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 .
Growth in preterm infants fed either a partially hydrolyzed whey or an intact casein/whey preterm infant formula
Objective : To compare feeding tolerance , nutrient intake and growth in preterm infants ( ⩽32 weeks , ⩽1750 g ) fed either a st and ard nonhydrolyzed whey – casein ( nHWC ) or a partially hydrolyzed whey ( pHW ) preterm infant formula .  Study Design : In this double-blind r and omized controlled trial infants were fed either formula for at least 3 weeks . Intake was monitored daily , serum chemistries and growth weekly . Data were analyzed using analysis of covariance . Result : A total of 80 infants were enrolled , 72 completed the study . No differences were noted in demographic characteristics . No differences were detected in feeding tolerance , intakes ( 118±21 vs 119±14 ; nHWC vs pHW ) or growth weight , 28±1.5 vs 28±1.6 g per day ; length , 1.0±0.7 vs 1.0±0.6 cm per week ; head circumference , 0.9±0.4 vs 1.0±0.44 cm per week ) . At the end of study , blood urea nitrogen ( 5.2±3.1 < 6.7±2.3 mg per 100 ml , nHWC < pHW ) , total serum proteins ( 4.7±0.4 > 4.4±0.5 g per 100 ml ) and albumin ( 2.7±0.3 > 2.6±0.4 g per 100 ml ) differed . Conclusion : A pHW preterm infant formula was not associated with improved feeding tolerance , enteral intake or growth but differences in serum chemistries . These are unlikely to be clinical ly relevant because values were well within normal limits for preterm infants , whereas growth was identical in both groups and paralleled that ‘ in utero ’
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 .