The Impact of Different Doses of Estrogen and Progestin on Mood and Sexual Behavior in Postmenopausal Women*

This study investigated the effects of various doses of estrogen and progestin on psychological functioning and sexual behavior of 48 healthy, naturally menopausal women. Subjects were tested before treatment and then randomly assigned to 1 of 4 cyclic sequential hormone regimens for 1 yr. Groups A and C received 0.625 or 1.25 mg conjugated equine estrogen (CEE), respectively, for days 1-25 and 5 mg medroxyprogesterone acetate from days 15-25. Groups B and D were given 0.625 or 1.25 mg CEE, respectively, from days 1-25 and placebo from days 15-25. The higher dose of CEE induced supraphysiological levels of plasma estrone. Plasma testosterone levels were lower in group A when blood was sampled during days 18-20 at a time when they were ingesting both 0.625 mg CEE and 5 mg medroxyprogesterone acetate (P less than 0.05), although these decreases were perhaps too trivial to have affected sexual behavior as was hypothesized. Women in group A also had more negative moods and more psychological symptomatology during treatment compared to those in group D who were receiving 1.25 mg CEE and placebo (P less than 0.01). Regardless of group, sexual desire and arousal were higher during the first 2 weeks of the treatment cycle than during week 4 when no hormones were being ingested (P less than 0.05). These findings demonstrate that the effects of progestin on the central nervous system are reflected by an increase in psychological, exclusive of sexual, symptomatology and are attenuated by a higher estrogen/progestin dose ratio.