Questions of safety have intensified with the increasing use of bioidentical hormones among menopausal and post-menopausal women. This month “Research Watch” looks at the controversies and issues surrounding hormone therapy and menopause.

Between the 1960s and 1980s many women and their doctors embraced the use of synthetic hormones to relieve menopausal symptoms. Then health concerns began to develop, culminating in 2002 with the early termination of the Women’s Health Initiative study, which had meant to demonstrate the safety of combination synthetic estrogens and progestins when used by post-menopausal women.

Instead, government researchers ended the study in year five, concluding that hormone replacement therapy increased incidences of breast cancer, stroke, heart attack, and blood clots.

Thousands of women stopped taking hormones virtually overnight. Within a few weeks, many found themselves experiencing the full complement of menopausal symptoms–from hot flashes to mood swings and loss of libido.

The Rise of Bioidentical Hormones

A wave of information about what looked like a safer alternative emerged about 2006. Generally known as bioidentical hormones, some physicians and women’s health organizations agreed that these substances might replace conventional therapy if accompanied by careful medical screening and follow-up.

Bioidentical hormones have the ability to bind to receptors in the human body and function in the same way as a woman’s natural hormones. They simulate three estrogens (estradiol, estriol, and estrone), as well as progesterone, testosterone, dehydroepiandrosterone (DHEA), thyroxine, and cortisol.

Bioidentical hormones are not, however, natural hormones. The estrogens are derived via a chemical process from soybeans (Glycine max) and progesterone from Mexican yam (Dioscorea villosa). As with conventional hormones, however, bioidentical hormones are available only with a physician’s prescription and through a pharmacy.

A Matter of Form Not Substance

The form of the bioidentical hormone administration may be important. Transdermal patches and cremes seem to allow for a smaller, steady hormone dose. Progesterone in this form, however, may not be able to counterbalance increased cell growth of the uterine lining that can occur with increased estrogen intake. Several studies, though not definitive, have demonstrated that transdermal progesterone creme does not control estrogen-induced endometrial cell growth.

Do Bioidentical Hormones Work and Are They Safe?

Bioidentical hormone estrogens and progesterone appear to be at least as effective as conventional hormone replacement therapy in relieving hot flashes and vaginal dryness. Assertions that they protect women against cardiovascular disease, hypertension,
and various cancers are more troubling.

Little research supports claims that bioidentical hormones are safer than conventional hormones. Instead, bioidentical hormone estrogens have been shown to increase the risk of breast and endometrial cancer, though at somewhat lesser rates than conventional hormone replacement therapy. Women with ovarian cancer or at high risk for the disease should avoid hormone therapy entirely.

Thousands of studies have been done on conventional hormone replacement therapy but very little work has been conducted specifically on bioidentical hormone therapy. In fact, of more than 100 open clinical trials for menopausal treatment, only one study is evaluating bioidentical hormones. Women want dependable scientific data on the safety and efficacy of all alternative therapies, including bioidentical hormones, but the scientific and medical community is failing us.

What Women Need to Know

Menopause is a natural process, not a medical condition. Just as increased hormonal activity activates puberty and reproduction, declining hormone levels move women into a different life phase.

Health care providers can help women navigate the difficulties of the menopausal process by managing their symptoms while protecting their long-term health. Bioidentical hormone therapy may be part of this management strategy, but caution argues that these substances carry some of the same adverse risks as conventional menopausal hormone regimens. Bioidentical hormones should be used at the lowest possible dose for the briefest period possible and always under a physician’s care.

Deborah Cramer is a long-time science and technical writer. She believes that women are their own best advocates for effective and safe health care.

Source: alive #309, July 2008