Objective To determine the prevalence and spectrum of congenital heart disease (CHD) and the impact of a national prenatal ultrasound screening programme on outcome in a well-characterised population.

Design and setting A comprehensive registry was created of all paediatric and fetal patients with CHD over a 21-year period (1986–2006) in the Czech Republic. The centralised healthcare system enabled confirmation of prenatal and postnatal findings clinically and by post mortem.

Patients and results In the entire cohort of 9475 fetuses referred for detailed cardiac evaluation, 1604 (16.9%) had CHD, of which 501 (31.2%) had additional extracardiac anomalies. In the pregnancies which continued, 59 (8.6%) of 685 fetuses died in utero, and 626 (91.4%) babies were born alive. Prenatal detection rate was highest in double outlet right ventricle (77.3%) and hypoplastic left heart (50.6%). Detection rate increased significantly (p<0.001) for 12/17 lesions comparing 1986–1999 and 2000–2006. In recent years, detection of hypoplastic left heart reached 95.8% while transposition of the great arteries was diagnosed antenatally in only 25.6%.

Conclusion The nationwide prenatal ultrasound screening programme enabled detection of major cardiac abnormalities in 1/3 of patients born with any CHD and 80% of those with critical forms. Nevertheless, owing to the severity of lesions and associated extracardiac anomalies, the overall mortality of antenatally diagnosed CHD remains high. These findings are important for the understanding natural history of CHD for the establishing of screening programmes in Europe.