Changes in Sleep Quality after Hormone Replacement Therapy with Micronized Progesterone in Japanese Menopausal Women: A Pilot Study

Sleep disturbances are common among women during menopause. Hormone replacement therapy (HRT) using micronized progesterone (MP) may improve sleep, owing to its neurosteroid effects. Studies on the impact of oral MP on sleep quality in Japanese women are limited, given the recent introduction of MP in Japan. We conducted a single-arm, open-label study to examine the effects of HRT with estradiol (E2) and oral MP on sleep quality in 15 peri- and postmenopausal Japanese women who chose HRT to address their menopausal symptoms. The participants completed the Pittsburgh Sleep Quality Index (PSQI) and menopausal symptoms questionnaires at baseline, 1 month, and 3 months after HRT. The changes in PSQI scores were evaluated. Responders were defined as those with a ≥ 25% reduction in the PSQI global score at 1 month. The PSQI components and menopausal symptoms at baseline were compared between responders and non-responders. Initially, 86.7% of the participants were categorized as poor sleepers. The PSQI global score and sleep quality significantly improved at 1 and 3 months after HRT (baseline to 3rd month mean scores: from 7.8 to 6.1 to 6.5 and from 1.7 to 1.0 to 1.2, respectively). Responders (n = 5) exhibited poorer habitual sleep efficiency before treatment than the non-responders. However, menopausal symptoms did not differ significantly between the groups at baseline. The results indicate that HRT with E2 and MP is a promising treatment option for peri- and postmenopausal Japanese women experiencing sleep disturbances, especially those with poor sleep efficiency.