Since the Women’s Health Initiative (WHI) results came out two years ago, millions of women have been scared off their hormone replacement therapy (HRT). Millions who have stayed on HRT feel insecure about it, and millions more women of menopausal years are suffering by going without replacement hormones, mostly for fear of getting breast cancer.

The WHI looked at the health effects of 27,000 women without a uterus using Premarin alone vs. placebo, and, in women with a uterus, Premarin + Provera vs. placebo. The trial was terminated early (after five years), when the study found that the Premarin + Provera group had more heart attacks, strokes, blood clots and breast cancer than the placebo group. The branch of the study that looked at Premarin alone vs. placebo showed an increased risk for stroke, but not for breast cancer.

In hard numbers, 10,000 postmenopausal women using Premarin + Provera for five years, compared to 10,000 non-treated postmenopausal women, will have six fewer cases of colorectal cancer, five fewer hip fractures, but eight more cases of breast cancer, eight more strokes, seven more heart attacks, and eighteen more blood clots. According to the study's authors, an individual woman's increased risk for breast cancer, with this hormone regimen, was less than one tenth of one percent a year.
The best outcome of the WHI, and one that the media has so far ignored, is that well-respected gyncologists are rethinking HRT. The Women’s Health Advisory Board, composed of some of the most respected gynecologists in this country, issued this statement, September 18, 2002, to doctors regarding the WHI study: “Hormone therapy, properly managed, remains a vital sustaining component in our efforts to enhance and extend the quality of life of women. The benefits outweigh the risks for almost all women. We are confident that the WHI findings, if objectively assessed and incorporated, have given physicians and their patients reasons to reconsider alternative and equally effective methods of post-menopausal hormone therapy.”

The numbers did not get reported like this two years ago. Since the WHI’s public premiere there has been time for further review and analysis of the study. Many respectable researchers have criticized the WHI study for flawed design methods. The media has been faulted for over-blowing the results and not presenting alternative interpretations and conclusions.

They go on to echo the same conclusions that integrative practitioners have advised for years: “CEE [Premarin] is not the estrogen produced by women during their menstrual life and may not be the most appropriate hormone to replenish a woman's body following menstrual life.”

Premarin, also known as conjugated equilin estrogen (CEE), is derived from pregnant mare’s urine. The estrogens in Premarin are perfect for a menopausal mare, but foreign to a human female. The same goes for Provera, aka, medroxy-progesterone acetate (MPA). This is a progestin, a progesterone-like substance that is also not native to the human female. It is these synthetic progesterones that appear to be the biggest culprit in increasing breast cancer risk.

WHI results have turned the tide away from using non-bioidentical hormones such as Premarin and Provera, and towards the use of bioidentical hormones. Integrative medical practitioners who have been using only bio-identical HRT for years will no longer be a fringe minority. The WHI writing group concluded, “It remains possible that transdermal estradiol and progesterone, which most closely mimic the normal physiology and metabolism of endogenous sex hormones, may provide a different risk profile.”

The primary naturally occurring estrogens in human females are estradiol, estrone, and estriol. Estradiol is most prominent during a women's reproductive years, and the weaker estrone, is more prominent in postmenopausal women. Estriol is produced in large amounts when a woman is pregnant. Progesterone is the proper name to signify identical-to-natural progesterone; progestin signifies non-bioidentical progesterone. All of these forms of bioidentical hormones are available now, some from your compounding pharmacist and some from your mainstream pharmacists.

These hormones are termed “bio-identical” or “natural” when used in replacement therapy. “Bioidentical hormones” are synthesized in a laboratory from either yams or soy, but the final molecule is identical to those made within the human female. The term “synthetic” has been used for the non-native, non-bioidentical hormones such as Premarin, Provera, Estratest, etc..

Women need to remember that estrogens do not cause cancer. Certainly the evidence indicates that some estrogens, at some levels, contribute to some breast cancer in some women. If estradiol caused breast cancer, then one would expect most breast cancers to occur in women during their reproductive years, when estradiol levels are at the very highest. Instead, it is exactly the opposite: we see breast cancer occurring more often in women in the years when their estrogen levels have fallen dramatically.
Research on the pros and cons of bioidentical hormones, is minimal when compared to the volumes of research done using the non-native-to-human-female hormones such as Premarin and Provera in the WHI. A Swedish study involving 29,000 women conducted in the 1990's, reported that estradiol alone did not increase breast cancer risk. An eight year study is underway to examine the health effects of transdermal estradiol and progesterone (bioidentical hormones) on peri-menopausal women.

Certainly, we do not have all the answers when it comes to the benefits and risks of bio-identical hormones. However, all the available evidence points to using bio-identical hormones over the now dethroned, non-bioidentical Premarin, Provera, and all their synthetic hormone cousins.

Anne Walch, MHS, PA-C is a Duke trained physician assistant practicing at Asheville Integrative Medicine.

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