THROMBOEMBOLIC EVENTS IN WOMEN UNDER HORM ONE-THERAPY - ACUTE CEREBROVASCULAR THROMBOSIS IN 2 YOUNG-WOMEN RECEIVING ORAL-CONTRACEPTIVES ANDEXPERIENCES AT SANZ 1991-1995

We describe 2 young patients with severe cerebrovascular thrombotic ev ents whose only risk factor was intake of oral contraceptives. A 41-ye ar-old woman suffered thrombosis of the basilar artery and remained di sabled with a locked-in syndrome; a 23-year-old woman had thrombosis o f the sinus sagittalis. These 2 cases and the current discussion regar ding the use of hormones either as oral contraceptives or hormonal rep lacement therapy with estrogens and/or progestins prompted a review of the literature and a review of all spontaneous reports from 1991 to 1 995 to SANZ (Schweizerische Arzneimittel-Nebenwirkungs-Zentrale), the Swiss Drug Side Effects Monitoring Center. The spontaneous reporting u nder this system does not allow conclusions on prevalence and incidenc e of adverse events. In these 5 years 33 vascular events associated wi th different hormones were reported. There were 28 reports of venous t hrombosis of the lower and upper limb or pulmonary embolisms, and 5 re ports of cerebrovascular complications. In 9 of 33 cases the hormones were used as hormonal replacement therapy and in 24 of 33 cases as ora l contraceptives. In half of these women other risk factors for thromb oembolic events such as overweight, family history of thrombosis and i mmobilization were known. Complications occurred with different prepar ations containing different estrogens and progestins. According to the literature, third generation progestins seem to involve a slightly in creased risk of venous thromboembolism but a reduced risk of arterial thromboembolic events, which was confirmed by the SANZ data (17 of all 24 cases). Increasing age and rising estrogen dosage of oral contrace ptives are associated with increased risk of vascular events. Although thromboembolic events also occur during hormonal replacement therapy with naturally occurring estrogens, the prophylactic potential of thes e drugs with regard to osteoporosis and cardiovascular events certainl y outweighs this risk.