Beneficial Effects and Factors Associated With Provision of Breast Milk at Neonatal Intensive Care Unit Discharge to Very Low Birth Weight Infants: A Nationwide Cohort Study in Korea.

BACKGROUND: The incidence of preterm birth in Korea increased from 6.5% in 2013 to 9.7% in 2020. Very low birth weight (VLBW) infants, defined as those weighing < 1,500 g, are particularly vulnerable to numerous health risks. Breast milk provision reduces the incidence of complications in this vulnerable population. The objective of this study was to examine the rate and factors associated with breast milk provision at neonatal intensive care unit (NICU) discharge and to investigate its potential effects on growth and developmental outcomes at 18-24 months corrected age (CA). METHODS: We conducted this cohort study using data from over 70 NICUs participating in the Korean Neonatal Network. VLBW infants born between January 2019 and December 2020 at a gestational age of 23+0 to 31+6 weeks were included. Discharge feeding types were analyzed of 2,490 infants, while follow-up assessments of growth and neurodevelopmental outcomes at 18-24 months of CA were available for 1,426 infants. Propensity score matching was used for comparative analysis. RESULTS: The rate of breast milk provision at discharge among VLBW infants was 55.9% in 2019 and 56.5% in 2020. Factors that were positively associated with breast milk feeding included higher maternal education level and antenatal steroid use. In contrast, maternal hypertensive disorders, cesarean section, and severe neonatal morbidities (e.g., necrotizing enterocolitis) were correlated with lower breast milk feeding rates at the time of discharge. The provision of breast milk at discharge was not associated with a higher risk of suboptimal growth (below two standard deviations) compared to control infants at 18-24 months of CA. Neurodevelopmental assessments indicated that breast milk was associated with a reduced risk of developmental delay (adjusted odds ratio, 0.72; 95% confidence interval, 0.56-0.94) at follow-up. CONCLUSION: Breast milk provision to VLBW infants at NICU discharge in Korea was comparable to that in other countries. This nationwide study highlights the critical role of breast milk in promoting the neurodevelopment of VLBW infants. Future efforts should focus on identifying the barriers to breast milk provision to improve health outcomes in vulnerable populations.