A twelve-month comparative clinical investigation of two low-dose oral contraceptives containing 20 μg ethinylestradiol/75 μg gestodene and 20 μg ethinylestradiol/150 μg desogestrel, with respect to efficacy, cycle control and tolerance

The aim of this study was to compare contraceptive reliability, cycle control and tolerance of an oral contraceptive containing 20 μg ethinylestradiol and 75 μg gestodene, with a reference preparation containing the same dose of estrogen combined with 150 μg desogestrel. This article presents interim data from centers in France and Austria, involving a total of 479 women and 4,991 cycles. Contraceptive reliability was good with both preparations. Two pregnancies occurred in the gestodene group, but neither were due to method failure. In the desogestrel group there were also two pregnancies, of which one was due to method failure. With respect to cycle control, there is a trend towards a lower incidence of intermenstrual bleeding in the gestodene group. The incidence of spotting (scanty bleeding) during the important first three cycles was 3.5% lower in the gestodene group, and over the first six cycles, it was 7.6% lower. Amenorrhea was similar in both groups, but the incidence of dysmenorrhea was significantly lower in the gestodene group (p = 0.001). Adverse events were similar in both groups, with headache, breast tension and nausea the most frequently reported symptoms. Body weight remained relatively constant during treatment in both groups, and no hypertension was reported for any woman during the course of the study. In each treatment group, 19 women discontinued because of adverse events. It is concluded that both preparations are reliable and well tolerated oral contraceptives; however, there is a more favourable effect on dysmenorrhea by the gestodene formulation.