Impacts of prenatal diagnosis of congenital heart diseases on outcomes

Prenatal diagnosis of congenital heart diseases (CHD) is increasingly performed in developed countries. Still, the current impacts of prenatal diagnosis on fetal and neonatal outcomes remains unclear or contradictory. We will review here the different consequences of prenatal screening and of fetal echocardiography on different categories of outcomes. Increasing detection may lead to a reduced birth incidence of severe complex CHD through a high rate of termination of pregnancy but this trend is not universal. Conversely, one of the main impacts of prenatal diagnosis is to optimize perinatal care and to improve hard outcomes such as mortality. Indeed, decrease of neonatal mortality is inconsistently observed in transposition of the great arteries and is not shown in other defects. The reduction of perinatal morbidity is a new end-point to scrutinize but how to examine this impact is controversial in the neonatal period. The influence of the reduction of neonatal distress may modify neurodevelopmental outcomes and quality of survival. The risk stratification after a prenatal diagnosis of CHD helps to optimize the timing, mode, and site of management with the aim to improve outcomes. The anticipated care is tailored according to the type of CHD and expected initial physiology. However, the imprecision of prenatal diagnosis even in expert centers hampers this logical outcome. Prediction of the type of repair is theoretically possible but remains challenging in defects such as double outlet right ventricles or pulmonary atresia with ventricular septal defect. The cost of prenatal diagnosis or of its absence is still a matter of debate and policies have to be tailored to regional health systems. Finally, the impact on parents and siblings is a rarely explored outcome. Screening and echography of fetal heart are currently performed in developed countries but it is still too early to talk about fetal cardiology.