Significance of high and normal neonatal nucleated red blood cell count in small-for-gestational-age newborns.

The objective of this study was to evaluate the obstetrical and neonatal outcome in small-for-gestational age (SGA) and appropriate-for-gestational-age (AGA) fetuses with normal and elevated neonatal nucleated red blood cell counts. Therefore the nucleated red blood cell count was assessed immediately after birth in 906 neonates delivered at our institution and the perinatal and neonatal data were compared. Postnatally, infants were classified as SGA if they had a birth weight for given gestational age below the 10th percentile. Neonates were allocated to four groups according to their nucleated red blood cell count: SGA neonates with normal and high nucleated red blood cell count and appropriate-for-gestational-age newborns (AGA) with normal and high nucleated red blood cell count. Statistical analysis included the Mann-Whitney U-Test, Student's t-test, chi2 analysis of variance and stepwise regression analysis. SGA newborns with high nucleated red blood cell count had a significantly lower birth weight, a lower gestational age at delivery, lower arterial and venous pH values, lower Apgar scores at 1 min, 5 min and 10 min as well as lower base excess values compared to the other groups. They had to be transferred significantly more often and stayed longer in the neonatal intensive care unit. Three cases of intraventricular hemorrhage, four cases of necrotizing enterocolotis and two neonatal deaths occurred all in the SGA group with high neonatal nucleated red blood cell counts. Neonatal outcomes of SGA and AGA newborns with normal nucleated red blood cell counts were comparable. Our data do therefore underline the possible value of neonatal nucleated red blood cell counts to differentiate the healthy small-for-gestational age newborn from the truely growth retarded newborn.