The identified trials provide only low quality evidence about the effects of feeding preterm infants  with protein hydrolysate versus st and ard formula .
The existing data did not support conclusions that feeding with protein hydrolysate affects the risk of feed intolerance or necrotising enterocolitis .
BACKGROUND When human milk is not available for feeding preterm infants , protein hydrolysate rather than st and ard cow 's milk formulas ( with intact proteins ) are often used because they are perceived as being tolerated better and less likely to lead to complications .
However , protein hydrolysate formulas are more expensive than st and ard formulas , and concern exists that their use in practice is not supported by high- quality evidence .
OBJECTIVES To assess the effect of feeding preterm infants with hydrolysed formula ( versus st and ard cow 's milk formulas )  on the risk of feed intolerance , necrotising enterocolitis , and  other morbidity and mortality in preterm infants .
Higher urinary excretion of essential amino acids in preterm infants fed protein hydrolysates
Aim : Protein hydrolysates have been introduced in preterm formulae , but it is not clear whether they are needed for the feeding of preterm infants . We design ed a r and omized , controlled trial to test the effects of a preterm formula with hydrolysed cow 's milk proteins on short‐term growth and urinary and plasma amino acids levels . Methods : Infants with a birthweight 1750 g and gestational age 34 wk fed a conventional preterm infant formula ( formula B ) or a hydrolysed formula ( formula A ) .  Weight was measured daily ; length , head circumference , mid‐arm circumference and total skinfold thickness were measured weekly . Blood and urine were analysed for amino acid concentrations at start , 14 and 28 d. Results : Twenty‐one infants met the criteria for r and omization . The daily feeding volumes were : formula A 172.8±5.6 vs formula B 170.1±2.8 ml/kg/d . Infants fed with formula A showed slower weight gain ( 17.4±3.4 vs 20.5±3.3 g/kg/d ; p=0.045 ) and lower mean change in Z‐scores for weight ( −0.18±0.16 vs 0.00±0.09 ; p=0.009 ) and for head circumference ( −0.06±0.13 vs 0.06±0.13 ; p=0.049 ) . After 14 d , infants receiving formula A had statistically significant higher urinary levels of essential amino acids compared to infants receiving formula
The identified trials provide only low quality evidence about the effects of feeding preterm infants  with protein hydrolysate versus st and ard formula .
The existing data did not support conclusions that feeding with protein hydrolysate affects the risk of feed intolerance or necrotising enterocolitis .
BACKGROUND When human milk is not available for feeding preterm infants , protein hydrolysate rather than st and ard cow 's milk formulas ( with intact proteins ) are often used because they are perceived as being tolerated better and less likely to lead to complications .
However , protein hydrolysate formulas are more expensive than st and ard formulas , and concern exists that their use in practice is not supported by high- quality evidence .
OBJECTIVES To assess the effect of feeding preterm infants with hydrolysed formula ( versus st and ard cow 's milk formulas )  on the risk of feed intolerance , necrotising enterocolitis , and  other morbidity and mortality in preterm infants .