Double-blind, multicenter comparison of efficacy, cycle control, and tolerability of a 23-day versus a 21-day low-dose oral contraceptive regimen containing 20 mu g ethinyl estradiol and 75 mu g gestodene

This prospective, double-blind, randomized study was conducted to compare t he contraceptive reliability, cycle control, and tolerability of a 23-day v ersus a 21-day oral contraceptive regimen containing 20 mug ethinyl estradi ol and 75 mug gestodene. Participants took trial medication daily for 28 da ys, either 23 tablets with active substances plus 5 placebo tablets or 21 t ablets with active substances plus 7 placebo tablets. Contraceptive efficac y, cycle control, and tolerability were evaluated over a period of seven cy cles. Efficacy data gathered from 4,878 treatment cycles (23-day regimen: 2 ,362 cycles; 21-day regimen: 2,516 cycles) were obtained from 703 participa nts {23-day regimen, n = 342; 21-day regimen, n = 361). Both preparations proved to be effective contraceptives and provided good c ycle control. One pregnancy because of method failure was recorded in each treatment group. This resulted in a study Pearl Index of 0.5 for each treat ment. For the 23-day regimen, 36.0% of participants reported at least one i ntracyclic bleeding episode during Cycles 2-4 (primary target) compared to 37.1% in the 21-day regimen. In the 23-day regimen group, intracyclic bleed ing episodes were reported by 42.4% of the participants in Cycle 1 but only in 14% in Cycle 7 and in the: 21-day regimen group by 44.6% in Cycle 1 and only 17.3% in Cycle 7. Overall, intracyclic bleeding was reported in 21.9% of the 23-day regimen cycles and in 22.7% of the 21-day regimen cycles. A greater number of 23-day regimen participants had shorter withdrawal blee ding periods than with the 21-day regimen. In significantly (p <0.0001) mor e cycles in the 23-day regimen group, participants reported withdrawal blee ding periods that lasted only 1-4 days compared to the 21-day regimen group . For the majority of the treatment cycles, the median number of bleeding d ays in the 23-day regimen group was 4 days and in the 21-day regimen group 5 days. Both preparations were well tolerated and showed a similar adverse events p attern. The discontinuation rate because of adverse events was low (23-day regimen, 6%; 21-day regimen, 4%). No serious vascular adverse events were r eported. More than 75% of the women in both groups either lost more than 2 kg of weight or did not gain weight during the study. The treatment effect on blood pressure was negligible. There were no appreciable changes in mean laboratory values over the course of the study. (C) 2001 Elsevier Science Inc. All rights reserved.