Oral micronized progesterone for vasomotor symptoms--a placebo-controlled randomized trial in healthy postmenopausal women.

OBJECTIVE The aim of this study was to compare oral micronized progesterone (progesterone) with placebo as therapy for postmenopausal hot flushes and night sweats (vasomotor symptoms [VMS]). METHODS Healthy volunteer community women 1 to 10 years since final menstruation were recruited for a randomized double-blind placebo-controlled trial of progesterone (300 mg daily at bedtime) between 2003 and 2009 and were screened for clinical, physical, or laboratory evidence of cardiovascular risks (nonsmoking, moderate body mass index [<35 kg/m], normal lipids, electrocardiogram, nondiabetic). Women recorded daily frequency and severity (1-4) of VMS in the Daily Menopause Diary during run-in (4 wk) and intervention (12 wk). Average daily VMS score (day frequency × day severity + night frequency × night severity) during final 28 therapy days was the primary outcome, analyzed by therapy, with run-in score as covariate. RESULTS Randomized participants were 133 healthy community women with VMS, ages 44 to 62 years, with a mean (SD) VMS score of 17.0 (10.4) at run-in (VMS frequency 6.8 [3.2] episodes/d). Women were randomized to progesterone (n = 75) or placebo (n = 58); analysis included all with VMS data at run-in and on therapy (n = 68 and 46, respectively). The VMS scores of women taking progesterone were better than placebo (mean adjusted difference, -4.3 (95% CI, -6.6 to -1.9), with mean reductions of 10.0 (95% CI, -12.0 to -8.1) and 4.4 (95% CI, -6.6 to -2.2) in the progesterone and placebo arms, respectively. Discontinuation with adverse events was 9% (progesterone, 8; placebo, 4), with no serious cases. CONCLUSIONS Oral micronized progesterone is effective for treatment of hot flushes and night sweats in healthy women early in postmenopause.