September 22, 2004
But now, confirmation has come out regarding another side effect that I talk about extensively in Chapter Six of Beyond Choice: the seeming increase in sexually transmitted diseases among pill users. This does not occur just because couples on the pill use fewer condoms, though they do; it occurs probably because there are physiological changes in the reproductive tract making it easier for the bacteria to penetrate and infect the body.
A new study confirms what I presented in Beyond Choice, but also makes clear that we must be careful to distinguish between different forms of hormonal contraception. This should not be surprising since there are different formulations used in various hormonal contraceptives and these could lead to different physiological changes in the woman's reproductive tract.
The new study by Charles S. Morrison and others from Family Health International is published in the September issue of the journal Sexually Transmitted Diseases. It can be accessed at www.stdjournal.com.
With the cooperation of Planned Parenthood, the study took a prospective look at almost 1000 women in their Baltimore clinics. The women could select their own method of contraception, or not. In fact 354 women selected the pill, 114 selected Depo-provera (DMPA) and 351 selected no hormonal method. The women were followed up every three months for a year and were examined and tested for chlamydia and gonorrhea.
There was an increased risk of infection in the DMPA and pill users, but the risk was far greater for the DMPA users. The authors called the DMPA risk "significant"---the hazard ratio was 3.6. The hazard ratio for the pill was 1.5. This was in line with 29 previous studies of the pill that averaged a 1.9 hazard ratio for chlamydia and a 1.7 hazard ratio for gonorrhea. The hazard ratio measures relative risk between the hormonal contraceptive users and the control group.
The study found varying sexual risks in the different groups. The control group (no pill or DMPA use) was more likely to have multiple sex partners and to have had sex with a possibly infected person. Pill and DMPA users were more likely to have sex but used condoms less frequently (this is in line with previous studies).
The mechanism by which there is an increased risk of infection is still a mystery. Cervical ectopy, also called cervical erosion, was found not to be what they called "an important mediator" of the hormonal contraception-cervical infection association---this was a surprise to the authors. Their hypotheses as to the physiological mechanism for the increased infection risk include: thinning of the vaginal walls by DMPA, the hormones enhancing the growth of the infection or the hormones depressing the immune system. Clearly more study is needed on the mechanism operating here.
The authors properly examined any biases in their study and concluded that "any residual bias might underestimate the risks for acquiring a cervical infection among hormonal contraceptive users".
The authors also correctly pose the issue of the effect on pill use and HIV acquisition. This remains unclear and studies are conflicting. There are also studies ongoing on whether hormonal contraception might increase HIV transmission to others, including to newborns, and whether it increases disease progression.
The challenge for us is to figure out a new approach to get couples using hormonal contraception to also use condoms. There has been an inverse relationship between more effective contraceptives and condom use---the more effective the method, the less likely the couple is to use condoms. Past studies have indicated that Norplant and Depo users were less likely than pill users to also use condoms.
A recent study published in the August issue of the American Journal of Public Health confirms what we already know--that condoms reduce the risk of gonorrhea, chlamydia and pelvic inflammatory disease. Women in the study always using condoms were half as likely to get a recurring case of PID, which is caused when gonorrhea or chlamydia travel into the upper genital tract. PID is a major cause of infertility. This study can be accessed at www.ajph.org. This should put to rest the fears that contraception opponents tried to raise a few years ago when they challenged the efficacy of condoms in preventing STDs.
So, what to do. First, admit there is a problem. I have seen no articles from health writers on this study. This study needs to be examined by experts, evaluated and suggestions made for further study and action. The IPPF Medical Committee is taking the lead and will be doing exactly this within a month.
Second, I think we need to come up with a new and balanced evaluation of hormonal contraception. There is now confirmation of the tradeoff between pregnancy prevention and disease acquisition. While this has been known since earlier studies, it has now been confirmed. How do we counsel patients? How do we, as providers, now feel about hormonal contraception? How do we develop new strategies to promote dual method contraception and condom use? Do we abandon trying dual method promotion? Clearly the old strategies are not as effective as we would wish.
Thirdly, how do we stay ahead of those who want to ban birth control entirely, or at least female controlled contraception? This political problem is real in the United States and elsewhere.
Fourthly, do we have a different standard for hormonal contraception depending on the health care and gender situation in each country? In some countries where childbearing is so risky, should there be a different standard for the use of hormonal contraception than in countries where there is less risk in childbearing and where abortion is readily available? What relevance is the status of women where men often control the use of contraception and women frequently surreptiously use hidden methods like Depo and the pill? Can hormonal contraception be discouraged and condoms be promoted in such a society where men won't use them?
The risks of sexually transmitted diseases are well known. In the United States 65 million people currently have one. STDs not only cause disease, but also infertility. There is a direct connection between rising infertility and STDs---infertility is not all age related. STDs can damage a woman's fallopian tubes, thus preventing conception and implantation. They also can cause birth defects in children born to an infected mother. Studies estimate that one-third to one-half of cases of female infertility are caused by pelvic inflammatory disease. In Africa, the WHO estimated that two-thirds of infertility is caused by STDs.
I believe the framework to approach analyzing this problem is through fertility. Fertility, the ability to have children, is after all the biological purpose of humanity, just like any other species. Hormonal contraception should be evaluated by its ability to promote fertility. This includes the ability to have the children one wants when one wants to have them, and no more than one wants. While men and women each have reproductive interests, women alone bear the risks of childbearing.
The reality is that a woman in order to get pregnant must have unprotected sex with her partner. This puts her at risk for the sexual behavior of her partner and everyone else he has had sex with. Thus a woman is a risk for a STD through no fault of her own but because of the decisions and actions of other members of society. And women are more likely to contract a STD than a man is because these diseases are more easily transmitted male to female than female to male.
STDs have an effect on the reproductive capacity of the entire society. Arguments in favor of hormonal contraception based on choice are now less persuasive. New thinking is needed. We owe it to our patients and to women and men everywhere.