Scheduled and unscheduled bleeding patterns with two combined hormonal contraceptives: application of new recommendations for standardization

Objective: To reassess and compare cycle control attained with two combined hormonal contraceptives, norgestimate (NGM)/ethinyl estradiol (EE) 25 μg and norethindrone acetate (NETA)/EE 20 μg, by new general criteria recommendations for all combined hormonal contraceptives. Design: Analysis of bleeding data for cycles 1-6 from a randomized, multicenter trial. Setting: 221 North American centers. Patient(s): Healthy, sexually active women (18-45 years old). Intervention(s): NETA/EE: 1 mg NETA/20 μg EE, days 1-21 of each cycle and 75 mg of ferrous fumarate, days 22-28; NGM/EE: triphasic NGM in 7-day increments (days 1-7: 180 μg; days 8-14: 215 μg; days 15-21: 250 μg) and 25 μg EE, placebo on days 22-28. Main Outcome Measure(s): Cycle control evaluated from patients' daily diaries. Result(s): For cycles 1-6, there was a statistically significant lower incidence of unscheduled bleeding/spotting with NGM/EE 25 μg (range 21.0%-34.4%) than with NETA/EE 20 μg (range 33.0%-46.6%). Of the women who had unscheduled bleeding/spotting, the mean number of days per cycle of bleeding/spotting was comparable. A statistically significant higher incidence of scheduled bleeding was seen with NGM/EE 25 μg (95.2%-97.5%) than with NETA/EE 20 μg (78.5%-84.2%). Conclusion(s): The NGM/EE 25 μg has a lower incidence and comparable length of unscheduled bleeding and a higher incidence of scheduled bleeding than NETA/EE 20 μg in this post hoc analysis.