PC1115: Early Postnatal Energy Deprivation and Divergent Growth in Preterm Infants

Background: Extremely preterm infants are at risk of early postnatal energy deprivation due to sub-optimal parenteral nutritional support, restrictive fluid administration, and prolonged nil per oral status. Postnatal illness, physiological instability resulting in increased energy requirements, and a limited anabolic capacity further exacerbate early postnatal malnutrition in preterm infants. Early postnatal calorie deprivation may even alter the body composition of preterm infants and may increase the risk of disproportionate postnatal growth and growth failure (divergent growth). The objective of our study was to evaluate the association between caloric intake during the first seven postnatal days and the risk of divergent growth at term equivalent age.

Methods: This retrospective, single-center study included preterm infants admitted at the neonatal intensive care unit of the Louisiana State University Shreveport from December 2018 to July 2021, with gestational age ≤28 weeks. The infants who died before postnatal day eight were excluded. Data on daily caloric intake (enteral and parenteral, in kcal/kg/day) for the first seven postnatal days were obtained, and the average daily total caloric intake was calculated. Weight for age, length for age, and BMI percentile at 36 weeks’ postmenstrual age (PMA) were estimated. Divergent growth at 36 weeks’ PMA was defined as weight or length for age percentiles < 10 or BMI percentile greater >85. A multivariable logistic regression model was used to establish the independent association of average caloric intake during the first postnatal week with divergent growth or death.

Results: Out of 78 infants included in the study, 47 (60%) infants developed divergent growth, 29 (37%) infants did not, and 2 (3%) infants died between day 8- and 36-weeks of PMA. The average daily total caloric intake during the first seven days of postnatal age was lower among infants who developed divergent growth or death [median (IQR): 69 (64, 78) vs. 75 (69, 85), p=0.03]. After adjusting for known confounders, average daily total caloric intake during the first seven days was not independently associated with odds for divergent growth or death [adjusted odds ratio (95% CI): 0.77 (0.45-1.31)].

Conclusion: Early postnatal caloric deprivation during the first postnatal week was not associated with an increased risk of divergent growth or death at 36 weeks of PMA.