Background: Asthma is a common disease affecting 12% of Australian women with 55% of women experiencing at least one exacerbation during pregnancy. Exacerbations during pregnancy are associated with low birthweight neonates and stillbirth. One of the main reasons for maternal exacerbations during pregnancy is non-compliance with inhaled glucocorticoid treatment due to the misconception that inhaled glucocorticoids are harmful to the fetus.
Aims and methods: We have therefore assessed whether the commonly used inhaled glucocorticoids reduce placental glucocorticoid metabolising capacity, by measuring 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD-2) activity. As these treatments potentially increase the exposure of the fetus to the growth-inhibiting effects of glucocorticoids, we also examined the question of whether inhaled glucocorticoid use was associated with reduced birthweight. Pregnant women using budesonide (n = 18), fluticasone propionate alone (n = 14) and fluticasone propionate in combination with the long-acting β2 agonist salmeterol (n = 9) were compared to a non-asthmatic control group (n = 20).
Results: The use of inhaled budesonide was associated with significantly increased placental 11β-HSD-2 activity relative to the control group. Inhaled glucocorticoid use for the treatment of asthma was associated with normal birthweight. In the small number of women using combination therapy (fluticasone and salmeterol), there was reduced birthweight compared to the control group.
Conclusion: Inhaled glucocorticoids alone do not adversely affect fetal growth and placental function.