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Throw out the baby; bring on the disease
Exogenous progesterone appears to enhance transmission of HIV
by Cathy Ramey

Looking to lower your risk of contracting the deadly AIDS virus? Better consider cleaning out your medicine cabinet. Start with those progesterone based chemicals used for "birth control."

A study published in the October 1996 journal Nature Medicine (Vol. 2, number 10) reveals that research involving progesterone implants (read: Norplant) showed a 7.7-fold increase in vaginal transmission of the AIDS-causing virus that destroys the immune system in subjects (monkeys in this case) who were implanted. In fact, out of 18, three of those monkeys with progesterone implants "developed relatively rapid disease courses." Placebo implants in a control group of monkeys did not result in increased susceptibility to HIV.

So why is this study so important? AIDS, or human immunodeficiency virus, according to the study, is "most often transmitted to women through sexual contact." And while millions of women are consumers of progesterone based "contraceptive" products, there has been little in the way of research done to determine how artificial hormone levels impact how the body interacts with pathogens. Pathogens are disease agents which may reside, actively or dormantly, in the body or attack as the result of transmission from an outside source.

While the research of Dr. Preston Marx and ten of his colleagues limited itself to the influence of just one progesterone based product, the implant, the implications are that any hormonal product with a similar function might well bring about the same results. Birth control pills and devices which rely upon a hormonal influence in order to effect the woman's reproductive cycle are all potential threats.

Under normal circumstances, the intact vaginal epithelium provides a boundary which acts as a barrier to the HIV virus (SIV—simian immunodeficiency virus—in monkeys). According to researchers this is so "because about 100 to 1000 times more virus is required to establish infection in animals by this route"—that is, through vaginal transmission—"compared to that required to establish infection by intravenous inoculation." However, given enough exposure to a virus, "the vaginal mucosa alone is sufficient for transmission." Transmission does not depend upon invasion into more protected reproductive tissues (cervix, uterus...).

In most cases, vaginal epithelium is the initial barrier which can and must be overcome in order for the virus to establish itself in the woman's body. And since the body's own progesterone is known to affect the vaginal epithelium by thinning the tissue, Marx, et. al., determined to test the influence of exogenous (artificially supplied) progesterone.

The test protocol involved, as already mentioned, a total of 28 simians, monkeys, 18 of them treated with progesterone implants and ten others with placebo implants. All monkeys were treated with vaginal inoculations of the SIV virus. The small dose administered (1 ml) was geared toward achieving a low infection rate in the control group. In that way researchers hoped to test their hypothesis that exogenous progesterone enhances vaginal transmission of the HIV/SIV disease. More simply, they hoped to offer a sufficiently small possibility of infection to all of the animals, one that would rarely result in infection, to see if those animals with artificially high progesterone levels reacted any differently.

In the control group, those not receiving progesterone, only one of the ten monkeys became SIV positive. At the close of the test period the virus had not transitioned to an active disease state. He continued to survive as a clinically healthy animal, positive for the SIV antibody, but asymptomatic for the disease.

Of the eighteen monkeys with progesterone implants, fourteen developed the SIV disease. Additionally, serum levels indicated that the virus was more virulent, more deadly, in the 14 test subjects than in the one control animal which tested positive.

Of the test group, the three monkeys which rapidly progressed through the disease process exhibited a variety of AIDS related clinical problems including sores, atrophy of the thymus, and cell distortion or giant cell disease involving the brain (encephalitis), lungs (SIV pneumonia), and lymphoid tissues. These findings led researchers to conclude that "progesterone treatment resulted in greater in vivo SIV replication during the early period of infection."

A later experiment was done to investigate what might more specifically account for the enhanced transmission and disease state in those monkeys with progesterone implants. Test and control monkeys were inoculated with SIV and subsequently killed in order that body tissues might be closely examined. Vaginal tissue, in particular, was observed for the number of cell layers.

Researchers discovered that the three control (no progesterone) monkeys had wide epithelial layers over 25 cells thick while the test monkeys (with progesterone) showed markedly thin epithelial layers. Two of the monkeys had layers fewer than 9 cells thick, and the third monkey showed areas of dramatic thinning (2-9 cells thick) and areas of more moderate thinning (10-25 cell layers thick).

Clearly the presence of exogenous progesterone created a more suitable environment for the transmission of SIV in the monkeys.

In the same way then, HIV transmission is facilitated in women. Progesterone, commonly included in birth control pills and devices such as Norplant, is known for its effect on the female genital tract. It thins the vaginal epithelium, brings about a change in the pH level, and reduces and thickens vaginal mucous.

While those changes, at least the thickened mucous, may reduce the possibility of becoming pregnant, it is worth considering whether the thickened mucous might also act to protect HIV or other pathogens in the body, preventing early discharge and destruction in the normally thinner mucous. Further, clearly supported by the research of Marx, et. al., as the epithelial barrier is reduced from a norm of over 25 cell layers thick to less than half that density through the use of progesterone in contraceptive products, transmission of HIV through the vaginal tract is made easier.

All research cited was sponsored through the Aaron Diamond AIDS Research Center, New York Medical Center, RR 1, Long Meadow Road, Tuxedo, NY 10987. The research summary can be found in an article, "Progesterone implants enhance SIV vaginal transmission and early virus load," in Nature Medicine magazine, Vol. 2, Number 10, October 1996.