Anatomic correlates of ultrasound prenatal diagnosis of urinary tract abnormalities.

In 52 fetuses, in utero sonographic diagnosis of urinary tract malformations was correlated with their autoptic or surgical findings. 39 malformations were correctly diagnosed prenatally, although 5 other extrarenal-associated anomalies were not detected; 10 diagnoses were incomplete; in 3 cases the characteristics of malformations found at sonography turned out to be different at the post-mortem examination. The following factors impaired sonographic diagnoses: limited number of examinations, gestational age at the time of examination, nature of malformation and, above all, oligohydramnios (which is common in most urinary tract malformations). The correlations between renal malformations and karyotype anomalies are also discussed in relation to the higher incidence present in polymalformative syndromes.