Shift work – working hours other than the traditional 9:00 A.M. until 5:00 A.M. – has grown in the United States. According to the U.S. Bureau of Labor Statistics, approximately 12 percent of women work shift work.  Some choose to do so because it allows for better family and child care arrangements.  But a recent study has linked shift work with lower fertility and menstrual problems. In addition, working nights was associated with a higher rate of miscarriages.
A recent study, completed at the University of Southampton, UK, and presented at the annual meeting of the European Society of Human Reproduction and Embryology, looked at previous studies (published between 1969 and 2013) on shift work and reproductive health and analyzed health information on almost 120,000 women. The finding included:
- Women working shift work had a 33 percent higher risk of menstrual problems
- Women working shift work had an 80 percent higher risk of experiencing fertility problems
- Women working consistent night shift hours did not have fertility or menstrual problems but did have a higher risk of miscarriage
The study did not look at cause and effect, but the researchers speculate that “one possible explanation…is that shift work’s disruption of the body’s circadian rhythm can affect the biological function of the ‘clock genes’ which have been shown to be associated with changes in biological functions.”  There may be an actual physiological change when natural body rhythms are changed, although women working different shifts may also have more difficulty sleeping, be sleep deprived, exercise less than women working traditional shifts and not eat properly. Researchers point out that the results from the study need to be further explored and researched to prove or disprove the findings.
Shift work has been found, in previous studies, to be harmful in later pregnancy but according to this recent study, may also create problems when trying to get pregnant.
For women who work shift work and are trying to conceive, this study may be disheartening, however, Dr. Linden Stocker, one of the researchers at the University of Southampton told the Huffington Post that “women who do shift work should not stress about the new findings, particularly until future studies have replicated the results.” 
And Dr. Kecia Gaither, director of maternal fetal medicine at Brookdale University Hospital and Medical Center in New York City stated, “women in these work circumstances should consider paying closer attention to some warning signs, such as menstrual irregularities in order to prevent any future reproductive issues. She also suggests talking with your doctor about any reproductive issues, cutting back on alcohol and caffeine and “simply finding time for consistent downtime with naps.” 
 “Shift Work Linked to Fertility Problems in New Study,” 2013, July 9, Catherine Pearson, Huffington Post
 “Shift Work Might Affect Women’s Periods, Fertility: Study,” 2013, July 10, Health Day: U.S. News and World Report
  “Workers on Flexible and Shift Schedules in 2004 Summary,” 2005, July 1, Staff Writer, United States Department of Labor, Bureau of Labor Statistics
Published On: July 10, 2013