New research claims nearly one in 10 last trimester stillbirths could be prevented if mothers slept differently.
A new Auckland University study has found the risk of stillbirth nearly quadruples for final trimester pregnant women who fall asleep on their backs.
The university's head of obstetrics, Lesley McCowan, said it's much safer for women to sleep on their side.
"When the mum is on her back there's evidence to suggest that babies go into a state where they use less oxygen.
"We're particularly excited about this finding, because the position that women in late pregnancy go to sleep in can be changed."
The study debunked an earlier theory that it's safer for pregnant women to fall on their left side.
LISTEN ABOVE AS LESLEY MCCOWAN SPEAKS WITH MIKE HOSKING
Healthpoint obstetrician and gynaecologist Khaldoun Aweidah told Rachel Smalley about 15 babies could be saved each year.
He said when a woman sleeps on her back, the weight of the baby can put pressure on major arteries, restricting blood flow to the baby.
"When you tilt or lie on your side, basically there will not be enough flow of blood to the baby," he said.