Lactate, lactate/pyruvate ratio and catecholamine interrelations in cord blood at delivery in complicated pregnancies

The interrelationships between lactate, lactate/pyruvate (L/P) ratio and catecholamines (CA) in cord artery and vein blood were studied in 56 pregnancies who had complications in the antenatal period or during labour. This group of babies had higher CA levels and were more acidaemic than fetuses after normal pregnancies and labour. There were stronger correlations between lactate and noradrenaline (NA) (R = 0.56, P < 0.001), adrenaline (A) (R = 0.41, P = 0.002) and dopamine (DA) (R = 0.42, P = 0.001) in cord artery blood, than previously reported for normal deliveries. Correlations between L/P ratio and CAs were also significant, although weaker. Multiple regression analysis, using cord artery lactate as the dependent variable, revealed significant correlations for pH (P = 0.01) and pyruvate (P < 0.001) but not for the CAs. The subgroups with high lactate (> 75th centile) had significantly higher NA (P = 0.007) and DA (P < 0.001) in cord artery and NA (P < 0.001) and A (P < 0.001) in cord vein blood, as compared with the subgroup who had lower lactate concentrations. We conclude that fetal hypoxia induces fetal CA production as well as anaerobic metabolism with lactate production. However, the adrenergic stimulation seems not to contribute significantly to the fetal lactate production.