CHANGES IN THE LIPOPROTEIN PROFILE IN POSTMENOPAUSAL WOMEN RECEIVING HORMONE REPLACEMENT THERAPY - EFFECTS OF NATURAL AND SYNTHETIC PROGESTERONE

OBJECTIVE: To compare the effects of medroxyprogesterone acetate and m icronized progesterone on the lipid profile of postmenopausal women re ceiving conjugated equine estrogen. STUDY DESIGN: A prospective, clini cal study of the changes in lipoprotein profile evaluated in 123 post- menopausal women receiving conjugated estrogen alone (group I), conjug ated estrogen combined with medroxyprogesterone acetate (group II) or micronized progesterone (group III) before treatment and six months af ter. RESULTS: Group I had significantly increased high-density lipopro tein cholesterol (HDL-C) levels (14.4%) after six months as well as de creased low-density lipoprotein cholesterol (LDL-C) concentrations (-6 .61%), LDL/HDL and total cholesterol/HDL-C ratios (P<.05). In groups I I and III, HDL-C concentrations increased 4.58% and 5.44%, respectivel y, after six months. LDL-C levels were markedly decreased in group 11 (8.98%). There tons no significant reduction in LDL-C levels in group III. Total cholesterol levels were significantly decreased only in gro up II (-4.93%). Triglyceride levels were increased with statistical si gnificance only in group III (21.2%, P<.05). LDL/HDL and total cholest erol/HDL-C ratios were significantly decreased in group II, and this e ffect was more pronounced in group I. There teas no change in the rati os in group III. CONCLUSION: Conjugated estrogen replacement therapy h ad a persistent cardioprotective effect in postmenopausal women, based on the positive effect on lipoprotein metabolism. Both natural and sy nthetic progesterones blunt the beneficial effects of estrogen on the lipoprotein profile, and micronized progesterone is not superior to me droxyprogesterone acetate.