Fetal obstructive uropathy: is urine sampling useful for prenatal counselling?
OBJECTIVE
To evaluate whether fetal urinary sodium and chloride provide clinically useful information in addition to ultrasound in bilateral obstructive uropathy.


METHODS
Sonographic features and urinary concentrations of sodium and chloride were evaluated in fetuses with bilateral obstructive uropathy. After a minimum of 12 months of postnatal follow-up, cases that developed increased serum creatinine (greater than 50 micromol/L) were compared with those that did not.


RESULTS
Of the cases studied, 16/35 died perinatally, all showing anamnios and markedly elevated urinary electrolytes. Of the survivors, ten maintained normal postnatal serum creatinine, whereas nine did not. The frequency of reduced amniotic fluid/olygohydramnios was higher in cases that developed increased serum creatinine (four out of nine) than in those that did not (nil). Sodium above the 95th percentile was 100% specific and 44% sensitive to predict an increased serum creatinine during early infancy, while chloride above the 95th percentile was 70% specific and 56% sensitive. All seven cases in which urinary sodium was elevated and/or amniotic fluid volume was reduced developed renal failure.


CONCLUSIONS
Urine sampling slightly improved renal function prediction, but this must be balanced against its fetal risks.
Miguelez
Javier
J
Department of Obstetrics and Gynecology, University of Sao Paulo Medical School Hospital, Sao Paulo, Brazil.
Bunduki
Victor
V
Yoshizaki
Carlos Tadashi
CT
Sadek
Lilian dos Santos Rodrigues
Ldos S
Koch
Vera
V
Peralta
Cleisson Fabio Andrioli
CF
Zugaib
Marcelo
M
D001938:Brazil; D003404:Creatinine / Q000097:blood; D004108:Dilatation, Pathologic / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000196:embryology / Q000401:mortality / Q000652:urine; D005260:Female; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000652:urine; D016216:Ultrasonography, Prenatal; D016482:Urinalysis / Q000592:standards*; D014570:Urologic Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000196:embryology / Q000401:mortality / Q000652:urine
D012965:Sodium Chloride; D003404:Creatinine