The influences of sleep duration, chronotype, and nightwork on the ovarian cycle

Abstract

Despite research indicating that sleep disorders influence reproductive health, the effects of sleep on reproductive hormone concentrations are poorly characterized. We prospectively followed 259 regularly menstruating women across one to two menstrual cycles (the BioCycle Study, 2005-2007, measuring fasting serum hormone concentrations up to eight times per cycle. Women provided information about daily sleep in diaries and chronotype and night/shift work on a baseline questionnaire. We evaluated percent differences in mean hormone concentrations, the magnitude of shifts in the timing and amplitude of hormone peaks, and the risk for sporadic anovulation associated with self-reported sleep patterns and night/shift work. We estimated chronotype scores-categorizing women below and above the interquartile range (IQR) as "morning" and "evening" chronotypes, respectively. For every hour increase in daily sleep duration, mean estradiol concentrations increased by 3.9% (95% confidence interval [CI] 2.0, 5.9%) and luteal phase progesterone by 9.4% (CI 4.0, 15.2%). Receiving less than 7 hours of sleep per day was associated with slightly earlier rises in peak levels for several hormones. Women reporting night/shift work (n=77) had lower testosterone relative to women employed without night/shift work (percent difference: −9.9%, CI −18.4, −0.4%). Women with morning chronotypes (n=47) had earlier rises in estradiol during their cycles and potentially an earlier rise in luteinizing

Role of Ovarian Hormones in the Modulation of Sleep in Females Across the Adult Lifespan

“…For example, 20+ months of rotating night shifts increases the risk of early menopause (before 45 years) ( 127 ). Shift work also increases the prevalence of menstrual disorders ( 128 ) and alters E2 level fluctuation ( 129 ) in women, implicating circadian rhythms in the physiological functions of E2.…”

Sex differences in the association between chronotype and risk of depression

“…Sex hormones can independently affect both chronotype and depression. Women with morning chronotype show earlier increases in oestradiol levels during their menstrual cycles than women with intermediate chronotype 26 . Higher testosterone levels are related to higher eveningness in adolescents 27 .…”

Impact of sleep on female and male reproductive functions: a systematic review

“…Five studies assessed the impact of sleep quality and/or sleep duration on menstrual cycle regularity and/or menstrual cycle disorders. Although no association was found between shorter sleep duration and menstrual problems or regularity (17,19,25), an increased risk of menstrual cycle irregularities was observed If the mean sleep duration was less than five hours as compared with when it was more than eight hours among both 801 female adolescents (20) and 4,445 women (17), respectively. Poor sleep quality was also associated with an increased incidence of menstrual cycle problems, such as longer menstrual flow length or premenstrual syndrome, in 1,006 female university students (25), whereas insomnia was associated with a two-fold increase in the incidence of menstrual cycle irregularity in a population of 287 nurses (16).…”

“…Ten studies (six cross-sectional studies, one case-control study and three prospective cohort studies) evaluating the association between sleep and ovarian function were selected (Table 1) (16)(17)(18)(19)(20)(21)(22)(23)(24)(25).…”