the estrogens to achieve a specific ratio. The monthly newsletter Harvard Women's Health Watch, published by Harvard Medical School, states that natural does not automatically mean safe, and that it can be used to indicate any product with an animal, plant, or mineral source—including hormones that are not bioidentical (such as Premarin), as well as the molecules extracted from soybean and yam sources used in many bioidentical and non-bioidentical commercial preparations. Cost Compounded BHT may be more expensive than conventional, FDA-approved HRT, and is often not covered by health insurance. Safety Bioidentical hormones are expected to carry the same risks and benefits as their non-bioidentical counterparts, but there have been no studies that directly compare compounded bioidentical hormones with their non-bioidentical counterparts. Hormones—as used in CHRT—have been studied for years and their risk, benefit, and effectiveness profiles are known and demonstrated through considerable research. In 2002, the Women's Health Initiative study (WHI) that was designed to demonstrate additional benefits of conventional hormone therapy (study participants were given Prempro or a placebo) was terminated prematurely after preliminary data indicated small increases in the risks of breast cancer, heart attack and stroke in older women using Prempro. Its early termination and the subsequent publicity about these previously unappreciated risks led to a decline in prescriptions for CHRT. The results from the study were used by BHT prescribers to promote bioidentical hormones as safer than the FDA-regulated preparations despite a lack of evidence; according to the FDA, the results found by the study apply to all estrogens. BHT has since been strongly promoted as a natural alternative with fewer risks than CHRT, though there is no evidence to support this claim. BHT practitioners recommend compounded products due to their claim that they more closely mimic the composition and ratio of circulating hormones in a woman's body than do commercially manufactured products. The Endocrine Society issued a position statement that bioidentical hormones carry essentially the same risks and benefits as non-bioidentical molecules. In February 2009 the American Congress of Obstetricians and Gynecologists reiterated its position (from November 2005) that there are no proven benefits in regard to the safety or efficacy of compounded bioidentical hormones, nor are there any benefits in salivary testing of hormone levels or customized dosing of hormones. The Mayo Clinic states that there is no evidence that pharmacy-compounded BHT is safer or more effective than conventional hormone replacement, and that