: Pregnancy carries a high risk of thromboembolic complications, especially in the postpartum period. This risk is particularly high in women with inherited thrombophilias, among these antithrombin deficiency seems to carry the highest risk. In this case, the use of low molecular weight heparin (LMWH) is recommended, while the use of antithrombin concentrate is controversial. We report our experience of seven pregnancies occurred in five women: two, with a personal and familiar history negative for venous thromboembolism, were treated with LMWH during pregnancy and antithrombin concentrate immediately before and after the delivery. The other three women had a personal and familiar history positive for venous thromboembolism and were treated with LMWH and antithrombin concentrate during all the pregnancy and the postpartum period. No thromboembolic or hemorrhagic complications were observed in both groups, demonstrating that our strategy could be safe and effective.