Efficacy of medroxyprogesterone treatment in infertile women with endometriosis: a prospective, randomized, placebo-controlled study.

OBJECTIVE: To determine the efficacy of medroxyprogesterone acetate (MPA), 50 mg/d for 3 months, in treating endometriosis, with a follow-up of 6 months.

DESIGN: Prospective, randomized, double-blind, placebo-controlled trial.

SETTING: Academic infertility unit in a teaching hospital.

PATIENT(S): One hundred infertile women found to have endometriosis at laparoscopy, with 50 recruited to each treatment arm.

INTERVENTION(S): Laparoscopy within 3 months of finishing therapy.

MAIN OUTCOME MEASURE(S): Initial and second-look laparoscopy for revised American Fertility Society stages and scores, pregnancies achieved, effects on well-being via symptomatic improvement, and side effects.

RESULT(S): Whether initially high or low, both MPA and placebo therapy achieved similar statistically significant reductions in stages and scores at second-look laparoscopy. MPA was rated more effective in improving overall well-being. Side effects were minimal in both groups (10% MPA; 2% placebo). Six pregnancies occurred without other endometriosis therapy being instituted in the placebo group (3 during therapy), and one with MPA (0 during therapy).

CONCLUSION(S): Both MPA and placebo appear equally and significantly effective in treating endometriosis over a 3-month period, as judged by comparative laparoscopy. Therefore, not only must the use of MPA at 50 mg/d over 3 months be questioned, but the performance of placebo also suggests the need to review whether therapy should be instituted at all as well as the present concept that endometriosis is frequently a spontaneously progressive phenomenon.