Table 3.
Methodological characteristics of the studies analyzed.
| Authors | Design | Sample Size | Inclussion Criteria | Exclussion Criteria | JADAD Scale | LE | |||
|---|---|---|---|---|---|---|---|---|---|
| RD * | BD ** | WD *** | FS | ||||||
| Baldassarre et al. (2019) [19] | RCT | 60 | 28–33 weeks GA. Birth of a singleton or twins. Birth weight between 700–1750 g and appropriate for GA. Enteral intake less than 30 mL/kg/day or none at baseline. | Apgar less than 4 at five minutes of life. Presence of chronic diseases, metabolic disturbance, congenital malformation, unstable blood pressure, and/or intraventricular haemorrhage. History of surgery. Need for ventilator or more than 40% inspired oxygen fraction. | 2 | 2 | 1 | 5 | I |
| Costa et al. (2018) [20] | QES | 70 | GA less than 32 weeks. Beginning of enteral feeding in the first seven days of life. Breast feeding not available or insufficient | Presence of infections, congenital malformation, abnormal prenatal Doppler flow velocity and/or abnormal prenatal velocimetry. | 2 | 0 | 1 | 3 | II |
| Toftlund et al. (2018) [21] | RCT | 235 | GA less than 32 weeks. | Serious illnesses or circumstances influencing feeding. | 1 | 0 | 1 | 2 | I |
| Corpeleijn et al. (2016) [22] | RCT | 373 | Birth weight less than 1500 g. | Toxic substance use during pregnancy. Presence of congenital defects or anomalies and/or infections. History of perinatal asphyxia with umbilical pH below 7 and/or intake of formula milk prior to surgery. | 2 | 2 | 1 | 5 | I |
| O’Connor et al. (2016) [23] | RCT | 363 | Birth weight less than 1500 g. Start of enteral nutrition in the first seven days of life. | Presence of congenital defects or anomalies. History of severe birth asphyxia. | 2 | 2 | 1 | 5 | I |
| Willteitner et al. (2017) [24] | RCT | 70 | Birth weight between 500 and 1499 g. | Presence of congenital anomalies and/or gastrointestinal diseases. | 2 | 2 | 1 | 5 | I |
| Da Cunha et al. (2016) [25] | RCT | 53 | Birth weight less than 1500 g. Infants admitted to the Neonatal Intensive Care Unit. | Presence of malformations, hydrocephalus, chromosomal abnormalities, hydrops fetalis, infections and/or necrotising enterocolitis. Born of a twin pregnancy. Consumption of toxic substances and/or corticosteroids during pregnancy. | 2 | 0 | 1 | 3 | I |
| Kim et al. (2015) [26] | RCT | 129 | GA less than 33 weeks. Birth weight between 700 and 1500 g. Enteral feeding in the Neonatal Intensive Care Unit and during the first 21 days of life. | Apgar less than 5 at five minutes of life. Presence of congenital anomalies. History of severe intraventricular haemorrhage, major abdominal surgery, severe asphyxia, necrotising enterocolitis, and/or consumption of probiotics and/or postnatal corticosteroids. | 2 | 0 | 0 | 2 | I |
| Chen et al. (2020) [27] | PCS | 60 | GA less than 36 weeks and/or birth weight less than 2500 g. Admission to Neonatal Intensive Care Unit. | Presence of congenital malformations. | 0 | 0 | 0 | 0 | II |
| Martins-Celini et al. (2018) [28] | RCS | 649 | Birth weight less than 1500 g. | Presence of congenital malformations. | 0 | 0 | 0 | 0 | II |
| Pillai et al. (2018) [30] | PCS | 29 | None. | Presence of congenital and/or macrosomic anomalies. Diagnosis of multi-organ and/or intestinal dysfunction. | 0 | 0 | 1 | 1 | II |
| Kim et al. (2017) [31] | RCS | 90 | Birth weight less than 1500 g. GA less than 32 weeks. Admission to the Neonatal Intensive Care Unit. | Presence of congenital and/or metabolic abnormalities. BM-fed exclusive before 130 mL/kg/day. | 0 | 0 | 1 | 1 | II |
| Lofti et al. (2016) [32] | PCS | 58 | Birth weight less than 1500 g. Admission to Neonatal Intensive Care Unit. | None. | 0 | 0 | 0 | 0 | II |
| Fernandes et al. (2019) [33] | PCS | 51 | GA less than 37 weeks. Birth weight less than 1250 g. | None. | 0 | 0 | 0 | 0 | II |
| Hogewind-Schoonenboom et al. [34] | RCS | 174 | GA less than 32 weeks. Birth weight less than 1750 g. | None. | 0 | 0 | 0 | 0 | II |
| Jang et al. (2018) [35] | RCS | 60 | GA between 29 and 32 weeks. Admitted to the Neonatal Intensive Care Unit. | Presence and/or history of sepsis, necrotising enterocolitis and/or asphyxia. | 0 | 0 | 0 | 0 | II |
GA: Gestational age; LE: Level of evidence; PCS: Prospective cohort study; RCS: Retrospective cohort study. * RD: Randomization (1 point if randomization is mentioned; 2 points if the method of randomization is appropriate). ** BD: Blinding (1 point if blinding is mentioned; 2 points if the method of blinding is appropriate). *** WD: Withdrawals (1 point if the number and reasons in each group are stated).