Clinical performance of a triphasic administration of ethinyl estradiol and levonorgestrel in comparison with the 30 + 150μg fixed-dose regime

In order to assess the overall tolerance of a new triphasic oral contraceptive containing ethinyl estradiol and levonorgestrel in comparison with a well-known low-dose pill containing the same hormones, 489 women were assigned at random to one of these two preparations. The study was planned to run over a period of 6 consecutive months and the case report forms were designed in a fashion to permit comparable evaluation of the two formulations with regard to their overall reliability and clinical performance, mainly in terms of cycle control.