Guidelines for the management of thrombophilia. Department of Haematology, The Royal London Hospital, Whitechapel, London, UK.

Although there are numerous risk factors for venous thromboembolic disease, the term 'thrombophilia' refers only to those familial or acquired disorders of the haemostatic system that result in an increased risk of thrombosis. The inherited thrombophilias include antithrombin III deficiency, resistance to activated protein C (factor V Leiden), protein C and protein S deficiencies as well as some rare forms of dysfibrinogenaemia. It is possible that other inherited conditions might also predispose to thrombosis. In contrast, when using the above definition, the antiphospholipid syndrome is the only genuine acquired thrombophilic state. Patients who have thromboembolic disease at a young age with no provoking event or who have a positive family history or whose thrombosis involves an unusual site should be investigated for thrombophilia. The management of a patient identified as having a laboratory abnormality associated with thrombophilia will depend on a variety of factors such as the patient's individual and family thrombotic history, the site of the thrombosis and the presence of other prothrombotic risk factors. The use of prophylactic anticoagulation during pregnancy and the puerperium requires particularly careful consideration in thrombophilic women. As more becomes known about the thrombophilias it will become possible to formulate more exact guidelines as to the management of these conditions.