[Antithrombin III deficiency and pregnancy. Apropos of a case].

Congenital deficiency of antithrombin III is a disease inherited as an autosomal dominant which predisposes to thromboembolism. Pregnancy and the postpartum period constitute a major additional risk factor for thromboembolism in deficient women. However, pregnancy may be envisaged without risk since there has been an improvement in knowledge concerning the physiology of the AT III molecule, its exact role in coagulation, the application of accurate laboratory tests which measure the deficiency, and especially the programming of pregnancy under cover of preventive treatment consisting of the perfusion of AT III concentrate in association with heparin. The treatment is restricting and costly but is, nevertheless, the only one to recreate conditions that are similar to physiological conditions, and its effect is therefore more certain.