Inherited thrombophilia and gestational venous thromboembolism

Thromboembolic disease remains a leading cause of maternal mortality during pregnancy and the puerperium. Rational and risk-adapted administration of heparin prophylaxis depends on the identification of those women who have an increased risk of thrombosis and the accurate quantification of this risk. In women without prior thrombosis, the presence of a heterozygous factor V Leiden or heterozygous G20210A mutation in the prothrombin gene is associated with a pregnancy-associated thrombotic risk of approximately 1 in 400. Thus, in pregnant carriers of either one of these mutations, the risk of venous thromboembolism is low. Therefore, no heparin prophylaxis is recommended. A combination of the two genetic risk factors can increase the risk to a modest level of 1 in 25. In all women with prior thrombosis, the authors recommend heparin prophylaxis throughout pregnancy and postpartum for 6 weeks (inconsistent data). However, according to the American College of Chest Physicians recommendations, in the subgroup of women with an episode of prior thrombosis associated with a transient risk factor, such as surgery or trauma, and no additional genetic risk factor, clinical surveillance throughout pregnancy and heparin prophylaxis postpartum is possible. Despite the remarkable progress in risk stratification, the absolute magnitude of risk and the optimum management is, in many cases, an issue of ongoing debate.