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Is Your Birth Control Contributing to the Spread of HIV?

by Stephen Propatier

January 17, 2015

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Donate Recent research about injectable long-acting hormone contraceptive suggests it may be increasing the risk of acquiring human immunodeficiency virus (HIV). Research with scary compelling narratives always get media exposure. This research is no different. Science reporting has become a lost art, and it is no surprise that facts and meaning seem to be displaced by catchy headlines. Let's take a close look at injectable hormonal contraceptives and the risk for developing HIV. How strong is this link, and how concerned should you be?

Hormonal contraception and the spread of HIV is actually a fairly contentious point. Most of the contention derives from the social nature of the discussion. Sex is interwoven into our society with moralizing often distorting the public health discussion. Cultural and religious mores, gender issues, politics, and activism all play a role in distorting the medical science of sexually transmitted diseases and contraception.

Most of the conflict comes from a behavioral-social viewpoint, i.e. the moral implications of sexual behavior and the often wrong perception that contraception is synonymous with careless sexual activity. In some religions all contraception is prohibited. Many western religions tend to colorize sexual behavior as procreation is good, any other purpose is bad. Such attitudes can pervade into cultural morality and even law. Negativity about contraception tends to be based more on a moral rather than medical ground. There are always downsides to any medical treatment. In this case there may be a direct link between injectable-hormone contraception and acquiring HIV. It is always prudent to look closely at the research and avoid making a leap to causality. Human sexuality is far too complex to approach it from simplistic good/bad categorization.

This month, the results of a recent meta-analysis were published in The Lancet Infectious Diseases, titled "Hormonal contraceptive use and women's risk of HIV acquisition." It's a systematic analysis of the available research, drawn from multiple observational studies. It had very reasonable inclusion-exclusion criteria, but the overall number of studies was relatively small—just 12. In the original research the sampling was biased and some of the reporting methods had issues. The interesting findings were specifically about the injectable long-acting hormonal contraceptive depot medroxyprogesterone acetate (DMPA), commonly known as Depo-Provera or Depo in the United States. The research suggests that DMPA seems to increase the risk of acquiring HIV. The findings show a moderate increase in risk for all groups, plus a considerable elevation in sex workers' risk—40% higher than oral contraception or no contraception. Those are pretty convincing numbers especially when compared to oral contraception, but what does this mean?

It is very plausible that this mode of contraception could make a significant difference raising susceptibility. It may affect some aspect of the vaginal lining, intra-vaginal environment, or some other factor and this effect is making transmission easier. Injectable hormone contraception has a slightly different combination of hormones than oral agents. There is a slightly different chemical structure, plus injection changes absorption. Any one of these differences over other hormone contraceptives may significantly change how it affects the people taking it.

Nonetheless, plausible is not the same as probable. Because these are observational studies and for the most part, small sized, the effect may be artificially magnified, or the population studied may be overly selected for other risk factors. There are many uncontrolled variables involved in the original research. It's an interesting finding, but this is only a starting point for more research. It is not a game-changer at this point. You wouldn't know that if you learn about it by news media outlets like Fox News, which leads with "Birth control shot linked to increased HIV risk."

Headlines suggesting that this injectable birth control method causes you to be at high risk for contracting HIV in just plain wrong. There are just too many unknowns in this research to make any predictive statements. At best, these data suggest that this is a statistical abnormality worthy of close evaluation. 41 million women worldwide use injectable birth control methods. It is especially popular in the UK. Like all contraception there are benefits and sacrifices. In many impoverished areas of the world, where healthcare is sporadic and access is unreliable, this shot is the only birth control option. The primary researcher Lauren Ralph has urged caution taking a prospective view of the data:
"The research is not enough to justify a complete withdrawal of DMPA for women in the general population. [...] Banning DMPA would leave many women without immediate access to alternative, effective contraceptive options. This is likely to lead to more unintended pregnancies, and because childbirth remains life-threatening in many developing countries, could increase overall deaths among women."
By far the biggest risk increase was among sex workers. Oral contraception has a higher rate of noncompliance, with low availability, and high pregnancy rates in those populations even when it is available. Barrier methods (such as condoms) are obviously the best option for HIV prevention, but have much lower contraception effectiveness. Yet, as is often seen in HIV-endemic regions, sex workers fail to use them because of customer desire, or complete unavailability.

This research is consistent with one big concern: many poor, probably abused, sex workers in HIV-endemic areas use this birth control method. Many engage in high-risk unprotected sex and their birth control method (probably the only one available) may add another significant layer of risk to their very risky life. A definitive answer is needed due to the critical nature of the dangers posed, but for now it is still just a curious statistical abnormality.

Even in well-developed western countries HIV is still a risk, and hormonal birth control methods offer no protection from HIV. It is important to note that even if these data are reliably replicated that does not mean, conversely, that oral birth control methods lower your risk of HIV infection. Additionally, there have been alternative/complementary medicine sites extrapolating that all hormone birth control methods raise risk of HIV infection. This is untrue and the opposite of what the meta-analysis shows. Again: conclusions should be drawn from the research cautiously, and a clear understanding of its significance can only be confirmed with more study.

Does this mean that for the average woman using DMPA for birth control, if she's having unprotected sex with multiple partners, should be very concerned about STDs including HIV? Well, yeah! Of course they should! The same is true for those on oral contraceptives, IUDs and topical contraceptives. Unprotected sex with multiple partners is just risky and foolish—not just for HIV, but also for the whole host of dangerous and incurable diseases out there. This study doesn't mean that every woman that uses a barrier-method birth control failure while on DMPA needs to run out and get HIV tested the next day. It doesn't mean that you need to go off of DMPA because other hormone methods are safer. If DMPA is an effective and safe birth control method for you should then you ought to stay on it. The far more complicated discussion that you need to have with your obstetrician or family practice doctor concerns the risks that remain, whatever birth control method is used. And that's an important discussion to have.

Here's the bottom line: if you're having sex and using any birth control method there are ways to minimize risks for HIV and ways to maximize risks. There is never zero risk, but there are several good ways to minimize risks. Switching to an oral agent is not a good way to minimize risk and it may not even be necessary; getting and using good advice from your doctor is a good way to minimize potential risks and is an important conversation for any sexually active person to have.

If you want to know more about STDs and you can't see a doctor in a timely fashion, the Centers for Disease Control has some good information:
How You Can Prevent Sexually Transmitted Diseases

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Disclaimer: This post is my personal opinion, it is not a substitute for medical care. It is for informational purposes only. The information on Skeptoid blog is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. This post does not reflect the opinion of my partners, professional affiliates, or academic affiliations. I have no financial conflicts of interest to disclose.

by Stephen Propatier

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