During the morphological Ultra Sound (US) evaluation (at 20 weeks of gestation) the occasional detection of a fetal urinary tract dilatation immediately generates a great anxiety in the future Parents.
The Pediatric Urologist who is counselling at the prenatal stage has the responsibility to provide the information and all the explanations based on the effective US findings and on multiple anatomical variables. The sex, the amniotic fluid amount, the dilatation entity, if uni or bilateral and finally the location (renal-ureteral-vesical) all represent fundamental elements to begin formulate a clinical diagnosis.
Fortunately there are mild conditions (pyelectasis) compared to severe situations where the renal function is much more compromised (megacystis with bilateral hydro-uretero-nephrosis).
Nevertheless it is always mandatory to remember that, despite the very significant advantages and benefits of the prenatal US screening, the correct and definitive diagnosis will be achieved only after birth.