Hypercalcaemia in extremely low birthweight infants.

We report 10 cases of hypercalcaemia associated with hypophosphataemia in the first two weeks of life in extremely low birthweight infants (birthweight less than 1000 g). At the time of diagnosis, the infants were fed mainly with expressed breast milk but they had also received intravenous nutrition. After treatment with additional phosphate plasma calcium concentrations returned to normal. There was a high incidence of rickets of prematurity in these infants.