Watterberg 1999.

Study characteristics
Methods	Two‐centre double‐blind randomised controlled trial
Participants	Inclusion: 40 infants weighing between 500 grams and 999 grams who were AGA and needed mechanical ventilation, < 48 hours of age Exclusions: maternal diabetes, congenital sepsis, SGA
Interventions	Hydrocortisone 1.0 mg/kg/d every 12 hours for 9 days, 0.5 mg/kg/d for 3 days Control infants were given an equal volume of normal saline
Outcomes	Primary outcome Survival without supplemental oxygen at 36 weeks' post conception Secondary outcomes among survivors BPD at 36 weeks Duration of mechanical ventilation, > 40% oxygen, > 25% oxygen Hospital stay Weight and head circumference at 36 weeks
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random allocation at each centre by constant block design with 4 participants per block to minimise bias over time. Separate randomisation tables were used for infants exposed to antenatal corticosteroids
Allocation concealment (selection bias)	Low risk	Allocation concealment: yes
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding of intervention: yes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding of outcome measurement: yes
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete follow‐up: yes
Selective reporting (reporting bias)	Low risk	All prespecified outcomes reported
Other bias	Low risk	None