Greater Light Exposure Before Bedtime May Increase Gestational Diabetes Risk

Light exposure and diabetes risk have been linked, with past research finding that sleeping with the lights on may increase your risk of developing the disease. A new study shows that gestational diabetes may be impacted by brightness, as well.

Research recently published in the American Journal of Obstetrics and Gynecology Maternal Fetal Medicine looked at light exposure before bedtime and its impacts on gestational diabetes risk. The team – from Northwestern Medicine – found that pregnant people exposed to greater light exposure within three hours of going to sleep had a higher likelihood of developing the condition.


Dr. Minjee Kim, lead author and neurologist at Northwestern Medicine, says, “Our study suggests that light exposure before bedtime may be an under-recognized yet easily modifiable risk factor of gestational diabetes.”

To gauge whether light exposure was a risk factor, the team looked at health data from 741 women across eight different clinical sites in the United States between 2011 and 2013. All of the women were in their second trimester and wore actigraphs to measure their light exposure.

The team found that for those who developed gestational diabetes, there was a common theme of greater light exposure in the three hours before falling asleep. This heightened risk remained even when adjusting for factors including age, BMI, sleep duration and regularity, daytime light exposure, and employment schedule.


The increase in gestational diabetes – which the researchers say is up to 7.8% of all live births – has been partially attributed to rising BMI scores and the older age at which people are having children.

However, Kim says, “But even after adjusting for BMI and age, gestational diabetes is still rising. We have a lot to prove, but my personal worry is that light may be silently contributing to this problem without most people realizing the potential harm.”

Kim adds, “It’s alarming. Gestational diabetes is known to increase obstetric complications, and the mother’s risk of diabetes, heart disease and dementia. The offspring also are more likely to have obesity and hypertension as they grow up.”

The researchers say the pre-sleep light exposure may impact glucose metabolism because it causes the heart rate to go up before sleep when it should be going down. Whatever the link, Kim suggests dimming your lights as much as possible in the later evening.


This isn’t the first Northwestern Medicine study that has linked light exposure around bedtime with diabetes. Researchers from the institution have also found that moderate light exposure during sleep may raise the risk of diabetes and heart disease, by increasing insulin resistance the following morning and causing the heart to work harder than it should during sleep. You can read more on that research here.

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