Effects of Work Schedules on the Menstrual Cycle of Nurses in a Tertiary-Level Hospital

Abstract

Introduction: Numerous studies have shown that night work can disrupt the circadian rhythm and affect reproductive health. Hospital activity belongs to what is known as 24/7 activity, and within this context, nurses represent a particularly exposed group due to the shift organization of their work. This study aims to verify a hypothesis of association between night shift work and a higher prevalence of menstrual cycle and menstruation disorders.

Method: A cross-sectional observational study was conducted in a tertiary care hospital. All nurses at the center were invited to participate; among them, 825 were under 46 years of age and constituted the target population. A total of 201 nurses completed the questionnaire. After applying the inclusion and exclusion criteria, the final sample consisted of 104 participants. Sociodemographic, occupational, and menstrual data were collected through a self-administered questionnaire. Descriptive analyses were performed, along with Chi-square, Wilcoxon, and Kruskal-Wallis tests, and prevalence ratios with 95% confidence intervals were calculated.

Results: A total of 64.4% of participants were working night shifts. Statistically significant differences between groups were observed in service type (p < 0.001), years worked on night shifts (p = 0.0195), and physical activity practice (p = 0.0335). Body mass index (BMI) was significantly associated with absence of menstruation ≥12 months (p = 0.026), menstrual cycle irregularity (p = 0.027), and dysmenorrhea lasting more than 2 days (p = 0.023). Furthermore, a higher number of night shifts worked per month was associated with shorter menstrual cycles (p = 0.0446).

Conclusions: From the perspective of work time organization and reproductive health in healthcare professionals, both the years of night shift work and the cumulative number of night shifts performed throughout a nurse’s professional career should be considered. Additionally, health promotion interventions, particularly those targeting overweight and obesity control, may contribute positively to the reproductive health of healthcare workers.