Study of nucleated red blood cells for evaluation of fetal asphyxia

ABSTRACT

Our purpose was to determine whether a relationship exists between the presence of nucleated red blood cells [NRBC], the timing of perinatal asphyxia and the severity of hypoxic insult. Nucleated red blood cells from 27 single full term asphyxiated neonates were compared with cord blood NRBC of 30 full term non-asphyxiated newborns. Our patients were classified into 3 groups according to the degree of neurological impairment suggestive of hypoxic ischemic encephalopathy [mild group I, moderate group II and severe group III]. The first and highest nucleated red blood cells value and the time to NRBC disappearance were assessed. Asphyxiated neonates exhibited a significantly higher number of nucleated red blood cells per 100 white blood cells [median=120 and range 5-835] than did the control group [median=1 and range 0-8] [P=0.001]. Newborns with severe neurological impairment [group III] had significantly higher cord blood nucleated red blood cells than group II and I [P=0.001 for each]. The time of clearance of nucleated red blood cells from the peripheral blood was significantly longer among patients of group III than in group II and I [median value of nucleated red blood cells on the 7[th] day was 0.0/range 0-10 in group I, 11/range 0-80 in group II and 122/range 0-500 in group III]. Meconium stained amniotic fluid was significantly present more in group III than groups II, I [P=0.001]. Correlation studies revealed highly significant positive correlations between cord blood nucleated red blood cells, cord blood pH, and degree of neurological impairment [P=0.001 in both]. In this limited study, counting of nucleated red cells appear to identify the presence of fetal asphyxia and correlated well with the severity of asphyxia. The peak value of nucleated red blood cells and the time of clearance together with the presence of meconium stained amniotic fluid can help in determining the time of fetal injury. In general, the closer the birth was to the asphyxial event, the lower the number of nucleated red blood cells