Cord Blood Erythropoietin and Markers of Fetal Hypoxia

Objective: To investigating the relationship between cord blood erythropoietin and clinical markers of fetal hypoxia. Methods: Erythropoietin (EPO) concentrations in umbilical venous blood were measured from 80 neonates with low-risk and different risk factors by radioimmunoassay (RIA). The relation between EPO concentration and clinical markers of fetal asphyxia was evaluated. Results: Median EPO concentrations were 29mU/mL, in infants with no risk factors or complications during pregnancy (n=23). In infants with complicated pregnancy and no complication during labor the median level of EPO was 68mU/ml (n=25) Infants showing abnormal FHR pattern during labor had median EPO levels of 42mU/ml (n=13) while infants showing umbilical blood acidosis showed a median EPO levels of 76mU/ml. Using multiple regression, we found that the erythropoietin concentration correlated significantly (p<0.01) with fetal growth retardation and umbilical acidosis but not with gestational age, abnormal fetal heart rate (FHRT) pattern or Apgar score at 5 minutes. Conclusion: Elevated Erythropoietin concentrations in umbilical venous blood may indicate prolonged fetal hypoxia. Introduction More than forty years have passed since Virigina Apgar introduced her score to evaluate the condition of the newborn (1). Although not meant primarily for this purpose, the score has become the most widely used indicator of perinatal asphyxia. Nevertheless, it is still difficult to determine the presence, duration and extent of fetal hypoxia. Certain abnormal fetal heart rate patterns are considered to indicate imminent fetal risk (2). Whether meconium stained amniotic fluid is related to fetal distress is controversial (3). Umbilical arterial pH is widely used as an indicator of fetal hypoxia. All of these are indirect markers. Moreover, neurologic outcome seems to correlate poorly with acidosis at birth (4,5), low Apgar score or meconium stained amniotic fluid (5). Therefore, additional markers are required to distinguish between acute and chronic fetal hypoxia. Erythropoietin production is stimulated by hypoxia in adults (6) and fetuses (7,9). Because this glycoprotein does not cross the placenta (10,11) elevated cord blood concentration should be a marker of fetal hypoxia. Increased cord EPO concentrations have been found in maternal diabetes (12,14), maternal hypertension (12,15) and acute fetal hypoxia (15,16). Fetal polycythemia frequently occurs in intrauterine growth retardation and increased levels of EPO have been reported in pathological pregnancies possibly associated with placental insufficiency (17). Severe anemia was accompanied by increased EPO concentration (18). Elevated EPO in these cases suggested that prolonged intrauterine hypoxia is an important factor among these fetuses. This study was conducted to investigate the relationship between erythropoietin concentration in umbilical venous blood and the indirect markers of fetal hypoxia (Apgar score, Abnormal FHR pattern, Meconium stained amniotic fluid, Umbilical arterial pH and blood gases). Subjects and Methods Eighty pregnant women with singleton pregnancy were selected for this study. Thirty women had no complications during pregnancy and fifty women had one or more complications during pregnancy; 19(38%) had pregnancy induced hypertension and/or pre-eclampsia; 11(22%) had Diabetes mellitus;