[Dynamics of calcium metabolism and calcium-regulating hormones in pregnancy-induced hypertension].

Serum concentrations of total calcium, ionized calcium and inorganic phosphorus in severe PIH were significantly lower than those in normal pregnancy during the 3rd trimester of pregnancy and continued to be low even at puerperium. On the other hand, serum concentrations of parathyroid hormone in severe PIH were significantly higher during the 3rd trimester of pregnancy and decreased at puerperium. Any remarkable differences in serum calcitonin levels were not found between severe PIH and normal pregnancy through the last trimester of pregnancy and puerperium. Serum concentrations of 1 alpha, 25-(OH)2 vitamin D3 increased significantly in the 3rd trimester of normal pregnancy, but in severe PIH, their increase was not observed, remaining at the normal levels of non-pregnant women. The kidney functions in the both groups were within the normal limits of non-pregnant women, but placental dysfunction was observed in severe PIH. These results suggest that the decrease in serum calcium and phosphorus levels might have occurred as a result of the decrease in the absorption of calcium and phosphorus from the intestine due to the decrease in serum 1 alpha, 25-(OH)2 vitamin D3 levels and that low serum 1 alpha, 25-(OH)2 vitamin D3 concentrations might be caused by the disturbance of the synthesis in the placenta rather than in the kidney.