Prophylaxis of thrombosis in antithrombin III-deficient women during pregnancy and delivery.

Prophylactic treatment of two asymptomatic antithrombin III (AT III) -deficient women with oral anticoagulants and heparin during pregnancy and after delivery appeared to be feasible. Oral anticoagulants caused no change in plasma AT III levels in either woman. A high dose of heparin intravenously in one of them caused a strong reduction in the AT III level which was corrected by infusion of AT III concentrate during delivery. A low dose of heparin subcutaneously in the other caused no significant change in plasma AT III levels. There is probably no need for AT III substitution during an uncomplicated pregnancy.