Google NuvaRing (a contraceptive vaginal ring changed monthly) and the top of the page will almost certainly have one (or more) advertisements from malpractice attorneys looking to sue the manufacturer and probably the doctor who prescribed it.

While the links in this shaded area are advertisements and don’t necessarily reflect, ahem, high-quality medical information, there has been murmurings for a few years over the NuvaRing and a possible increased risk of blood clots above and beyond the risk imparted by the standard birth control pill.

There are a couple of ways NuvaRing could increase the risk of blood clots: blood levels of hormones are higher with vaginal delivery compared with a pill and one of the hormones in the ring, etonogestrel, is closely related to desogestrel and birth control pills with this hormone do have a higher risk of blood clots. But just because it’s biologically plausible doesn’t mean it’s true.

So what does the latest medical research tell us? A recent study in the BMJ (Lidegard et al 2012) tells us that if 10,000 women are followed for one year:

  • 2.1 women not using any hormonal birth control will have a clot
  • 6.2 users of the regular birth control pill will have a clot
  • 7.8 NuvaRing users will have a blood clot.

One weakness of this study is that it looked at medical records and there was no data about other risk factors for blood clots (obesity, for example), but a big strength is that a very large number of women were studied (the equivalent of 9 million women over one year).

Another study (Dinger J et al) followed 33,000 women in a prospective study, so higher a quality design because other factors that increase the risk of blood clots were factored in. This study tells us that the risk of a blood clot is essentially the same with the pill and the NuvaRing; however, there are a few issues with this study:

  • It’s still unpublished (presented at a meeting but as of yet has not seen print)
  • Was funded by the manufacturer
  • The abstract doesn’t tell us how many of the birth control pill users were on pills with a higher risk of blood clots (such as Desogen, Mircette, or Yaz) and how many were on a regular lower-risk pill. Whether the NuvaRing has the same clotting risk as the higher risk or the lower risk pills makes a difference.

When faced with conflicting studies (as an aside, if you really to see conflict check out the comments section for the Lidegard study in the BMJ, some of these contraception researchers appear to despise each other’s scientific methods) it’s probably best to assume the highest risk, understanding that it may be an over estimation.

Taking that approach it appears that an additional 1 to 2 women for every 10,000 who use the NuvaRing for a year may be risking a blood clot.

What should you do with this information?

It is important to individualize medical care. For women who have been pregnant due to birth control pill failure, have side effects with the birth control pill that they don’t get from the ring, have trouble remembering to take a pill, or have a medical condition that is specifically improved by the NuvaRing the potential increased risk might be worth it. Women who have never had an issue with the pill may feel differently and women with a higher risk of blood clots may wish to stay away from the ring until there’s more information.

But ultimately risk is perceived very differently by different people. Some people will feel a blood clot risk of 1-2/10,000 per year (or 0.01%-0.02%) is high and others will think it’s low. For comparison, the risk of dying in a motor vehicle accident in the United States is 1.6 per 10,000 licensed drivers per year (or 0.0016%). It is also important to remember that it is medical safer to be on the pill or to use the ring than to be pregnant.

Just don’t get me started on the risks of making medical decisions based on information provided by a malpractice attorney.

Remember, this post does not represent individual medical advice.

Join the Conversation


  1. nice post! Your last sentence is the key one though… BOLD it 🙂 . “remember that it is medical safer to be on the pill or to use the ring than to be pregnant.”

  2. What about comparing the Nuvaring or other hormonal contraceptives (such as Yaz and Yasmin) to non-hormonal methods that are just as effective at preventing pregnancy? It is nonsense to compare hormonal contraceptive use with pregnancy. Those are not the only two options open to women. Is any risk worth it when it’s an otherwise healthy woman taking a drug she does not NEED? I don’t use hormonal contraceptives but use barrier methods and Fertility Awareness in combination. I avoid any health risks this way and am as protected from pregnancy, if not more protected, than when I was on the pill.

  3. Jen, one important point to remember is that medical device makers sometimes have their own internal data, which they choose not to publish. Often, lawyers who bring these medical device lawsuits have insider information showing a much higher risk of injury than is known publicly. In fact, that’s one of the few ways to win a medical device lawsuit.

  4. Thank you for your article. I’d like to point out that women use birth control so is not to become pregnant, so using the higher risk of blood clot during pregnancy or postpartum to make NuvaRing look more attractive seems idiotic. If you don’t want to become pregnant use the safest birth control you can find. There are safer methods out there. Don’t take risks with your body. My 29 year old daughter died from blood clots in both lungs while she was on NuvaRing. If I can help a woman avoid that fate I will do everything in my power to do so.

  5. Hi, Can you write a post on what is biologically happening to your cycle when on hormonal birth control? I read that your period on hbc is not a real period, but actually just ‘withdrawl bleeding’. Is this true? If so, what is the point of going through the withdrawl bleeding if you aren’t really having a cycle?

      1. Hi Jen, I was referenced to you by a great friend. I’m in search of information regarding birth control and find your page to be absolutely full of great info. Can you link to the article you mention above regarding a woman’s cycle on birth control? Also, do you have any other thoughts on the side effects of BC besides blood clots? Specifically libido, depression, acne, cancer… the list goes on…

        If you would humor me at all, I would love if you could point me to some tools to learn more about BC and the evidence behind its benefits and downfalls. I’m finding this to be quite the rabbit hole, and your site is the only one that has helped as opposed to just debunking others’ claims.

        Thank you!

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