Hello and Happy New Year! The CWRWC blog went on vacation over the holidays but is now back to work...
There is a new contraceptive product coming on the market, and since I don't get out much, I'm very excited to tell you all about it.
Birth control options usually fall into one of two categories: short-term, such as pills, patches, and rings, and long-term, such as IUDs and the Nexplanon arm implant. Short-term options require trips to the pharmacy--or at least your mailbox if you use a mail-order pharmacy--and long-term options require trips to the doctor's office for insertion and removal.
The Annovera ring can be described as a midpoint between the short-term and long-term options. It's is a vaginal contraceptive device that can be used for up to 1 year. Similar to Nuvaring, it has both estrogen and progesterone, but the type of progesterone (called segesterone acetate) is a new compound. Like Nuvaring, this ring is placed in the vagina for 3 weeks at a time followed by 1 week without the ring. Unlike Nuvaring, one Annovera ring is used for the whole year.
As a physician, I think it's noteworthy that the amount of daily estrogen released by the device is quite low--about 13 micrograms per day, compared to birth control pills which typically range from 20 to 35 micrograms per day. It's important to understand that less estrogen does not mean less effective to prevent pregnancy. Lower doses of estrogen are associated with fewer side effects like breast tenderness and nausea, but lower doses of estrogen can also be associated with more irregular bleeding. Reviewing the data from Annovera's clinical trials (see my post about clinical trials), about 7% of women using Annovera reported bleeding between periods, but only about 2% of women stopped using this ring because of that bleeding.
Like any other contraceptive containing estrogen, Annovera can increase the risk of developing blood clots in the legs or lungs. Therefore women with certain medical conditions such as high blood pressure or migraine headaches with visual symptoms may not be able to use this ring.
Obese women may also want to think twice before using Annovera. Women with a body mass index or BMI (a ratio of a person's weight to height) higher than 29 were not included in the clinical trials, so we don't really know how their bodies might respond to this medication. That doesn't mean that women with a BMI of 30 or more can't use this ring; it simply means that we don't have much scientific data at this point.
On to the most important question: does Annovera work to prevent pregnancy? Yes. In clinical trials, about 3% of women using this ring got pregnant over the course of one year. This percentage is comparable to women using birth control pills and Nuvaring (anywhere from 2-9%), but it's much higher than women using IUDs or Nexplanon (less than 1%).
In summary, is Annovera a good contraceptive method? And the answer is: it depends! As I have said about a million times in 20 years of practice, the best birth control method for a woman is the method that she can use safely, consistently and correctly and that she likes. If she can't use it consistently, or she hates it, then it doesn't matter whether it's a "good" method or not...it's not a good method for that particular woman. But women's health research has been low on pharmaceutical companies' priority list for many years. So any time a new birth control method becomes available, that means there's one more option for women to take control of their reproductive futures. And the more choices, the better!