The contraceptive efficacy, cycle control, safety, and subject acceptance of the new contraceptive (OC) preparations containing gestodene (GTD) plus ethinyl estradiol (EE) are being compared with the combination containing desogestrel (DSG) plus EE in a randomized, open-label outpatient study. Interim data from six cycles of this ongoing study were obtained for 378 women receiving 75 micrograms GTD + 30 micrograms EE per day and 384 women receiving 150 micrograms DSG + 30 micrograms EE per day. Each group received OCs for 21 days per cycle. There were no pregnancies in subjects receiving either OC during 1,658 cycles of GTD + EE or 1,707 cycles of DSG + EE use. The continuation rates were similar in the two groups, and no major differences in type or incidence of side effects were observed. There were also no clinically significant changes in blood pressure or body weight in either group. Slightly better cycle control was observed for subjects taking GTD + EE, since the incidence of spotting and breakthrough bleeding was slightly greater for women taking DSG + EE. The incidence of amenorrhea (missed periods) tended to be lower for the subjects taking the GTD-containing preparation: 7 (0.5%) cycles compared with 12 (0.9%) DSG + EE cycles. The GTD + EE-treated subjects also had a lighter menstrual flow. Fewer subjects taking GTD + EE withdrew because of side effects typically associated with OCs. The data from this study indicate that the new combination of GTD + EE provides safe and effective oral contraception, with good tolerance and cycle control.