Transdermal progesterone cream as an alternative progestin in hormone therapy.

OBJECTIVE To evaluate the endometrial effects and determine patients' acceptance of transdermal progresterone cream compared to standard hormone therapy. METHODS Healthy menopausal women were recruited and received a pretreatment endometrial biopsy (EMB). They were randomized to 0.625 mg conjugated equine estrogen (CEE) daily and 2.5 mg medroxyprogesterone acetate (MPA) (Prempro, Wyeth USA) or daily 0.625 mg CEE and twice daily 20 mg transdermal PC (Pro-gest, Transitions for Health USA). At the end of 6 months, a repeat EMB was obtained, and the women were crossed over to other treatment. A final EMB was performed after the final 6 months. RESULTS Twenty-six women completed both arms of the study. Seventy-seven percent of women preferred the CEE/PC to the CEE/MPA (P<.001). Of the 52 post-treatment endometrial biopsies: 40 revealed atrophic endometrium and 12 proliferative endometrium (7 in the oral progestin group and 5 in the PC group). There was no evidence of endometrial hyperplasia in any of the specimens. The incidence of vaginal spotting was similar in both groups. CONCLUSION Patients preferred transdermal PC over oral MPA. This preliminary data indicate that CEE/PC has a similar effect on the endometrium as standard oral HT over a 6-month period.