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.
