To assess the cost-effectiveness of mother's own milk supplemented with donor milk vs mother's own milk supplemented with formula for infants of very low birth weight in the neonatal intensive care unit (NICU).

A retrospective analysis of 319 infants with very low birth weight born before (January 2011-December 2012, mother's own milk + formula, n = 150) and after (April 2013-March 2015, mother's own milk + donor milk, n = 169) a donor milk program was implemented in the NICU. Data were retrieved from a prospectively collected research database, the hospital's electronic medical record, and the hospital's cost accounting system. Costs included feedings and other NICU costs incurred by the hospital. A generalized linear regression model was constructed to evaluate the impact of feeding era on NICU total costs, controlling for neonatal and sociodemographic risk factors and morbidities. An incremental cost-effectiveness ratio was calculated for each morbidity that differed significantly between feeding eras.

Infants receiving mother's own milk + donor milk had a lower incidence of necrotizing enterocolitis (NEC) than infants receiving mother's own milk + formula (1.8% vs 6.0%, P = .048). Total (hospital + feeding) median costs (2016 USD) were $169 555 for mother's own milk + donor milk and $185 740 for mother's own milk + formula (P = .331), with median feeding costs of $1317 and $936, respectively (P < .001). Mother's own milk + donor milk was associated with $15 555 lower costs per infant (P = .045) and saved $1812 per percentage point decrease in NEC incidence.

The additional cost of a donor milk program was small compared with the cost of a NICU hospitalization. After its introduction, the NEC incidence was significantly lower with small cost savings per case. We speculate that NICUs with greater NEC rates may have greater cost savings.