Annovera is a soft, flexible and reusable silicone ring measuring 5.715 cm in diameter containing ethinyl estradiol and segesterone acetate. While ethinyl estradiol is an old and well known estrogen, segesterone acetate is quite new. It is a synthetic 19-norprogesterone derivative progestin without a CH3 group radical in position 6. Its progestational activity is very high, 100 times that of Progesterone. It binds selectively to progesterone receptors and has no androgenic, estrogenic or anabolic activity.
Annovera is inserted and removed by the woman who is using it. This may be a detractor, when handling of the genitals is disliked by the user. When she is comfortable with the insertion and removal process, it is totally under her control, which is important in keeping the pregnancy rates low, especially when the male partner cannot be relied on to use a condom consistently. It is kept in the vagina continuously for 3 weeks, followed by its removal for one week. It need not be kept in a refrigerator, which is important in resource poor populations. It gives protection for one year (thirteen cycles), which is quite useful because the user does not have to visit the provider again and again, especially when the family members of the woman may not be very supportive. But it does need training for its use, which may be difficult to arrange in populations with few healthcare providers. US FDA approved its use after studying data of 17 clinical trials, which included 2 phase 3 efficacy and safety studies. Its success rate was 97.3%. Satisfaction rate was 89%. It was found to be easy to use. The device was not felt by most of the couples during its use. No serious effects due to over dosage were reported. In studies on rats over 2 years, no tumors developed with its use, while mice showed an increased incidence of adenocarcinoma and lobular hyperplasia in the breast with a supratherapeutic dose (30 mg/kg/day). No mutagenic or clastogenic effect was seen with the use of segesterone acetate. The risk of serious cardiovascular adverse events is as with other estrogen-progestin contraceptives. Segestrone acetate's metabolism can be increased or decreased when combined with different drugs, which may have an effect on its contraceptive efficacy. While Annovera is available for use in USA, it is not yet available in many countries. It may be a disadvantage, but one may find solace in the thought that a post marketing surveillance is being carried out in another country and when it is found to be safe, women may embrace its use freely.