Being born prematurely can triple a baby’s risk of developing childhood asthma, 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 8% 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% of children are now born pre-term.
The research showed that average asthma rates rose to 14% 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% 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 Dr 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.”
The researchers studied data on around 1.5 million children pooled from 30 studies from six continents. Four of the research papers were from the UK.
Combining the findings of different studies, known as “meta-analysis”, can reveal trends that may otherwise remain hidden.
Many premature babies experience breathing problems because their lungs are immature.
Previous research has suggested this can lead to asthma, but whether or not it affects long-term risk is still unclear.
Dr Samantha Walker, executive director of research at Asthma UK, said: “This is a robust study providing further evidence that babies born before their due date are at increased risk of childhood asthma. We know that uncontrolled asthma in pregnant women, amongst other things, can increase the risk of premature birth, which reinforces the need for good asthma management during pregnancy.
“Standard asthma medicine is very safe to use in pregnancy, and by far the most important way to reduce this risk is for pregnant women to take their medication as prescribed. Other things to bear in mind are maintaining a healthy weight, staying active and avoiding stress, smoking and infections.”
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