Antenatal dexamethasone vs. betamethasone dosing for lung maturation in fetal sheep

Augusto F. Schmidt, Matthew W. Kemp, Paranthaman S. Kannan, Boris W. Kramer, John R. Newnham, Suhas G. Kallapur, Alan H. Jobe*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


BACKGROUND: Dexamethasone-phosphate (Dex-PO4) and the combination betamethasone-phosphate (Beta-PO4) + betamethasone-acetate (Beta-Ac) are the most used antenatal corticosteroids to promote fetal lung maturation. We compared fetal lung maturation induced by Beta-Ac+Beta-PO4, Dex-PO4, or Beta-PO4 alone.

METHODS: Pregnant ewes received two intramuscular doses 24 h apart of 0.25 mg/kg/dose of Beta-Ac+Beta-PO4, Dex-PO4 or Beta-PO4; or 2 doses of 0.125 mg/kg/dose of Beta-PO4 at 6, 12, or 24h intervals. Fetuses were delivered 48 h after the first dose and ventilated for 30 min. We assessed ventilatory variables, vital signs, and blood gas. After ventilation pressure-volume curves were measured and lungs were sampled for analysis.

RESULTS: All treatments improved lung compliance and ventilation efficiency. Only Beta-Ac + Beta-PO4 required lower positive inspiratory pressure compared with control. Beta-Ac + Beta-PO4, and Beta-PO4, alone, but not Dex-PO4, increased the mRNA of surfactant proteins compared with control. Low-dose Beta-PO4 did not increase mRNA of surfactant proteins. There were no differences among Beta-PO4, treatment intervals.

CONCLUSION: Beta-Ac + Beta-PO4 given as two doses 24 h apart was more effective in promoting fetal lung maturation than Dex-PO4 or Beta-PO4 alone, consistent with a prolonged exposure provided by the Beta-Ac + Beta-PO4. These results support the clinical use of combined Beta-Ac + Beta-PO4, preparations over phosphate corticosteroids alone for fetal lung maturation.

Original languageEnglish
Pages (from-to)496-503
Number of pages8
JournalPediatric Research
Issue number3
Publication statusPublished - Mar 2017


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