Pregnant women who sleep on their back are at greater risk of having a stillbirth, a new study suggests.

Mothers-to-be who sleep in this position are five times more likely to have a baby with a low birth weight, and for some women this results in the tragedy of a stillbirth, researchers said.

More than a quarter of cases might be avoided simply by ensuring that women change their sleeping position, researchers said.

The study was conducted in Ghana, Africa, where between 20 to 50 out of every 1,000 babies are stillborn, compared with just 3.5 in the UK.

But a recent study in New Zealand suggests that supine sleep - the technical term for sleeping on your back - is linked to higher stillbirth rates in high income countries also.

Scientists found that pregnant women who sleep on their backs risk uterine compression on their inferior vena cava, which can lead to reduced cardiac output, and stillbirth.

Researchers said the study shows that giving pregnant women simple advice on how to sleep could radically reduce the number of stillbirths.