Rationale for hormone replacement therapy in atherosclerosis prevention

Progestogens are clearly useful to balance the proliferative effects of est rogens on the endometrium; however, some progestogens have been shown to at tenuate the cardiovascular benefits of estrogen, and this has been the subj ect of considerable debate. Accumulating evidence confirms the deleterious effects of medroxyprogesterone acetate on estrogen's cardioprotective effec ts and provides new and compelling evidence that not all progestogens are a like in this regard. Maintaining estrogen's cardioprotective effects is str ongly dependent upon the type of progestogen and route and method of admini stration. Numerous periclinical studies conducted on nonhuman primates and other models have demonstrated that certain progestogens, such as micronize d progesterone, can be administered concurrently with estrogen replacement therapy, providing protection against endometrial hyperplasia without signi ficantly affecting the beneficial effects of estrogen on lipid profiles, at herosclerosis and vascular reactivity.