Table 1.

Society for Fetal Urology (SFU) grading system of congenital hydronephrosis based on longitudinal ultrasound scan of the kidneys

Grade	Central renal complex	Renal parenchymal thickness
0	Intact	Normal
1	Urine in pelvis barely splits sinus	Normal
2	Evident splitting of pelvis and major calyces	Normal
3	Wide splitting of pelvis, major & minor calyces	Normal
4	Further splitting of pelvis, major & minor calyces	Reduced