Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "the infants were randomly assigned to two groups by random number table sequence"
Allocation concealment (selection bias)	Unclear risk	No details are provided
Blinding of participants and personnel (performance bias)	Unclear risk	No details are provided
Blinding of outcome assessment (detection bias)	Unclear risk	No details are provided
Incomplete outcome data (attrition bias)	Low risk	Minimal loss to follow up
Selective reporting (reporting bias)	Low risk	Authors seem to report all the relevant outcomes
Other bias	Low risk	No other risk of bias was noted