Friday, June 24, 2011

Summer of the Pill: The latest fashion accessory to hit your uterus: the IUD!

Found here. IUDs are back in style.
Neon sunglasses? Not so much.
What is used by 20-26% of European, 30% of Israeli, 34% of Chinese, 34% of Egyptian, and 49% of Korean women… but only 1-2% of US women (Harper et al. 2008)? The intrauterine device, or IUD! The IUD is found in two forms: the copper IUD, and the hormone-releasing IUD that releases a tiny amount of progesterone. Both make the uterus inhospitable to pregnancy.

The modern incarnation of the IUD is possibly safer and more effective than oral contraception. Chances of pregnancy on the IUD range from 0-1.1 per 100 woman-years of use, and they get lower with each year you use it (Prager and Darney 2007). That is far better than your chances on the pill.

The IUD suffers from a bad reputation, in part due to misinformation or misunderstanding on the part of medical providers. Harper et al (2008) surveyed 816 physicians, nurse practitioners and physician assistants who each serve more than 100 contraceptive patients per year in the California State family planning program. They found that 40% of medical providers didn’t offer IUDs to patients, 36% provided infrequent counseling. Further, 46% thought nulliparous women, and 39% thought postabortion women were good candidates for the IUDs. Younger physicians were more likely than older physicians to recommend the IUD (Harper et al. 2008), which suggests a generational gap due to the overinflated descriptions of the dangers of early IUDs.

So let’s go through the actual pros and cons of this form of contraception, so that over the course of the summer you can compare this information to what you’ll be learning about the pill.

Remember, I’m just an anthropologist who studies this stuff. I am not a medical doctor.

Danger danger! Or not

The biggest danger from an IUD is that it could perforate the uterus, or be expelled from it. And that can certainly be painful, reduce fertility, or get you pregnant when you think you are protected. So let’s look at how often this happens.

Prager and Darney (2007) wrote a review on the levonorgestrel IUD (hormone-releasing, like Mirena) in nulliparous (that means no parity, or no children) women. This is important because many still carry the misconception that nulliparous women shouldn’t use IUDs, because of an increased risk of perforation, infertility, pelvic inflammatory disease risk, and difficulty in placement.

There are notable differences between the parous (has had children) and nulliparous (no kids) uterus. The parous uterus is a little bigger, and the cervix dilates a bit more easily. However, it turns out that for the most part these differences are not great enough to produce any differences in side effects or danger to the woman using it.

Prager and Darney (2007) found six studies on perforation or expulsion rates for IUDs (some copper, some hormone-releasing, which are made of plastic and are flexible). They did not find enough data to support a link either way for nulliparity and perforation, because the studies they found had anywhere from zero to two nulliparous women in them. That said, the perforation rates for each study ranged from 0-1.3% in one study, and 2.6 out of 1000 in another (Prager and Darney 2007).

Expulsion rates do not seem to differ between parous and nulliparous women, and again, are very low for all women. The annual expulsion rate among cited studies was 0-4.2 per 100, 0-1.2% per year, and 0-0.2% per year (Prager and Darney 2007). The one important point they do make is that there is a very slightly increased risk of expulsion for lactating women – perhaps this is due to the oxytocin released during nipple stimulation, which could contract muscle?

The other concern sometimes mentioned is that of pelvic inflammatory disease. PID is an infection of the uterus and is usually associated with a sexually transmitted disease. PID can increase the risk of infertility. So for women who haven’t had a kid, but want to some day, the concern about getting PID can loom large.

However, Prager and Darney (2007) surveyed the literature and found that the only studies that support a link between PID and IUDs involves an IUD no longer on the market, or was associated with high-risk sexual behavior.

Hidden benefits

In some women, copper IUDs can increase menstruation. However, the hormone-releasing IUDs tend to decrease menstruation, and many women stop getting periods altogether. Hormone-releasing IUDs can be prescribed to women with menorrhagia, or pathologically heavy menstruation, too.

Prager and Darney (2007) describe a study in which hormone-releasing IUD users were compared to oral contraceptive users. These IUD users had less dysmenorrhea (painful periods), less spotting, fewer days of bleeding, fewer cycles. Further, 88% of the IUD users wanted to continue with that method of contraception after a year, compared to 68% of pill users, and this difference was statistically significant (p = 0.003).

Romer and Linsberger (2009) also looked at satisfaction with the hormone-releasing IUD in a sample of 8680 women across 18 countries: 95% were satisfied with their method of contraception.

The fine print

Insertion of the IUD can be a little more painful in a nulliparous woman, since her cervix has not dilated before. Also, a minority of women may spot for a while after insertion of the IUD... and by a while, I mean a few months. But once those few months of light spotting are over, they often don’t get a period again until removing the IUD. And of course, the IUD is not conducive to sudden desires to start the babymaking process: you will need to schedule its removal first.

However, with the number of women who are ambivalent at best about birth control pills, but do not want to use a barrier method, the IUD offers a lot in the way of safety, efficacy and ease of use.


Harper CC, Blum M, de Bocanegra HT, Darney PD, Speidel JJ, Policar M, & Drey EA (2008). Challenges in translating evidence to practice: the provision of intrauterine contraception. Obstetrics and gynecology, 111 (6), 1359-69 PMID: 18515520

Prager, S., & Darney, P. (2007). The levonorgestrel intrauterine system in nulliparous women Contraception, 75 (6) DOI: 10.1016/j.contraception.2007.01.018

Römer, T., & Linsberger, D. (2009). User satisfaction with a levonorgestrel-releasing intrauterine system (LNG-IUS): Data from an international survey The European Journal of Contraception and Reproductive Health Care, 14 (6), 391-398 DOI: 10.3109/13625180903203154


  1. Thanks for this post; I was one of the women scared off by problems with the older generation of IUDs, and it can be difficult to get good (scientific) information about current models and outcomes.

