Update on contraceptive vaginal rings

Abstract

Since the development of the combined oral contraceptive pill (OCP) four decades ago, women have been able to plan their childbearing more effectively than before. Studies of women’s attitudes, however, show that many regard the compliance required with daily pill use as a drawback to the use of the oral contraception and would prefer a monthly contraceptive option. The first contraceptive vaginal rings (CVR’s) were developed in the 1970s and contained only progestogen(s). Recently, a combined contraceptive vaginal ring that releases 15 μg of ethinylestradiol (EE) and 120 μg of the progestogen etonogestrel (ENG)/24 h has been introduced. Each ring is intended for one cycle of use only, comprising 3 weeks of ring use and 1 week ring-free period. EE and ENG were rapidly absorbed from NuvaRing® resulting, within 24 h, in serum levels sufficient to inhibit ovulation. Serum levels then remained virtually constant throughout the 3 weeks of use. The contraceptive efficacy was studied in 2322 women using NuvaRing® for 23,298 cycles equivalent to 1786 women-years, giving a Pearl Index of 1.18 (95% confidence interval 0.73–1.80). Ring use is associated with a very low incidence of irregular bleeding (<5%), which was maintained from the first cycle onwards. It is well tolerated and accepted, with minimal metabolic effects and does not appear to be associated with unfavourable local effects on the cervix or vagina.