Work Schedule – Reproductive Health
Work Schedule (Shift Work and Long Working Hours)
Working at night and working long hours have been related to menstrual disorders, miscarriages, and preterm birth. Here, you can learn more about work schedules and shift work and what you can do about your work schedule for a healthier pregnancy.
What are work schedule issues?
- Working during the night, or working during your normal sleeping hours
- Shift work includes working nights or rotating day, evening and/or night shifts
- Irregular shifts and jet lag
- Working long hours
Why should I be concerned about my work schedule?
- Working at night, during your normal sleep hours, can change your circadian rhythmsexternal icon, which regulates your menstrual cycle and your pregnancy hormones.
- Shift work and long working hours have been related to menstrual disorders, miscarriages, and preterm birth.
- Women who work at night, or who work long hours, often do not get enough sleep.
Who works long hours and rotating or night shifts?
- The number of hours Americans work each week is more than Japan and most of western Europe.
- 15 million Americans work full-time on evening shift, night shift, rotating shifts, or other irregular schedules.
- 30% of American workers get less than six hours of sleep per night, on average.
- Healthcare workers, flight attendants and pilots, law enforcement workers, and workers in the service industry commonly work long hours and rotating or night shifts.
What is not known?
- We don’t know what causes most cases of menstrual disorders, miscarriages or preterm birth. If you work shift work or long hours and have a menstrual disorder, miscarriage or preterm birth, we often can’t tell if it was caused by your work schedule or if it was caused by something else.
- We don’t know what amount of night shifts or how many hours per week are safest to work during pregnancy.
What can I do to make my work schedule better?
- If possible, avoid working during normal sleep time during pregnancy.
- Good sleep hygiene (sleep practices and habits) is always important, but especially for shift workers. Read about general recommendations on sleep hygieneexternal icon.
- Read sleep hygiene tips for shift workersexternal icon.
- The health effects of long or irregular work schedules may be partly due to stress. Trying to reduce stress and improve your ability to handle stress (resilience) may help. Some ways to improve your resilience include relaxation, exercise, and following a healthy diet.
Where can I get more information?
Learn more about NIOSH guidance on work schedules and long working hours.
Learn about sleep hygiene tips for shift workersexternal icon.