Gross 1983

Methods	Randomised controlled trial
Participants	67 preterm infants (27 to 33 weeks) Birth weight < 1600 g. Excluded if "congenital anomaly or major disease" Department of Pediatrics, Duke University, USA 1980 to 1982
Interventions	Term formula milk (N = 26) versus unfortified, pasteurised donor breast milk (N = 41). Feeds were assigned until the infant reached a weight of 1800 g or until withdrawn from the study because of feeding intolerance or NEC
Outcomes	Time to regain birth weight Mean daily gain in weight, length and head circumference, from regaining birth weight until reaching 1800 g Data on adverse events can be determined, although these were not primary endpoints of the study
Notes	Although the report gave information on adverse outcomes, the 7 affected infants were withdrawn from the study and not included in the analyses of growth rates. Therefore, growth data are reported for 20 infants in each arm of the trial
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random number table
Allocation concealment (selection bias)	Unclear risk	Method not stated "Any infant withdrawn from the study was replaced by the next one enrolled"; implies lack of allocation concealment for these infants
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No information given
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	7 out of 67 (10%) with adverse outcomes (NEC, mortality) were not assessed for growth outcomes. This included 6/26 (23%) in the formula group and 1/41 (2.4%) in the donor breast milk group, so potential bias 100% follow‐up and low risk of bias for mortality and NEC
Selective reporting (reporting bias)	Unclear risk	Protocol not available
Other bias	Unclear risk	Funded by Mead Johnson Nutrition