[Pyelectasy]

Abstract

Ultrasonography is undoubtedly an effective tool for identifying fetal urinary tract anomalies. Fetal pyelic dilatations are common and of controversial pathological significance. A 5 mm threshold for a pelvic anteroposterior diameter can be used to detect dilatation during the second trimester of pregnancy, if, and only if, all suspected dilatations are verified during the third trimester. Only the dilatations larger than 10 mm after 28 weeks merit further postnatal exploration. Urological postnatal exploration should be done if the abnormalities persist at the postnatal sonographic control. This control, if normal, should be repeated at least once at the age of one month. Further investigations are necessary to evaluate the incidence and significance of VUR, since it has been reported associated in certain cases with isolated pyelic dilatation. However, there are no grounds at present for justifying routine retrograde cystography in case of an isolated fetal pyelic dilatation. A karyotype study is not indicated in the presence of an isolated pyelic dilatation.