Long-term effects on growth in preterm and small for gestational age infants: A national birth cohort study.

Background: Premature and small-for-gestational-age (SGA) infants tend to have long-term growth morbidities such as short stature, failure to thrive, and obesity. Although most of these infants show catch-up growth at 2-4 years of age, they are still more susceptible to childhood obesity and related metabolic disorders. Those who fail to achieve catch-up will suffer from pathological short stature and neurodevelopmental impairment through adulthood. This study aims to depict the growth pattern of premature or SGA infants and their growth morbidities in Taiwan.

Methods: Data were obtained from a nationally representative cohort of 24,200 pairs of postpartum women and newborns in the Taiwan Birth Cohort Study (TBCS), using structured questionnaire interviews. A total of 16,358 infants were included and three follow-up surveys were completed at 6, 18, and 36 months after the deliveries. We constructed growth curves to conduct an in-depth investigation into anthropometric data, applying a linear mixed model. Logistic regression was used to model the relevant outcomes, with adjustment for various potential confounding factors.

Results: Despite being born shorter and lighter, preterm and SGA infants generally showed catch-up growth and had no higher odds ratios (ORs) of developing short stature or failure to thrive compared to appropriate-for-gestational-age (AGA) term infants before 3 years of age. Preterm SGA infants, particularly females, had higher ORs for obesity at the 36-month follow-up.

Conclusion: This is the first nationwide population-based study depicting the growth of SGA infants in Taiwan. The growth patterns of preterm and term SGA infants are different from those of preterm and term AGA infants. Further research is necessary to understand the growth trajectories of preterm and SGA infants and their associations with later diseases.