A twelve-month comparative clinical investigation of two low-dose oral contraceptives containing 20 micrograms ethinylestradiol/75 micrograms gestodene and 30 micrograms ethinylestradiol/75 micrograms gestodene with respect to efficacy cycle control and tolerance.

A double-blind comparative study of oral contraceptives (OCs) containing 75 mcg of gestodene and either 20 mcg or 30 mcg of ethinyl estradiol (EE2) indicates that the lower-dose formulation neither compromises contraceptive effectiveness nor produces unacceptable cycle control. Study subjects included 649 randomly selected healthy women requesting contraception from 10 family planning centers in Germany; the 20 mcg EE2 pill was evaluated in 428 women for a total of 4470 cycles while the 30 mcg preparation was tested in 221 women for 2377 cycles. During the 12-month study period the incidence of at least 1 episode of intermenstrual bleeding (generally in the first cycle) was significantly greater in the 20 mcg EE2 group (47.4%) than in the 30 mcg group (35.5%); however the cumulative breakthrough bleeding rates (14.5% and 11.8% respectively) were not dissimilar. In relation to the sum of all cycles the spotting rates were 11.5% for the 20 mcg EE2 OC and 7.2% for the 30 mcg OC and the breakthrough bleeding rates were 2.6% and 1.6% respectively. The 3 pregnancies that occurred all involved user failure. The discontinuation rates due to side effects including spotting were 9.8% in the 20 mcg EE2 group and 7.2% in the 30 mcg group. 66.6% of women in the former group and 71.0% of those in the latter group never complained of an adverse effect during the study. The incidences of spotting and discontinuation were well within the range reported for other OCs. These findings indicate that the 20 mcg EE2 preparation should be prescribed first; if cycle control problems persist a 30 mcg EE2 OC can be considered.