Plasma Adrenaline and Noradrenaline in the Neonatal Period, and Infants With Respiratory Distress Syndrome and Placental Insufficiency

Abstract

The fluorometric method of Weil-Malherbe and Bone was used to investigate plasma catecholamine levels in the neonatal period. Full-term normal infants were found to have plasma adrenaline levels of 0.35 ± 0.64 µg/l and noradrenaline levels of 2.39 ± 2.69 µg/l. Premature infants had plasma adrenaline levels of 0.86 ± 1.21 µg/l and noradrenaline levels of 3.24 ± 2.03 µg/l. Twelve premature infants with the respiratory distress syndrome showed a significant and fourfold increase in adrenaline concentration and a nonsignificant increase in the level of noradrenaline. In seven infants with placental insufficiency and postmaturity there was a significant and eightfold increase in adrenaline. The importance of these findings is discussed, particularly with respect to hypoxia.

Fetoplacental vascular effects of maternal adrenergic antihypertensive and cardioprotective medications in pregnancy

“…In the plasma of preterm newborns, the concentrations of both adrenaline and noradrenaline are approximately two-fold higher compared with full-term babies [ 90 ]. Adrenaline levels have been found to be four-fold higher in preterm new-borns with respiratory distress syndrome, and eight-fold higher in those with placental insufficiency [ 90 ]. A study investigating fetal plasma noradrenaline responses to invasive procedures showed no correlation between maternal and fetal plasma levels of noradrenaline [ 91 ]; furthermore, although physiological infusion of adrenaline in pregnant sheep elevated fetal plasma adrenaline, the reduction of uterine, but not umbilical blood flow [ 92 ], suggests the likely barrier function of the placenta.…”

“…Some evidence has suggested that in hypertensive pregnancies, these transporters are downregulated, thus increased levels of endogenous catecholamines may compromise this placental defence [89]. In the plasma of preterm newborns, the concentrations of both adrenaline and noradrenaline are approximately twofold higher compared with full-term babies [90]. Adrenaline levels have been found to be four-fold higher in preterm new-borns with respiratory distress syndrome, and eightfold higher in those with placental insufficiency [90].…”