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Updated: Jun 19, 2026
Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings
Published on: October 25, 2015
Betamethasone dose and formulation for induced lung maturation in fetal sheep
Alan H Jobe1, Ilias Nitsos, J Jane Pillow
1Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA.
Objective:
We hypothesized that maternal treatments with betamethasone acetate induce fetal lung maturation comparably to the betamethasone phosphate+betamethasone acetate used clinically.
Study Design:
Ewes with singleton pregnancies were treated with single doses of 0.25-mg/kg or 0.5-mg/kg betamethasone acetate, 4 doses of 0.25-mg/kg betamethasone phosphate, a single dose of 0.5-mg/kg betamethasone acetate+0.25-mg/kg betamethasone phosphate, 2 doses of 0.25-mg/kg betamethasone acetate+0.25-mg betamethasone phosphate or vehicle beginning 48 hours before preterm delivery. Fetal lung maturation was evaluated.
Results:
All treatments induced lung maturation relative to vehicle controls. The relatively insoluble betamethasone acetate resulted in low maternal blood betamethasone and no detectable fetal blood betamethasone in 2 of 3 fetuses, but it induced fetal lung maturation comparable to the 2-dose betamethasone acetate+betamethasone phosphate or 4 doses of betamethasone phosphate.
Conclusion:
A single maternal dose of betamethasone acetate effectively induces fetal lung maturation in sheep with minimal fetal exposure.
