Serum concentrations of calcitonin and parathormone in the cord blood of premature infants

Determinations of serum calcium (Ca), calcitonin (CT) and parathyroid hormone (PTH) were carried out in mixed cord blood of 23 preterm infants. Gestational age ranged between 25 and 37 weeks. 17 of theme were vaginally delivered while 6 were delivered by emergency Caesarean section. 4 neonates died because of respiratory distress syndrome. The serum was stored at -30 degrees C until the determinations. Serum Ca levels were determined by spectrophotometry while CT and PTH levels by RIA (Immuno Nuclear Co). In cord serum the mean (M +/- SE) Ca,CT and PTH concentrations of all neonates examined were respectively: 9,9 +/- 0,6 mg/dl; 176 +/- 44 pg/ml and 1100 +/- 446 pg/ml. Serum values of CT and PTH in preterm newborns delivered by emergency Caesarean section were significantly higher than in those neonates vaginally delivered (CT: 302 +/- 115 vs 94 +/- 9 pg/ml; p less than 0.005) (PTH:2655 +/- 1857 vs 466 +/- 59 pg/ml; p less than 0.05). No differences were observed between serum CT and PTH levels in preterm neonates of different gestational age. Both CT and PTH serum concentrations were higher in neonates who died. In conclusion, the preterm neonate is able to secrete both peptides and to maintain Ca homeostasis; the mode of delivery likely affects the CT and PTH secretion; unexplainable high CT and PTH serum levels were detected in poor outcome preterm infants.