For the near future two routine examinations by sonar for every pregnancy in Austria were announced by government. Therefore an analysis of 3076 ultrasonographic examinations of 1217 pregnancies seen in 1984 may lead to an estimation of the frequency of pathological factors to be expected. More than 90% of all pregnant women seen in our department for delivery or other indications had had sonographic examinations during pregnancy, 74% of them as outpatients. The most common pathological factors diagnosed were discrepancies between sonographic estimated and anamnestic gestational age (14.1% of cases), pathological fetal growth (11.0%), pathologics of placenta and umbilical cord (8.6%), pathological presentation (5.9%). Accompanying pathological factors as a cervical length less than 30 mm, an uterus myomatosus, uterine malformations, cystic adnexal masses were found in 1-2% of cases each. Fetal malformations and anomalies were seen in 0.8%. Problems arising from low frequencies of certain rare pathological findings, especially for their detection by office sonographiers or small departments, are discussed. For solution of such problems the multiple step programs as well as an intensive interdisciplinary local or countrywide collaboration is proposed. In Upper-Austria, such collaboration takes place organized by the collaboration group for antenatal detection of fetal malformations, which was founded in 1985 by the Upper-Austrian part of the Osterreichische Gesellschaft für Ultraschall in der Medizin (OGUM).