From parenteral to enteral nutrition: A nutrition-based approach for evaluating postnatal growth failure in preterm infants

Background: Nutrition practices for preterm infants include phases of parenteral nutrition (PN), full enteral nutrition (EN), and the transitional phase in between. Our aim was to identify the nutrition phases during which infants are most likely to exhibit poor growth that would affect risk for growth failure (GF) at discharge and to examine factors associated with GF. Methods: A retrospective chart review was conducted on infants born <32 weeks' gestation. The neonatal intensive care unit stay was divided into 3 nutrition phases: (1) full PN, (2) transitional PN + EN, and (3) full EN. Weekly growth rates were calculated, and for each growth velocity <10 g/kg/d, the coinciding phase was recorded. GF was defined as a discharge weight below the 10th percentile. The nutrition phases during which growth inadequacy predicted GF at discharge were determined, correcting for other clinical factors associated with GF. Results: In total, 156 eligible infants were identified. Seventy-six infants (49%) were discharged with weights <10%. Incidence of poor growth was highest during the transitional phase (46%) and was predictive of GF when adjusted for gestational age, birth weight, and severity of illness. Although energy intakes during the transitional phase were comparable to baseline parenteral provision, protein intakes progressively decreased (P <.0001), consistently providing <3 g/kg/d as PN was weaned. Serum urea nitrogen also declined and was correlated with protein intake (r = -0.32, P <.001). Conclusion: Growth was compromised during the transitional phase, likely related to decreased protein intake. Optimizing protein provision while PN is weaned is an important strategy to prevent postnatal growth failure.