A study by the Population Council and partners has found that use of the Council's investigational one-year reusable contraceptive vaginal ring (CVR) does not increase the risk of vaginal infections or disrupt the balance of microbes in the vagina when it is used for up to 13 cycles. Although past studies have examined the effects of short-term contraceptive vaginal ring use on risk of vaginal infection, this is the first study of a CVR intended for a full year's use.
The one-year reusable CVR contains Nestorone[R] and ethinyl estradiol. Nestorone (NES) is an investigational progestin that has been shown in clinical studies to prevent ovulation and pregnancy. Ethinyl estradiol (EE) is an approved, marketed, synthetic version of the female hormone estrogen.
"We are very excited about this new contraceptive ring," said Ruth Merkatz, PhD, RN, Director of Clinical Development, Reproductive Health, at the Council's Center for Biomedical Research and corresponding author of the study. "It can be inserted and removed by the woman herself rather than by a specially trained health care provider, it does not require daily action, and it can be reused for a full year. It has been designed so that refrigeration is not required when it is not being used, which will be important in many low-resource settings."
To assess the microbiological safety of the new CVR, the researchers looked for vaginal infections and changes in the balance of microbes in the vagina during cyclic use of a single NES/ EE CVR for up to one year. This study, part of a Phase III safety and efficacy trial of the NES/ EE CVR, took place at the Magee-Womens Research Institute in Pittsburgh under the direction of Dr. Mitch Creinin, and was supported by the National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health. The study protocol was approved by the Institutional Review Boards of the NICHD Coordinating Center, the Population Council, and the University of Pittsburgh.
120 women enrolled in the study. Participants were seen by the researchers seven times throughout the study year and were interviewed about any problems they may have encountered with the ring. At three of the visits researchers obtained vaginal swabs to measure vaginal microflora and the presence of bacteria. At the completion of the study, the ring surface was swabbed and compared with the vaginal swab sample to measure for the same organisms.