Conception control by vaginal administration of pills containing ethinyl estradiol and dl-norgestrel

One hundred twenty-four women of reproductive age have used vaginal pills containing 50 micrograms dl-norgestrel and 35 micrograms ethinyl estradiol to prevent conception for periods ranging from 6 to 20 months. One thousand four hundred thirty-eight woman-months were recorded. No pregnancies occurred. Cycle control was good. Bleeding usually lasted 3 to 5 days, and the interval between withdrawal bleeding events was 26 to 30 days in 86% of the cycles. Amenorrhea, breakthrough bleeding, and spotting occurred rarely. The continuation rate at 1 year was 64%.