International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Child health. Women`s health

Objectives: Several studies have shown a shortening of the menstrual cycle following light therapy in women with abnormally long menstrual cycles (summarized in1) or with seasonal affective disorder2, which suggests that bright light may influence sex hormones and ovulation. The study was designed to investigate this possibility.

Methods: Twenty-two women aged 19-37 y with baseline menstrual cycle length from 28.1-37.8 days and without clinically evident endocrine abnormalities completed a study lasting for two menstrual cycles separated by an off-protocol episode of at least 1 menstrual cycle. Bright light therapy was administered for a week at home during one experimental cycle, and dim light during another cycle (crossover, counter-balanced order). The light box (Outside In®) provided white light of 4300 lux at a distance of 41 cm for 45 min shortly after awakening; dim light (placebo control) was <100 lux at 41 cm from a 1-tube fluorescent source. Daytime blood sampling and ultrasound scan were performed before and after light therapy, on the ~7th and 14th days after menstruation onset. Ultrasound investigation was repeated further to document ovulation. Serum was assayed for thyroid-stimulating hormone, prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol.

Results: Prolactin, LH, FSH and follicle size were significantly increased after bright vs. dim light (ANOVA, Light ґ Day, p=0.0043, 0.014, 0.049, and 0.042, respectively). The number of ovulatory cycles was higher with bright vs. dim light (12 vs. 6 cycles, Wilcoxon tied p=0.034).

Conclusions: Morning bright light therapy administered in the follicular phase of the menstrual cycle stimulates the secretion of hypophyseal sex hormones, ovary follicle growth, and the occurrence of ovulation in women with slightly lengthened menstrual cycles.

Note. Abstracts are published in author's edition

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Last update: 06-Jul-2012 (11:52:05)