Oral contraception and hormonal postmenopausal treatment is used worldwide by more than 100 million women. Since 1960 it is known that female sex hormones increase the risk of venous thrombosis, myocardial infarction and acute cerebrovascular attacks. This risk diminishes when small doses of oral contraceptives are administered but it still remains the main cause of thromboembolism in young women. The risk is greatest during the first year of contraceptive use, in women taking desogestrel and gestoden (so-called third generation progesterones) and in women with a prethrombotic predisposition. Hormonal substitution treatment (HRT) increases the risk of venous thrombosis, in particular in the first year of HRT use. In women pregnancy and the puerperium are risks for the development of venous thromboembolism.

        Key words: Venous thrombosis - Myocardial infarction - Oestrogens - Progesterone - Oral contraception - Postmenopausal hormonal treatment