The Relationship Between Early Weight Z-Score Changes and Nutritional Differences in Very Low Birth Weight Infants During Hospital Stay

Background: Advances in neonatal care have resulted in improved survival for very low birth weight infants (VLBWIs). However, the main factors that lead to early weight Z-score [standard deviation score (SDS)] changes during hospital stay in VLBWIs still need to be studied more. Objectives: In this study we aimed to investigate the differences in specific factors that relate to VLBWIs’ early weight Z-score changes as the scientific basis for clinical practice of VLBWIs during the entire hospital stay. Methods: We retrospectively reviewed baseline characteristics, nutrition management, clinical outcomes, and complications between non-catch-down (NCD) (∆weight SDS≥ -0.67) and catch-down (CD) groups (∆weight SDS < -0.67) in VLBWIs during hospital stay. Results: A total of 227 infants (NCD group = 117, CD group = 110) met the inclusion criteria. No significant differences were found in baseline characteristics between the two groups. The NCD group received higher parenteral lipids (g/kg/d) from day 5 to day 7 and higher enteral feeding volume (mL/kg/d) from day 5 to week 5. The NCD group had higher protein:energy ratios at day 2 to day 4 and day 7 and higher total energy (kcal/kg/d) during the first six weeks. The NCD group had lower incidence of bronchopulmonary dysplasia (BPD) and parenteral nutrition-associated cholestasis (PNAC). Conclusions: This study showed that adequate parenteral lipid and energy at the first week of life and earlier enhanced enteral feeding volume might significantly improve the VLBWIs’ weight Z-scores during hospital stay. The VLBWIs with catch-down growth might be more prone to developing BPD and PNAC.