Prevention of venous thromboembolism in pregnancy.

Pulmonary thromboembolism, rising from deep venous thrombosis (DVT), is a major cause of maternal death in the developed World. DVT is a significant source of morbidity in pregnancy and the puerperium with long-term sequelae such as post-thrombotic syndrome. The major risk factors for venous thromboembolism (VTE) are: increasing age, particularly over 35 years; operative vaginal delivery; Caesarean section, especially emergency Caesarean section in labour; high body mass index; previous VTE, especially if idiopathic or thrombophilia-associated; thrombophilia; and a family history of thrombosis suggestive of an underlying thrombophilia. Thromboprophylaxis centres largely on the use of low-molecular-weight heparin (LMWH). LMWHs, such as enoxaparin and dalteparin, have substantial clinical and practical advantages compared with unfractionated heparin, particularly in terms of improved safety with a significantly lower incidence of heparin-induced osteoporosis and thrombocytopenia. Such agents should be used in women with significant risk factors for VTE both antenatally and post-partum.