[The value of radio-isotope investigations of the urinary tract for the diagnosis of urinary tract calculi during pregnancy (author's transl)].

According to the literature, urinary tract calculi are a rare complication of pregnancy. Because of the radiation effect of excretory urography on mother and fetus, intravenous pyelography can only rarely be used for the diagnosis of calculi in pregnancy. A sequential radio-isotope nephrogram and the simultaneous determination of the J 131 hippurate clearance equivalents were used in two pregnant patients. The cases are reported. The results are discussed and compared to reports in the literature. The exposure to radiation is about 50 mrem for radio-isotope nephrography compared to from 500 to 4000 mrem for excretory urography. Radio-isotope nephrography is therefore useful for the preliminary diagnosis of urinary tract calculi in pregnancy and the simultaneous clearance determination yields additional data on the function of the urinary tract.