title: Antenatal dexamethasone vs. betamethasone dosing for lung maturation in fetal sheep.
abstract: 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-PO4alone.
  
  
  
  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-PO4at 6, 12, or 24 h 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.
  
  
  
  All treatments improved lung compliance and ventilation efficiency. Only Beta-Ac + Beta-PO4required lower positive inspiratory pressure compared with control. Beta-Ac + Beta-PO4and Beta-PO4alone, but not Dex-PO4, increased the mRNA of surfactant proteins compared with control. Low-dose Beta-PO4did not increase mRNA of surfactant proteins. There were no differences among Beta-PO4treatment intervals.
  
  
  
  Beta-Ac + Beta-PO4given as two doses 24 h apart was more effective in promoting fetal lung maturation than Dex-PO4or Beta-PO4alone, consistent with a prolonged exposure provided by the Beta-Ac + Beta-PO4. These results support the clinical use of combined Beta-Ac + Beta-PO4preparations over phosphate corticosteroids alone for fetal lung maturation.
authors.affiliation: Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Augusto F
authors.initials: AF
authors.lastname: Schmidt
authors.affiliation: School Women's and Infants' Health, University of Western Australia, Perth, Australia.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Kemp
authors.affiliation: Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Paranthaman S
authors.initials: PS
authors.lastname: Kannan
authors.affiliation: Department of Pediatrics, University of Maastricht, Maastricht, Netherlands.
authors.forename: Boris W
authors.initials: BW
authors.lastname: Kramer
authors.affiliation: School Women's and Infants' Health, University of Western Australia, Perth, Australia.
authors.forename: John P
authors.initials: JP
authors.lastname: Newnham
authors.affiliation: Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Suhas G
authors.initials: SG
authors.lastname: Kallapur
authors.affiliation: Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Alan H
authors.initials: AH
authors.lastname: Jobe
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use; D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000627:therapeutic use; D001794:Blood Pressure; D003907:Dexamethasone / Q000008:administration & dosage* / Q000627:therapeutic use; D005260:Female; D005325:Fetal Organ Maturity; D005865:Gestational Age; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use; D007273:Injections, Intramuscular; D008168:Lung / Q000187:drug effects* / Q000196:embryology* / Q000502:physiology; D008297:Male; D011247:Pregnancy; D012756:Sheep; D034561:Sheep, Domestic; D013997:Time Factors
chemical_list: D000305:Adrenal Cortex Hormones; D005938:Glucocorticoids; C028994:betamethasone sodium phosphate; D003907:Dexamethasone; D001623:Betamethasone