While there are many factors at play, research from New Zealand has confirmed that women who sleep on their backs in the last three months of their pregnancy are 3.7 times more likely to have a late stillbirth.
The research was led by Professor Lesley McCowan from the University of Auckland and was co-funded by Cure Kids and the Health Research Council.
“Our findings make sense as lying on the back in late pregnancy is associated with physical effects that can compromise the baby's wellbeing," Professor McCowan told Fairfax's Stuff.co.nz.
"When you lie on your back in late pregnancy, the weight of the pregnant uterus compresses a big vein in the abdomen called the inferior vena cava, and that reduces the blood going back to the heart and it reduces the blood supply going to the womb,” she explained to News Hub.
The study has supported the findings of earlier research from Auckland University in 2009.
"Now that we have confirmed our earlier findings, public health education encouraging women to go to sleep on their side in the last three months of pregnancy needs to be considered," Professor McCowan said.
The researchers suggest that pregnant women may benefit from putting a pillow behind their back to increase their chances of staying on their side during the night.