A new contraceptive vaginal ring which can be used for a whole year has been found to be a highly effective method of birth control in a recent clinical trial.
The Annovera ring is a combined hormonal contraceptive and the first vaginal ring to provide effective contraception for an entire year, or 13 cycles.
It is left in place inside the vagina for 21 days, where it releases a daily dose of 150 mcg segesterone acetate and 13 mcg ethinyl estradiol, and then is removed for seven days, during which time women may experience a period.
Segesterone acetate is a new progestin that specifically binds to progesterone receptors and, unlike other combination hormone birth control products, has no estrogenic or androgenic activity.
In the recent clinical trial, researchers reviewed data from earlier trials which measured how long segesterone stayed in a woman’s bloodstream and at what levels.
The findings, which were presented Tuesday at ENDO 2019, the Endocrine Society’s annual meeting in New Orleans, USA, showed that segesterone acetate serum levels above 105 pmol/L had successfully inhibited ovulation in the early trials.
Approved last August by the FDA (Food and Drug Administration), the ring has a Pearl index, or failure rate, of 2.98.
“This rate means that only about three unintended pregnancies occur per 100 women in a year compared to a Pearl Index of 80 in couples not using a contraceptive method,” explains investigator David F Archer, MD, who added that the ring’s 97% success rate is comparable to the most effective birth control methods already on the market, which are at least 95% effective.
“We wanted to prove whether the segesterone in combination with the low dose of ethinyl estradiol in this unique vaginal system was adequate at inhibiting ovulation and pregnancy as well as providing good cycle control,” Archer said.
“The segesterone acetate release in the current vaginal ring effectively inhibits ovulation, resulting in the high level of contraceptive efficacy for this long-acting, reversible contraceptive.”
“Annovera represents a novel, procedure-free and long-acting reversible contraceptive method that can provide contraceptive benefits for up to one year,” Archer said.
A report due to be published in the May issue of the Journal of Controlled Release also details how “contraceptive jewellery” could be another future method of birth control.
Researchers at the Georgia Institute of Technology describe how absorbing contraceptive hormones into the body from special backings on jewellery such as earrings, wristwatches, rings or necklaces could potentially be a simple and effective way for women to protect themselves against unwanted pregnancy.
However, although initial testing suggests that contraceptive jewellery may deliver sufficient amounts of hormone to provide contraception, no human testing has been done yet.