CONCLUSION Estrogen with an osteoblast P4R-acting progestin ( EPT ) in these five published RCT provides Level 1 evidence that MPA caused significantly greater annual percent spinal BMD gains than the same dose of ET .
OBJECTIVE To assess whether progesterone ( P4 ) or osteoblast P4 receptor-acting progestin ( P ) contributed to estrogen ( E ) therapy-related  increased areal bone mineral density ( BMD ) in r and omized controlled trials ( RCT ) with direct r and omization to estrogen ( ET ) or estrogen-progestin ( EPT ) therapy .
Progesterone or progestin as menopausal ovarian hormone therapy: recent physiology-based clinical evidence
Purpose of review Provide evidence -based recent data on oral micronized progesterone ( OMP ) and progestins in menopausal hormonal therapy ( MHT ) . Recent findings Medroxyprogesterone acetate ( MPA ) increases breast cancer acting through the glucocorticoid receptor ; progestins in MHT increase thrombosis more than oral estrogens ; MPA , but not OMP or other progestins , increase monocyte cell endothelium adhesion ; MPA and estradiol (E2)/MPA have negative brain effects , whereas E2/progesterone ( P4 ) has neuroregenerative brain effects . The ‘ window of opportunity ’ cardiovascular disease hypothesis is not supported by a r and omized controlled trial showing that transdermal estradiol with sequential OMP in early menopause does not prevent increased carotid intimal media thickness ; P4 in the cardiac electrical system opposes E2 effects and prevents sudden death/long QT syndrome ;  transdermal estradiol/OMP does not increase venous thromboembolism in observational data . P4 decreases breast cell proliferation and improves prognosis through P4 receptor alteration of estrogen receptor & agr ; genetic effects ;  OMP with conjugated equine estrogen (CEE)/estrogen (E)/E2 does not increase breast cancer in two prospect i ve cohorts , one population -based . Endometrial cancer is increased in MHT of CEE/E/E2+cyclic OMP at 200 mg/day . Summary New data show CEE/E/E2+MPA/P mechanisms for negative breast cancer , venous thromboembolism , cardiovascular system , and brain effects .  OMP/P4 counterbalances CEE/E/E2-related negative effects on breast cancer and long QT syndrome .  OMP effectively treats vasomotor symptoms and sleep disturbances , and could safely be used alone for symptomatic menopause
CONCLUSION Estrogen with an osteoblast P4R-acting progestin ( EPT ) in these five published RCT provides Level 1 evidence that MPA caused significantly greater annual percent spinal BMD gains than the same dose of ET .
OBJECTIVE To assess whether progesterone ( P4 ) or osteoblast P4 receptor-acting progestin ( P ) contributed to estrogen ( E ) therapy-related  increased areal bone mineral density ( BMD ) in r and omized controlled trials ( RCT ) with direct r and omization to estrogen ( ET ) or estrogen-progestin ( EPT ) therapy .