Rectus sheath hematoma in pregnancy following low molecular weight heparin administration

Introduction: This case report examines a rare complication of low molecular weight (LMW) heparin use during pregnancy. It details the presentation, diagnosis, treatment, and follow-up of rectus sheath hematoma (RSH) associated with enoxaparin prophylaxis. Case Report: A 35-year-old woman with a history of recurrent pregnancy loss and methylenetetrahydrofolate reductase deficiency (MTHFR) mutation was on enoxaparin for venous thromboembolism (VTE) prevention. At 37 weeks gestation, she presented with right abdominal pain and ecchymosis near the injection site, which was diagnosed as RSH. Initially, no further diagnostic tests were conducted. Two days later, she returned with worsening pain, significant hemoglobin drop, and required a blood transfusion. Non-stress testing showed inconclusive fetal heart rate monitoring, prompting an induction of labor. Due to a non-vertex lie, an emergency cesarean section was performed. In the cesarean section extensive blood clots were seen with a dark-colored rectus muscle. The decision was made to leave the clot in place to minimize further bleeding. Postoperatively, she received additional blood and antibiotics, and LMW heparin was stopped and pneumatic stockings for VTE prophylaxis were used. The patient recovered well and was discharged on postoperative day 3. A follow-up ultrasound showed a resolving hematoma at three days, one month, and three months postpartum. Conclusion: This case highlights rectus sheath hematoma as a rare but serious complication of LMW heparin use during pregnancy. It underscores the need for careful monitoring and risk-benefit assessment of anticoagulant therapy in pregnant patients. Further research is needed to better understand the indications and risk factors for LMW heparin use during pregnancy.