Comparison of Two Dose Adjustment Strategies of a Human Milk Protein Fortifier in Preterm Infants

Inclusion Criteria: * Gestational age in weeks: 23 weeks 0 days and 31 weeks 6 days. * Birth weight less or equal to 1500 g * Minimum enteral intake of 150-160 mL/kg/d fortified HM * Parents, liable parent, or legal representative (LR) if applicable are willing and able to sign written informed consent and written informed consent is obtained prior to trial entry Exclusion Criteria: * Infants with weight z-score \< -2 SD, based on the Fenton growth chart (Fenton 2013) * Intra-ventricular hemorrhage (grade 3-4) determined using cranial ultrasonography or periventricular leukomalacia. * Renal disease determined by symptoms (oliguria, anuria, proteinuria, hematuria) associated with an increased creatinine. * Cholestasis (total bilirubin \> 5 mg/dL or 85 umol/L and direct bilirubin \> 20% of total bilirubin) associated with one or more abnormal liver function tests (AST, ALT, or GGT). * Major congenital malformations that may impact ability to accept enteral feedings (i.e., severe cleft palate, etc.). * Suspected or documented systemic or congenital infections (i.e., human immunodeficiency virus, cytomegalovirus, etc.). * Evidence of cardiac, respiratory, endocrinologic, hematologic, gastrointestinal, or other systemic diseases that may impact growth, e.g.,: * NEC grade above or equal to 2 * Uncontrolled sepsis * Suspected or documented maternal substance abuse: * Born to mothers who smoked \> 10 cigarettes per day during pregnancy * Born to mothers who used illicit drugs (e.g. marijuana, cocaine, amphetamines, or heroin) or alcohol (\> 3 alcoholic beverages per week) during pregnancy * Subjects' parent(s) or legal representative who are not willing and not able to comply with scheduled visits and the requirements of the study protocol * Infants who have received any experimental treatment or received any other investigational intervention (procedure or product) unrelated to this trial, prior to enrollment