Women who slept on their back or right side on the last night of pregnancy had twice the risk of a late stillbirth, according to a new study from the University of Auckland, reports Medical News Today.
The risk is small, however it doubled from 1.96 in a 1,000 to 3.93, the authors noted after speaking to 155 women who delivered stillborns between 2006 and 2009, compared to a control group of 310 women.
Researchers theorize that blood flow to the fetus may be restricted when a mother lies on her back or right side for long periods.
Other strong correlations with stillbirth included sleeping regularly during the day near the end of pregnancy, and not needing to get up and use the washroom more than once during the night.
In publishing their findings in the British Medical Journal, the authors concluded that this is the first study to report maternal sleep related practices as risk factors for stillbirth, and further studies are needed to confirm these results.