Diagnosis, treatment, and prevention of venous thromboembolism in pregnancy

Pregnancy and the puerperium put women at increased risk of venous thromboembolism (VTE) due to both baseline maternal risk factors and the development of pregnancy-related prothrombotic anatomic and physiologic changes. Pregnant women are at an approximately 5-fold increased risk of VTE compared with nonpregnant women, and the risk of VTE increases further (to ≥ 20-fold) in puerperium; risk remains increased until approximately 12 weeks postpartum. Pregnancy-related VTE accounts for about 10% of maternal deaths in the developed world. Clinicians should promptly evaluate any signs or symptoms suspicious for VTE, generally starting with ultrasound of the lower extremities. For treatment of women with established VTE, low molecular weight heparins (LMWHs) are preferred due to a favorable safety and efficacy profile. Unfractionated heparin (UFH) and potentially fondaparinux are alternatives. Warfarin should be avoided in the antepartum period due to teratogenicity, and the non-vitamin K oral anticoagulants are currently not recommended due to the lack of data. Low molecular weight heparin, UFH, and warfarin are all acceptable in the postpartum period and for breast-feeding women, but the non-vitamin K oral anticoagulants should be avoided. Prophylaxis (generally with LMWH or in some cases UFH) is recommended for women at highest risk of pregnancy-related VTE, such as those with inherited thrombophilias and a strong family or personal history of VTE. Prophylaxis with LMWH and aspirin is recommended for women with antiphospholipid syndrome. Clinicians should engage in multidisciplinary discussion, particularly around the time of delivery, to manage the details of anticoagulation in their pregnant patients.