Lower hormone dosage with improved cycle control

ABSTRACT

Cycle control is a key factor that influences contraceptive acceptability and compliance. In combined oral contraceptives (COC), reducing the daily dose of ethinylestradiol (EE) can compromise cycle control. As NuvaRing, the novel combined contraceptive vaginal ring, releases only 15 μg/day EE, it was therefore important to closely assess cycle control. A 1-year, multicenter study examined cycle control during NuvaRing use in 1182 women. Withdrawal bleeding during the 1-week ring-free period occurred in 98.8% of cycles. Early withdrawal bleeding was relatively uncommon (5.6% of cycles); in 24.2% of cycles, withdrawal bleeding, comprising mainly spotting, extended into the next cycle. From cycle 1 onwards, there was a low incidence of irregular bleeding during the 3 weeks of ring use; on average, irregular bleeding occurred in only 4.4% of cycles and consisted mainly of spotting only. In a combined analysis, cycle control achieved using NuvaRing (n = 121) was compared with that of a standard COC containing 30 μg/day EE and 150 μg/day levonorgestrel (n = 126) over six cycles. Late withdrawal bleeding was significantly more frequent with the COC in all cycles. Irregular bleeding occurred in < 5% of all cycles with NuvaRing and between 5.4% and 38.8% per cycle with the COC. Significantly more women using NuvaRing experienced an ideal ‘intended bleeding pattern’ compared with COC users at every cycle. This excellent cycle control with NuvaRing is expected to improve convenience and acceptability and result in a high level of compliance.

KEY WORDS:

• NuvaRing
• Contraception
• Vaginal ring
• Bleeding
• Cycle control