Is bio-identical hormone replacement therapy safer than traditional hormone replacement therapy?: a critical appraisal of cardiovascular risks in menopausal women.

Recent clinical trials have demonstrated an increase in the risk of cardiovascular disease (CVD) in women using oral hormone replacement therapy (HRT). Bio-identical HRT (BHRT) is widely used by alternative healthcare practitioners for the treatment of symptoms of menopause, with the prevailing assumption that BHRT provides the benefits of HRT while attenuating the risks. However, considering the serious risks of HRT, the use of any form of HRT, including BHRT, without sufficient scientific evaluation may create considerable risk.The main hormone found in BHRT is estriol. Estriol is used alone or in combination with estradiol and estrone. The total daily oral dose of BHRT used is, on average, ten times higher than that used in HRT, and both oral and topical forms are used for bio-identical hormone administration. The clinical trials that have examined cardiovascular outcomes associated with estriol therapy are limited, and there is evidence to demonstrate variable effects on markers associated with cardiovascular risk.Based on the current evidence, the same cardiovascular risks that have recently been found to be associated with oral HRT may also be associated with the administration of oral estriol in BHRT. The use of oral bio-identical hormones cannot be promoted until further evidence is available to demonstrate its safety.