The relationship of prolactin in cord blood, gestational age and respiratory compliance after birth in newborn infants

Abstract

In 29 healthy newborns (gestational age 30-41 wk) and 7 newborns with respiratory distress syndrome [RDS] (gestational age 28-31 wk) the prolactin [PRL] levels in the cord blood and respiratory compliance was measured. PRL was determined by radioimmunoassay, the respiratory compliance was measured with the airway occlusion technique in spontaneously breathing newborns and with injection of known volumes and measuring the airway pressure in newborns with ventilatory support. In healthy newborns PRL and gestational age were significantly correlated (r = 0.62, P < 0.001), while PRL did not correlate with respiratory compliance (r = 0.22 not significant). Comparing 5 healthy newborns and the 7 RDS infants with PRL values < 170 ng/ml, there was no significant difference in the PRL levels, but in the compliance values. Evidently, PRL does not directly influence lung maturation, but is associated with gestational age.