One of the best things about teaching is the regular hours. During the years I taught, I could always expect to get up at the same time and usually be off by the same time every day. I also had weekends and summers off as well. Many women, however, do not have this type of regularity in their jobs and they have to work hourly shifts that can switch at any time. One week they work a morning shift, the next they work nights, maybe during the week, they have to work a couple of swing shifts. Besides being exhausting, this type of work schedule can also affect a woman’s fertility and menstrual cycles. 

A study reported by Dr. Linden Stocker from the University of Southampton says that irregular hourly shifts disrupt the body’s natural circadian rhythm and for women, this could mean an increased risk of menstrual disruption and subfertility to the point where women are more likely to have a miscarriage. 

The study conducted was an analysis of all of the studies on how irregular shifts disrupt the body’s circadian rhythm. The studies were conducted between 1969 and January 2013, and the new study compared the effect of irregular working schedules, including night and swing shifts, with women who did not work hourly shifts. The study specifically looks for early reproductive outcomes, such as irregular menstrual cycles, female fertility, and frequency of miscarriage. The research included data on nearly 120,000 women and it was found that women who worked a mix of swing and even shifts were 33% more likely to have irregular menstrual cycles than women with a more traditional work schedule. The women with swing and night work shifts also had an 80% increase in subfertility. 

The study found that women who worked only night shifts were not more likely to experience irregular menstrual cycles or fertility issues, but they did experience a higher chance of miscarrying. The research team believes that if the study can be replicated to produce further concrete information about the influence of irregular shift work on female fertility, they could help alter the regulations for pregnant women who have irregular work hours.   

However, Dr. Stocker also says that the underlying biological disturbances involved in reproductive difficulties "are complex and not the same across all the disease processes Indeed, it is probable that completely different causes underlie menstrual dysfunction, miscarriage, and subfertility. This may explain why the effects of different types of shift work are seen in some groups of women, but not others."

Source: European Society of Human Reproduction and Embryology (2013, July 9). Women working shifts are at greater risk of miscarriage, menstrual disruption, and subfertility. ScienceDaily.