Increased enteral lipid supplementation is not associated with weight gain in extremely preterm infants with sufficient energy intakes

Objectives: Practices for fortifying human milk vary among neonatal intensive care units (NICUs). It is unclear whether enteral energy intake above 140 kcal/kg/day with increased fat supplementation leads to greater weight gain in breastmilk-fed extremely preterm (EPT) infants. Methods: Anthropometric and nutritional data were collected from clinical records for Swedish EPT infants born between gestational weeks 26 + 0 and 27 + 6. Included infants were treated at NICU A (n = 17) or NICU B (n = 39). The primary outcome was change in standard deviation (SD) scores (Delta SDS) for weight between postmenstrual weeks 29 + 0 and 34 + 0. Results: At birth, the mean gestational age was 26.9 (+/- 0.45 SD) weeks and the mean birthweight was 969 (+/- 107 SD) g. Between postmenstrual weeks 29 + 0 and 33 + 6, the energy intake was significantly higher at NICU B: mean (SD) 149 (+/- 14.9) versus 132 (+/- 11.2) kcal/kg/day, p <= 0.001. This was driven by a higher fat intake at NICU B: mean (SD) 7.97 (+/- 1.05) versus 6.20 (+/- 0.92) g/kg/day, p <= 0.001, which in turn was explained by more liberal use of lipid supplements at NICU B. No significant differences were found in Delta SDS for weight, length or head circumference between the two NICUs. Conclusions: Despite considerable differences in energy intake due to the use of enteral lipid supplements, our study showed no differences in Delta SDS for weight, length or head circumference. This may be due to limited fat absorption in infants already receiving adequate energy and fat, and poor absorption of fat from human donor milk.