Clinical performance and menstrual bleeding patterns with three dosage combinations of a Nestorone® progestogen/ethinyl estradiol contraceptive vaginal ring used on a bleeding-signaled regimen

Objective We examined the clinical performance of contraceptive vaginal rings (rings) delivering Nestorone (NES) progestin and ethinyl estradiol (EE). Ring removal times were signaled by menstrual events. Bleeding patterns, adverse events, patterns of use and continuation rates were the principal parameters evaluated. Methods In a two-stage 6-month trial, subjects were randomized to use rings releasing 50 μg/day of NES and either 10 (50/10) or 20 (50/20) μg/day of EE. Subjects were to keep rings continuously in situ until menstrual bleeding or prolonged spotting-signaled removal. Reinsertion was to occur 96 h later. After the randomized stage, an open-label 6-month trial of rings releasing 150 μg/day of NES and 15 μg/day of EE (150/15) began with the same menstrually signaled regimen. Results Two-hundred forty-six subjects participated in the trial. Six-month pregnancy rates ranged by ring dose from 1.3 to 3.9 per 100. For each ring dose combination, 6-month continuation rates were above 80 per 100. Bleeding and spotting (B+S) days in women with the 50 μg/day NES rings were similar in number to those experienced by cycling women not using contraception. Nevertheless, in the initial 90 days, fewer B+S days were reported by subjects with the 50/20 ring than by subjects with the 50/10 ring (p<.05). Throughout the trial, subjects using the 150/15 ring reported significantly fewer B+S episodes than did subjects with either 50 μg/day NES ring. Conclusion Combined contraceptive rings used with a bleeding-signaled regimen led to few terminations attributed to bleeding problems and to acceptable continuation rates. The 150/15 ring appeared to induce fewer bleeding problems than did the lower-dose NES combination rings, but no important difference in 6-month continuation rates among the three doses was noted.