Trends in the Prevalences of Selected Birth Defects in Korea (2008-2014)

Little information is available on the prevalences of birth defects in Korea. The aims of this study were to estimate recent prevalences of selected birth defects and to analyze the prevalence trends of these defects during the period from 2008 to 2014. Prevalences were calculated for 69 major birth defects using health insurance claim data obtained from the Korea National Health Insurance Service (NHIS). Prevalence rate ratios were calculated using Poisson regression to analyze trends over the 7-year study period. The overall prevalence of a major birth defect was 446.3 per 10,000 births (95% CI: 444.0-448.6); 470.9 per 10,000 births (95% CI: 467.6-474.2) for males and 420.2 per 10,000 births (95% CI: 417-423.4) for females. The prevalence rates of the most common birth defects over the study period were; septal defect (138.2 per 10,000; 95% CI: 136.9-139.5), congenital hip dislocation (652 per 10,000; 95% CI: 64.1-65.9), and ventricular septal defect (62.62 per 10,000; 95% CI: 61.7-63.5). During the study period, a significant increase in the prevalence of a major birth defect was observed with a prevalence rate ratio (PRR) of 1.091. The strongest trend was observed for renal dysplasia, which had a PRR of 1.275 (95% CI: 1.211-1.343), and upward trends were observed for urogenital anomalies, such as, renal agenesis (PRR 1.102, 95% CI: 1.067-1.138), undescended testis (PRR 1.082, 95% CI: 1.072-1.093) and hypospadias (PRR 1.067, 95% CI: 1.044-1.090). This study shows an overall increase in the prevalences of birth defects, including hypospadias and undescended testis, which are known to be associated with endocrine factors. In the future, standardized birth defect registries should be established to enable these trends to be monitored.