American Board of Internal Medicine (ABIM) Certification Practice Exam

What therapy should pregnant patients with antithrombin deficiency receive?

1. Low-dose aspirin

2. Anticoagulant therapy throughout pregnancy

3. Nothing; they are not at risk

4. Oral contraceptives for immediate postpartum

The correct answer is: Anticoagulant therapy throughout pregnancy

Pregnant patients with antithrombin deficiency are at a significantly increased risk for venous thromboembolism (VTE). Antithrombin is a natural anticoagulant that helps regulate blood clotting; deficiency in this protein can lead to hypercoagulability, particularly during the physiological changes of pregnancy, which further predispose women to clotting disorders. Given this context, the recommended therapy for these patients is the initiation of anticoagulant therapy throughout the pregnancy. This is typically achieved using low molecular weight heparin (LMWH), which is preferred during pregnancy due to its safety profile. Warfarin is contraindicated in pregnancy as it can cause fetal harm, and traditional oral anticoagulants are not the best choice during this time. While low-dose aspirin may be beneficial in certain high-risk populations for reducing the risk of preeclampsia and placental complications, it is not sufficient as a stand-alone treatment for preventing thrombotic events in patients with antithrombin deficiency. The notion that they are "not at risk" is incorrect since they are indeed at a higher risk for thrombosis, especially during pregnancy. The use of oral contraceptives postpartum is also not relevant to management during pregnancy and may pose risks