Sleep quality and the menstrual cycle.

Objective: This study aimed to assess the temporal relationship of subjective sleep quality to menstrual cycle phase in a community (non help-seeking) sample of adult women over six months. Previous work has produced contradictory results and often used student samples.

Patients/methods: This was a cohort study, using daily electronic data collection in the Greater Toronto Area, Ontario, Canada; 76 women aged 18-42 years recruited by random digit telephone dialing, recorded mood, sleep quality, and other health variables on a daily basis for 24 weeks.

Results: Using linear mixed models, we assessed the relationship between subjective sleep quality and three menstrual cycle phases (menses, premenstrual and midcycle) over 395 cycles. Premenstrual sleep quality was poorer than during the rest of the cycle, with a mean difference of 1.32 between premenstrual and midcycle reference phase, on a 1-100 quality scale (higher score denotes poorer quality). This difference held when the independent variables of daily exercise and physical health were added to the model; it became non-significant when perceived stress and later, social support were also added to the model.

Conclusions: Sleep quality in adult non-help seeking women is statistically poorer in the premenstruum but the size of the difference is of little clinical significance and was no longer statistically significant with inclusion of the potentially confounding variables, perceived stress and social support.