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.
“This suggests that there may be a potential beneficial effect of inhaled corticosteroids therapy in pregnancy for reducing childhood asthma risk,” the researchers wrote in the Journal of Allergy and Clinical Immunology.
“ We propose that FeNO-guided asthma management resulted in an optimised monthly treatment decision regarding the use and dose of inhaled corticosteroids by considering Th2 cytokine-induced airway inflammation along with clinical symptoms.
The results supported the clinical consensus that the benefits of ICS therapy in pregnancy largely outweigh their potential risks,” the researchers said.
“Our study has important clinical implications because asthma is the most common chronic disease to affect pregnant women, making improvements in this area clinically relevant for a significant number of women and their children.
“Implementation of this approach in clinical practice has the potential to reduce asthma rates among a group of children at high-risk of developing the disease,” they concluded.