Relationship between nRBC counts and fetal hypoxia, perinatal outcome in severe preeclampsia

Lim, Yun Kyung; Chang, Suk Joon; Mun, Se Hee; Yang, Jeong In; Kim, Haeng Soo; Ryu, Hee Sug

Abstract

OBJECTIVE
To determine the usefulness of neonatal nucleated red blood cell counts (nRBC) as an independent predictor of fetal hypoxia and perinatal outcome in severe preeclampsia.
METHODS
One hundred thirty eight patients with severe preeclampsia were studied. Umbilical artery Dopppler velocimetry was performed in all patients, and were divided into two groups, the control group with present umbilical artery end diastolic velocity, and the case group with absent or reversed velocity. The patients were also separately grouped as another control (n=58), acute (n=19), and chronic hypoxia (n=55) according to abnormal Doppler findings, presence of oligohydramnios, intrauterine growth restriction (IUGR), and pattern of fetal heart rate tracings during labor. At delivery, the umbilical cord blood was collected and the levels of nRBC per 100 WBC were measured from the samples along with blood gas analysis. The results were compared between the control and acute groups, and chronic hypoxic fetus. Correlation with perinatal outcomes was also evaluated. Student's t-test, ANOVA, and regression analysis were performed for statistical analysis.
RESULTS
Those with absent or reversed end diastolic velocity did not have significantly greater nRBC counts, but had lower platelet counts (p=0.02), lower pO2 (p=0.005), and higher pCO2 saturation levels (p=0.01). There were no significant differences with regard to nRBC counts among the control, acute, and chronic hypoxia groups. Elevated nRBC counts were significantly associated with neonatal intensive care unit stay of more than 28 days (p=0.013), respiratory distress syndrome (p=0.003), disseminated intravascular coagulopathy, or sepsis (p=0.041).
CONCLUSION
nRBC counts did not show significant difference according to umbilical artery Doppler velocity. Also we could not find any difference between the control, acute, and chronic hypoxic group, suggesting that nRBC counts does not correlate with both hypoxic status, or duration of hypoxia. Correlation with elevated nRBC counts and neonatal intensive care unit stay of more than 28 days, respiratory distress syndrome, disseminated intravascular coagulopathy, and sepsis was observed. However, the overlapping results and the wide range of nRBC counts according to the complications limits its role as a predictor of poor perinatal outcome.