Background
Breast milk contains prebiotic oligosaccharides that promote enteral tolerance and intestinal colonisation with non-pathogenic bacteria. However, many mothers delivering preterm are unable to provide sufficient milk.

Aim
To investigate the effect of a preterm formula containing 0.8% prebiotic oligosaccharides (90% galacto-oligosaccharides, 10% fructo-oligosaccharides) on enteral tolerance.

Study design
We conducted a UK multicentre randomised controlled trial involving 160 infants born <33 weeks. Infants were randomised within 24h of birth with stratification by gestational age and centre, to receive Nutriprem 1 (standard preterm formula) or Nutriprem 1 containing prebiotic oligosaccharides (trial formula), to augment insufficient maternal milk volume. Primary outcomes were time to establish a total milk intake of 150 ml/kg/day and extent to which a total milk intake of =150 ml/kg/day was tolerated between birth and term/discharge. Secondary outcomes included growth, faecal characteristics, gastrointestinal signs, necrotising enterocolitis and infection. Outcomes were adjusted for pre-specified covariates.

Results
There were no significant differences in baseline characteristics, time to tolerate 150 ml/kg/day or secondary outcomes. Significant benefit occurred in infants <29 weeks gestational age receiving trial formula with a 12.3% increase in the proportion of days between birth and term/discharge that a total daily milk intake of =150 ml/kg was tolerated (p=0.03).

Conclusions
Prebiotic oligosaccharide supplementation improves enteral tolerance in extremely preterm infants.