The U.S. Food and Drug Administration approved The Population Council Inc.'s Annovera, a reusable combination hormonal contraceptive ring.

Annovera, or segesterone acetate and ethinyl estradiol vaginal system, is a ring-shaped hormonal contraceptive developed by the nonprofit research organization to prevent pregnancy for women of reproductive age. It is the first approved vaginal ring that can be used for one year.

The contraceptive's safety and effectiveness were evaluated in three clinical studies involving healthy women of 18 to 40 years old. According to the studies, about two to four of the 100 women who used Annovera may get pregnant during the first year of using the vaginal ring.

The FDA warned that women over 35 who smoke should not use the contraceptive ring since cigarette smoking increases the risk of serious cardiovascular events from combination hormonal contraceptives.

The U.S. regulator is also requiring postmarketing studies to examine the risks of venous thromboembolism, a condition in which a blood clot forms in the deep veins of the leg, groin or arm and travels in the circulation.

The postmarketing studies also aim to check the effects of CYP3A modulating drugs and tampon use in Annovera's pharmacokinetics, or movement of drugs within the body.

The Population Council has a license agreement with TherapeuticsMD Inc. to make Annovera available to women in the U.S. As part of the license agreement with the Population Council, the pharmaceutical company has agreed to provide significantly reduced pricing to federally designated Title X family planning clinics serving lower-income women.