Pregnant women could be harming their unborn baby if they sleep for fewer hours than this

Pregnant women who sleep less than seven hours a night may be harming their unborn baby. Four in 10 mums-to-be suffer from a lack of sleep, often due to hormonal changes and discomfort.

Scientists say they may have a higher risk of impaired glucose tolerance, insulin resistance and gestational diabetes. A study analysed sleep data from more than 7,000 pairs of mums and kids.

They found a lack of sleep can lead to developmental delays, particularly in boys.

Lead author Dor Peng Zhu, of Anhui Medical University in China, said: “Improving sleep habits during pregnancy may prevent or reduce the risk of neurodevelopmental issues in children.”

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Last year research revealed pregnant women should stay away from artificial light at bed time in a bid to reduce their risk of developing gestational diabetes.

Five in every 100 women in the UK are affected by the condition according to the Royal College of Obstetricians and Gynaecologists and it can lead to complications and health issues for their unborn child.

Dr Minjee Kim, who led the study at Northwestern University, in Illinois, USA, and her team worked with 714 women, who were in their second trimester and wore light sensors around their wrists and kept sleep diaries.

The results reveal 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 said: “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."