Lally 2006.

Methods	RCT.
Participants	All women with fetus shown to have CDH prior to 34 weeks.
Interventions	Intervention: Betamethasone (12.5 mg) 2 doses 24 hours apart (given at 34 weeks) followed by 2 weekly doses. Control: placebo (the composition of the placebo was not stated in the trial report).
Outcomes	Mortality, ventilator days, need for oxygen at 30 days, length of hospital stay, birth data, Apgar scores, treatments received.
Notes	Women were randomised women from participating hospitals in the US, Italy, Germany and Australia. This trial was partly funded by NIH grants K24RR17050 and M01RR002558.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"central randomisation centre."
Allocation concealment (selection bias)	Unclear risk	Not stated other than "central randomisation centre".
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	"Investigators were blinded", no other mention of blinding.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	"Investigators were blinded", no other mention of blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	One woman in each group withdrew with outcome data not available, analysis by intention‐to‐treat.
Selective reporting (reporting bias)	Low risk	No apparent selective reporting.
Other bias	Low risk	Stopped early as interim analysis suggested unlikely that sufficient patients would be enrolled to determine an outcome. No apparent baseline differences.