OBJECTIVE

This multicenter, open-label study was conducted to compare the cycle control, efficacy and safety of a 24-day regimen of a new ultra-low-dose oral contraceptive containing gestodene (GTD) 60 microg/ethinylestradiol (EE) 15 microg and a 21-day regimen of desogestrel (DSG) 150 microg/EE 20 microg.

METHODS

Healthy women at least 18 years of age who had had regular menstrual cycles for the prior 3 months were randomly assigned to treatment for six cycles.

RESULTS

Data from 1074 women were included in the analyses. Overall, 65% of cycles were normal with GTD/EE and 78% with DSG/EE. The overall incidence of breakthrough bleeding and/or spotting was 29% with GTD/EE and 20% with DSG/EE, with absence of bleeding occurring in 6% of cycles in the GTD/EE group and 1% of cycles in the DSG/EE group. The GTD/EE group had a significantly shorter length of bleeding episodes (4 vs. 5 days, p < 0.001), a significantly lower intensity of bleeding (p < 0.01) and a significantly shorter time for onset of withdrawal bleeding than the DSG/EE group (p < 0.001). Safety profiles for the two treatment groups were similar. Significantly more subjects in the DSG/ EE group withdrew because of breast pain (p = 0.03) and nausea or vomiting (p = 0.05). One pregnancy occurred in each treatment group.

CONCLUSIONS

The 24-day regimen of GTD 60 microg/EE 15 microg provided good efficacy, acceptable cycle control and a favorable safety profile compared with DSG/EE. This ultra-low-dose formulation offers unique advantages in efficacy and safety for oral contraception.