Babies born into large families less likely to thrive, say scientists

BABIES born into larger families are more likely to struggle to put on weight during the first nine months of their lives, researchers said yesterday.

An investigation into why some babies grow slower than others found a fourth child is twice as likely to develop slower than a first child. Even second and third babies are more likely to "fail to thrive", according to the study.

Academics at Bristol University also discovered a strong link between the height of parents and their baby's growth rate. Babies of short parents were eight times more likely to grow slowly when compared with babies with tall parents.

The research involved more than 11,700 children who are part of the Children of the 90s study, based at the University of Bristol.

The project has been monitoring the progress of 14,000 children in the Avon area since 1991.

The latest discovery challenges traditional theories that poor growth is associated with low socio-economic status.

The research found babies born to parents in social class V (unskilled manual) are no more likely to grow slower than babies whose parents are classified as professional.

Dr Peter Blair, lead author of the project, said: "We found that babies in larger families are likely to grow more slowly. The reasons for this association are not clear and deserves more research.

"While it may not be surprising that babies of short parents are more likely to grow slowly, we are the first study to establish this association." The 11,700 babies were weighed at birth, at six to eight weeks and at nine months. The study concentrated on the 5% of children who put on least weight over that time.

Failure to thrive is a term used to describe infants and young children whose growth is substantially less than that of their peers.

Dr Pauline Emmett, head of nutrition on the project, said: "Not all infants grow well in the first year and this very slow growth has been associated with problems in later life.

"We've looked very carefully at family characteristics and the growth of all the children to try to find out why some infants do not do as well as others."

The project is already investigating the growth and development of the children at seven and eight to assess the longer-term consequences of poor growth in the first year of life.

The research was published in the International Journal of Epidemiology.