Effect of Antenatal Corticosteroid Treatment on Lung Function in Full-term Newborn Infants

Background: Antenatal treatment of pregnant women with corticosteroids in order to stimulate surfactant production has been shown to be effective. However, lung structure is also affected by the treatment.

Objective: We tested the hypothesis that changes within lung acini, induced by maternal corticosteroid treatment, persist during lung development.

Methods: Twenty-two healthy infants, whose mothers were treated with up to three doses of betamethasone at 25-33 weeks of pregnancy because of preterm labour, but where labour terminated and the infants were born at term, were studied at term and compared to a group of 50 healthy newborn infants without prenatal treatment with corticosteroids. Gas-mixing efficiency was measured in terms of moment ratio with a nitrogen washout method together with functional residual capacity. Mechanical parameters were assessed with the single occlusion technique.

Results: There were no signs of disturbed gas mixing or changed lung volume or mechanics in the treated group.

Conclusion: The result contributes to an emerging body of evidence that antenatal treatment with corticosteroids does not permanently affect lung structure or function.