Most women don't plan their lives around their pregnancy. Rather, they fit their pregnancy into their lives. They might make some adjustments to their lifestyle or work schedule, but for the most part, the majority of us don't have the option to leave our jobs or find new jobs with better schedules or hours just because we're pregnant. Pregnant or not, if you work long hours as part of your job, or work late or overnight shifts, most of us find a way to continue doing that because we have to!
However, new research out of Denmark shows that some working conditions may increase the risk of miscarriage for women. Specifically, women who work nights may be greater risk of miscarrying in the first trimester. The data doesn't show that night shifts cause miscarriage necessarily; but it does highlight risk factors that some women may face.
The study, which was published in Occupational & Environmental Medicine, suggests that working two or more night shifts in a week may increase the risk of miscarriage in the following week. Researchers analyzed payroll data from 22,744 pregnant women working in public services, like hospitals. They linked that data with information and data from Danish national registers on births and admissions to hospitals for miscarriage. They were looking to see if the risk of miscarriage between weeks 4-22 of pregnancy was at all influenced by working night shifts.
They found that at the eighth week of pregnancy, women who had worked two or more night shifts in the previous week had a 32% higher chance of miscarriage when compared to women in the same week of pregnancy who had not worked any night shifts. Additionally, the risk of miscarriage increased even more if the woman worked more night shifts, or worked consecutive night shifts. The association between night shifts and risk of miscarriage was strongest after the eight week of pregnancy.
Researchers hypothesize that this is when environmental factors that attribute to miscarriage are more easily identifiable. It's possible that the risk between night shifts and miscarriage has to do with the production and release of melatonin. Women who work nights are exposed to light at nighttime, which disrupts their natural circadian rhythm and decreased the release of melatonin. Melatonin has been shown to be crucial in preserving the function of the placenta and maintaining a healthy and successful pregnancy.
Again, this study doesn't necessarily show a causation relationship between working nights and the risk of miscarriage. But it's definitely something to consider if you happen to work in a job where night shifts are common.