Serial Long-Term Growth and Neurodevelopment of Very-Low-Birth-Weight Infants: 2022 Update on the Korean Neonatal Network

BACKGROUND: We aimed to evaluate the long-term growth and neurodevelopmental outcomes of very-low-birth-weight infants (VLBWIs, birth weight < 1,500 g) born between 2013, the establishment of the Korean Neonatal Network (KNN), and 2018, both at 18–24 months of corrected age and three years of age, using a nationwide large cohort, and to evaluate whether these outcomes have improved over time since 2013. METHODS: This study used data from the annual reports of the KNN for 18–24 months of corrected age (follow-up 1) and three years of age (follow-up 2). Follow-up 1 data were collected from 10,065 eligible VLBWIs born between January 1, 2013, and December 31, 2018. Follow-up 2 data were collected from 8,156 eligible VLBWIs born between January 1, 2013, and December 31, 2017. RESULTS: The overall follow-up rates of VLBWIs at follow-ups 1 and 2 were 74.6% (7,512/10,065) and 57.7% (4,702/8,156), respectively. The overall mortality rate between discharge from the neonatal intensive care unit and follow-up 1 was 1% (104/10,065). The overall mortality rate between follow-ups 1 and 2 was 0.049% (4/8,156). Growth restrictions decreased over time, especially weight growth restrictions, which significantly decreased according to era (17% in infants born in 2013–2014 and 13% in infants born in 2017–2018). Fewer infants were re-hospitalized and required rehabilitative support according to era at follow-up 1. More infants had language developmental delays and required language support according to era, both at follow-ups 1 and 2. The incidence of cerebral palsy has significantly decreased over time, from 6% in infants born in 2013–2014 to 4% in infants born in 2017–2018 at follow-up 1, and from 8% in infants born in 2013–2014 to 5% in infants born in 2017 at follow-up 2. CONCLUSION: Long-term outcomes of VLBWIs regarding weight growth and cerebral palsy, the most common motor disability in childhood, have improved serially according to era since 2013. However, the rate of infants with language delays requiring language support has increased according to era. Further studies are required on the increased trends of language delay and language support while improving motor outcomes.