Being born prematurely can triple a baby’s risk of developing childhood asthma, new research has shown.

The link between pre-term birth and asthma, or wheezing conditions, is higher than was previously thought, a study suggests.

Asthma is already the most common chronic disease in childhood, affecting around eight per cent of offspring born after a normal-length pregnancy.

With increasing numbers of babies surviving premature birth, childhood asthma is set to become a significant health problem, say scientists.

An estimated 11 per cent of children are now born pre-term.

The research showed that average asthma rates rose to 14 per cent in babies born prematurely, defined as at least three weeks early.

Those born more than three weeks before the usual 40-week pregnancy term were almost 50 per cent more likely than full-term babies to develop asthma. And babies born more than two months early were three times more at risk.

The findings, published in the online journal Public Library of Science Medicine, also suggest that children born prematurely do not outgrow their vulnerability to asthma.

The risk of developing asthmatic symptoms was the same for both pre-school and school-age children.

Study leader Jasper Been, from the University of Edinburgh’s Centre for Population Health Sciences, said: “Doctors and parents need to be aware of the increased risks of asthma in premature babies, in order to make early diagnosis and intervention possible.

“By changing the way we monitor and treat children born preterm, we hope to decrease the future risks of serious breathing problems, including asthma. Our findings should help find better ways to prevent and treat asthma and asthma-like symptoms in those born pre-term.”