[Urinary calcium excretion in toxemia of pregnancy]

The amount of urinary calcium excretion is an useful marker for distinction between patient with preeclampsia and normal pregnancy of chronic hypertension has been reported. This study was performed to investigate the extent and the etiology of decrease in urinary calcium excretion in toxemia of pregnancy. The subjects in this study were 20 patients with severe toxemia of pregnancy (group T) and 20 subjects with normal pregnancy (group N). In these subjects, serum calcium (s-Ca), phosphate (s-Pi) and uric acid (s-UA) and urinary calcium (u-Ca), phosphate (u-Pi) and uric acid (u-UA) were measured. The values of u-Ca and u-Pi in the group T were significantly decreased than the group N (p less than 0.001, p less than 0.01). The values of s-Ca and s-Pi made no distinction between group T and group N. There was significant relationships between u-Ca and, s-UA (r = -0.70), clearance of UA (r-0.82), Ccr (r = 0.64), and FEca: Cca/Ccr (r = 0.87). These results indicated that the decrease of u-Ca was evident in severe toxemia of pregnancy. And the decrease of u-Ca has resulted from increase of tubular reabsorption. The change of u-Ca of patients with toxemia was studied. After the onset of toxemia, u-Ca was decreased rapidly (less than 50 mg/day) and u-Ca was restored to the normal range (more than 100 mg/day) promptly after delivery. The value of u-Ca was over 100 mg/day in the second pregnancy that developed on toxemia of pregnancy among the cases who has severe toxemia in the first pregnancy. However, toxemia of pregnancy have relapsed in the case with low u-Ca excretion of less than 100 mg/day during the second pregnancy.