Critical dosages for oral contraceptives

An investigation was carried out into the effectiveness of Ovostat E, a low dosage oral contraceptive. One hundred women, aged between 17 and 39 years, participated in the trial; 47 women completed 12 treatment cycles and 42 of these completed all 24 treatment cycles. The following results were obtained by computer analysis: Reliability was 100% and the Pearl Index therefore = 0; Cycle Control; length: an obvious regulating effect; 85-3% was the average percentage of women with a cycle length of 26 to 30 days; withdrawal bleeding occurred in 94-6% of cycles; duration of withdrawal bleeding: no change in 26-0%; 1--2 days shorter in 51-7%; 1--2 days longer in 5-6%; intensity of withdrawal bleeding: no change in 61-9%; decreased in 29-3%; increased in 3-4%; irregular bleedings occurred in 4-6% of cycles. The most common complaints were nervousness, headache and nausea, the last two virtually disappearing after the 3rd treatment cycle. Of the 49 women who continued the investigation for the further eighteen months, 2 dropped out because of intolerance, 1 because of objections to the periodic check-ups and 1 for reasons unknown.