Neonatal hypocalcemia occurs in full-term infants, and more frequently, in premature infants.
Various etiologic factors for hypocalcemia of new-born infants have been proposed in the literatures: parathyroid insufficiency or functionally imature parathyroid, serum phosphorus levels, fasting and various diets, rate of growth and vitamin D deficiency.
There was large literature on the so-called normal serum calcium level in newborn infant, but less was known in newborn infant in our country.
Thus, author attempts to evaluate blood serum levels of calcium and inorganic phosphorus in premature versus full-term infants, before and after first feeding, correlation between serum calcium and inorganic phosphorus, and changes of blood serum levels of calcium and phosphorus according to age, but the etiology of neonatal hypocalcemia was not elucidated by this study.
The blood serum levels of calcium and inorganic phosphorsu were determined repeatedly in 14 premature and 10 full-term infants durine first three weeks of life, and the results are obtained as following:
1. Serum calcium levels were lower in premature infants, with a mean value of 8.77±0.86mg% versus 9.34±1.03 mg% for full-term infants. serum inorganic phosphorus levels were higher in premature infants, with a mean value of 7.38±1.27 mgo versus 6.32±0.26 mg% for full-term infants.
In the levels of calcium and phosphorus there were significant differences between premature and full-term infants respectively, which suggested that risk of hypocalcemia was greaterin premature infants.
2. 14.2% of premature infants had serum calcium levels below 8mg%> but none of full-term infants had. 23.1% of premature infants had serum inorganic phosphorus levels above 8mg% versus 11.1% for full-term infants.
3. Serum calcium levels were lower before first feeding, with a mean value of 8. 50±0.88mg/% versus 9.22±0.82 mg% after firstfeeding.
4. There was no significant correlation between serum calcium and inorganic phosphorus.
5. Lower serum calcium value and higher serum inorganic phosphorus value were found in the first and fourth to seventh days of life, which suggested that the neonatal hypocalcemia tends to occur in these periods of early life.
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