PURPOSE: We aim to assess the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III), Adaptive Behavior (AB) and Social-Emotional (SE) scales at 18 to 24 months of corrected age (CA) to examine their associations with school-age cognitive and behavioral outcomes in children born preterm. METHODS: Eighty-eight infants born with a very low birth weight ( < 1,500 g) or a gestational age of less than 32 weeks who were admitted to the neonatal intensive care unit from 2008 to 2009 were included. Of the 88 children who completed school-age tests at 6 to 8 years of age, 37 were assessed using the Bayley-III, including the AB and SE scales, at 18 to 24 months of CA. Correlation, cross-tabulation, and receiver operating characteristic analyses were performed to assess the longitudinal associations. RESULTS: A significant association was observed between communication scores on the Bayley-III AB scale at 18 to 24 months of CA and the Korean version of the Wechsler Intelligence Scale for Children (K-WISC) full-scale intelligence quotient (FSIQ) at school age (r=0.531). The total behavior problem scores of the Korean version of the Child Behavior Checklist (K-CBCL) at school age were significantly negatively related to the Bayley-III SE and AB scales but not to the cognitive, language, or motor scales. CONCLUSION: Our findings encourage AB and SE assessments during the toddler stage and have important implications for the early identification of children in need of intervention and the establishment of guidelines for follow-up with high-risk infants.
Adaptation, Psychological* ; Checklist ; Child Behavior ; Child* ; Follow-Up Studies ; Gestational Age ; Humans ; Infant ; Infant, Newborn ; Infant, Very Low Birth Weight ; Intelligence ; Intensive Care, Neonatal ; ROC Curve ; Weights and Measures*

Background: In Korea, the birth rate is declining at an alarming pace. This study aimed to investigate the changes and trends in the population count, number of births, and birth rate in Korea, in the past and future. Methods: Data regarding the total number of births, crude birth rate, and total fertility rate were collected from the “Statistics Korea Census” of the national statistical portal, census report, and Statistics Korea’s “2020 Population Trend Survey for 1981–2020, provisional results of birth and death statistics.” We used the Organisation for Economic Co-operation and Development 2019 Family Database for the TFR. To develop a better understanding of the data in this study, we classified it according to the modern history of Korea. Results: The changes and trends in the number of births and fertility rate in Korea, after liberation, were due to the birth control policy that restricted births. In Korea’s low fertility society, which began in the mid-2000s, the fertility rate dropped to below 0.84 in 2020, despite policies to improve the quality of the population. The death toll has reached 300,000, entering an era of population decline. Conclusion As we enter the era of population decline, we are in a direction that will cause various socioeconomic problems, from demographic problems to future population decline.