Effectiveness of prenatal diagnosis of congenital heart defects in South Australia: a population analysis 1999-2003

Abstract

Aims: To report on the efficiency of fetal echocardiography, outcome after prenatal diagnosis of congenital heart disease (CHD) and the effectiveness of South Australia's obstetric screening program in detecting CHD.

Methods: A retrospective audit of our institutional cardiac database, the South Australia Birth Defects Register and the South Australia Pregnancy Outcome Unit from 1999 to 2003.

Results: CHD was present in 10.7 per 1000 births and was potentially detectable in 5.2 per 1000 births. Of these, only 22.5% were referred for fetal echocardiography. Prenatal detection of transposition of the great arteries occurred in four of 27 (14.8%), atrioventricular septal defect in five of 21 (23.8%), tetralogy of Fallot in seven of 28 (25.0%) and hypoplastic left heart syndrome in 20 of 33 (60.6%). Fetal echocardiography had 95.2% sensitivity, 99.5% specificity, 99.0% positive predictive value and 97.6% negative predictive value for CHD. A prenatal diagnosis of CHD resulted in termination in 30.1%, stillbirth in 7.8% and neonatal death in 3.9% of cases.

Conclusion: Routine obstetric ultrasound detects CHD infrequently. Outflow tract lesions are most commonly missed. Fetal echocardiography is an accurate tool for prenatal diagnosis of CHD. Pregnancy outcomes after prenatal diagnosis are comparable to other Australasian and western countries, suggesting uniformity in parental counselling and population behaviour. Strategies that improve routine obstetric ultrasound detection of CHD are likely to yield the greatest impact.