The vaginal ring is thin, flexible, and approximately 2 inches in diameter. It delivers a combination of a synthetic estrogen (ethinyl estradiol) and a progestin.
The ring is inserted into the vagina, where it continually releases hormones for 3 weeks. The woman removes it for the fourth week and reinserts a new ring 7 days later.
Risks for this method of contraception are similar to those for the combined oral contraceptive pills, and a vaginal ring is not recommended for any woman with a history of blot clots, stroke, or heart attack, or with certain types of cancer.
Currently, the NuvaRing® is the only FDA-approved vaginal ring. A new contraceptive vaginal ring that can be used for 13 cycles is under clinical development.
Reference: Dept. of Health and Human Services