Effectiveness of routine ultrasound in screening congenital defects.

During one year 26 cases of fetal malformations were diagnosed by means of ultrasound alone at the 1st Department of Obstetrics and Gynaecology of the University of Milano. Frequency of congenital defects first detected in the Centre was 5.6% which can be estimated to be approx. 25% of the anomalies detectable at birth in an unselected population. The total number of congenital defects detected was 31. A wrong diagnosis was done in two suspected cephaloceles resulted to be a cystic hygroma of the neck and a nuchal cephaloematoma while a pleural effusion was misdiagnosed as a thoracic cyst. On the other hand a precise evaluation of diagnostic errors (false negatives) has not been possible. Most malformations not detected by scanning involved splanchnic organs rather than central nervous system (Tab. V). Ultrasonic procedures for measurement of fetal head and trunk could partly account for this result. Termination of pregnancy was performed in 4 cases and post-partum surgical correction in 3 (Tab. I). Antenatal diagnosis of fetal malformations should be then considered as a major end-point of routine US.