[Low dose estrogens and synthetic estrogens. Options for hormone replacement therapy in climacteric women]

A significant increase for cardiovascular disease and breast cancer risks was found in the Women's Health Initiative study in 2002, for current users of conjugated equine estrogens in the habitual dose of 0.625 mg for hormone replacement therapy (HRT) for treating menopausal symptoms. This unexpected finding has caused new-found interest in the world to determine if the use of low-dose estrogens or synthetic estrogens can be useful and safer. At present, there is no scientific evidence about the reduction of such risks with the use of low-dose estrogens. Current medical information has showed that HRT is effective to treat climacteric syndrome and to prevent postmenopausal osteoporosis. In addition, HRT reduces significantly the frequency and severity of vaginal bleeding. Currently the Climacteric and Menopause Program at the Instituto Mexicano del Seguro Social only considers the use of conjugated equine estrogens at the standard dose (0.625 mg). The purpose of this paper is to present some results about use of low-dose estrogens and points of view about synthetic estrogens found in current medical literature. This review aims at contributing to the analysis a possible future use of this type of hormone treatment within the institutional program with the goal of giving safer options to clinicians in managing women with menopausal symptoms.