For very low birth weight infants, the availability of donor human milk to newborns was associated with a decreased incidence of necrotizing enterocolitis and an increased rate of breastfeeding at discharge from a neonatal intensive care unit.

The researchers based their findings on data obtained from the California Perinatal Quality Care Collaborative, which gathers information on the care of greater than 90% of California’s neonatal intensive care unit (NICU) admissions of very low birth weight (VLBW) infants (defined as weighing less than or equal to 1.5 kg at birth), and the Mother’s Milk Bank of San Jose, a human milk bank serving 94 hospitals across several states, including California. All of the data was collected between 2007 and 2013 in over 42,000 VLBW babies. Babies were classified as breastfeeding at discharge, if they were feeding with human milk or human milk with fortifier or formula, but not if they were only feeding with formula.

Agata Kantorowska , a medical student at the University of Rochester (N.Y.) School of Medicine and Dentistry, and her colleagues noted that they did not know if donor human milk (DHM) was used primarily as a back-up feeding if mother’s milk was unavailable, in another way, or in conjunction with human milk-derived fortifiers; the proportion of VLBW infants within each NICU that received DHM; or the length of time that an individual received DHM.

Among the 22 hospitals studied that went from not having DHM available to making it available, on average, the rate of breastfeeding at discharge increased by 10% after DHM became available (P less than .0001). Among these same hospitals, the mean change in necrotizing enterocolitis (NEC) prevalence, following the introduction of DHM, was a 2.6% decrease (P = .0006). Before DHM became available in the 22 hospitals, 52.8% of VLBW infants were breastfeeding at discharge, compared with 61.7% after DHM became available. The rate of NEC was 6.6% among VLBW infants prior to DHM having becoming available at a hospital, versus 4.3% following the introduction of DHM to a hospital.

Following risk adjustment, not having DHM available in a hospital was a negative predictor for breastfeeding at discharge (odds ratio, 0.70) and a positive predictor of NEC (odds ratio, 1.15).

Ms. Kantorowska and her associates said while they found “a significant association between a hospital’s DHM status and increased breastfeeding and decreased NEC rates among VLBW infants,” factors other than the availability of DHM contributed to changes in breastfeeding and NEC rates that occurred. They also noted that they saw an increased rate of breastfeeding and a similar decreasing rate of NEC in hospitals that did not transition to using DHM.

“Societal attitudes toward breastfeeding are likely influencing mothers’ attempts to provide breast milk to their VLBW infants. … The NICU battle against NEC is ongoing, and other advances in care that occurred from 2007 to 2013 could be contributing to the observed decrease in NEC rate in hospitals that acquired DHM,” the researchers said.

Read the full study in Pediatrics ( doi: 10.1542/peds.2015-3123 ).