• Summary
• Credits

1. The Long Road of Contraceptive Development
2. Vaginal Rings
• Two Combined Vaginal Rings
• Two Progestin-Only Rings
• Acceptability
3. Transdermal Contraception
4. Contraceptive Implants
5. Combined Injectables
6. Condoms
7. Fertility Awareness-Based Methods
8. Oral Contraceptives
9. Intrauterine Devices
10. Transcervical Female Sterilization
11. Male Hormonal Contraception
12. Bibliography
13. Web Supplements

• Clinical trials assess effectiveness and safety of new contraceptives
• New low-dose DMPA formulation
• More long-term choices for men

• INFO Project
• Order
• Online Reports
• Upcoming Reports
• POPLINE

Vaginal Rings

Vaginal Rings Description: Hormone-releasing ring kept in the vagina and remaining in place day and night for three weeks or one year, depending on the formulation. Stage of development: Two on the market and several others in clinical trials. Effectiveness: 1.2 to 1.5 pregnancies per 100 women in the first year as typically used. How they work: Release progestin alone or progestin with estrogen into the vaginal walls and through to the bloodstream, preventing ovulation, thickening cervical mucus, and suppressing endometrial growth. What’s new? New, user-controlled method of hormone delivery. Combined rings offer better cycle control with more steadily released hormones than combined OCs.

Vaginal rings, recently approved by the US FDA and on the market in some countries, offer a new way to deliver hormones into the bloodstream to prevent pregnancy. Combined estrogen and progestin rings offer good cycle control and deliver hormones more steadily than combined oral contraceptives (OCs).

Women can control the use of vaginal rings. To use the vaginal ring, a woman inserts it into the vagina with her fingers, placing it anywhere that feels comfortable. It fits best in the higher part of the vagina. Studies in developed countries have found that women follow rules for correct use at rates higher than those seen in studies of combined OCs (38, 69, 198).

The ring remains in place all day and night and requires no further attention (187). Hormones diffuse continuously from a reservoir within the ring, first into vaginal tissues and then into the bloodstream. If necessary, the ring can be removed for up to three hours for comfort during sexual intercourse, for cleaning, or for any other reason. Rings come both as combined formulations—containing a progestin and an estrogen—and as progestin-only formulations.

The combined formula NuvaRing^®, developed by the pharmaceutical company Organon, is the first vaginal ring to be widely introduced. It has been approved in nine European countries since the late 1990s—more than 30 years since the first patent was granted for vaginal rings (28). The US FDA approved NuvaRing in 2001 (249).

Brazil and Chile are the only developing countries where NuvaRing is available, and its availability in other developing countries is unlikely because of its high cost. NuvaRing is also available in Europe and the US. Organon plans to introduce NuvaRing in Australia and Canada in 2005 and in the UK no sooner than 2006 (5).

NuvaRing releases 120 µg (micrograms) of the progestin etonogestrel and 15 µg of the estrogen ethinyl estradiol per day. Women use NuvaRing for three weeks, then remove it for one week, during which they have withdrawal bleeding. A new NuvaRing is needed for each four-week cycle. Thus a woman would require 13 rings per year; a single ring can last up to 35 days (167). While large studies have not examined continuous use of the vaginal ring, smaller studies suggest that women may be able to safely use combined vaginal rings consecutively for four weeks at a time, skipping the withdrawal bleeding (63, 166). Studies on continuous use are underway.

Another ring, still in clinical trials, releases a combination of 150 µg of a different progestin, Nestorone^®, and 15 µg of the estrogen ethinyl estradiol per day. The Population Council, with USAID support, is developing this ring specifically for use in developing countries. It will be effective for over 12 months, making it more cost-effective than NuvaRing. Users would keep the ring in place for three weeks, then remove it for the fourth week to allow a withdrawal bleed, and then reinsert the same ring for another three weeks (119). Early clinical trials have been promising (136), and phase III trials are planned to begin in 2005 (214).

