A retrospective study of the management and outcomes of pregnancies with inherited antithrombin deficiency.

Introduction: Antithrombin (AT) deficiency is a rare but highly thrombogenic inherited thrombophilia. Its association with adverse pregnancy outcomes (APO) is undefined. There is limited guidance on managing AT deficiency in pregnancy. Some significant issues remain controversial, including risk assessment for prophylactic anticoagulation, anticoagulant therapy, and monitoring. Our goal was to examine if the antepartum management of patients with AT deficiency affected their pregnancy outcomes. Materials and Methods: This retrospective, single‐center observational study included pregnant women with inherited AT deficiency in Peking Union Medical College Hospital between 2013 and 2024. Results: Seventeen pregnancies in 6 women with AT deficiency were identified. A total of 7 pregnancies received adjusted‐dose low‐molecular‐weight heparin (LMWH) and were monitored by anti‐Xa level, AT activity, and D‐dimer. There were 5 live births (all received LMWH), 7 second‐trimester abortions (1 received LMWH), and 5 early pregnancy losses (1 received LMWH). There were 5 abruptio placentae events (3 received LMWH) and 7 thrombotic events (2 received LMWH). Conclusions: AT deficiency is at least an important partial factor contributing to APO. It is suggested to make a full assessment of AT patients both for venous thrombus embolism and APO risk. We observed a high prevalence of heparin resistance and a positive correlation between adequate anticoagulation and pregnancy outcome based on tight monitoring with anti‐Xa level and timely adjustment of the LMWH dosage. [ABSTRACT FROM AUTHOR]