Cord blood erythropoietin in relation to different markers of fetal hypoxia.

OBJECTIVE

To investigate the relationship between erythropoietin concentration in umbilical venous blood and clinical signs of fetal hypoxia.

METHODS

We measured erythropoietin concentrations in umbilical venous blood from 200 consecutively born neonates using an enzyme-linked immunosorbent assay (ELISA) with two monoclonal antibodies. Results were available within 6 hours. Inter-assay variation was 8.5% and the mean intra-assay variation was 14.2%.

RESULTS

Using a multiple regression analysis, we found that the erythropoietin concentration correlated significantly (P < .01) with fetal growth retardation and umbilical acidosis but not with gestational age, meconium-stained amniotic fluid (AF), abnormal fetal heart rate (FHR) pattern, or Apgar score at 5 minutes. Median erythropoietin concentrations were 25.1 mU/mL in infants with no risk factors or complications during pregnancy and delivery (n = 19), 25.8 mU/mL after complicated pregnancy (n = 95), 50.6 mU/mL with meconium-stained AF (n = 12), 44.7 mU/mL with abnormal FHR pattern (n = 40), 47.8 mU/mL with both stained AF and abnormal FHR pattern (n = 10), and 72.6 mU/mL with umbilical acidosis (n = 24). The median erythropoietin concentration increased significantly with decreasing pH and with increasing base deficit in umbilical arterial blood. The erythropoietin concentration in umbilical venous blood (cutoff value 50 mU/mL) discriminated between infants with no clinical signs of fetal hypoxia and those with umbilical acidosis with a sensitivity of 75% and a specificity of 90%.

CONCLUSIONS

Elevated erythropoietin concentrations in umbilical venous blood indicate prolonged fetal hypoxia. The ELISA technique might be a useful tool for determining the exact time course of erythropoietin concentrations in fetal hypoxia.