Comparison of umbilical venous erythropoietin concentration between appropriate and small-for-gestational-age neonates of term pregnancy

Chun, Sun Hee; Park, Mi Hye

Abstract

OBJECTIVE
To evaluate the intrauterine hypoxic effect in term small-for-date (SGA) neonates by comparing the umbilical venous erythropoietin (EPO) concentration between appropriately-grown (AGA) and SGA neonates at delivery and to determine the variables that correlate with the umbilical venous EPO concentration by multiple regression analysis.
METHODS
183 term singleton neonates (gestational weeks > OR =37) were enrolled and divided into 136 cases of AGA (10th-90th percentile of birth weight for the gestational age) and 47 cases of SGA (< 10th percentile of birth weight for the gestational age. At each delivery, blood gas values, concentration of EPO by radioimmunoassay and the number of nucleated erythrocytes (NRBC) per 100 white blood cells in smear of umbilical venous blood were obtained. The placentas were examined microscopically for presence of pathological infarct. Statistical analysis was done by Mann-Whitney U test, x2 test, and univariate and multiple regression analysis using SPSS statistical package (version 10).
RESULTS
The median umbilical venous EPO concentration, fetal hemoglobin level were significantly higher in SGA neonates than those in AGA neonates. There was no difference in number of NRBC between AGA and SGA neonates. Multiple regression analysis model with level of NRBC, presence of placental infarct and SGA provided prediction of EPO level in umbilical venous blood at delivery (regression equation: EPO=-103.94+4.75NRBC+68.07placental infarct+36.40SGA F=15.57. r2=0.47).
CONCLUSION
Term SGA neonates was considered to have compensatory, not pathological intrauterine hypoxic effect by showing increased level of EPO and normal level of NRBC in umbilical venous blood at delivery, compared with thoses of AGA. In the suspected cases of SGA antenatally, measurement of NRBC level and placental pathologic examination for infarct can be informative for estimating the extent and duration of intrauterine hypoxia.