Pregnant women who are exposed to a lower level of light before bedtime are less at risk of developing gestational diabetes compared to those who are surrounded by greater levels of light before they sleep, latest research reveals.

Academics from the Northwestern University in Illinois have found that light exposure three hours before sleeping can increase a women’s chances of developing diabetes during pregnancy.

Five per cent of women are impacted by gestational diabetes during their pregnancy, the Royal College of Obstetricians and Gynaecologists has reported.

Senior author Dr Minjee Kim said: “Light at night may be an unrecognised risk for acquiring a serious pregnancy complication.”

Prior research has discovered that shift workers are more likely to develop type 2 diabetes compared to people who work during the day.

In addition, previous studies have found that frequent exposure to outdoor artificial light at night can trigger the development of type 2 diabetes.

Light exposure at night suppresses melatonin levels, impacts the body’s internal clock and affects different metabolic processes, including the regulation of blood sugar levels.

Dr Kim noted: “While we can’t prove it from this observational study, similar mechanisms may play a role in pregnant women.”

More than 740 pregnant women in their second trimester took part in the study by wearing light sensors on their wrist for seven days, as well as filling in a daily sleep log.

The participants were split into three groups depending on their average exposure to light in the three hours before sleep.

The findings identify that 16 of the 247 women who only spent about 1.7 hours in dim light developed gestational diabetes, compared with 12 of those who spent about 2.2 hours in dim light, and three of those who spent about 2.6 hours in dim light.

Dr Kim added: “Women who spent the least time in dim light had fivefold greater odds of developing gestational diabetes compared to those who spent the most time in dim light.”

“Starting three hours before bedtime, try to dim the lights whenever possible. Try to put phones away if possible, but if not, at least try to dim the screen or put them on the night mode.”

Research Communications Manager at Diabetes UK, Dr Faye Riley, said: “The study hints at a link between artificial light exposure before sleep and increased risk of gestational diabetes but we’ve a lot more to learn before we can say with any confidence that limiting artificial light exposure could be helpful in the prevention of the condition.

“What we do know is that managing your weight, eating healthily and keeping active before pregnancy can help to reduce your risk of gestational diabetes.”

Read the full study in the American Journal of Obstetrics and Gynecology Maternal Fetal Medicine.

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