Asthma starts in womb
THE origins for asthma start in the womb, new Australian research has found, with small babies having structural differences in their airways that put them at higher risk.
Researchers say their findings will help better identify which infants are at risk of longer-term respiratory problems, as well as highlighting the importance of pregnancy lifestyle changes that can reduce the chance of having a growth-restricted baby.
Lead researcher Kimberley Wang, from the University of Western Australia, said that while it had long been known babies who experienced intrauterine growth restriction – weighing less than the 10th percentile or 2.7kg at birth – were at higher risk of developing asthma, the cause had not been known.
Australia has one of the highest rates of asthma in the world, with one victims in nine.
“One of the causes of asthma is allergy, so if you are born small and you have an allergy, are you just more sensitive to that allergy because you are born smaller? Or are your lungs different to begin with? We haven’t known this until now,” Dr Wang said.
“This is important to know so that parents can look out for their child’s respiratory health as they get older.”
Looking in mice, Dr Wang found the period around the time the airway passage develops in the womb appeared to be a critical time window for influencing long-term lung function.
She saw that in baby mice, whose growth was restricted in the womb, they had abnormal airway walls that predisposed them to asthma. This was regardless of whether there was an allergy involved.
Dr Wang, whose fellowship was funded by National Asthma Council Australia and the Thoracic Society of Australia and New Zealand, said the findings highlighted the need to increase antenatal efforts to give babies the best chance of growing in the womb.
Intra-uterine growth restriction affects about 800 Victorian babies a year, with high blood pressure, drug and alcohol use, obesity, poor nutrition and diabetes among the causes. “Prevention in pregnancy is also important, so women can control their blood pressure, stop drinking and smoking, and eat nutritious food,” she said. “They can start preparing their body before pregnancy to ensure the womb and placenta is healthy, as that’s what is transferring the nutrients from mum to baby.”