Mums-to-be should dim the lights for three hours before bedtime to reduce the risk of gestational diabetes, according to a new study.
Gestational diabetes is a rise in blood sugar levels and is a common pregnancy complication.
Women with the condition are at higher risk of developing heart disease and dementia.
They are also nearly ten times more likely to develop type 2 diabetes.
The condition can also affect their child, putting them at a higher risk of obesity and high blood pressure.
Light exposure before sleeping increases the probability of this condition as it causes heart rate to go up when it should go down, leading blood sugar levels to rise.
Study lead author Dr. Minjee Kim, Assistant Professor of neurology at Northwestern University Feinberg School of Medicine, said: “It seems there is inappropriate activation of the fight or flight response when it is time to rest.”
Pregnancy can also cause cardiometabolic disease. This is a cluster of conditions that include abdominal obesity, insulin resistance and increased blood pressure.
It can also lead to an imbalance of lipids, which make up the building blocks of the structure and function of cells in our body.
All the conditions increase the chances of developing cardiovascular disease and gestational diabetes.
As these things are difficult to prevent when going through pregnancy, dimming a few lights and using screens less before bed could be an easy solution to help stop further issues.
Dr Kim said: “Our study suggests that light exposure before bedtime may be an under-recognised yet easily modifiable risk factor of gestational diabetes.”
Gestational diabetes is on the rise across the globe.
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In the U.S., around 4.5 per cent of first-time pregnant women with a baby born between 2011 and 2013 developed the condition.
This number has been increasing on average by 3.4 per cent every three years up until 2019.
In 2020, the rate of gestational diabetes jumped to 7.8 per cent of all births in the US.
While the condition usually goes away after giving birth, women who suffered with it during their first pregnancy are more likely to develop it again during their next.
According to Diabetes UK, in the UK it affects around four per cent of women.
Dr Kim said: “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.”
Gestational diabetes often does not come with any symptoms.
However, some women may experience increased thirst, a dry mouth, tiredness, blurred eyesight or thrush.
While scientists know that light can have an effect, they do not know which source causes the most problems.
Dr Kim said “We don’t think about the potential harm of keeping the environment bright from the moment we wake up until we go to bed.
“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.
“Try to reduce whatever light is in your environment in those three hours before you go to bed.
“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.”
The study of 741 women was conducted at eight clinical U.S. sites between 2011 and 2013.
Researchers measured the amount of light exposure they experienced through a sensor worn on their wrist.
The women were examined during the second trimester of pregnancy. This is the time when women receive their routine screening for gestational diabetes.
Being over the age of 40 and having a high BMI could also increase the risk.
Dr Kim said: “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.”
“Losing body weight and exercising also reduce the risk of developing gestational diabetes.
Turning down the lights is an easy modification you can make.”
She added: “Now I’m the light police at home.
“I see all this light I never thought about before.
“I try to dim the light as much as possible. Just for evening activities such as dinner and bathing the kids, you don’t need bright light.”
The study was published American Journal of Obstetrics and Gynecology MFM.
