Table 5.

Proposed Classification for Fetal Renal Disease in Lower Urinary Tract Obstruction According to Severity

Variable	Stage I	Stage II	Stage III	Stage IV
Description	Mild lower urinary tract obstruction	Severe lower urinary tract obstruction, with prenatal findings suggestive of preserved fetal renal function	Severe lower urinary tract obstruction, with prenatal findings suggestive of fetal abnormal renal function	Lower urinary tract obstruction with intrauterine fetal renal failure
Amount of amniotic fluid	Normal	Oligohydramnios or anhydramnios	Oligohydramnios, but usually anhydramnios	Anhydramnios
Echogenicity of fetal kidneys	Normal	Hyperechogenic	Hyperechogenic	Hyperechogenic or absent
Renal cortical cysts	Absent	Absent	Can be present	Can be present
Renal dysplasia	Absent	Absent	Can be present	Can be present
Fetal urinary biochemistry	Favorable	Favorable within 3 consecutive evaluations	Not favorable after 3 consecutive evaluations	Not favorable after 3 consecutive evaluations
Fetal intervention	Not indicated	Indicated to prevent pulmonary hypoplasia and severe renal impairment	May be indicated to prevent pulmonary hypoplasia but not postnatal renal impairment; further studies are necessary	May be indicated to prevent pulmonary hypoplasia but not postnatal renal impairment; further studies are necessary

Data from references 13 through 15.