outcome after prenatal and postnatal diagnosis of complex congenital heart defects and the influence of genetic anomalies objective determine prenatal detection rate mortality and association with genetic abnormalities in patients with severe chdmethod single center retrospective study in patients with severe chd diagnosed prenatally or postnatally 2006 to 2014results a total of 567 patients were included 176 31 after prenatal diagnosis with large differences in prenatal detection rate among chd types coarctation 24 tetralogy of fallot 21 and univentricular heart 19 were the most prevalent chd overall mortality rate was 30 with important contributions of prenatal mortality including termination of pregnancy 40 and postnatal compassionate care 15 in the group requiring surgery mortality rate was 12 genetic testing was available in 70 a genetic cause was present in 140394 patients tested 36 25 in the total group mortality was higher in the group with abnormal genetic testing compared with those with normal or no genetic testing 57141 vs 112423 p 0002conclusion only one third of severe chd are detected overall mortality remains high 30 with major contributions of termination of pregnancy and compassionate care a genetic cause was found in 36 and was associated with a decreased survival counseling must include the possibility of associated genetic pathology and its impact on survival 2017 john wiley sons ltd