Thrombosis and embolism.

Prevention offers the best approach to limiting morbidity and mortality from deep vein thrombosis and pulmonary embolism in obstetric patients. The use of anticoagulant drugs during pregnancy, however, can be problematic, from the maternal or the fetal point of view. Deciding on the best management is further limited by the lack of controlled clinical trials in the obstetric setting. From the data available, it can be recommended that anticoagulant prophylaxis should be targeted at groups of patients at high risk of thrombosis during pregnancy and the puerperium. Heparin is the agent of choice in most situations during pregnancy for the prophylaxis of venous thrombosis, while warfarin is still the most effective agent for the prevention of systemic embolism from artificial cardiac valves. Prophylactic measures against venous thrombosis are probably underused in the puerperium. Controlled clinical studies are urgently required to optimize prophylaxis of venous thromboembolism associated with pregnancy, and large studies may be more feasible in the puerperium when the incidence of thromboembolism is highest.