Comparison of levels of umbilical venous erythropoietin and nucleated erythrocytes between appropriate and small for gestational age preterm neonates

Chun, Sun Hee; Park, Mi Hye; Kim, Young Ju; Jeong, Kung Ah; Lee, Kyung A

Abstract

OBJECTIVE
To evaluate any difference in levels of umbilical venous eryhthropoietin (EPO) and nucleated red blood cells (NRBC) between appropriate for gestational age (AGA) and small for gestational age (SGA) preterm neonates at birth and to evaluate the peripartal factors that influence the secretion of the nucleated red blood cells in preterm neonate.
METHODS
43 preterm singleton neonates born at the gestational age between 27 weeks and 37 weeks of gestation from January 1998 to December 2004 were enrolled and divided into 25 cases of AGA and 18 cases of SGA. At each delivery, umbilical venous blood gas values, concentration of EPO by radioimmunoassay and the NRBC count expressed per 100 white blood cell (WBC) were obtained. The placenta were examined microscopically for the presence of pathologic infarct and inflammation. Statistical analysis was done by Mann-Whitney U test, Fisher exact test, univariate and multiple regression analysis using SPSS statistical package.
RESULTS
The median umbilical venous EPO concentration and fetal hemoglobin level in SGA preterm neonates were 48.0 mIU/mL and 15.7 g/dL, which were significantly higher than those in AGA preterm neonates (12.5 mIU/ML, 14.6 g/dL). The median NRBC in SGA group was 8.0 NRBC/100 WBC which was higher than in the AGA group (2.5 NRBC/100 WBC), showing no significant difference between groups. Stepwise multiple regression analysis identified O2 saturation, emergency cesarian section, infarct and inflammation in placental pathology and premature rupture of membranes as independent variables associated with the NRBC count.
CONCLUSION
Measurement of the level of EPO and NRBC in umbilical venous blood at birth of the preterm neonates can be used as a helpful index for evaluation of intrauterine hypoxia. In addition, cord blood gas ananlysis and placental examination on the infarct and inflammation are informative value for the elevated NRBC.