ABSTRACT
The relationship between oral contraceptives and venous and arterial thromboembolic disease has been established in a series of epidemiologic studies. Impairment in the fibrinolytic system has also been correlated with development of venous thrombosis. In patients suffering from idiopathic deep venous thrombosis, defects in the fibrinolytic function are the most common biochemical and hemostatic disturbance observed. Conflicting results concerning the effects of high-dose and low-dose oral contraceptives on the fibrinolytic system have been published. Very few studies on the effects of oral contraceptives have assessed the fibrinolytic capacity after venous occlusion. A slight decrease of basal tissue-type plasminogen activator antigen levels was recorded in plasma from the young women after 4 months on oral contraceptives low in estrogen. Teenagers also seem to have lower fibrinolytic capacity compared to adults; however, substantial profibrinolytic changes were induced by low-dose oral contraceptives.
