Study design for the Triphasic Randomized Clinical Trial

The Triphasic Randomized Clinical Trial was a multicenter, open-label, controlled, 6-month study to determine the influence of three currently marketed triphasic oral contraceptives on lipid and carbohydrate metabolism, cyclic bleeding profiles, and other adverse drug experiences. The study protocol mandated four clinic visits: an initial visit during which study eligibility was determined, a second visit during which baselines were obtained for lipid and carbohydrate parameters, and visits at 3 and 6 months while taking the study drug. The study enrolled healthy women between the ages of 18 and 35 years who were within 20% of their ideal body weight and who had a history of normal and regular menstrual cycles. Patients were randomly assigned to one of three treatment groups: 51 patients to Tri-Levlen, 50 patients to Ortho-Novum 7/7/7, and 56 patients to Tri-Norinyl. The control group consisted of 49 patients using nonhormonal forms of birth control. Eighty-eight percent (181/206) of the patients completed all four visits and were considered evaluable for subsequent analyses.