Inherited thrombophilias and anticoagulation in pregnancy.

Thromboprophylaxis, primary or secondary, should be considered in selected pregnant women with inherited thrombophilias; such women may be divided into high-, medium- and low-risk categories on the basis of the specific thrombophilic defect and any personal or family history of venous thromboembolism (VTE). Women at high risk of VTE should receive treatment doses of low-molecular-weight heparin (LMWH) throughout pregnancy and should remain on anticoagulation for 6 weeks postpartum, or, where appropriate, long-term. Women at moderate risk should be treated with prophylactic fixed-dose LMWH throughout pregnancy and for 6 weeks postpartum. Women at low risk should receive prophylactic fixed-dose LMWH for 6 weeks postpartum, and low-dose aspirin LDA should be considered during pregnancy. LWMH offers important advantages over unfractionated heparin (UFH); heparin-induced thrombocytopaenia (HIT) and osteopaenia are rarely seen. For treatment doses of LMWH, dosage adjustment based on anti-Xa levels is usually required as pregnancy progresses. Warfarin should be avoided throughout pregnancy. LMWH, UFH and warfarin are safe for breast-feeding mothers.