[Vascular complications of oral contraception. In whom and how to prevent them?].

Oral contraception entails an increased risk of arterial and venous thrombosis which can only be prevented by detecting women at risk. The relative importance of various predisposing or precipitating factors was evaluated by comparing 3 groups of women: 50 oral contraceptive (OC) users with thrombosis; 50 healthy OC users and 30 controls who had never used OC's. The factors investigated were: duration of use and dose of oestrogens, age, blood pressure, serum lipid levels and tobacco smoking. In addition, all women were tested for the presence of anti-ethinylestradiol antibodies (anti-EE ab) which we had previously shown to be induced by OC's in a number of women. Our results indicated that the most frequently encountered risk factor associated with vascular thrombosis was the presence of anti-EE ab and that the risk was further increased by smoking in women with these antibodies.