Effectiveness. Combined rings release sufficient amounts of estrogen and progestin to prevent ovulation (166). In addition, the progestin thickens cervical mucus and suppresses endometrial growth (235). In a pooled analysis of 2,322 women using NuvaRing in Canada, the US, and Europe, there were 1.2 pregnancies per 100 women in the first year of use. Women used the ring correctly in 86% of cycles (69).

Side effects. In general, bleeding problems are less frequent among users of combined vaginal rings than among users of combined OCs (38, 69, 175) or of progestin-only rings (29). Breakthrough bleeding can occur, but this side effect is not common (198).

Other side effects occur about as often among users of combined rings as with combined OCs (38). In the pooled analysis of 2,322 women, the most commonly reported side effects were headache and vaginitis, each of which occurred among less than 6% of users. Less than 5% reported white vaginal discharge, vaginal discomfort, weight increase, nausea, mood changes, breast tenderness, uterine cramps, or acne (69).

Two types of progestin-only rings are available or in development—Progering, a ring containing the natural hormone progesterone, and a ring yet to be named containing the synthetic progestin Nestorone. Progestin-only rings function mainly by thickening cervical mucus to prevent sperm penetration. They also have some effect on preventing ovulation and build-up of the endometrium (164).

While progestin-only rings are less effective overall than rings containing both a progestin and an estrogen, they are highly effective among breastfeeding women because breastfeeding itself provides some protection from pregnancy. Also, they may be more appropriate than combined rings for breastfeeding women because they do not contain estrogen, which could reduce milk production (152). The most common reason for discontinuation of progestin-only rings is weaning, as mothers choose more effective contraception after they stop breastfeeding. Bleeding disturbances, a common side effect of all progestin-only methods, is another frequent reason for discontinuation, but it is less likely to be noticed while a woman is breastfeeding (39, 152, 153).

Progesterone rings. Progesterone rings are highly effective at preventing pregnancy among lactating women, studies show—not significantly different from the IUD. Each ring releases 10 mg (milligrams) of progesterone daily and lasts for three months. Women can use these rings continuously for up to one year, after which effectiveness declines (152, 217, 220). Progering was registered and approved in Chile and Peru in 1998 for use by breastfeeding women. The Population Council, CONRAD, and the private company Silesia, funded its research and development.

In clinical trials women using the progesterone ring reported experiencing vaginal problems related to discharge, urinary discomfort, bleeding disturbances, and reproductive tract infection (152, 199). In a Chilean study of breastfeeding women, less than 5% of users experienced any one of these side effects (153).

Nestorone rings. Nestorone rings, which also were developed by the Population Council (215), are similar to progesterone rings but rely on ST-1435, a more potent synthetic progestin that has unique properties. This ring will release 50, 75, or 100 µg of Nestorone per day (214).

The Population Council focused research on Nestorone after discovering that, when taken orally, it is rapidly metabolized and inactivated. This feature makes it particularly appropriate for use by breastfeeding women, because infants who ingest breast milk will not absorb the progestin in the breast milk, not even in the tiny and probably unimportant amounts that are ingested when other progestin-only methods are used (215). (For information on other Nestorone-based methods, see “Nestorone spray gel” and “Nestorone implants”.)

Nestorone-releasing rings provide effective protection from pregnancy for lactating women for up to one year, even if weaning takes place earlier (41, 152, 215). Clinical trials on Nestorone rings have been suspended until the Population Council obtains more funding to continue them (214).

Generally, women like vaginal rings, according to acceptability studies in Australia, Canada, Chile, the Dominican Republic, the US, and 12 European countries. Primary reasons for approval include that rings were effective, easy to insert, use, and remove, and did not require daily action (173, 258).

The studies find that some women dislike the vaginal ring for the same reasons others like it, however. That is, they do not want the responsibility of inserting and removing it (258). A participant in one clinical trial chose an IUD over the ring because, as she said, “I may forget to put [the ring] back in, or I might remove it and then not be able to reinsert it” (199). Additionally, some women did not like the ring because they prefer not to touch their vaginas, and some dislike its tendency to slip out (173).

Disclaimer: The information provided on this web site is not official U.S. Government information and does not represent the views or positions of the U.S. Agency for International Development or the U.S. Government.