Effect on serum calcium of a alpha-hydroxy-vitamin D3 supplementation in infants of low birth weight, infants with perinatal asphyxia, and infants of diabetic mothers.

Thirty infants of low birth weight, 35 infants with perinatal asphyxia, and 16 infants of diabetic mothers were investigated for early neonatal hypocalcaemia. The infants were randomized into a group prophylactically given 1 alpha-hydroxy-vitamin D3, 0.05 or 0.10 micrograms/kg i.v. on the first 3 days of life, and an untreated control group. In infants of low birth weight and infants of diabetic mothers there were no differences in serum ion-Ca concentrations on days 2, 3, 5, and 7 between the treated and untreated groups. In infants with perinatal asphyxia, however, serum ion-Ca concentrations on days 5 and 7 were significantly higher in the treated than in the untreated group, while on days 2 and 3 the differences were not statistically significant. The hypocalcaemia in asphyctic infants was not correlated to bicarbonate treatment, but infants with severe signs of asphyxia had lower serum ion-Ca concentrations than infants with only mild or no signs. Hypocalcaemia in asphyctic infants might be explained by a decreased concentration of 1 alpha, 25-dihydroxy-vitamin D3 following reduced 1 alpha-hydroxylation in the kidney as a consequence of anoxia during perinatal asphyxia.