Prenatal screening for structural congenital heart disease.

Congenital heart defects can be diagnosed during fetal life using echocardiography. Prenatal diagnosis allows full investigation of affected fetuses for coexisting abnormalities, and gives time for parents to be informed about the prognosis of the fetus and treatments that might be required. In a minority of cases, where the natural history suggests an unfavourable outcome, prenatal diagnosis provides an opportunity for fetal cardiac intervention. For some cardiac lesions, notably hypoplastic left heart syndrome, transposition of the great arteries, and coarctation of the aorta, prenatal diagnosis has been shown to reduce postnatal morbidity and mortality. Some costs of care, notably the transport of critically ill infants, are reduced by prenatal diagnosis. Prenatal screening programmes typically recommend detailed assessment of fetuses judged to be at high risk of congenital heart disease. However, most cases of congenital heart disease arise in the low-risk population, and detection of affected fetuses in this setting depends on recognizing abnormalities of the heart during the midtrimester scan. Evidence supports the use of structured training interventions and feedback to those undertaking sonographic examinations, to improve the prenatal detection of congenital heart disease.