Long-term outcome according to birthweight in term pregnancy: a nationwide cohort study

초록

Objectives To evaluate the long-term outcome according to birthweight in term pregnancy. Methods This retrospective observational cohort study included all women who had a singleton term delivery between 1 January 2015 and 31 December 2016 recorded in the claims database of the Korea National Health Insurance, with at least one follow-up recorded in the database of the National Health Screening Program for Infants and Children. Birthweight for gestational age was categorised according to percentiles (3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97th). Long-term adverse outcome included any neurological or neurodevelopmental outcome, defined by prespecified neurological and developmental diagnoses; these were identified by a diagnosis according to the International Classification of Diseases 10th Revision and assessed by following up all neonates until the end of 2021. Results In this study, 514,166 women and their offspring were included. Compared to the 50-75th birthweight control group, the group with birthweight below 3% (adjusted HR, 1.242; 95% confidence interval, 1.201–1.284), the group with birthweight 3-5% (adjusted HR, 1.101; 95% confidence interval, 1.053–1.152), the group with birthweight 5-10% (adjusted HR, 1.095; 95% confidence interval, 1.063–1.129), the group with birthweight 10-25% (adjusted HR, 1.046; 95% confidence interval, 1.023–1.07), the group with birthweight 25-50% (adjusted HR, 1.019; 95% confidence interval, 0.998–1.039), the group with birthweight 75-90% (adjusted HR, 0.984; 95% confidence interval, 0.958–1.01), the group with birthweight 90-95% (adjusted HR, 0.986; 95% confidence interval, 0.949–1.024), the group with birthweight 95-97% (adjusted HR, 1.045; 95% confidence interval, 0.977–1.118) and the group with birthweight above 97% (adjusted HR, 1.088; 95% confidence interval, 1.034–1.145) were associated with any neurological or neurodevelopmental delay. Conclusions The study found that birthweight percentiles of less than 25% or greater than 97% were associated with any neurological or neurodevelopmental delay.