Preterm Infants Fed a Human Milk Fortifier

Inclusion Criteria: * Birth weight between 700 g-1500 g. * ≤ 32 weeks and 0 days GA at birth. * Participant has been classified as appropriate for GA (AGA). * Enteral feeding of human milk must be initiated by 21 days of life (birth date is day of life 0) * Mother agrees to provide human milk as the exclusive feeding during the study period; use of donor milk is permitted if fortified with study fortifier and use of mother's own milk (when available) is prioritized. * Parent(s) agrees to allow infant to receive both human milk and study HMF. * Singleton or twin births only. * Infant's parent(s) or a LAR has voluntarily signed and dated an ICF, approved by an IRB/IEC and provided HIPAA (or other applicable privacy regulation) authorization prior to any participation in the study. Exclusion Criteria: * Enteral feeding of preterm infant formula or HMF for \> 7 days. * Expected to be transferred to another facility within 30 days of randomization. * Serious congenital abnormalities or underlying disease that may affect growth and development. * 5-minute APGAR ≤ 4. * Receiving systemic steroids at time of randomization. * Receiving probiotics at time of randomization. * Grade Ill or IV PVH/IVH. * Dependent on invasive ventilation at time of randomization. * Maternal incapacity. * Mother or infant is currently receiving treatment consistent with HIV therapy. * Documentation of maternal use of alcohol or marijuana during pregnancy that in the opinion of the physician is considered abuse. * Positive toxicology report for cocaine, opiates, or methamphetamine in mother or infant. * Infant has a history of major surgery (intra-thoracic or intra-abdominal procedures or other surgery requiring general anesthesia). * Asphyxia defined as progressive hypoxemia and hypercapnia with significant metabolic acidemia characterized by APGAR score \<3 at 10 minutes, seizures within the first 12 hours of life, or a cord blood gas \< 7.0 and seizures and/or severe tonic abnormalities in the first 12 hours of life. * Confirmed NEC (Bell's Stage II or III). * Confirmed current sepsis. * Infant has any other condition that, in the opinion of the investigator, precludes participation in the study. * Participation in another study that has not been approved as a concomitant study by AN. * Participant has an allergy or intolerance to any ingredient in study fortifier.