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.