Intestinal Microbiota and Short Term Outcomes in Very Low Birth Weight Infants Fed Primarily Donor Human Milk Compared to Infants Fed Primarily Mother's Own Milk

Background: Human milk feeding provides numerous benefits to preterm infants due to improvements in gastrointestinal maturation, host defense, infection rates, and improved long-term outcomes in neurodevelopment as well as cardiovascular and metabolic disease. There is accumulating evidence that an exclusive human milk-based diet decreases the rates of necrotizing enterocolitis (NEC) and death, and is associated with better feeding tolerance in very low birth weight (VLBW) infants than a diet of bovine milk-based products. In order to provide VLBW infants the benefits afforded by human milk feeding, the use of donor milk (DM) in neonatal intensive care units (NICU) has increased as many mothers are unable to provide sufficient milk needed for their premature infants. While there have been numerous studies that have favorably compared feeding of mother's own milk (MOM) to formula as well as studies that compare DM to formula, there are relatively few that compare maternal milk to donor milk.

In regard to feeding tolerance and infection prevention, it has been proposed that DM may be less beneficial than MOM due to reduction in biologically active components during pasteurization, including human milk oligosaccharides (HMOs) and other immunological factors, growth factors, and hormones. Finally, alterations in the intestinal microbiota of preterm infants are suspected to contribute to disease states such as NEC, specifically within infants who have decreased microbial diversity. To the investigators knowledge, no studies comparing the intestinal microbiota among infants fed primarily MOM versus those fed primarily DM have been published.

Purpose: To compare growth velocities, time to reach full enteral feeding volume, intestinal microbiota, and short term outcomes (NEC, late-onset sepsis, white matter injury) between infants fed primarily mother's own milk versus pasteurized donor human milk.

Hypothesis: Infants fed primarily (50% or greater) mother's own milk will have increased intestinal microbiome diversity compared to infants fed primarily pasteurized donor human milk.

Design: This prospective cohort study will be conducted in the Level III NICU at Texas Children's Hospital - Pavilion for Women and the Level II NICU at Texas Children's Hospital -- West Tower. Infants less than 1500 g birth weight will be fed exclusively human milk (mother's milk and or donor breast milk) fortified with donor human milk-derived fortifier per the investigators hospital guidelines. Once enteral feeding is established, infants will be categorized into cohorts based on percentage of feeding volume consisting of mother's own milk, including broad categorization of greater than 50% maternal milk versus less than 50%, and possibly tiered analysis of infants who receive less 25% maternal milk, 25-75% maternal milk, and greater than 75% maternal milk.