Asthma management in pregnancy and infant respiratory outcomes

<bold>Background:</bold> Improved asthma management in pregnancy has been associated with reduced respiratory symptoms in infants. We analysed a randomized controlled trial which adjusted maternal asthma medication based on fractional exhaled nitric-oxide (FeNO) and symptoms to assess whether infant respiratory outcomes improved. <bold>Methods:</bold> From 2013-2022, 1315 pregnant women from 6 centres in Australia were recruited (12-23 weeks gestation) and randomized to FeNO-based management or usual care (Breathing for Life Trial). At 12 months of age, hospital records for bronchiolitis and wheeze were accessed and respiratory information was reported by parents using a validated questionnaire. Logistic regression was used to assess associations between FeNO management and bronchiolitis, croup and wheeze. A secondary multivariate analysis assessed whether exacerbations in pregnancy were associated with infant respiratory outcomes regardless of randomisation. <bold>Results:</bold> FeNO management in pregnancy was not associated with reduced exacerbations in pregnancy, hospital presentations for bronchiolitis (OR 1.07, 95%CI 0.73,1.59), recurrent bronchiolitis (OR 1.08 95%CI 0.65,1.80), any wheeze or croup. Asthma exacerbations in pregnancy were associated with parent-reported bronchiolitis (aOR 1.74, 95%CI 1.06,2.87) and wheeze (aOR 1.81, 95%CI 1.17,2.94) but not with hospital presentations for bronchiolitis or wheeze. <bold>Conclusion:</bold> FENO-based asthma management had no impact on respiratory infant outcomes. However, exacerbations in pregnancy increased the risk of parent-reported bronchiolitis and wheeze in the first year of life. Novel approaches for asthma management which reduce exacerbations in pregnancy are needed and may improve infant respiratory health.