An asthma management study developed by University of Newcastle researchers, which halved asthma attacks in pregnant women, has also yielded a 90 per cent postnatal reduction in bronchiolitis and croup episodes among their children.
The MAP (Managing Asthma in Pregnancy) study provided asthma treatment to two groups based on either clinical symptoms or airway inflammation measured using a marker known as Fraction of Exhaled Nitric Oxide (FeNO). A follow-up study of the infants led by Professor Joerg Mattes, Dr Vanessa Murphy, Professor Peter Gibson and Heather Powell has now confirmed that respiratory risk factors are at play beyond a genetic predisposition.
“A family history of asthma, particularly when it’s the mother, markedly increases the risk for babies to have respiratory disease in early life and later to develop asthma,” Professor Mattes said. “We wondered whether giving women better asthma treatment during their pregnancy would have a flow-on effect.”
“The difference was stunning and somewhat unexpected in its magnitude. Of the babies born to mothers who were managed according to FeNO, only 1.5 per cent had recurrent bronchiolitis in the first year of life compared to 16 per cent for mothers managed according to symptoms.”
Figures for croup showed an almost tenfold difference in incidence rate, with 1.5 per cent compared to 11 per cent. Combined for both diseases, it was just 3 per cent for the FeNO group versus 26 per cent for the symptoms group.
From the 220 women assessed for MAP, 146 babies were initially followed up at 12 months of age and most recently at the age of four. The study results are published today in the international respiratory journal Thorax.
At the same time, laboratory-based researchers are now investigating possible causes.
“There are some question marks on what mechanisms are occurring and we are exploring various angles,” Professor Mattes said. “It’s possible that asthma attacks trigger an immune system response in both the mother and her unborn baby. Stress from an attack also releases hormones that may affect lung growth.”
The team has just commenced an expanded trial (Breathing for Life Trial) for pregnant mothers with asthma, which will involve more than 1000 women across multiple centres.
Virus-induced bronchiolitis is one of the most common causes of hospitalisation for infants and in rare circumstances can be fatal. Babies who suffer the disease have a substantially increased risk of developing asthma later in life.
Professor Gibson said clinicians in John Hunter Hospital were now using the MAP findings to help minimise drug exposure to the mother and developing foetus. “Treatments based on clinical symptoms alone can lead to over-treatment or under-treatment, both of which can have a significant impact on the health of the mother and baby,” he said.
Funding for the research has been provided by the NHMRC, the Gastronomic Lunch, HMRI and HCRF.
* Professor Joerg Mattes is Chair of Paediatrics and Child Health at the University of Newcastle, leads the Experimental and Translational Respiratory group at HMRI’s VIVA program and is a Respiratory Paediatrician at the John Hunter Children’s Hospital. HMRI is a partnership between the University of Newcastle, Hunter New England Health and the Community.