[Radioimmunologic analysis of calcitonin and parathyroid hormone in the study of calcium homeostasis in the newborn infant during the first days of life].

Measurements of serum calcium on the first, third and sixth day of life and serum Parathyroid hormone (PTH) and Calcitonin (CT) by radioimmunoassay on the first and third day of life have been effected on a group of 31 infants born after 29-42 weeks of gestation and weighing at birthday 1300-3510 g. The mean serum iCT levels on the first day of life (996 +/- 95 pg/ml) were significantly higher than on the third day of life (533 +/- 79 pg/ml; p less than 0,001) and both were upper normal range of method (200 pg/ml). Mean serum iCT values were found negatively correlated both with birthweight (p less than 0,025) and with gestational age (on 1st day p less than 0,02; on 3rd day p less than 0,001) in AGA newborns. No correlation was found between iCT values and serum Calcium values. The mean serum iPTH levels on the first and third day of life were in the normal range (on 1st day 416 +/- 61 pg/ml; on 3 rd day 640 +/- 114 pg/ml) and not correlated neither with serum Calcium and serum iCT levels, nor with birthweight and gestational age of the newborns. It is excluded that any transient hypoparathyroidism can cause early neonatal hypocalcemia and it is confirmed the presence of high levels of serum Calcitonin in term and premature infants.