Increased catecholamine levels in cord venous plasma of distressed fetuses.

The concentrations of catecholamines in cord venous plasma were measured by trihydroxyindole fluorimetric assay in four fetuses with normal fetal heart rate (FHR) and three distressed fetuses with late deceleration of pathologic FHR. The concentrations (nmol/l) of norepinephrine and epinephrine in normal fetuses were 40.3 +/- 7.9 (mean +/- SD) and 5.4 +/- 1.5, respectively, whereas those in distressed fetuses were 156.8 +/- 48.0 and 12.1 +/- 4.5, respectively. In normal fetuses about 88% of total catecholamines consisted of norepinephrine, the remaining 12%, epinephrine. The ratio of norepinephrine to epinephrine in distressed fetuses (12.9) was thus higher than the ratio in normal fetuses (7.5). Higher levels of total catecholamine concentrations were associated with the presence of late deceleration of pathologic FHR pattern, low one-minute Apgar score, low umbilical arterial pH value (pH less than 7.20), and fetal hypertriglyceridemia (greater than 48 mg/100 ml). The relationship between fetal hypertriglyceridemia and elevated concentration of cord plasma total catecholamines is elucidated and the physiologic significance of increased secretion of catecholamines in distressed fetuses is discussed.