Although the epidemiology of congenital heart disease (CHD) has been described, the authors believe changes in prenatal factors such as termination of pregnancy for fetal anomaly and prenatal vitamin supplementation have altered the birth prevalence of severe CHD. This population-based study reviewed the Nationwide Inpatient Sample (NIS) database and identified all cases with a severe CHD diagnosis among all live birth entries from 1999 to 2008. A time trend analysis then was performed for specific severe CHD diagnoses stratified by race, socioeconomic status, and geographic location. Overall, severe CHD prevalence was 147.4 per 100,000 live births, with a temporal decrease in prevalence from 168.9 per 100,000 in 1999 to 129.3 per 100,000 in 2008 (p = 0.03). Among the 12 severe CHD diagnoses included in our cohort, the prevalence of truncus arteriosus (p = 0.02), tetralogy of Fallot (p = 0.001), hypoplastic left heart syndrome (p = 0.001), and pulmonary atresia (p = 0.01) decreased significantly during the study period. The observed prevalence trends varied significantly by race (Caucasians), socioeconomic class (upper income quartiles), and geographic location (Northeast and West regions). The study findings showed a temporal decrease in severe CHD prevalence, which varied by race, socioeconomic status, and geographic location. The authors speculated that the observed trend might be due to increased termination of fetuses with prenatally diagnosed CHD. The impact of sociodemographic variables on the observed prevalence trend might be due to differences in access to specialized perinatal care and fetal heart programs or because of variability in termination of pregnancy.