Pregnant women who get less than six hours of sleep a night are almost twice as likely to get gestational diabetes (GDM) compared with those who sleep for seven to eight hours.

While GDM disappears once the baby is born, the problems do not, as one in 10 women who had GDM becomes diabetic within five years of giving birth, while three in four of their babies will also be severely obese or diabetic later in life.

The findings from Singapore’s largest birth cohort study found that 27.3 per cent of pregnantwomen who slept less than six hours a night had GDM, compared with 16.8 per cent of those who slept seven to eight hours a night.

The Gusto (Growing Up in Singapore Towards healthy Outcomes) study recruited 1,247 patients at KK Women’s and Children’s Hospital (KKH) and the National University Hospital (NUH) between June 2009 and September 2010. The 1,176 babies born, and their mothers, are still being tracked.

The study has already published many significant findings – such as that one in five women here suffers from GDM and babies exposed to two languages may have better memory.

The latest findings were published online in the internationally accredited Sleep journal last month.

The study’s senior author, Associate Professor Joshua Gooley from Duke-NUS Medical School, said the results “raise the possibility” that good sleep habits could reduce the incidence of GDM among pregnant women here – which, at one in five, is double that in the United States.

The paper pointed out that adults in urbanised Asian countries such as Japan, South Korea and Singapore “sleep substantially less than their counterparts in Western countries”.

However, the paper said the study did not track if the women took any daytime naps, and could not say if it made a difference in their risk of getting GDM.

The study also found that Indians were at the highest risk with 25 per cent getting GDM, compared with 20.5 per cent among Chinese and 12.4 per cent for Malays. But Prof Gooley said this is due to other factors as their sleep patterns were fairly similar.

The study could not ascertain if the shorter hours of sleep were induced by hormonal changes, physical discomfort and anxiety during pregnancy, as the researchers did not know the sleep patterns of the women prior to their pregnancies.

Prof Gooley said women with a sleep disorder should see a doctor as it is “often treatable without medication”. He added: “The fast-paced lifestyle in Singapore can make it difficult to achieve adequate sleep, but it is important to recognise that sleep is a pillar of good health.”