Prevention of venous thromboembolism in pregnant women with congenital antithrombin deficiency: a retrospective study of a candidate protocol

Background The best thromboprophylaxis for pregnant women with congenital antithrombin deficiency (CAD) is controversial. Objective To clarify the effectiveness of a protocol for venous thromboembolism (VTE) prevention in pregnant women with CAD. Methods Women at high risk of VTE were administered antithrombin concentrate and heparin after conception, whereas those at low risk of VTE were administered heparin alone until delivery. All women received antithrombin concentrate at delivery except for one who was diagnosed with CAD. Results Ten women had CAD, including one in the high-risk group and nine in the low-risk group. No women had VTE at delivery as per the protocol for VTE prevention. Almost all women had increased antithrombin activity before delivery followed by maintenance at >= 70% due to antithrombin concentrate administration. VTE prophylaxis during and after delivery was successful in all women with CAD. However, one woman in the low-risk group did not receive heparin and developed VTE induced by severe hyperemesis at 9 gestational weeks, before the diagnosis of CAD. Women in the high-risk group received antithrombin concentrate after delivery but had increased D-dimer levels at postpartum. Conclusions Our protocol to prevent VTE in pregnant women with CAD is safe and effective.