The impact of early caloric intake on growth parameters in extremely preterm neonates

Introduction: Even though adequate caloric intake is essential for the promotion of growth in extremely premature infants, this is rarely achieved. We investigated how total caloric intake in the first week of life and other events during the hospitalization impact head circumference and weight at 36 weeks of corrected age in extremely preterm infants. Patients and methods: The study sample consisted of extremely preterm infants treated at Osijek University Hospital Centre, born between January 2018 and December 2020. Records were collected regarding nutritional data, sex, gestational age, birth weight and head circumference, invasive respiratory support, bacterial infection, necrotizing enterocolitis, postnatal steroids, need for supplemental oxygen at 36 weeks gestation, day of introduction of enteral nutrition, duration of parenteral nutrition, length of stay, hemodynamically significant patent ductus arteriosus, cystic periventricular leukomalacia and retinopathy of prematurity. Results: The study cohort included 30 infants. At 36 weeks gestation for weight, median Z scores were -1.63 (IQR -2.34 to -1.15; 95% CI -2.09 to -1.52), and for head circumference were -1.32 (IQR 2.37 to - 0.81; 95% CI -1.75 to -0.91). Median energy intake on the first day of life was 33.42 kcal/kg, and 80.78 kcal/kg on day 7. Early caloric intake was not correlated with changes in Z scores for head circumference and weight at 36 weeks of gestation. Other factors influenced changes in head circumference and weight Z scores, namely: gestational age, respiratory support during the first week, need for additional O2 at 36 weeks, and retinopathy of prematurity requiring intervention. Conclusion: In our cohort of premature infants at 36 weeks corrected age other factors, not primarily total caloric intake influenced growth parameters.