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By Rebecca Bowers
Scientists are now investigating a nonhormonal monthly ring (Ovaprene) as a potential contraceptive. The device involves a permeable mesh in the center of the ring that creates a partial barrier to sperm and locally acting spermiostatic agents to create an inhospitable environment for sperm.
When it comes to contraception, more women are considering the contraceptive vaginal ring. According to national statistics, 6% of U.S. women had used the contraceptive ring during 2006-2010, behind the contraceptive injectable and the contraceptive patch.1
Currently available contraceptive rings offer effectiveness rates that are similar to or slightly better than the Pill. The rings also do not require the user to remember to take them daily and allow the user to control initiation and discontinuation of the contraceptive.2 Two contraceptive rings currently are available in the United States. Annovera, a soft, reusable, flexible silicone ring containing segesterone acetate and ethinyl estradiol, was approved by the U.S. Food and Drug Administration (FDA) in 2018. Left in place for 21 days and removed for seven days each cycle, it is indicated to prevent pregnancy for up to one year. Clinicians are more familiar with NuvaRing, which was approved in 2001. NuvaRing releases a combination of etonogestrel and ethinyl estradiol from a ring made of ethylene vinyl acetate copolymers. Each ring is designed for three weeks of continuous use, with a one-week break, followed by insertion of a new ring.
Scientists are investigating a nonhormonal monthly ring (Ovaprene) as a potential contraceptive. The device involves a permeable mesh in the center of the ring that creates a partial barrier to sperm and locally acting spermiostatic agents to create an inhospitable environment for sperm. Daré Bioscience of San Diego has received a grant providing up to $1.9 million for research of the ring from the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
The company initiated a postcoital clinical trial in 2018 designed to assess general safety, acceptability, and effectiveness in preventing progressively motile sperm from reaching the cervical canal following intercourse. The study’s design calls for enrollment of 50 couples, with the woman to be evaluated over the course of five menstrual cycles; investigators plan to have at least 25 women complete a total of 21 visits. Each woman’s cervical mucus will be measured at several points during the study, including a baseline measurement at the first menstrual cycle that excludes the use of any product. Subsequent cycles and visits will include the use of a diaphragm for the second menstrual cycle, and the Ovaprene vaginal ring for the third, fourth, and fifth cycles. Data from the study are expected to be available in the second half of 2019.
Many women are seeking alternatives to traditional hormone-based options, notes study investigator Andrea Thurman, MD, professor of obstetrics-gynecology at CONRAD/Eastern Virginia Medical School. Although an effective long-acting, implanted, nonhormonal contraceptive is available, half of contraceptive users prefer a short-acting method, she notes.
“We don’t have an effective short-acting, nonhormonal method that does not require intervention at the time of intercourse to offer these women,” said Thurman in a press statement. “The opportunity to address this unmet need is compelling.”
While the contraceptive vaginal ring offers comparable efficacy, risks, and benefits as other combined hormonal methods, it also provides the simplest regimen.3 In clinical trials of the etonogestrel and ethinyl estradiol ring, 85% of women were satisfied with the ring, and 90% would recommend its use to others.4
Adverse effects associated with the method also are similar to hormonal methods, with the additional vaginal symptoms of discharge, discomfort, and problems related to the device.5 Clinicians may consider the etonogestrel and ethinyl estradiol ring for extended use. Although it is labeled for 28 days of use, the ring contains enough medication to be used for up to 35 days, allowing it to be replaced once every calendar month.6
Results of studies presented at the recent American College of Obstetricians and Gynecologists 2019 Annual Meeting indicate that the segesterone acetate/ethinyl estradiol ring is a highly effective contraceptive option that lasts for an entire year and can be inserted and removed by the patient each cycle.7,8 Data show a high level of user satisfaction. Women who used the device for up to 13 cycles did not experience any unexpected safety findings, and only 1.7% of women discontinued use because of irregular bleeding.7,8
Financial Disclosure: Consulting Editor Robert A. Hatcher, MD, MPH, Nurse Planner Melanie Deal, MS, WHNP-BC, FNP-BC, Author Rebecca Bowers, Executive Editor Shelly Morrow Mark, Copy Editor Josh Scalzetti, and Editorial Group Manager Leslie Coplin report no consultant, stockholder, speaker’s bureau, research, or other financial relationships with companies having ties to this field of study.