Bartter syndrome is characterized by renal potassium and chloride loss, 
hypokalaemia, hypochloraemic metabolic alkalosis and increased plasma renin 
activity along with elevated angiotensin II and hyperaldosteronism. For 
diagnosis we conducted biochemical examinations of both amniotic fluid and the 
mother's urine. Except for potassium, amniotic fluid electrolytes in a mother 
with a fetus with Bartter syndrome were high. Urinary chloride, sodium and 
calcium were very low. Thus, the latter parameters may allow prediction of fetal 
Bartter syndrome during the prenatal period.