Oral contraceptives and thrombosis - From risk estimates to health impact

Objective. The scientific debate on oral contraceptives (OCs) and thromboti c diseases continues unabated. The aim of this survey was to evaluate avail able scientific data on OCs and thrombotic diseases and to make tentative p rescription recommendations of OCs to women with and without various thromb otic risk factors. Consensus. In women 15-29 years old, venous thromboembolism is about twice as common as arterial complications. In women between 30 and 44 years, the number of arterial complications exceeds venous diseases by about 50%. The mortality from arterial diseases is 3.5 times higher than the number of dea ths from venous diseases in women below 30 years, and 8.5 times higher in w omen 30-44 years old. A significant disability is more frequent in women su ffering and surviving an arterial complication than in women with venous th romboembolism. Although many important scientific issues still have to be addressed, the a vailable scientific data suggests a differential influence of OCs with seco nd and third generation progestagens on the risk of venous and arterial dis eases. OCs with second generation progestagens seem to confer a smaller inc rease in the risk of venous diseases and a higher increase in risk of arter ial complications, compared with OCs containing third generation progestage ns. The possible difference on the venous side seems to be smaller than pri marily anticipated. Results. Young women without any known risk factor for thrombotic diseases may use any low-dose OC. If OCs are prescribed to women with known risk fac tors for arterial thrombotic disease; e.g. smoking, diabetes, controlled hy pertension, migraine without aura, family disposition of acute myocardial i nfarction (AMI) or thrombotic stroke, a low-dose pill with a third generati on progestagen may have an advantage. If OCs are considered for women with risk factors for venous disease such as severe obesity, varicose veins, fam ily history of VTE or with factor V Leiden mutation, a low-dose combined pi ll with a second generation progestagen may be preferable. In women above 30 years, OCs with third generation progestagens generally s eem to confer less overall thrombotic morbidity, mortality and disability t han OCs with second generation progestagens. These women should reconsider, however, the indication of combined OCs in the presence of significant ris k factors of thrombotic diseases.