Nucleated red blood cells: a marker for fetal asphyxia?

OBJECTIVE: Our purpose was to determine whether a relationship exists between the presence of nucleated red blood cells, hypoxic ischemic encephalopathy, and long-term neonatal neurologic impairment. STUDY
DESIGN: Nucleated red blood cell data from 46 singleton term neurologically impaired neonates were compared with cord blood nucleated red blood cells of 83 term nonasphyxiated newborns. The neurologically impaired neonates group was also separated as follows: nonreactive, nonreactive fetal heart rate from admission to delivery; tachycardia, reactive fetal heart rate on admission followed by tachycardia with decelerations; rupture, uterine rupture. The first and highest nucleated red blood cells value and the time to nucleated red blood cells disappearance were assessed.
RESULTS: The neurologically impaired neonates group exhibited a significantly higher number of nucleated red blood cells per 100 white blood cells (34.5 +/- 68) than did the control group (3.4 +/- 3.0) (p < 0.00001). When the neurologically impaired neonates are separated as to the basis for the neurologic impairment, distinct nucleated red blood cell patterns were observed. Overall, the nonreactive group exhibited the highest mean nucleated red blood cell (51.4 +/- 87.5) count and the longest clearance times (236 +/- 166 hours).
CONCLUSION: In this limited population, nucleated red blood cell data appear to aid in identifying the presence of fetal asphyxia. When asphyxia was present, distinct nucleated red blood cells patterns were identified that were in keeping with the observed basis for the fetal injury. In general, the closer the birth was to the asphyxial event, the lower was the number of nucleated red blood cells. Thus our data suggest that cord blood nucleated red blood cells could assist in the timing of fetal neurologic injury.