A 2011 study of 3,790 African couples published in The Lancet Infectious Diseases found that hormonal contraceptive use is associated with a doubled risk of HIV infection in women. The same study found that HIV-infected women using hormonal contraception are twice as likely to pass on that HIV to their uninfected male partner.1

How? The mechanism of action is unclear, but in a summary of their 2005 meeting “Hormonal Contraception and HIV Transmission: Links? Mechanisms? Implications?” the research agency Gynuity Health Projects listed the main hypotheses:

• HC [hormonal contraception] use may increase women’s susceptibility to acquiring RTIs/STIs (Chlamydia; cervicitis; candidiasis) and/or to expressing STIs with which they may already be infected (Herpes simplex). Presence of an active RTI or STI could then, in turn, increase women’s susceptibility to HIV;

• HC use may increase cervical ectopy (the number of cells normally within the cervical canal which
are exposed to the vagina), giving rise to increased uptake of HIV via these cells;

• HC use may disrupt populations of lactobacilli and other microorganisms which in the normal
vaginal environment provide protection from certain pathogens, possibly including HIV;

• HC use may change the vagina’s immunologic environment so as to affect receptor cells
(macrophages, T cells and dendritic cells) and co-receptor expression;

• HC use may increase the viral variety, set point, and expression of HIV in infected women;

• HC use may promote shedding of HIV into the vaginas of infected women, thus increasing their
ability to transmit the virus to others.

Their analysis goes on to note that “these mechanisms appear to be activated primarily by progestin.” More research is needed to determine precisely why hormonal contraceptives have this detrimental effect on women’s health, but it appears that HIV is not the only disease for which hormonal contraception puts women at a higher risk.

Hormonal Contraception and the Female Immune System

The mini-pill (progesterone only) is linked to an increased risk of chlamydia. According to the study “Interferon-ε Protects the Female Reproductive Tract from Viral and Bacterial Infection” published in Science Magazine, progesterone suppresses the protein Interferon-epsilon, which is essential to a woman’s immune system.2 A review of the study explains that: “When women are taking this mini pill, their bodies receive high levels of progesterone. The extra amounts of progesterone in combination with the high levels of oestrogen in the body cancel out the effects of the epsilon.”

Similarly, the study “The intracellular progesterone receptor regulates CD4+ T cells and T cell-dependent antibody responses” published in the Journal of Leukocyte Biology suggests a possible reason why women taking birth control shots have a higher risk of malaria, Listeria, HIV, and the herpes simplex virus: Progesterone suppresses interferon gamma — a protein critical for immunity against viral and intracellular bacterial infections — in T cells.3


This general detriment to the female immune system may be the reason why the a 2012 study published in Clinical Infectious Diseases found that hormonal contraception is associated with a doubled risk of staph colonization.4 In a commentary on the study, it was pointed out that “if the findings hold up in future studies it would mean that about 20 percent of women who carry the bacteria do so because they use hormonal contraception.” The research regarding the effects of hormonal contraception on the immune system is still relatively new, but these preliminary investigations suggest that the artificial hormones may be a detriment to a woman’s immune health.

Natural methods of family planning enable couples to family plan without negatively impacting their overall health. In fact, the scientific knowledge thatcomes with learning a natural method actually empowers women to discover and begin healing a multitude of reproductive health issues — before they even become a problem.

  1. Heffron et al, “Use of hormonal contraceptives and risk of HIV-1 transmission: a prospective cohort study.” The Lancet Infectious Diseases 12(2012) 19-26. doi: 10.1016/S1473-3099(11)70247-X. 

  2. Fung et al, “Interferon-ε Protects the Female Reproductive Tract from Viral and Bacterial Infection.” Science, March 2013,
    Volume 339, Number 6123, Pages 1088-1092 

  3. Hughes et al, “The intracellular progesterone receptor regulates CD4+ T cells and T cell-dependent antibody responses.” Journal of Leukocyte Biology, Volume 93, Number 3, Pages 369-375 

  4. Zanger et al, “Hormonal Contraceptive Use and Persistent Staphylococcus aureus Nasal Carriage.” Clinical Infectious Diseases, 2012