Growth in preterm infants has long-term implications for neurodevelopmental outcomes. We aimed to estimate the nationwide growth outcomes from birth to 5 years in infants born under 1500 g and to analyze the effects of major morbidities in preterm infants on growth. In total, 2961 children born in 2013 with a birth weight under 1500 g who underwent an infant health checkup between 2013 and 2018 according to the National Health Insurance Service database were included. Checkups were conducted at 4–6, 9–12, 18–24, 30–36, 42–48, and 54–60 months of age. Information was obtained from the International Classification of Diseases-10 codes or a questionnaire administered during the check-up. At 60 months of age, the mean percentiles of weight, height, and head circumference fell within only the 30–40th percentile of normal growth values. About 30% of infants had growth parameters below the 10th percentile and showed worse neurodevelopmental outcomes. Using multiple logistic regression, infants with bronchopulmonary dysplasia showed a significantly higher incidence of growth restriction in all three categories of weight (odds ratio [OR] 1.50), height (OR 1.33), and head circumference (OR 1.36) at 60 months. Sepsis was associated with growth restriction in weight (OR 1.43) and head circumference (OR 1.33). Periventricular leukomalacia infants had relatively small head circumferences (OR 1.91) and poor developmental screening results (OR 2.89).
Conclusion: Catch-up growth remains a major issue in infants born under 1500 g, especially those with some morbidities from preterm birth. Regular checkups to monitor and early intervention to achieve normal growth are essential.
What is Known:
• Growth in preterm infants has long-term implications for neurodevelopmental and cardiometabolic outcomes.
• Data are lacking on the time-serial effects of many preterm morbidities simultaneously on long-term growth outcomes.
What is New:
• All growth parameters of VLBW infants, including weight, height, and head circumference, fell within the 30–40th percentile of normal growth for infants at 60 months of age, indicating that catch-up growth for VLBW infants remains an issue.
• VLBW infants with major preterm morbidities, including BPD, PVL, and sepsis, showed difficulties in achieving normal catch-up growth and neurodevelopment at 60 months of age.