Recurrent Thrombosis of a Mechanical Heart Valve During Pregnancy: A Case Report

Recurrent thrombosis of mechanical heart valves during pregnancy is a rare but serious complication associated with significant maternal and fetal risks, largely due to the hypercoagulable state induced by pregnancy. Anticoagulation management in this context is particularly challenging, as it requires balancing the prevention of maternal thromboembolic events with minimizing fetal harm. This case report presents a 34-year-old pregnant woman at 33 weeks of gestation with a history of a mechanical mitral valve, recurrent miscarriages, and acute limb ischemia, who was admitted with exertional dyspnoea. Her anticoagulation regimen had been recently changed from Acenocoumarol to weight-adjusted Enoxaparin. She was diagnosed with mitral valve thrombosis and initially treated with unfractionated heparin, followed by surgical valve replacement. Postoperatively, the fetus showed no cardiac activity, leading to an emergency caesarean section. The patient subsequently developed another episode of valve thrombosis, initially managed with fibrinolysis, but ultimately requiring a second valve replacement with a bioprosthetic valve. Further workup identified lupus anticoagulant antibodies, suggestive of antiphospholipid syndrome. This case illustrates the heightened thrombotic risk in pregnancy for patients with mechanical valves, the limitations and complications of various anticoagulation strategies, and the critical need for a personalized, multidisciplinary approach to management. The findings underscore the importance of early recognition, timely intervention, and consideration of underlying prothrombotic disorders in cases of recurrent valve thrombosis during pregnancy.