Quality of praenatal diagnostic ultrasound - Comparison of sonographicallydetected foetal anomalies with diagnostic findings verified post-partum inSwitzerland

Aim: Comparison of all praenatally detected cases of foetal anomalies to ac tual diagnostic findings post partum during a one year period in Switzerlan d. Methods: A retrospective question nai re-based evaluation including the 5 university hospitals and 6 large hospitals in Switzerland as a population -based study. Analysis of all foetal anomalies detected praenatally by ultr asound in the year of 1995 in these centres. Results: 347 cases have been i ncluded in the study. 89% of cases were detected using screening methods. 2 /3, were referred by obstetrical practitioners and GPs. 62 % of the pregnan cies were completed and 33 % terminated, while the rest resulted in abortio n or stillbirth. In terminated pregnancies there was a 82 % agreement betwe en praenatal and postmortem findings. Sonographic results and clinical/post mortem diagnosis were in agreement about the presence of major foetal anoma lies in 18 % of cases. Additional minor anomalies unperceived by sonography , however, were seen post mortem. There was no false positive case. Conclus ions: Without ultrasound screening almost 90 % of anomalies would have been missed due to the absence of clinical symptoms. The Swiss two-step system for praenatal ultrasound screening, based on screening scans done by the ob stetrician and GP in practice, or residents in the public outpatient clinic s respectively, and the detailed scan done by a subspecialized perinatologi st shows excellent results especially in the subgroup of terminated pregnan cies.