Ultrasound detection of fetal structural abnormalities in Auckland 1988-9

To conduct an audit of ultrasound screening for fetal abnormalities in central Auckland 1988-89.

All babies born at National Women's Hospital in the time period were examined and fetal abnormalities coded on to a computer database. All terminations of pregnancy for fetal abnormality in the area were similarly audited.

There were 12,909 births. 218 babies had a congenital abnormality of whom 88% were scanned antenatally. 48% of abnormalities were detected (27% before 24 weeks). In fetuses that were scanned the detection rate was 52% (44% before 24 weeks). The range of detection of specific abnormalities included neural tube defects 95% and congenital heart defects 16%.

1. Major abnormalities of the central nervous system, renal tract and abdominal wall have a high detection rate. 2. Cardiovascular, facial and gastrointestinal abnormalities are either not detectable or difficult to detect. 3. Detection rates could be improved by routine scanning, better ultrasound equipment and training, and by the introduction of maternal biochemical screening tests. 4. The detection rate is similar to other overseas surveys.