[Prevention and treatment of thrombosis in pregnancy].

Pregnancy and especially delivery and the puerperium are associated with an increased risk of thromboembolic disease. Intravenous high dose heparin is the therapy of choice for manifest thromboembolic disease in pregnancy. However, high-dose heparin fails to prevent postthrombotic chronic venous insufficiency in more than one-third of the cases. Low-dose heparin may be used for antithrombotic prophylaxis during pregnancy. However, low-dose heparin may induce a substantial loss of bone density in up to 30% of cases and may be complicated by heparin-associated thrombopenia in up to 2%. This review discusses strategies to reduce these considerable risks. Prospective studies suggest that the risk of recurrence after prior deep vein thrombosis may be somewhat overestimated. These data suggest new therapeutic options in women with no risk factors other than a personal history of thrombosis. Improved diagnostic techniques may contribute to a better evaluation of the individual risk by assessing possible underlying problems such as resistance to activated protein C or deficiencies of coagulation inhibitors. Also, duration of prophylactic anticoagulation may be reduced by targeting treatment to periods of increased risk such as immobilisation, dehydration, surgery, delivery and the puerperium. Recently, evidence has been provided indicating that the use of low molecular weight heparins may be associated with reduced loss of bone density and a significantly attenuated risk of heparin-associated thrombopenia.