By Wm. LeRoy Heinrichs, MD, PhD. Women’s Healthcare Consultant Professor(Emeritus) and Past Chair of the Department of Gynecology and Obstetrics Stanford University School of Medicine

A recent legislative initiative by Hon. Rep. Carole Maloney (H.R.890, assigned to the Commerce Committee) concerns the potential for producing cancer and endometriosis from the repetitious, monthly introduction of dioxin contained in vaginal tampons. Dioxin, a potent chemical known as 'Agent Orange', is one of several hormonally active agents (HAA's) present in the environment.

An Aug. 3, 1999, a report available as a book from a committee of the National Research Council, concludes that high doses of HAA's are known to produce harmful reproductive and immunologic effects, especially in developing biological organisms, including humans, but the effects from amounts present in the environment remain uncertain.

The H.R. seeks public distribution of corporate information of tampon manufacturers about the content of dioxin in tampons, derived from the bleaching process during manufacture, and it directs the NIH to conduct studies of the potential harm to women from tampon use.

Endometriosis as an "Orphan Disease"

Endometriosis is for too many women a disease that may severely compromise the quality of their lives through delayed diagnosis, menstrual cramps, pelvic pain, and infertility. The cause of this disease remains discovered, but communicable agents are very unlikely to be related, and therefore, the role of the Communicable Disease Center for monitoring endometriosis has no primary rationale.

Still, the CDC monitors the population rate for hysterectomies, and endometriosis is one 'last-resort' indication for that surgical procedure. A national debate about universal reporting of medical conditions is limited in the US to major conditions such as heart disease and cancer. So, we fail to identify some of the trends of medical conditions such as endometriosis that would perhaps be helpful to know about. Fortunately, the NIH has initiated research on gynecological diseases.

The tissue that normally lines the inside of the uterus is called the endometrium. In some women endometrium grows outside the uterus. When this happens a woman has a condition called endometriosis. The most common areas for this abnormal growth of endometrium are the reproductive organs (ovaries, fallopian tubes, uterus). Endometrium may also grow on the intestines, bladder, or even in the rectum. Learn more Click here to view the endometrium layer in the uterus.

On Diagnosing Endometriosis

The standard diagnostic procedure for pelvic pain is surgery, usually laparoscopy under local or general anesthesia. Many of these patients harbor endometriosis. We have recently analyzed our research data from placebo-controlled, multi-center, clinical trials including hundreds of women with endometriosis, and have found that three months of medical therapy with GnRH-a's (gonadotropin releasing hormone-agonists) produces a significant improvement in symptoms equivalent to the relief afforded bysix month of treatment, but without as-severe side-effects.

We have introduced physicians to the option that a trial of treatment may provide relief, and with it, a 'presumptive' diagnosis of the disease , while avoiding surgery for a majority. However, many gynecologists will disagree with this approach because of the imprecise definition of the cause of the symptoms, and those of us advocating the non-surgical approach are a very small minority of gynecologists.

Dioxin and Cancer

Research on the topic of dioxin and cancer has recently added new information that shows a small (15-20%) increase in occupational risk considering all cancers among workers exposed to amounts 100-1000 times those experienced by the average citizen. This adverse effect was identifiable only in those with large exposures.

Further, the Sevseo, Italy community exposed to dioxin in 1976 has shown a small increase in cancers of the gastrointestinal tract, and in the lymph and blood-forming systems, worse in those exposed to the greatest amounts. Observations continue.

Heart disease and respiratory diseases were more common, also. And clearly, no evidence has been found there or elsewhere for an increase in breast, vaginal or uterine cancers after dioxin exposure. In summary, no epidemiological evidence exists in population-based studies for the association of dioxin and gynecological cancers.

Dioxin and Endometriosis

House Resolution 890 correctly states that the association of dioxin and endometriosis is confusing, and is based on provocative observations made at the Wisconsin Primate Center where in the 1970's, dioxin was given to pregnant monkeys to discover potentially harmful effects on fetuses.

Now, investigators have found endometriosis in about 45% of the aging, treated monkeys, and in a dose-responsive manner, too. But the numbers are small, and untreated monkeys, there and elsewhere develop endometriosis with the same rates, too. So unambiguous conclusions are impossible with the current information. It is fair to say that no epidemiological study to date has demonstrated in humans an association between dioxin and endometriosis.

A recent report indicates that the blood and fat levels of dioxin in the women in Seveso, IT are similar to the levels found in the Wisconsin-located monkeys. Those of working in this field hope that the Italian study will search for the association in those individuals with the acute exposure, but one that was protracted because of the retention of the chemical in the environment.

Indeed, I began my interest in this topic years ago when it became apparent that some species of birds (eagles and perigrine falcons) were being decimated by organochlorine pesticides (DDT) and I participated in hearings in the State of Washington that prompted the cessation of DDT distribution there.

Our efforts at that time to establish an association in young women exposed as fetuses, between menstrual disturbances and DDT exposure were entirely negative. Our subjects offered no complaints of menstrual or pelvic pain to suggest endometriosis, either.

Is Vaginally Introduced Dioxin Harmful?

Finally, the hypothesis that vaginally-introduced dioxin in/on tampons used cyclically for many years of a woman's life, may produce endometriosis is improbable, although one can 'never say never'!. It has been demonstrated that tampon use itself, does not influence the risk of developing endometriosis.

Could dioxin introduced by tampon use be selectively absorbed and produce gynecologic disturbances locally?

Perhaps, but no data exist to permit that deduction. I find interesting the observation described recently in my personalMD.com page, that the utero-vaginal circulation has now been identified as as one nearly unique in the body; hormones placed at the apex of the vagina appear promptly in the uterine arteries, as if they were absorbed locally, not being distributed by the general circulation to the uterus.

If dioxin were so absorbed, one would expect estrogen-like effects appearing in the uterus, and menstrual disturbances would be a hallmark of such an effect. I'm unaware of any such association or suggestions in that direction. I'd say that no one knows!

This response is of educational value only, and may not be construed as medical advice or opinion useful for making decisions. Consultation with a qualified physician is advisable before any action is considered based upon this response. WLH

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