The characteristics of the dataset
In Korea, 97% of the population is enrolled in the Korea National Health Insurance (KNHI) program. All claims information for these individuals is contained within the KNHI claims database. Nearly all information about the prevalence of different diseases and procedures can be obtained from this centralized database, with the exception of procedures not covered by insurance. As part of the KNHI system, children aged 4–80 months are eligible for a National Health Screening Program for Infants and Children (NHSP-IC). An NHSP-IC is composed of seven consecutive health examinations based on age groupings. The first to the seventh health examinations are performed at ages 4–9, 9–18, 18–30, 30–42, 42–54, 54–66, and 66–80 months. An NHSP-IC consists of history taking, physical examination, anthropometric examination, developmental screening, and visual acuity testing based on the child’s age. Women’s data in the KNHI claims database were linked to the data of their offspring contained within the NHSP-IC database.
Data on women’s health conditions including obstetric diagnosis were obtained from the KNHI claims database using ICD-10 codes. Data on preterm birth and birth weight were corrected from the NHSP-IC database. We have obtained the approval of this study by the Institutional Review Board (no. 2020GR0012).