Study	Reason for exclusion
Abrams 2014	A combined reanalysis of Sullivan 2010 and Cristofalo 2013 studies. The control group received bovine milk‐based preterm formula instead of donor breast milk to supplement mother's own milk.
Adhisivam 2018	The control group did not receive any fortification.
Assad 2016	The study design involved a retrospective study.
Colacci 2017	The study design involved a retrospective study comparing human milk‐derived fortifier with bovine milk‐derived fortifier.
Corpeleijn 2016	In this study, the comparison was between donor milk and formula.
Cristofalo 2013	The control group received preterm formula instead of donor breast milk to supplement mother's own milk.
Ganapathy 2012	This was a cost‐effectiveness analysis of human milk‐based diet. The subjects comprised the study groups from Sullivan 2010 study. The control group was supplemented with bovine milk‐based formula instead of donor breast milk.
Ghandehari 2012	Reanalysis of Sullivan 2010 study
Sullivan 2010	In this study, the control group received bovine milk‐based formula instead of donor breast milk to supplement mother's own milk.