Prevention and treatment of venous thromboembolism in pregnancy in patients with hereditary antithrombin deficiency

Objective: The aims of the study reported here were to provide data from six pregnant subjects who were enrolled in a clinical trial of antithrombin ( AT) concentrate, discuss other published case series and case reports, and provide general guidance for the use of AT concentrate for inherited AT deficiency in pregnancy. Methods: In the late 1980s, 31 AT-deficient subjects were enrolled in a prospective treatment trial of the plasma-derived AT concentrate Thrombate III (R). Herein, newly available treatment data about the six pregnant subjects in the trial is tabulated and summarized. Results: All six experienced venous thromboembolism (VTE) during pregnancy, were dosed according to a weight-based protocol, and were treated concomitantly with anticoagulation. Loading doses of AT concentrate of 54-62 units/kg were followed by maintenance doses of 50%-100% of the loading dose for 3-10 days. At the time of labor, loading doses of 46-50 units/kg were followed by maintenance doses of 50%-75% of the loading dose for 5-7 days. None of the six experienced recurrent thrombosis while receiving treatment with AT concentrate. Conclusion: Currently we suggest that women with AT deficiency who are pregnant or postpartum and have a personal history of VTE or current VTE receive AT concentrates.