Influence of chronotype on sleep quality and menstrual regularity in nurses on monthly shift rotations

Objectives: This study aimed to investigate factors that influence the sleep quality and menstrual cycles of female rotating-shift nurses. Methods: A cross-sectional study was conducted in which 213 female rotating-shift nurses between the ages of 20 and 45 were recruited from a medical center in Taiwan from November 1, 2023, to December 31, 2023. Binary logistic regression analysis was performed with regard to sleep quality or menstrual cycle. Results: Female rotating-shift nurses who perceived a higher level of stress (P <. 001), were late chronotypes (P =. 020), or were working the night shift (P =. 006) were more likely to have poor sleep quality. Late-type nurses working the day shift were more likely to have poor sleep quality than were early- and intermediate-type nurses (P <. 001). With regard to menstrual cycles, female rotating-shift nurses who perceived a higher level of stress (P =. 008), were working the night shift (P <. 001), or had poor sleep quality (P =. 001) were more likely to have irregular menstrual cycles. Late-type nurses working the day shift were more likely to have irregular menstrual cycles than were early- and intermediate-type nurses (P =. 013). Conclusions: A higher likelihood of poor sleep quality was found in female rotating-shift nurses when they perceived high levels of stress, and the interactions between chronotype and shift type could influence sleep quality. Shift type and the interactions between chronotype and shift type could also influence menstrual regularity.