Incidence of endometrial hyperplasia in postmenopausal women taking conjugated estrogens (Premarin) with medroxyprogesterone acetate or conjugated estrogens alone. The Menopause Study Group

Am J Obstet Gynecol. 1994 May;170(5 Pt 1):1213-23. doi: 10.1016/s0002-9378(94)70129-6.


Objective: We evaluated four oral combinations of conjugated estrogens (Premarin) and medroxyprogesterone acetate in preventing endometrial hyperplasia, which can occur with conjugated estrogens alone.

Study design: This was a 1-year prospective, double-blind, randomized, multicenter study in 1724 postmenopausal women. All five groups took conjugated estrogens (0.625 mg) daily. The respective medroxyprogesterone acetate dosages were 2.5 and 5.0 mg daily (groups A and B) and 5.0 and 10.0 mg for 14 days per 28-day cycle (groups C and D).

Results: Among the 1385 patients with valid biopsy data, endometrial hyperplasia developed in 20% in the conjugated estrogens-treated group and < or = 1% in each of the four conjugated estrogens/medroxyprogesterone acetate-treated groups. The incidence of endometrial hyperplasia did not differ significantly between any of the conjugated estrogens/medroxyprogesterone acetate regimens. However, none of the patients receiving the two higher medroxyprogesterone acetate dosages (groups B and D) had endometrial hyperplasia.

Conclusion: The endometrial hyperplasia incidence was significantly lower in women treated with conjugated estrogens and medroxyprogesterone acetate than in women treated with conjugated estrogens alone.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Double-Blind Method
  • Drug Therapy, Combination
  • Endometrial Hyperplasia / chemically induced*
  • Endometrial Hyperplasia / epidemiology
  • Endometrial Hyperplasia / prevention & control
  • Estrogen Replacement Therapy / adverse effects*
  • Estrogens, Conjugated (USP) / adverse effects
  • Estrogens, Conjugated (USP) / therapeutic use*
  • Female
  • Humans
  • Incidence
  • Medroxyprogesterone Acetate / administration & dosage
  • Medroxyprogesterone Acetate / therapeutic use*
  • Middle Aged
  • Prospective Studies


  • Estrogens, Conjugated (USP)
  • Medroxyprogesterone Acetate