Inhaled corticosteroids may enhance respiratory health of infants born to women with asthma: Study

Tidal breathing flow–volume loops and functional residual capacity were used to evaluate infant lung function. The ratio of time to peak tidal expiratory flow to expiratory time (tPTEF:tE), normalized to functional residual capacity to account for variations in lung size and maturation, was used to quantify airway function.

The results of 232 newborns were compared: infants of mothers without asthma, infants of mothers with asthma who did not use ICS during pregnancy (n = 25), and infants of mothers with asthma who used ICS during pregnancy (n = 161). Prenatal or postpartum self-report was used to determine the usage of ICS by mothers.

When asthmatic mothers used ICS during pregnancy, the ratio of time to peak tidal expiratory flow to expiratory time (tPTEF:tE), adjusted for end-expiratory lung volume (FRC), was better in the offspring (n=161 ICS use vs. n=25 no ICS use; coefficient 0.06 /mL, 95% CI 0.01 to 0.11, p=0.014).

Infants born to asthmatic mothers who did not use ICS had a lower tPTEF:tE to FRC ratio (n=46 no asthma vs. n=25 asthma no ICS use; coefficient −0.08 /mL, 95% CI −0.01 to −0.02, p=0.012) than infants born to asthmatic mothers who did use ICS. Overall, interestingly, tPTEF:tE adjusted for FRC [functional residual capacity] did not significantly vary between infants born to moms without asthma and those born to mothers with asthma who took ICS throughout pregnancy. 

Source:

Martins Costa Gomes, G., Collison, A. M., Karmaus, W. J. J., Da Silva Sena, C. R., Murphy, V. E., Brew, B. K., Grace, T., Robinson, P. D., Sly, P. D., Frey, U., Latzin, P., Wyler, F., Pennell, C. E., Gibson, P. G., & Mattes, J. (2025). Association between maternal asthma and impaired infant lung function is diminished by inhaled corticosteroid use in pregnancy. Thorax, thorax-2025-223539. https://doi.org/10.1136/thorax-2025-223539