ABSTRACT: BACKGROUND:Most studies have not demonstrated improved survival after prenatal diagnosis of critical congenital heart disease, including hypoplastic left heart syndrome (HLHS). However, the effect of delivery near a cardiac surgical center (CSC), the recommended action after prenatal diagnosis, on HLHS mortality has been poorly investigated. METHODS AND RESULTS:Using Texas Birth Defects Registry data, 1999 through 2007, which monitored >3.4 million births, we investigated the association between distance (calculated driving time) from birth center to CSC and neonatal mortality in 463 infants with HLHS. Infants with extracardiac birth defects or genetic disorders were excluded. The associations between prenatal diagnosis, CSC HLHS volume, and mortality were also examined. Neonatal mortality in infants born <10 minutes from a CSC was 21.0%, 10 to 90 minutes 25.2%, and >90 minutes 39.6% (P for trend <0.001). Prenatal diagnosis alone was not associated with improved survival (P=0.14). In multivariable analysis, birth >90 minutes from a CSC remained associated with increased mortality (odds ratio, 2.03; 95% confidence interval, 1.19-3.45), compared with <10 minutes. In subanalysis, birth >90 minutes from a CSC was associated with higher pretransport mortality (odds ratio, 6.69; 95% confidence interval, 2.52-17.74) and birth 10 to 90 minutes with higher presurgical mortality (odds ratio, 4.45; 95% confidence interval, 1.17-17.00). Higher surgical mortality was associated with lower CSC HLHS volume (odds ratio per 10 patients, 0.88; 95% confidence interval, 0.84-0.91). CONCLUSIONS:Infants with HLHS born far from a CSC have increased neonatal mortality, and most of this mortality is presurgical. Efforts to improve prenatal diagnosis of HLHS and subsequent delivery near a large volume CSC may significantly improve neonatal HLHS survival.