Deep venous thrombosis and pulmonary embolism in pregnancy.

Deep venous thrombosis and pulmonary embolism are relatively frequent occurrences in pregnancy and the postpartum period. The diagnosis of deep venous thrombosis and pulmonary embolism requires accurate objective tests because clinical diagnosis is unreliable. Procedures that expose the fetus to ionizing radiation must sometimes be performed to make an accurate diagnosis; current evidence suggests that the adverse effects to the fetus associated with such procedures are minimal. Heparin is the anticoagulant of choice during pregnancy and is used for both the treatment and prevention of venous thrombosis and pulmonary embolism. Patients with deficiencies of antithrombin III, protein C, or protein S as well as patients with antiphospholipid antibodies are at increased risk for thrombotic complications and require particular vigilance during pregnancy.