McEvoy 2010.

Methods	Type of study: randomised trial.
Participants	Location: 2 centres in USA (Sacred Heart Hospital, University of Florida, Pensacola, Florida recruited first 8 patients; Oregon Health and Science University). Timeframe: From June 2001 to May 2007. Eligibility criteria: women at 26 to < 34 weeks' gestation; at least 14 days after first course of antenatal corticosteroids (93% received betamethasone); at continued risk of preterm delivery as determined by their care provider; who provided informed consent. Gestational age range: 26 to < 34 weeks' gestation. Exclusion criteria: women were excluded if they were insulin‐dependent diabetics, had a major documented fetal or chromosomal abnormality; multiple pregnancy greater than twins; clinical chorioamnionitis; first course of antenatal corticosteroids given < 24 weeks' gestation; chronic steroid use during pregnancy for clinical care. Total recruited: 85 women randomised (113 babies alive at randomisation). 44 women (56 babies) in the rescue corticosteroids group and 41 women (57 babies) in the placebo group.
Interventions	In the rescue group: course of antenatal corticosteroids (2 doses of 12 mg/dose betamethasone (Celestone Soluspan; Schering Corporation, Kenilworth, New Jersey), intramuscularly, 24 hours apart. In the placebo group: 2 doses of placebo (identical in appearance to betamethasone: 25 mg cortisone acetate, an inactive steroid).
Outcomes	Primary outcomes: respiratory compliance and functional residual capacity (measured within 72 hours of birth (before any surfactant). Secondary outcomes: growth measurements including weight, head circumference and length at birth and hospital discharge; surfactant administration; RDS (defined as clinical signs of respiratory distress with radiographic appearance and needing supplemental oxygen with FiO2 > 0.21); respiratory distress requiring ≥ 0.30 and ≥ 0.40 at 24 hours of age; days on mechanical ventilation and days on supplemental oxygen.
Funding Support	Oregon Health and Science University, GCRC/PHS Grant 5 MO1 RR000334; OCTRI UL1 RR02414001; and The American Lung Association.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Group assignment performed using a randomisation table. A staff pharmacist performed randomisation and study drug preparation at each institution. Stratification: ≤ 28 versus > 28 weeks' gestation; multiple gestation (twins versus singletons).
Allocation concealment (selection bias)	Low risk	Method of treatment allocation: "group assignment was performed using a randomisation table. A staff pharmacist performed randomisation and study drug preparation". Stratification: ≤ 28 versus > 28 weeks' gestation; multiple gestation (twins versus singletons).
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"All patients, investigators and care providers were unaware of the treatment allocation."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Losses to follow‐up: neonatal data not available for 1 baby in the placebo group. Intention‐to‐treat analyses: yes.
Selective reporting (reporting bias)	Low risk	No obvious risk of selective reporting.
Other bias	Low risk	No other obvious risk of bias detected.