An effect of asthma in pregnancy on the development of childhood asthma may be preventable. Members of our research team have trialled a highly innovative approach to managing asthma during pregnancy using a non-invasive inflammatory biomarker in exhaled air (fractional exhaled nitric oxide, FeNO) for personalised asthma medication adjustments.
The results from the Management Asthma in Pregnancy (MAP) randomised controlled trial (RCT) have demonstrated a significant reduction in asthma exacerbations during pregnancy using FeNO-guided management as compared to management guided by clinical symptoms only. In hypothesis-generating studies, we have also found a lower prevalence of recurrent bronchiolitis in the first year of life (odds ratio [OR] 0.08; p=0.02) and early-onset childhood asthma (OR 0.46, p=0.04) in MAP children born to mothers from the FeNO group.
In the NHMRC funded Breathing for Life Trial, a follow-up RCT, lung function is being measured at 6 weeks of age and again at 4 years of age in children born to mothers randomised to FeNO-guided asthma management or routine clinical care during pregnancy. White blood cells in the cord blood correlated with improved lung function at 6 weeks of age in the case of neutrophils and worsened lung function at 6 weeks of age in the case of eosinophils suggesting they are crucially important but no data has been gathered on the function of these cells or their relationship to lung function in childhood asthma (4 years).
The current NHMRC funding covers the clinical characterisation of babies born to mothers in the BLT trial but does not extend to studies designed to understand the mechanisms or immunological alterations associated with this world-first primary prevention of asthma development. The BLT paediatric cohort provides a well clinically characterised population randomised to the pregnancy intervention that is a unique opportunity to conduct preliminary hypothesis generating studies and generate novel data as the first step to expanding the primary prevention of asthma to other high-risk individuals whose mothers did not have asthma during pregnancy.
Here we will for the first time investigate if infants and children born to mothers who randomly allocated to FeNO-guided management of asthma during pregnancy have; Altered immune function at birth and/or 4 years of age detectable by differences in white blood cells levels and activity compared to infants and children born to mothers who were randomly allocated normal asthma management during pregnancy, corresponding to improved lung function at birth and improved lung growth in childhood. This represents a major breakthrough towards a primary prevention strategy for asthma.