Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: " Study participants were randomly assigned to probiotic or placebo by the use of a computer‐generated balanced block randomization scheme"
Allocation concealment (selection bias)	Low risk	Quote: "Treatment assignment was performed by using sealed, sequentially numbered, opaque envelopes, color‐coded for strata, available in each NICU pharmacy"
Blinding of participants and personnel (performance bias)	Low risk	Quote: "Infants were administered probiotic or placebo regardless of whether enteric feeds were started"
Blinding of outcome assessment (detection bias)	Low risk	The authors do not report clearly if the outcome assessment was blinded, however in the setting of adequate allocation concealment and blinding of interventions it is less likely the outcome assessors knew the intervention vs placebo group
Incomplete outcome data (attrition bias)	Low risk	Quote: "The study was terminated before the completion of the targeted sample because of a substantial drop in patient recruitment among participating institutions as well as funding restrictions that limited our ability to recruit the required additional subjects"
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