Women who are pregnant or in the postpartum period have a fourfold to fivefold increased risk of thromboembolism compared with nonpregnant women (1, 2). Approximately 80% of thromboembolic events in pregnancy are venous (3), with a prevalence of 0.5–2.0 per 1,000 pregnant women (4–9). Venous thromboembolism (VTE) is one of the leading causes of maternal mortality in the United States, accounting for 9.3% of all maternal deaths (10). The prevalence and severity of this condition during pregnancy and the peripartum period warrant special consideration of management and therapy. Such therapy includes the treatment of acute thrombotic events and prophylaxis for those at increased risk of thrombotic events. The purpose of this document is to provide information regarding the risk factors, diagnosis, management, and prevention of thromboembolism, particularly VTE in pregnancy. This Practice Bulletin has been revised to reflect updated guidance regarding screening for thromboembolism risk and management of anticoagulation around the time of delivery.


Deep vein thrombosis (DVT) and pulmonary embolism (PE) are collectively referred to as VTE. Approximately 75–80% of cases of pregnancy-associated VTE are caused by DVT, and 20–25% of cases are caused by PE (3, 7, 11). Although approximately one half of these events occur during pregnancy and one half occur during the postpartum period, the risk per day is greatest in the weeks immediately after delivery (3–8, 12).