Study	Reason for exclusion
Al Mofada 1994	Patients were enrolled immediately after birth. The volume of RBC transfusions was reported as mL/week over the study period. We could not use this information in our outcome of total volume (mL/kg) of blood transfused per infant.
Amin 2002	This study was not a randomised controlled trial.
Basiri 2015	Infants were > 6 days old. Will be included in the 'Late EPO' review.
Bierer 2006	One of the authors of this study, Dr. R.K. Ohls, informed us that this study reported on a subgroup of Ohls 2001A. All outcomes of Bierer 2006 were included in the 2004 follow‐up publication of Ohls 2001A.
Brown 1999	This study compared 2 different dosing regimens for the same total weekly dose of EPO. The trial included no control or placebo group.
Costa 2013	This study assessed the effectiveness of IV vs SC administration of EPO and included no non‐treated group.
Fearing 2002	This study did not reveal the number of infants allocated to treatment and control groups, nor the age at which the infants entered into the study.
Haiden 2006a	This study reported the same findings as Haiden 2005.
Haiden 2006b	Both study groups received erythropoietin.
Juul 2008	This was not a randomised controlled trial.
Klipp 2007	This was a randomised controlled trial, but results showed no clinical outcomes of interest for this review.
Krallis 1999	No outcomes of interest for this review were reported.
López‐Catzín 2015	Upon consultation with one of the trial authors (Bolado‐Garcia PB), it was clarified that this was not a randomised controlled trial.
Maggio 2007	This randomised controlled trial compared the effectiveness of EPO administered by continuous intravenous vs subcutaneous route.
Maier 1998	This randomised controlled trial compared 2 doses of EPO: 750 IU/kg/week vs 1500 IU/kg/week without a non‐treated control group.
Ohls 1996	This study compared different routes of administration (SC EPO vs EPO added to the total parenteral nutrition fluid). This study included no untreated control group.
Saeidi 2012	This was a randomised controlled trial in which one group received oral EPO, and the other group SC EPO. The trial included no untreated control group.
Soubasi 2005	128 infants were randomised early (first week of life) to EPO group (n = 66) or control group (n = 62). The dose of EPO is not stated in the abstract. Infants randomised to EPO received significantly fewer transfusions and had less IVH.
Soubasi 2009	Not a randomised controlled trial (20 study participants and 20 concurrent controls).
Turker 2005	This study was labelled by trial authors as a quasi‐randomised (assignment on an alternating basis) trial. Study authors reported on uneven numbers in the 2 groups (42 infants in the EPO group and 51 in the control group). On request, the principal author provided the following information. "In the study period 112 premature infants < 1500 grams were followed in the NICU. Informed consents were obtained from the parents of 97 babies, but only 93 babies completed the study because 3 patients were lost to follow‐up after discharge and one baby died of bronchopulmonary dysplasia before completing the 12 week monitoring period. These 4 babies were omitted from the study group (r‐Hu EPO+enteral iron). These infants are included in the result section. At the end of the study r‐Hu EPO was not available, and 2 more patients had only iron supplementation. Then the study was closed and these 2 babies were also added to the control group". 97 participants (48 in EPO group; 3 lost‐to follow‐up; 1 death; ‐2 rHuEPO unavailable; 49 controls; +2) Based on this information, we excluded the study, as it was not a quasi‐randomised trial.
Vázquez López 2011	This randomised controlled trial compared 2 different dosing schedules of EPO. Group 1 (60 infants; mean postnatal age at entry 6 ± 3.1 days) received SC EPO at 250 units per kg per dose, 3 times weekly for 6 weeks. Group 2 (59 infants; mean postnatal age at entry 7 ± 3.9 days) received SC EPO at 750 units per kg per dose once weekly for 6 weeks. No untreated group was included.
Zhu 2009	Trial population consisted of infants > 37 weeks' PMA.

EPO: erythropoietin. IV: intravenous. IVH: intraventricular haemorrhage. RBC: red blood cell. SC: subcutaneous.