Long periods of undisturbed sleep a risk factor for stillbirth

February 13 2019

Sleeping more that nine hours per night during pregnancy may be associated with late stillbirth, according to findings from an international study involving the University of South Australia.

Researchers from the US, Australia, UK and New Zealand surveyed 153 women who had experienced a late stillbirth (after 28 weeks of pregnancy) as well as 480 women with an ongoing third trimester pregnancy or who had recently delivered a live baby.

The findings, which appear in the journal Birth, suggest an association between lengthy periods of undisturbed maternal sleep and stillbirths that were independent of other risk factors.

UniSA Associate Professor Jane Warland – one of the principal investigators for the study – says disturbed sleep during pregnancy is a common complaint among pregnant women but it could in fact be a protective factor.

“Blood pressure reaches its lowest point during sleep but when someone wakes up there is a surge in the nervous system activity that causes increases in blood pressure,” Assoc Prof Warland says.

“This is important because low blood pressure has been linked with fetal growth problems, pre-term birth and stillbirth.”

No relationship was found between the reported position that women fell asleep in and stillbirth, either in the last month or on the last night.

Assoc Prof Warland says established risk factors for stillbirth include advanced maternal age, obesity, smoking, and conditions such as diabetes and pre-eclampsia.

“Until now, maternal sleep has been overlooked as a potential risk factor for stillbirth, but these study findings warrant further investigation,” she says.

About 2,400 babies are stillborn in Australia each year. For Indigenous women and women from other disadvantaged groups, this risk is often doubled.

According to the Australian Institute for Health and Welfare (AIHW) Australia’s stillbirth rates have barely improved in the past 20 years. The Lancet stillbirth series (2016) reported that the late stillbirth rate (after 28 weeks of pregnancy) is 30 per cent higher in Australia than that of the best performing countries, such as Finland, Denmark and the Netherlands.

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