A multicenter randomized comparison of cycle control and laboratory findings with oral contraceptive agents containing 100 μg levonorgestrel with 20 μg ethinyl estradiol or triphasic norethindrone with ethinyl estradiol☆☆☆★

Abstract 

Objective: This study was undertaken to compare the effects of 2 oral contraceptive regimens on menstrual cycle control and laboratory findings. Methods: In a multicenter randomized study 100 μg levonorgestrel with 20 μg ethinyl estradiol (Alesse or Loette) was given to 155 healthy women. A triphasic preparation of 500, 750, and 1000 μg norethindrone with 35 μg ethinyl estradiol (Ortho-Novum 7/7/7 or TriNovum) was given to 167 women for 1 to 4 cycles of treatment. Results: Overall, the percentages of normal menstrual cycles and the percentages of cycles with intermenstrual and withdrawal bleeding were similar between the 2 treatment groups. In the levonorgestrel with ethinyl estradiol group, there was a statistically significantly longer latent period and a statistically significantly shorter withdrawal bleeding episode. Adverse events were similar between treatment groups, and none were serious. Most mean changes from baseline laboratory values were comparable between groups, although the mean increase in cholesterol concentration was statistically significantly lower in the levonorgestrel with ethinyl estradiol group. Changes in triglyceride and glucose concentrations were not statistically significantly different between groups. Conclusions: Levonorgestrel (100 μg) with ethinyl estradiol (20 μg) provides menstrual cycle control equivalent to that obtained with triphasic norethindrone with ethinyl estradiol (75% higher estrogen dose) with similar safety and tolerability. (Am J Obstet Gynecol 1999;181:S45-52.)

Keywords:  Cycle control, ethinyl estradiol, intermenstrual bleeding, levonorgestrel, norethindrone, oral contraceptive