Bioidentical Hormone Therapy in Postmenopausal Women

Lee, Suk Woo; You, Young Oak

Abstract

Bioidentical hormone therapy (BHT) refers to the use of hormones that are molecularly and chemically identical to endogenous hormones for purposes of hormone replacement therapy. The specific hormones used in BHT include estrone, estradiol, estriol, progesterone and testosterone. Since the result of the Women's Health Initiative (WHI) trial documented the increased risk of breast cancer, cardiovascular disease and stroke in users of conventional hormone therapy (CHT), use of CHT has declined and there has been increased interest in BHT. Bioidentical hormones have some distinctly different physiologic effects compared with synthetic hormones. Synthetic progestin is associated with an increased risk for breast cancer and cardiovascular disease, while natural progesterone is associated with a decreased risk of breast cancer and cardiovascular disease. Estriol has some unique physiologic effects, which differentiate it from estrone and estradiol. Estriol is associated with a lower risk of breast cancer and would be expected to prevent breast cancer, but few randomized controlled trials have been documented. Some clinical data demonstrate that BHT is associated with a lower risk of breast cancer and cardiovascular disease, and is more efficacious than synthetic hormones. However, there is little evidence in support of this claim. Moreover, estriol has not been approved by the U.S. Food and Drug Administration (FDA). Further studies are needed to confirm the safety and efficacy of BHT.