Comparison of types of breast milk fortification at discharge from the neonatal intensive care unit and breast milk feeding rates and growth at 4 months corrected age

Background: Effects of breast milk (BM) enhancement on long-term BM feeding in preterm infants discharged from the neonatal intensive care unit (NICU) have not been examined previously. This study compares any BM feeding rates at 4 months corrected age (CA) in preterm infants discharged from the NICU on BM enhancement by fortification of expressed BM with infant formula additives (BM-F) versus BM supplemented with infant formula feeds (BM-S). Subjects and Methods: We compared infants born between January 1, 2013, and December 31, 2017, with gestational age <32 weeks or birth weight <1500 g, discharged home on BM-F or BM-S from two NICUs and followed at 4 months CA. Multivariate logistic regression with propensity scoring estimated the adjusted associations between nutrition at discharge and any BM feeding at 4 months CA. Results: Two hundred eighty-five infants were followed at 4 months CA. Infants discharged on BM-F were more likely to have mothers with multiple gestation, private insurance and not Caucasian, initiate feeds of human milk, be discharged from NICU-1, and receive any BM at 4 months CA ( p < 0.03). No significant difference in growth parameters <10th percentile at 4 months CA was observed between the two groups. After adjusting for confounding factors, discharge from the NICU on BM-F was significantly associated with BM feeding at 4 months CA (odds ratio: 3.89, 95% confidence interval 1.66-9.14, p = 0.002). Conclusion: In this observational study, preterm infants receiving BM fortified with formula powder additives at discharge from the NICU had better BM feeding outcomes without poor growth at 4 months CA relative to those infants receiving BM supplemented with infant formula feeds.