Characteristics of menstrual cycle in shift workers

Glob J Health Sci. 2013 Feb 28;5(3):163-72. doi: 10.5539/gjhs.v5n3p163.


Background: In this study, the characteristics of menstrual cycle in shift workers employed in the pharmaceutical industry are investigated.

Method: This study was conducted in a pharmaceutical industrial complex in Tehran in 2012. 406 female workers in packaging units were studied on the menstrual cycle characteristics. The studied workers were divided into two groups of shift workers and non-shift workers and were compared in terms of the frequency of menstrual disorder (short-term cycle, long-term cycle, irregular cycle and bleeding during menstrual cycle) as well as hormonal values (FSH, LH, TSH, and Prolactin).

Results: The odds ratio (OR) for menstrual disorder in the shift workers was 5.54 (95% CI=2.78-11.02) compared to the non-shift workers. The mean difference of hormonal values (except prolactin) between shift workers and non-shift workers was not significant (P>0.05).

Conclusion: This study suggests that shift work may disrupt the menstrual cycle.

MeSH terms

  • Adult
  • Circadian Rhythm*
  • Drug Industry
  • Female
  • Follicle Stimulating Hormone / blood
  • Humans
  • Iran / epidemiology
  • Luteinizing Hormone / blood
  • Menstrual Cycle / blood*
  • Menstruation Disturbances / blood
  • Menstruation Disturbances / epidemiology*
  • Odds Ratio
  • Prolactin / blood
  • Surveys and Questionnaires
  • Thyrotropin / blood
  • Young Adult


  • Prolactin
  • Luteinizing Hormone
  • Follicle Stimulating Hormone
  • Thyrotropin