Congenital heart disease, malformation of the heart or great arteries, is the most common form of major birth defect, being six times more common than chromosomal abnormalities and four times more common than neural tube defects.1 Approximately 8 out of 1000 babies are born in the UK each year with congenital heart disease, nearly 1% of live births.2–4 Congenital heart disease accounts for approximately 40% of perinatal deaths due to congenital anomalies,5 more than 20% of deaths in the first month of life6 and the majority of deaths from congenital defects in childhood.5,7,8 These defects therefore place a significant economic burden on the NHS and society and the psychological wellbeing of affected families.
Antenatal diagnosis of congenital heart disease allows planning and delivery of timely and appropriate neonatal care.7–9 This is increasingly important with accumulating evidence that early diagnosis may have the potential to save babies' lives.1,10–15 Early knowledge of congenital heart disease also allows further monitoring, testing for known associated non-cardiac structural and chromosomal anomalies16–19 and parental counselling about pregnancy management options including termination.
Various methods of antenatal ultrasound assessment of a baby's heart are currently available. The ‘four-chamber view’ is the most basic assessment. This allows a general examination of the main structure of the heart and the atrioventricular junctions. ‘Basic fetal echocardiography’ is a more extensive antenatal ultrasound examination of the heart and its associated structures, through additional assessment of the ventricular outflow tracts. ‘Extended fetal echocardiography’ is also available. During this examination, two-dimensional scanning of the heart and its associated structures is supplemented by spectral and colour-flow Doppler, and on occasion, M-mode scanning to assess blood flow within the heart. Fetal echocardiography has been used as a diagnostic tool to identify congenital heart disease in high risk groups for some years,20,21 and has been found to have sensitivities ranging from 60% to 100%.10,22–24 Its routine use in unselected obstetric populations including those at low risk is uncommon and more controversial.19,25–27 Against this background, a systematic review was conducted to determine the accuracy of fetal echocardiography to detect congenital heart disease to inform whether it should be included in a routine 20-week anomaly scan for an unselected obstetric population including newborn at low risk for developing cardiac defects.