Medroxyprogesterone acetate was administered orally at the daily dose of 50 mg for four months to 21 symptomatic women with moderate to severe
endometriosis, staged according to the American Fertility Society classification. The efficacy of the
therapy was evaluated prospectively by the patients' symptomatology, monthly pelvic examinations, and by restaging the disease at second-look laparoscopy during the last week of treatment. The effects of
therapy on the serum
gonadotropin and ovarian
steroid levels and on the endometrium and the implants of
endometriosis were also evaluated. Improvement of symptoms, pelvic nodularity, and tenderness occurred in 80% of the patients. The mean stage score of disease by the American Fertility Society classification decreased from 18.2 +/- 2 before
therapy to 5.9 +/- 1 after
therapy (P less than .005).
Amenorrhea,
breakthrough bleeding, and persistent cyclic
bleeding occurred in 75, 20, and 10% of the patients, respectively. Ovulation was inhibited in all patients, but serum
hormone changes were statistically significant only for LH, which decreased from 9.5 +/- 4 to 5.2 +/- 2 IU/L (P less than .001), and
estradiol (E2), which decreased from 80 +/- 30 to 46 +/- 26 pg/mL (P less than .02). Atrophic changes and pseudodecidualized reaction occurred in both the endometrium and the implants of
endometriosis. In summary, oral
medroxyprogesterone acetate is effective in relieving symptoms and objectively improving
endometriosis. Besides inducing a pseudodecidualized reaction and atrophic changes in the endometrium and ectopic implants,
medroxyprogesterone acetate also suppresses ovulation and the serum levels of both LH and E2.