Results are presented of a Phase III international multicentre trial to study the effect of a new low-dose oral contraceptive (OC) containing 20 micrograms ethinylestradiol and 150 micrograms desogestrel (Mercilon) regarding efficacy, cycle control, blood pressure, and acceptability. Altogether 1,684 women from 12 European countries were included in the study. Four pregnancies occurred, 3 of them patient failures, one tablet failure. The overall Pearl Index was 0.20. The frequency of irregular bleeding was comparable to that recorded with other commonly used low-dose OCs. No serious side effects occurred. The incidence of the most frequently reported subjective side effects--headache, nausea and breast tension--was already low after the first cycle of treatment and decreased to below pretreatment levels with continued use. There was a small increase in mean body weight, which was confined essentially to young women. The preparation did not affect the mean systolic or diastolic blood pressure. This new preparation has thus proved to be an effective, safe and well-accepted ultra low-dose oral contraceptive.

Desogestrel is the most selective progestogen used in oral contraceptives (OCs). The clinical characteristics of the monophasic combined OC containing 150 micrograms desogestrel and 30 micrograms EE per tablet (Marvelon) are in accordance with the strong progestogenic and minimal androgenic effects of desogestrel: a very high contraceptive efficacy is combined with minimal and, in the case of lipid metabolism, even potentially positive effects on metabolic parameters. Through increasing the plasma levels of sex hormone binding globulin, and thereby decreasing the plasma levels of free testosterone, the desogestrel-containing OC also has substantial beneficial effects on acne.