Cycle control with NuvaRing is superior to a 30 µg ethinylestradiol oral contraceptive

K. Oddsson (1), C. Verhoeven (2)

Women’s Health Associates, Kopavogur, Iceland (1); Department of Clinical Development, NV Organon, Oss, The Netherlands (2)

Introduction: Decreasing the dose of ethinylestradiol (EE) to 20 µg or lower in combined oral contraceptives (OCs) may produce poor cycle control. NuvaRing, a monthly contraceptive vaginal ring releasing 15 µg EE and 120 µg etonogestrel, has been shown in large efficacy and safety trials to provide excellent cycle control. This is the first large comparative trial conducted to demonstrate that cycle control with NuvaRing is superior to that with an OC containing 30 µg EE and 150 µg levonorgestrel.

Design and methods: This was an open-label, randomized, comparative, multi-centre, 1-year trial carried out in 11 countries, involving healthy women (aged >18 years) seeking contraception. Subjects received either NuvaRing (n=512) or the OC (n=518) for 13 cycles. Each cycle comprised 3 weeks of NuvaRing or pill use, followed by a 1-week ring- or pill-free period. Diary cards were used to record daily bleeding patterns, including spotting (requiring one pad or less) and breakthrough bleeding (two pads or more). The primary parameter, the incidence of breakthrough bleeding-spotting, was calculated for cycles 2–13 (cycle 1 data were excluded due to differences in starting procedures). Secondary parameters included the absence of withdrawal bleeding, the incidence of early and continued withdrawal bleeding and intended bleeding (absence of breakthrough bleedingspotting during ring or pill use and presence of withdrawal bleeding in the ring- or pill-free period). Efficacy and tolerability data are presented separately at this meeting.

Results: A total of 363 women in the NuvaRing group (70.9%) and 369 women in the OC group (71.2%) completed the trial. The incidence of breakthrough bleeding-spotting was lower with NuvaRing (range 2.0–6.4%) than with the OC (range 3.5– 12.6%) for all cycles (2–13), the difference being statistically significant in cycles 2 (p=0.003) and 9 (p=0.002). The incidence of intended bleeding was statistically significantly higher for NuvaRing (58.8–72.8%) than for the OC (43.4–57.9%) for all cycles (1–12). Absence of withdrawal bleeding ranged from 0.3–3.5% for NuvaRing and 1.6–3.6% for the OC (p=0.01; cycle 6). Occurrence of early withdrawal bleeding ranged from 2.5–6.2% for NuvaRing and 2.0–8.7% for the OC. Continued bleeding after ring or pill withdrawal was more frequent with the OC (33.8–39.0%) than with NuvaRing (21.7%–27.3%) and this was statistically significant for all cycles.

Conclusions: Cycle control with NuvaRing, with a daily dose of 15 µg EE, was excellent and superior to that with an OC containing 30 µg EE and 150 µg levonorgestrel.