continued shrinkage. An elective cesarean section was performed at 39 + 1 weeks. Intraoperative exploration identified normal bilateral ovaries, with no evidence of cysts or adhesions in the pelvic cavity. Postpartum MRI confirmed a residual mass with mixed signals in the original location, leading to a definitive diagnosis of retroperitoneal hematoma. Subsequent imaging showed near-complete resolution of the hematoma, with only organized tissue remaining. This case culminated in a successful full-term delivery with favorable outcomes for both the mother and the neonate. Spontaneous retroperitoneal hematoma should be considered in the differential diagnosis for pregnant women presenting with acute abdominal pain or back pain, particularly when associated with an adnexal mass. Furthermore, the favorable natural course of the hematoma observed in this stable patient provides valuable insights into the potential for conservative management of this condition.