WIDENING the definition of "at risk" babies based on predicted birth weight may reduce the number of stillbirths and infant deaths, according to new research.

A Glasgow University study, published in PLOS Medicine, found that babies with a birth weight in the lowest 25 per cent and those in the heaviest 15 per cent are are at greater risk of stillbirths and infant deaths.

The study suggests that closer surveillance, or earlier delivery of babies with these predicted birth weight, may reduce these adverse outcomes.

In developed countries, like the UK, one-third of stillbirths and infant deaths still occur at full term babies. However, there is no consensus on what defines a small or large foetus or infant at term and what birth-weight thresholds should trigger surveillance or intervention. However, currently only the top and bottom 10 per cent are considered to be in danger.

The research, led by Dr Stamatina lliodromiti from Glasgow University's School of Medicine, was based on data from 979,912 term single-infant pregnancies over a 19-year period in Scotland.

It examined associations of birth weight centiles - also known as percentiles - with stillbirth, infant mortality, admission to the neonatal unit and low Apgar score, an assessment of a baby’s overall well-being at birth.

Dr Iliodromiti said: “Currently babies that are predicted to be too small (most frequently less than the 10th centile) or too large (most frequently over the 90th centile) are considered at risk.

“We provide convincing evidence that how we define whether a baby is too small or too large needs to be re-visited. We anticipate that by redefining this, we can continue to reduce stillbirths.”