Abstract
Congenital heart disease occurs in about 1 in 125 live births, approximately half of which require urgent evaluation and management. Cardiovascular malformations account for 10% of infant deaths and nearly half of all deaths from all malformations. They are, therefore, both important and common, but are still frequently missed in primary screening programmes worldwide. The UK average detection rate is 23% with wide postcode variation. The reasons for missing defects are difficult to ascertain. However, with 'hands-on' training of obstetric sonographers in their own unit, detection levels may increase to 70–80%. With ongoing support these levels are sustainable. This 'hands-on' training uses a systematic protocol, the five transverse views, which allows the majority of defects to be detected at the routine 20-week scan without increasing routine examination time.