Nucleated red blood cells as a marker of acidemia in term neonates.
OBJECTIVE
Nucleated red blood cells are produced in increased numbers under hypoxic conditions. We sought to examine the relationship between nucleated red blood cell count in the circulations of term neonates and other possible markers of fetal hypoxia.


METHODS
We prospectively collected umbilical blood from all live-born neonates delivered at our institution. Arterial blood was analyzed for pH and blood gas values. Venous blood was analyzed for nucleated red blood cell count. We reviewed the medical records for maternal data and neonatal outcomes of gestations of >/=37 weeks' duration.


RESULTS
We evaluated 1561 cases. The mean nucleated red blood cell count per 100 white blood cells was 9.2 +/- 18.1 (range, 0-327). Nucleated red blood cell counts were higher in infants with pH <7.20 (P =.001). Both patients with respiratory acidemia and patients with uncompensated metabolic acidemia had elevated nucleated red blood cell counts (P =.013 and P =.014, respectively). As umbilical artery pH and base excess decreased, nucleated red blood cells became more prevalent. Elevated nucleated red blood cell counts were associated with presence of meconium (P =. 020) and neonatal intensive care unit admission (P =.024).


CONCLUSIONS
We found that nucleated red blood cell counts vary widely in the circulation of term neonates. Elevated nucleated red blood cell counts are associated with fetal acidemia, meconium, and neonatal intensive care unit admission.
Hanlon-Lundberg
K M
KM
Department of Obstetrics and Gynecology, University of Wisconsin Medical School-Milwaukee Clinical Campus, Milwaukee, Wisconsin, USA.
Kirby
R S
RS
D000138:Acidosis / Q000175:diagnosis*; D001034:Apgar Score; D015415:Biomarkers; D001784:Blood Gas Analysis; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D005311:Fetal Hypoxia / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn / Q000097:blood*; D008499:Medical Records; D011247:Pregnancy; D011446:Prospective Studies; D012189:Retrospective Studies
D015415:Biomarkers