ASSESSMENT OF LESS-THAN MONTHLY PROGESTIN THERAPY IN POSTMENOPAUSAL WOMEN GIVEN ESTROGEN REPLACEMENT

Objective: To study progestin administration at less than monthly inte rvals in postmenopausal women given continuous estrogen replacement. M ethods: Eighty postmenopausal women received 0.625 mg/day of conjugate d equine estrogens for 48 weeks. Using a double-masked design, the sub jects were randomized to medroxyprogesterone acetate 10 mg/day for 14 days every 28 or 84 days, or the same dosage for 28 of 84 days. Bleedi ng patterns, endometrial histology, and serum lipids were assessed. Re sults: The total days of bleeding during the 48-week study were signif icantly reduced (P < .05) in the women given the progestin for 14 days every 3 months (mean +/- standard deviation 29 +/- 16 days) than with the other two regimens. In all groups, secretory endometrium was repo rted in 17-39%. At 24 but not 48 weeks, simple hyperplasia was observe d in one subject in each of the less than monthly progestin groups. Si gnificant increases (P < .05) of high-density lipoprotein cholesterol were observed before but not after medroxyprogesterone acetate in the women receiving it less than monthly. No change was seen with monthly progestin. Conclusions: In this direct comparison, medroxyprogesterone acetate given for 14 days every 3 months elicited less vaginal bleedi ng than standard monthly administration. Only a single woman had simpl e hyperplasia with each regimen of progestin given every 84 days. Medr oxyprogesterone acetate given for 14 days every 3 months represents a possible alternative to standard monthly therapy if coupled with regul ar assessment of the endometrium.