Which of the following is a low-risk thrombophilia that does NOT require anticoagulation during pregnancy?

Factor V Leiden heterozygous is considered a low-risk thrombophilia that generally does not require anticoagulation during pregnancy. In patients who are heterozygous for Factor V Leiden, the risk of venous thromboembolism (VTE) is increased compared to the general population, but it remains significantly lower than in those who are homozygous for the condition or have other high-risk thrombophilias.

Clinical guidelines typically suggest that women with a heterozygous Factor V Leiden mutation can safely proceed with standard obstetric care without the need for anticoagulation unless they have additional risk factors for thrombosis. This nuanced approach helps to balance the risks of thrombosis against the concerns related to anticoagulation during pregnancy, such as bleeding complications and effects on fetal development.

In contrast, conditions like antithrombin deficiency, Protein S deficiency, and homozygous Factor V Leiden are associated with a much higher risk for thromboembolic events and typically necessitate careful management with anticoagulation during pregnancy to mitigate these risks effectively. Understanding the differences in risks associated with various types of thrombophilia is crucial for providing appropriate antenatal care.