Venous thromboembolism occurs approximately in 1 of 1000 pregnancies. It is one of the leading causes of maternal mortality. Physiologic changes associated with pregnancy and delivery favor for developing venous thromboembolism, and there are individual risk factors, too, contributing to its manifestation. The most frequent risk factors of venous thromboembolism developing during pregnancy are the previous venous thromboembolism and the thrombophilias, furthermore, some other diseases and some unique complications of pregnancy and delivery. Beyond mechanical prevention only heparin preparations can be used for preventing and treating venous thromboembolism in pregnancy and among them the low-molecular-weight heparins are preferred for applying. Dosage of low-molecular-weight heparin preparations is determined by the type and strength of thrombophilia. For treatment of venous thromboembolism presented during pregnancy subcutaneous 100 IU/kg low-molecular-weight heparin is generally used at every 12 hours. Postpartum the oral anticoagulants can be safely applied, too.