Pathogenesis of hypocalcemia in neonatal polycythemia.

Hypocalcemia (HC) is a frequent complication of neonatal polycythemia (NP): 9.93% in the present study. Its pathogenesis is not clear. We suggest that one of the main pathogenetic explanation of HC in NP is the high level of phosphate significantly different (P less than 0.01) than serum phosphate of normal normocalcemic non-polycythemic newborns. The intense postnatal erythrocyte breakdown will increase the serum level of phosphate. This hyperphosphatemia will decrease calcium ion concentration by their combination and bone deposition, a process allowed by inadequate postnatal parathyroid gland response.