Human Milk alone is unable to meet the high nutritional requirements of preterm infants. The American Academy of Pediatrics recommends fortification of human milk as a standard practice in all very low birth weight (VLBW) infants. Multi-nutrient human milk fortifiers (HMFs) are designed to meet the macro and micro-nutrient needs of VLBW infants. HMFs differ by the origin of milk and by nutrient composition. Traditionally, bovine milk has been the main source of multi-nutrient HMFs.

Recent advances in lacto-engineering techniques allowed the manufacturing of multi-nutrient HMF from human milk as an alternative to bovine milk. Since exposure to infant bovine-based formula feeds is frequently shown to increase neonatal morbidities, human milk-derived HMFs (H-HMFs) have been frequently proposed to minimize exposure to bovine products prior to 34 weeks gestation with an intent to decrease the risks of necrotizing enterocolitis and feeding intolerance. The use of multi-nutrient H-HMFs is a promising intervention however currently available H-HMFs are expensive.

The main objective of this randomized controlled trial is to compare the weight gain achieved by preterm infants born <1250 g and fed human milk fortified with H-HMFs (made from mother's own milk (MOM) when MOM supply exceeds the daily need of her preterm infant or from donor human milk (DHM) compared with counterparts fed human milk fortified with the currently used bovine-derived fortifier (B-HMF).

Inclusion Criteria:

• Birthweight between 400 g-1250 g
• Less than or 32 weeks gestational age at birth
• Subject has been classified as appropriate for gestational age
• Enteral feeding of human milk is initiated by 72 hours
• Subject is expected to be on human milk for at least 3 weeks.

Exclusion Criteria:

• Congenital abnormalities or underlying disease that may affect growth
• Maternal cocaine, alcohol, or opioid abuse during pregnancy
• Mother or infant is currently receiving treatment for HIV infection
• Infant with major surgery