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 .
Application effect of extensively hydrolyzed milk protein formula and follow-up in preterm children with a gestational age of less than 34 weeks: study protocol for a randomized controlled trial
Background The average incidence of preterm birth in the world is up to 11.1 % , and deaths of preterm children account for more than 50 % of neonatal deaths . Gastrointestinal function of preterm children with a gestational age less than 34 weeks is immaturely developed . For preterm children who can only be fed with formula due to their mothers ’ sickness , choosing a suitable formula can not only meet the high nutritional needs of preterm children , but also solve their low gastrointestinal tolerability , and is thus very important . Methods / Design The study is a prospect i ve , r and omized , single-blind and controlled clinical trial . Preterm children with a gestational age less than 34 weeks meeting the inclusion criteria who can not be breastfed will be included . To demonstrate the application effect of extensively hydrolyzed milk protein formula on the target population , preterm children will be r and omized into two groups , 185 subjects in each group . The observation group will be fed with extensively hydrolyzed milk protein ( 100 % whey protein ) formula , while the control group will be fed with preterm children ’s formula until the children are discharged from the neonatal intensive care unit ( NICU ) . All the formula involved in this study will be from Dumex . After discharge , both groups will be uniformly fed with formula for 0 to 6-month-old infants . For statistical analysis , a chi-square test and Student ’s t test will be applied using SAS 9.4 . Discussion This will be the first r and omized controlled clinical study with long-term observation of the growth and development of preterm children during the NICU stay and at 3-month follow-up after discharge from the NICU . Results from this study will be used to determine whether the extensively hydrolyzed formula is more suitable for the low gastrointestinal tolerability of preterm children , and also whether feeding preterm children who are fed with such formula during the NICU stay with ordinary infant formula after discharge from the NICU would affect the normal growth and development of preterm children in the early stage of their lives . Trial registration This study was registered with the Chinese Clinical Trial Registry ( http://www.chictr.org.cn/ ) with number ChiCTR-IOR-14005696 , on December 22 , 2014
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 .