Lying on back during pregnancy may up stillbirth risk

Melbourne: Moms-to-be, take note! Women who lie on their backs in the last three months of pregnancy may have a higher risk of stillbirth, a new study has warned.

Researchers at the University of Auckland in New Zealand have found that lying face up while pregnant can change the baby's heart rate and activity state which suggests that the foetus adapts by reducing its oxygen consumption. This finding may explain the increased risk of stillbirth in the supine (lying upwards) position, researchers said.

Recent studies have shown that maternal position is important for the baby's health, but it was unclear as to how this can affect the wellbeing of the foetus. The researchers found that lying on your back can add stress and may reduce oxygen provided to the foetus, increasing the risk of stillbirth.

They monitored the foetal and maternal heart rate for 29 healthy pregnant women in the third trimester while changing and maintaining maternal positions for 30 minutes at a time. The 'foetal behavioural state', a measure of foetal health, was recorded for each maternal position. Each woman was followed until delivery and all babies were born in a
healthy condition.

"Our controlled study found that lying on your back can add extra stress to the baby, contributing to the risk of stillbirth. The risk is likely to be increased further in women with underlying conditions," said Peter Stone, Professor at University of Auckland and lead investigator of the study.

"We have only looked at the effect of maternal positions for a short period of time while the mother is awake. Further research is needed to see the effect of staying in certain
maternal sleeping positions overnight," he added. The study was published in The Journal of Physiology.