ABSTRACT
The objective of this study was to compare cycle control, efficacy and tolerance of an oral contraceptive containing 20 microg ethinylestradiol and 150 microg desogestrel with a preparation containing 30 microg ethinylestradiol combined with 75 microg gestodene. This study involved 342 women and 4104 cycles use in Argentina, Brazil, Chile, and Mexico. Contraceptive efficacy was good with both formulations. Two pregnancies occurred in the desogestrel group but were not due to method failure. With respect to cycle control, the incidence of intermenstrual bleeding was higher during the first 3 cycles in the desogestrel group; it was significant (p <0.01) during the first 3 days of the cycle for a normal or heavy bleeding only in the Mexican group. Amenorrhea was not reported for any group, but the incidence of dysmenorrhea was significantly higher (p <0.01) in the Brazilian desogestrel group (13.8%) and was significantly lower (p <0.01) in the Mexican gestodene group (8.5%). Adverse events were similar in all the countries with headache, breast tension, and nausea, the most frequently reported symptoms. The range of mean increase in body weight varied from 0.2 kg in the Argentine group to 2.6 kg in the Chilean group (95% confidence limit, +/- 2.51) in the gestodene group, and 0.2 kg in the Argentine group to 2.5 kg in Brazilian group (95% confidence limit, +/- 2.36) in the desogestrel group. Fifteen women discontinued because of headache, but there were no significant differences between the groups regarding discontinuation for this and other medical or non-medical reasons. Both oral contraceptive preparations are reliable and well tolerated, and both have favorable effects on control cycle.
