Sleeping more than nine hours per night during pregnancy could be associated with late stillbirth, suggests a recent study.
Researchers analysed online surveys involving 153 women who had experienced a late stillbirth the previous month and 480 women with ongoing third-trimester pregnancy or who had recently delivered a live-born baby during the same period.
The findings, which appeared in the Journal of Birth, suggested an association between lengthy periods of undisturbed maternal sleep and stillbirths that were independent of other risk factors.
But researchers caution that further research is needed to better understand the relationship and what it means for pregnant women.
"Pregnant women often report waking up and getting up in the middle of the night. While multiple awakenings during the night may concern some women, in the context of stillbirth it appears to be protective," said Louise O'Brien, lead author of the study.
She notes that while there is already evidence that very disrupted sleep and clinical sleep disorders are associated with poor pregnancy outcomes, few studies have looked at the opposite end of the spectrum such as long periods of undisturbed sleep.
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"Our findings add to research indicating that maternal sleep plays a role in fetal wellbeing. Studies aiming to reduce stillbirths should consider maternal sleep as this is a potentially modifiable risk factor. Understanding the role of maternal sleep may help us identify interventions that would put us in a better position to advise women," asserted O'Brien.
Smoking, advanced maternal age, diabetes, obesity and drug abuse are among well-established risk factors for stillbirths. Maternal sleep practices, however, cover a relatively new area of investigation.