Belgian Trial of an Oral Contraceptive Containing 0.150 mg Desogestrel and 0.020 mg Ethinylestradiol

The efficacy and cycle control of and tolerance to a new oral contraceptive combination containing 0.150 mg desogestrel + 0.020 mg ethinylestradiol was investigated by seven Belgian investigators in a total of 295 women (7257 cycles). The trial was set up as a part of a larger European open multi-center study. This very low estrogen-dose combination was found to be a highly effective oral contraceptive preparation with a good cycle control. Only one pregnancy occurred (not a product failure). The frequency of absence of withdrawal bleeding was low (generally less than 6% during the initial treatment cycles, gradually decreasing to less than 3% after 20 cycles) and in most women the amount and duration of withdrawal bleeding showed no change or a slight decrease in comparison with those of the menstrual bleeding before treatment. The incidence of irregular bleeding (spotting and breakthrough bleeding) rapidly decreased over the subsequent treatment cycles, from 11.7% after 3 cycles to 8.8% after 6 cycles and less than 5% after 12 or more cycles. The preparation was well tolerated. There were no serious side effects and only 8 (2.7%) women dropped out because of minor side effects.