Dimming lights at night may lower risk of gestational diabetes, study shows

Lauren Manaker MS, RDN, LD, CLEC
·5 min read

You may already be familiar with the link between evening light exposure and sleep challenges. Since our body’s natural circadian clock responds to light (and darkness) as a cue to be awake (or asleep), light exposure before bedtime can wreak havoc on our ability to naturally lull to sleep, leaving us tired and frustrated while we lay bug-eyed in bed.

Along with having a hard time catching some quality sleep, pregnant people may experience another downside to nighttime light exposure, as 2023 data published in the American Journal of Obstetrics and Gynecology: Maternal and Fetal Medicine suggests that, among pregnant people, evening light exposure and gestational diabetes risk may be related.

While mindlessly scrolling on IG into the wee hours won’t guarantee that you will develop this condition, the study results do highlight an important reason why you may want to break that late-night habit.

Evening light exposure and gestational diabetes risk

Gestational diabetes is a common condition that can occur during pregnancy, affecting 6 out of every 100 US pregnancies every year. While most people who develop gestational diabetes experience zero complications, having this diagnosis does increase the risk of having a baby who is very large at the time of delivery (which can make a vaginal delivery more difficult), is born prematurely, and has low blood sugar at the time of birth. Having gestational diabetes can also increase mom’s risk of developing type 2 diabetes later in life.

Some risk factors for developing gestational diabetes are completely out of your control, like your family history, having a diagnosis of PCOS, or your age.

And according to new study results, we may need to add “evening light exposure” to our list of gestational diabetes risk factors.

What the study found

This study evaluated a sample size of 741 pregnant people from 8 different clinical sites in the US who were in their second trimester. Each participant was given a wrist monitor to record light exposure, and they were instructed to complete a sleep diary for 7 consecutive days.

After adjusting for confounding factors, the results of the analysis showed that those who had greater light exposure (from sources like TV, cell phones, and laptops) three hours prior to sleep had a higher risk of developing gestational diabetes vs. those who had less exposure during this period. Specifically, those who spent the most time in evening light had five-fold greater odds of developing gestational diabetes vs. those who had the least exposure to evening light.

“Our study suggests that light exposure before bedtime may be an under-recognized yet easily modifiable risk factor of gestational diabetes,” said lead study author Dr. Minjee Kim, assistant professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine neurologist, in a statement.

Interestingly, the likelihood of developing gestational diabetes didn’t appear to be impacted by daytime light exposure. It is also important to note that this study was observational in nature, and it was based on a relatively small sample size.

This study didn’t address whether there is any benefit to limiting evening light exposure if a person already has a gestational diabetes diagnosis.

The researchers suggest that there may be a few factors at play that can impact blood sugar regulation and gestational diabetes risk, including the negative impact pre-sleep light exposure can have on melatonin levels and glucose metabolism.

How to reduce gestational diabetes risk

According to the findings, limiting your evening light exposure may help you reduce your gestational diabetes risk. So, simple steps like swapping nighttime TV watching with reading a book or listening to a podcast, setting an alarm on your phone to indicate when it’s time to turn off screens, and dimming lights and the glow from electronic devices may offer some benefit. Wearing blue light blocking glasses may help you sleep better, but more data is needed to confirm this link in reducing evening light exposure.

Along with trying to limit evening light exposure, there are other steps that may help reduce gestational diabetes risk:

A note from Motherly on reducing gestational diabetes risk

Developing gestational diabetes can occur for many reasons, with some being completely out of your control. And receiving this diagnosis is not a guarantee that you will experience any negative side effects, especially if you commit to taking the steps your health are providers have advised to help manage your blood sugar.

But if you are focused on doing everything you can to reduce your risk of developing this condition, limiting your nighttime light exposure comes with very little downside, and it may help you experience a healthier pregnancy, too.

Sources

Hester L, Dang D, Barker CJ, et al. Evening wear of blue-blocking glasses for sleep and mood disorders: a systematic review. Chronobiology International. 2021;38(10):1375-1383. doi:10.1080/07420528.2021.1930029

Kim M, Facco FL, Braun RI, et al. The association between light exposure before bedtime in pregnancy and the risk of developing gestational diabetes mellitus. American Journal of Obstetrics & Gynecology Mfm. 2023;5(8):100922. doi:10.1016/j.ajogmf.2023.100922

Mijatovic J, Capling L, Cheng S, et al. Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis. Nutrients. 2018;10(6):698. doi:10.3390/nu10060698

Sun H, Dong H, Zhang Y, et al. Specific fruit but not total fruit intake during early pregnancy is inversely associated with gestational diabetes mellitus risk: a prospective cohort study. Public Health Nutrition. 2021;24(13):4054-4063. doi:10.1017/s1368980021001920