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 .
Hydrolysed protein accelerates the gastrointestinal transport of formula in preterm infants
Vomiting , large gastric residuals and abdominal distension are common in very immature infants on formula feeding . The present trial investigated whether a protein hydrolysate formula reduces the gastrointestinal transit time in preterm infants . Fifteen preterm infants ( median gestational age 29 ( 24–32 ) wk , birthweight 1241 ( 660–1900 ) g , postnatal age 18 ( 5–54 ) d ) on full enteral feeds ( > 150 ml/kg*d ) were enrolled . It was hypothesized that the gastrointestinal transit time is at least 2 h shorter when protein hydrolysate formula is fed compared with st and ard preterm formula . In a r and omized cross‐over design study , each formula was fed for 5 d. On days 4 and 9 the gastrointestinal transit time was estimated using carmine red . The protein hydrolysate formula had a markedly shorter gastrointestinal transit time ( 9.8 h ) than the st and ard formula ( 19 h ) ( p= 0.0022 , two‐sided Mann‐Whitney U test )
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 .