Growth In Low Birth Weight And Very Low Birth Weight Infants Fed Fortified Breast Milk Versus Formula Milk: A Retrospective Cohort Study

Abstract

Background and Aims There has been a dramatic rise in preterm births in developed countries owing to changes in clinical practices and greater use of assisted reproductive techniques. Few studies have examined the growth and outcomes of preterm infants according to the type of feeding. The aim of this study was to examine the effect of breast milk feedings and formula on the growth and short-term outcomes of preterm infants in Hong Kong. Methods A single-center retrospective cohort study was employed. From 2010-2014, we included 642 preterm infants at gestational age < 37 weeks with birth weights > 750 g and < 2500 g. Results 466 were classified as low birth weight (LBW) infants and 176 were classified as very low birth weight (VLBW) infants. The mothers of approximately 80% of VLBW infants and 60% LBW infants initiated breast milk feeding. When compared with no breast milk intake, LBW infants that received breast milk were significantly more likely to have growth z-scores closer to the median of the reference population and experienced slower weight gain from birth to discharge (See Fig.1). When breast milk was categorized by percent of total enteral intake, significant differences were seen among LBW infants, with lower percentages of small-forgestational-age (SGA) status at discharge with increased proportions of breast milk intake. Conclusions LBW infants showed slower growth when predominately fed fortified breast milk than those solely fed formula. Overall, LBW infants fed breast milk had better growth z-scores and lower SGA status at discharge compared with those predominately fed preterm formula.