Various studies conducted all over the world have concluded that women working for long hours or in overnight shifts are more prone to preterm delivery and miscarriage.
A study conducted by the University of Alberta over one year appeared in July's issue of the American Journal of Obstetrics and Gynecology. This exhaustive research included 196,989 different women, covering 62 independent studies from 33 countries dating as far back as 1960.
It revealed that expectant women working in a fixed night shift have a 21 percent higher likelihood of experiencing a preterm delivery. They're also a 23 percent more likely to miscarry than those working in a regular day shift.
Margie Davenport researcher of the University of Alberta said, "We were able to see that there's an association between work schedule and increased risk of having an adverse pregnancy outcome."
Another study conducted in Denmark, which looked at 23,000 pregnant women, concluded that late-night shifts and long hours impact pregnancy adversely.
Dr. Luise Molenberg Begtrup, study author and researcher at the Department of Occupational and Environmental Medicine at Bispebjerg and Frederiksberg Hospital in Denmark, said, "Women working night shifts are exposed to light at night, which disrupts their circadian rhythm and decreases the release of melatonin. Melatonin is important in maintaining a successful pregnancy, possibly by preserving the function of the placenta."
According to CDC, irregular work schedule can not only affect a woman's pregnancy but can also be the cause of menstrual disorders. Erratic work schedules include working during regular sleep hours, working in rotating shifts or night shifts, long hours, and also jet lag.
The circadian rhythm regulates the menstrual cycle and pregnancy hormones. When a woman works night shifts during the time the body is supposed to take rest, this circadian rhythm gets disrupted. In general, this affects the body's clock and can be a common cause for lack of sleep and fatigue.
Dr. Shannon Clark, an associate professor in the department of obstetrics and gynecology at University of Texas Medical Branch at Galveston, said, "Women do require more sleep during pregnancy, particularly in the first and third trimester. Fatigue is more evident in these trimesters when compared to the second trimester when many women experience more energy. As to exactly how many hours a day is needed, it varies from woman to woman based on her baseline needs when not pregnant."
However, most of the researchers said it is still unclear what a safe working schedule looks like or what are a safe number of working hours for pregnant women. Further research needs to look at the direct relationship between the findings and the cause. Furthermore, future labour policies need to be framed to bestow pregnant women with a healthy pregnancy.