Hormonal management of male to female gender identity disorder occurs in the offices of family practitioners, internists and endocrinologists, as well as in established gender dysphoria clinics. Despite detailed and updated standards of care for diagnosis, namely, the Harry Benjamin International Association guidelines, those same guidelines state that ìphysicians have a wide latitude in what hormone preparation they may prescribe and what routes of administration they may selectî. Treatment is varied and often includes doses of estrogen that are supraphysiological for biological women, sometimes even higher than those in currently prescribed oral contraceptives. Despite clinical experience and published evidence that thromboembolic phenomena are induced by a high estrogen regimen, the practice continues. Both theoretical arguments and clinical experience support the use of doses of estrogen that would be physiological for a biological woman but, nevertheless, do allow feminization. This is possible because testosterone production is simultaneously suppressed and its action antagonized using progestins and selected antiandrogen medications that lack serious medical side effects. Oral estrogen, medroxyprogesterone and spironolactone are commonly prescribed, but certain variations are demanded by different risk factors. Some of estrogenís most likely cardiovascular protective mechanisms in the biological woman have been shown to apply to the transgendered person, and others have not. Low dose estrogen regimens were used in 279 persons with male to female gender identity disorder who were followed in the authorís clinic for periods of up to 12 years. Fewer patients experienced myocardial infarctions, cerebrovascular accidents and thromboembolic events than would be expected in the general male population.
