Children whose mothers have asthma are 50% less likely to develop asthma themselves if their mother’s asthma is well controlled with inhaled steroids in pregnancy, an Australian study has shown.
The findings come from a long term follow up study of children whose mothers had their asthma treatment in pregnancy guided by a treatment algorithm based on the fraction of exhaled nitric oxide (FeNO) – a marker of airways inflammation.
The FeNO-guided treatment had previously been shown in a randomised trial of 179 mothers to reduce asthma exacerbations in pregnancy compared to symptom-guided treatment. According to researchers at the Hunter Medical Research Institute and University of Newcastle, NSW, this was presumed to be related to more optimal dosing of inhaled corticosteroids achieved with FeNo-guided treatment.
In their follow up study of 140 of the children, those born to mothers who received FeNO-guided treatment in pregnancy had about half the rate of doctor-diagnosed asthma by the age of 4-6 years (25.9% vs 43.2%) compared to those born to mothers in the control group.
Furthermore, children born to mothers with FeNO-guided asthma treatment also had significantly less wheeze and bronchiolitis (Odds Ratio 0.27), less use of short-acting beta-agonists (OR 0.49) and fewer emergency department visits (OR 0.17) compared to children whose mothers did not have FeNO-guided asthma treatment in pregnancy.
The asthma was diagnosed in children by doctors blinded to the mother’s pregnancy asthma treatment and the asthma was shown to be independent of the 17q21 locus alleles for early-onset asthma.
The study also showed that the reduction in childhood asthma seen with FeNO-guided treatment in pregnancy was linked to more consistent use of inhaled corticosteroids in the mother’s pregnancy.