Ultrasound screening for fetal anomalies in southern Sweden: a population-based study.

Background: The accuracy of ultrasound in the diagnosis of congenital malformations has been the subject of many studies. Most of these are hospital-based studies over a limited period of years presenting high detection rates and also relatively high incidence of major malformations. We present here a large population-based study over a long period of years.

Methods: The prenatal diagnoses are compared with the diagnoses of the newborns and aborted fetuses, including autopsy results. The detection rate of some common structural malformations is studied.

Results: The overall detection rate of malformations in our study was 28.4%. We noticed an improved detection rate of heart defects and cleft lip during the study period. The prevalence of malformations in the population was 2.6%. The false positive diagnoses were few, 54 cases, and mainly of a mild nature.

Conclusions: Ultrasound screening of fetal malformations in our population has a low false positive rate and even though the overall sensitivity is low, 28.4%, the detection rate for many common structural malformations is relatively good.