Dimming the lights before going to bed may help reduce the risk of gestational diabetes. Exposure to bright light in the evening has been shown in studies to disrupt the body’s natural sleep-wake cycle, resulting in hormonal imbalances that increase the risk of gestational diabetes.
According to a new study, pregnant women should dim their home lights and turn off or at least dim their screens (computer monitors and smartphones) a few hours before bedtime to reduce their risk of gestational diabetes mellitus. In the multisite study, women who developed gestational diabetes had more light exposure three hours before falling asleep. They did not differ in their light exposure during daytime or sleep or in their activity levels compared to those who did not develop it.
A new Northwestern Medicine study suggests that pregnant women dim the lights in their homes and turn off or at least dim their screens (computer monitors and smartphones) a few hours before bedtime to reduce the risk of gestational diabetes mellitus.
Women in the multi-site study who developed gestational diabetes mellitus had more light exposure three hours before sleep onset. They did not differ from those who did not develop it in terms of light exposure during the day or sleep, or activity levels.
Our study suggests that light exposure before bedtime may be an under-recognized yet easily modifiable risk factor of gestational diabetes. Try to reduce whatever light is in your environment in those three hours before you go to bed.
Dr. Minjee Kim
“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.
Light exposure before bedtime may be linked to impaired glucose regulation in non-pregnant adults, according to growing evidence. However, little is known about the effect of evening light exposure on the risk of developing gestational diabetes, a common pregnancy complication with serious health consequences for both mother and child.
This is one of the first multi-site studies to look at the effect of light exposure before sleep on the risk of developing gestational diabetes. The findings will appear in the American Journal of Obstetrics and Gynecology Maternal Fetal Medicine.
Dim lights before bedtime to reduce risk of gestational diabetes
Gestational diabetes rise is ‘alarming’
Gestational diabetes is on the rise in the United States and around the world. Approximately 4.5% of first-time pregnant women with a baby born between 2011 and 2013 developed gestational diabetes, with the rate increasing by 3.4% every three years until 2019. In 2020, the rate of gestational diabetes in the United States was 7.8% of all births.
“It’s alarming,” Kim said. “It is well known that gestational diabetes increases the risk of obstetric complications as well as the mother’s risk of diabetes, heart disease, and dementia.” As the children grow older, they are more likely to develop obesity and hypertension.”
According to Kim, women who have gestational diabetes are nearly ten times more likely to develop type 2 diabetes mellitus than those who do not have glucose issues during pregnancy.
Bright light exposure prior to sleep can come from bright lights in your home and from devices like TVs, computers and smartphones. “We don’t think about the potential harm of keeping the environment bright from the moment we wake up until we go to bed,” Kim said. “But it should be pretty dim for several hours before we go to bed. We probably don’t need that much light for whatever we do routinely in the evening.”
Scientists don’t know which source of bright light causes the problem, but it might all add up, Kim said. “Try to reduce whatever light is in your environment in those three hours before you go to bed,” Kim said. “It’s best not to use your computer or phone during this period. But if you have to use them, keep the screens as dim as possible,” Kim said, suggesting people use the night light option and turn off the blue light.
If a pregnant woman develops gestational diabetes during her first pregnancy, she is more likely to develop it during her second pregnancy. Pre-sleep light exposure raises the heart rate and has been linked to abdominal obesity, insulin resistance, and high blood pressure. Pre-sleep light exposure may affect glucose metabolism via sympathetic overactivity, which means that the heart rate rises before bed when it should fall. “It appears that the fight or flight response is being activated when it is time to rest,” Kim said.
According to the data, sympathetic overactivity may lead to cardiometabolic disease, which is a group of conditions that include abdominal obesity, insulin resistance, high blood pressure, and a lipid imbalance, all of which lead to cardiovascular disease.
Between 2011 and 2013, 741 women in their second trimester were studied at eight clinical sites in the United States. The light exposure of the participants was measured using an actigraph worn on their wrists. The women were assessed during their second trimester of pregnancy, when they are routinely screened for gestational diabetes.
Pre-sleep light exposure remained significantly associated with gestational diabetes after adjusting for age, BMI, race/ethnicity, education, commercial insurance, employment schedule, season, sleep duration, sleep midpoint, sleep regularity index, and daytime light exposure separately.
The rising prevalence of gestational diabetes has been attributed in part to rising BMI and the older age of pregnant women. “However, even after adjusting for BMI and age, gestational diabetes is still on the rise,” Kim explained. “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.”
Losing weight and exercising lower the risk of developing gestational diabetes, both of which are important but require some effort.
