NOTE – THIS POST HAS BEEN UPDATED TO INCLUDE TWO NEW RESEARCH STUDIES THAT DO NOT FIND AN INCREASED CLOT RISK AMONG NEW RING USERS
You’re probably here because you read the recent article in Vanity Fair that highlights the stories of young women who suffered blood clots while using Nuvaring, and asks why this method is still on the market.
You may be wondering whether or not you should stop using the ring, and worried about what risks you’d be taking if you kept on using it.
I’m not going to get into the Vanity Fair article itself, except to say that highlighting individual stories, while making compelling reading, does little to really educate women about their own risks. Making Pharma into the bad guy is also compelling, and given how they behave in general, pretty easy to do. But compelling reading does not necessarily make for good medical advice. Which is what women really need.
So let’s see if I can help out a bit with that.
As I see it, this issue at hand, is this – are the risk of blood clots, which are inherent in any estrogen-containing birth control method, higher in Nuvaring than in other birth control methods you might choose to use? If so, is that difference big enough for you to consider using something other than the Ring? Or are the benefits you may get from using the Ring (convenience, compliance, and for some women, steadier hormone levels) enough to outweigh the increased risks?
LET’S START WITH THE BASICS
You need to know a few things before we start.
1. If you have sex, unless you use birth control, you will most likely get pregnant. The odds are about 80% in a year. So unless you plan on being pregnant, you’ll need to use something for birth control. That something is most effective if it is either hormonal or an IUD.
2. On average, your annual chance of getting a blood clot is about 3 in 10,000 if you don’t use birth control. This background risk varies with age, increasing from a low of 0.7 per 10,000 at age 17 to about 6 per 10,0000 at age 45. Other factors can increase your risk even further – genetics, obesity, and varicose veins can double the background risk at any given age.
3. Having a baby is always riskier that using birth control. The risk of blood clots in pregnancy is the highest risk any woman can take, ranging from 4-28 times the background risk.
4. All estrogen containing birth control methods increase the risk of blood clots. Quantifying that risk is difficult, but it ranges from 3-6 times the background risk, depending on which study you quote and which method you are comparing. The risk is related to both the dose of estrogen (the higher the dose, the higher the risk) and the type of progestin used.
5. First and second generation pills have the lowest clot risk – These pills contain levonorgestrel, norethindrone and norgestimate, and their clot risk is about 3 times higher than the background risk. Newer pills using gestodene, desogestrel and drosperinone have risks about twice that of levonorgestrel pills, as do the Nuvaring and Patch. That risk is about 6 times the background risk.
6. Overall, your chance from dying from estrogen-containing birth control methods is about 1 in a million.
7. Birth control has benefits as well as risks. Birth control pills, the Ring and the Patch lower the risk of ovarian and uterine cancer. Birth control pills also lowers the risk of colon cancer and do not increase the lifetime risk of breast cancer. Birth control pills, the Nuvaring and the Patch are effective treatments for heavy menstrual periods, endometriosis, PMDD, acne, menstrual cramps and fibrocystic breast disease.
8. If you don’t want to be pregnant, and don’t want the risk of estrogen containing birth control, there are other methods you can use. These include condoms, progesterone only pills, spermacides diaphragm, and IUD. These methods each carries their own set of benefits and risks, but do not cause blood clots.
NOW, WHAT ABOUT NUVARING?
A large Danish study suggested that the risk for a blood clot among users of the Nuvaring is about twice that of older levonorgestrel-containing pills, and is about the same as that from using the Patch, Yaz or pills containing desogestrel. Initial data from the FDA in 2011 suggested the same thing.
However, when only new hormonal contraceptive users are studied, that increased risks is not seen. Two newer studies – one funded by the FDA, the other by the ring manufacturer, have shown equivalent risks between the ring and older pills. This data makes mores sense clinically than the Danish study because prior research has shown equivalent estrogen levels in the ring compared to pills. It is important in studies of clot risk to compare new users to new users, since clot risks are generally highest in the first 6-12 months of hormonal contraceptive use.
At this point (As of update 2/16/14), the FDA has not changed the RING labeling other than to include the data from these last two trials. The manufacturer, however has settled lawsuits pending against it. (See this post for more)
Only you (hopefully with your doctor) can decide if the benefits you are getting from using Nuvaring warrant the risk of clots inherent in all estrogen containing contraceptives. For now, that risk seems that it may not to be larger than that in older pills, at least in two of three studies published to date.
For those who cannot remember to take a pill, or who have gotten pregnant due to missed pills in the past, the convenience of the Nuvaring may far outweigh their concerns about the potential for added risk. I have patients who have been through most of the major pills brands, and only found satisfaction on the Nuvaring. For such women, the relative difference in risk seems small in comparison to the benefit they are getting.
But if you’re considering starting hormonal birth control for the first time, and especially if your are over age 35, most experts would say to start with a low dose levonorgestrel, norethindrone or norgestimate containing pill first. If these pills work for you, why take an additional risk by starting with the Ring (or the patch, or Yaz or a desogestrel pill), even if that risk is a small one?
- Birth Control & Blood Clots – Visualizing the risk: A previous post with pictures to help you see just how large (or small) the clot risks really are.
- FDA Study on DVT and Cardiovascular Disease Among Pill Users – Among the first to raise a flag about the Ring.
- The Danish Study of hormonal contraception and Clot Risk. Source of much if the data I quote on relative risks.
Additional Reading on Clots & Contraception from TBTAM