Thrombophilia and pregnancy complications.

Venous thromboembolism is the leading cause of pregnancy-associated morbidity and mortality. Women with thrombophilia have an increased risk of VTE in pregnancy and puerperium. In individuals with hereditary thrombosis risk factors a relative risk of pregnancy associated VTE ranging from 3.4 to 15.2 has been found. Women with previous VTE have an approximately 3.5-fold increased risk of recurrent VTE during pregnancy compared to non-pregnant periods. Data on the association of thrombophilia and pregnancy loss and pre-eclampsia are conflicting. Besides an established association with antiphospholipid antibodies, available data suggest associations for antithrombin deficiency, hyper-homo-cysteinemia, factor V Leiden, prothrombin G20210A variation and protein S-deficiency. A contribution of thrombophilia to the risk of pre-eclampsia is less well established. A limited number of prospective studies did not reveal an increased risk of pregnancy complications in unselected women with thrombosis risk factors. Data of only one controlled trial on the prevention of pregnancy loss with low molecular weight heparin (LMWH) are available, which revealed a strikingly positive effect. Thrombophilia screening might be justified in women with pregnancy loss and treatment with LMWH might be considered in those with pregnancy loss and thrombophilia. Further prospective studies and controlled interventional trials are urgently needed.