  2. I got a hormone-releasing IUD (Mirena) about three years ago after moving to Canada and having spent most of the previous 15 years on the pill. Never having been pregnant before, the insertion was a little painful (a little less pleasant than a pap smear) but not that bad. I had spotting only for a few days and then regular, light periods, similar to being on the pill, after that. (Actually, the only contraceptive that stopped menstruation for me was the progestin-only pill.) I love the IUD - all of the stress about remembering to take the pill is gone. While the up-front cost is higher, if you use it for at least a year, it's less expensive than the pill, depending on health coverage, I guess.

  3. Thanks for this. IGot my copper IUD after baby #2 - because my doc specifically mentioned it as an option. I knew about them, but I don't know if I would have mentioned/requested it at all.

    Highly recommend them now to friends.

  4. Thanks for your comments, all!

    PI, I do think it's hard to get good information, and one of the articles I read suggests that older docs in particular are biased against IUDs. The older generation was definitely more dangerous, but it turns out even some of those claims are overinflated.

    Anon, yes, I have heard that about the IUD, that insertion is a bit more painful for someone who hasn't been pregnant before. But, similar to your point about the cost, it's about experiencing something up front or long term, I suppose!

    Peanut, glad your doc gave you options!

  5. 1) It is very painful (and I have had three natural childbirths, and can tolerate painful);
    2) Copper IUDs "can increase menstruation" like 40% of your month (period to period) is spent discharging an amazing amount of blood of all colors at maximum volume.
    There are some good message boards about IUDs and I would encourage women to research this option. No accidental pregnancies, no reliance on being able to hit the pharmacy once a month, but an unlucky few get some unhappy side effects (myself included).

  6. The use of copper in IUDs strikes me as a careless choice, since it can contribute to oxidative stress---even though its an essential co-factor for the synthesis of superoxide dismutase. I imagine this effect contributes to the increased rate of menstruation, no? However, I imagine there is only a danger with repeated use, but wouldn't there be a similar risk with progestin? Furthermore, what about the risk of autoimmunity? Anyway, for either choice, I think the risk is functionally related to frequency of use, but nonetheless, I remain concerned about the potential effects that inflammatory reactions might have on fertility---not to mention the incidence of birth defects.

    This might seem exceedingly silly, but would it possible to create a synthetic device that has effects that are more specific to sperm, or perhaps able to mitigate the incidence of autoimmunity? But this would change price levels, of course, since it wouldn't be practical with the disposability and unit costs of these types of contraceptives.

    Regardless, I'm highly troubled by the notion of confining the choice of medical treatment to the determination of medical professionals, since it conflicts with a fundamental right that should be considered beyond the authority of governing bodies---unless, of course, such a right threatens systemic harm. To be sure, existing laws are based on this interest, but also on the false notion that medical professionals have a near monopoly on wisdom, and that ostensible differences in capacity will in most cases prevent the achievement of parity or informed decisions.

    By altering incentives, I imagine some harmony can be created between these competing interests. Preferably on a case-by- case basis, and through tying individual choice to complete ownership of liability, and a higher price for access. If professionals are liberated from the threat of liability, then there would be a greater incentive to explore a greater range of options, but due to the potential reputational costs of failure, I think an agreement on confidentiality should also be reached. For patients, differences in prices would disincentivize the assumption of greater personal risk, and thus, reduce the potential of individual harm having systemic consequences. But still, I'm not completely certain that the predicted behavioral effects will play out in accordance with theory, and I'd prefer that any change in policy be preceded by validation in small pilot studies.

  7. I know I am coming to this post a bit late, but here is my story for the value of science: I had the copper IUD for four miserable years. Without underestimation I can say it ruined my life, and I am currently in the midst of a two-year recovery period (supervised by doctors) of having to take physiologic doses of hormones to restore my adrenal function. From the moment of insertion (which incidentally was accompanied by half an hour of the worst uterine spasms and pain I have ever experienced), the following symptoms grew in severity over years until I was unable to function on a daily basis. From the moment the IUD was removed, the symptoms were either greatly reduced or eliminated:

    Extreme poor coordination (I went from graceful to bumping into things multiple times per day); shortness of breath; impaired mood regulation; social anxiety; constant feeling of headache, dizziness, and inability to focus; severely impaired short-term memory; decreased visual acuity; depression; anemia due to consistent menses of 4-5 oz. or more; decreased resistance to infections; decreased attractiveness (my face lost its natural fluctuation of attractive during ovulation and less attractive during menses and simply stayed less attractive); complete loss of singing voice/ability to sing correct notes; extreme fatigue (from exercising for hours daily pre-IUD to not being able to carry laundry or go up stairs); complete disinterest in sex; premature aging (ages 27-31, I was getting wrinkles and gray hair and losing my skin tone).

    For four years none of my doctors could find what was wrong. Finally I figured it out (long detective story), and after starting progesterone, cortisol, and DHEA, I am repairing the damage done. For dozens more similar examples, see here:

    Feel free to ask questions. Since I have been into evpsy for a long time, I did notice quite a few interesting changes due to taking and being deficient in hormones (within minutes even). For example, my husband can tell when I have taken progesterone within minutes due to a change in the sound of my voice he describes as “more attractive.” The IUD changed our relationship significantly, and all of those dynamics disappeared with the IUD’s removal and the right hormones.