Neonatal nucleated red blood cell counts in the first week of life-choosing the best analysis to predict perinatal outcome

Abstract

LIFE-CHOOSING THE BEST ANALYSIS TO PREDICT PERINATAL OUTCOME AHMET BASCHAT, MICHELLE KUSH, CHRISTOPH BERG, ULRICH GEMBRUCH, CHRISTOPHER HARMAN, University of Maryland at Baltimore, Obstetrics, Gynecology and Reproductive Sciences, Baltimore, Maryland, Friedrich Wilhelm University, Bonn, Obstetrics & Prenatal Medicine, Bonn, Germany, University of Maryland at Baltimore, Obstetrics, Gynecology, and Reproductive Sciences, Baltimore, Maryland OBJECTIVE: Abnormal nucleated red blood cell (NRBC) dynamics are prominent fetal hematologic responses to placental dysfunction, hypoxemia, and overt asphyxia. NRBC elevated at birth or persistent neonatally, are statistically linked to adverse outcome, but clinical predictive value is variable. We evaluated the role of novel indices to better define overall magnitude of NRBC response. STUDY DESIGN: Peripheral NRBC count was obtained from preterm (!34 weeks) growth-restricted (birthweight (BW) !10th centile) neonates, after birth. Daily counts and days of NRBC persistence O30 were determined. Mean counts (NRBC-mean), area under the curve (NRBC-auc) and declination (NRBC-slope) were analyzed over week One. NRBC parameters were related to cord artery pH !7.20, Apgar !7 at 5 minutes, major morbidity (bronchopulmonary dysplasia (BPD), Grade III/IV intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC) included) and neonatal death (NND). RESULTS: Among 176 patients, 22 (12.5%) had acidosis and 19 (10.8%) low Apgar. Complications included BPD (n=36, 20.5%), IVH (n=18, 10.2%), NEC (n=18, 10.2%), NND (18, 10.2%). NRBC-auc and NRBCmean correlated most strongly with pH, BW and gestational age (Pearson’s = 0.45 to –0.18, all p!0.001). NRBC-auc varied most between non-morbid (50) and morbid (595), while NRBC-mean varied most between survivors (14) and NND (211) (all, p!0.001). NRBC persistence strongly predicted NND: Day 4 clearance was achieved by 80% of survivors and only 35% NND. Logistic regression identified prematurity and persistent NRBC as primary determinants of morbidity (r=0.56, p!0.01). While importance of individual NRBC counts varied, Day 4 NRBC O70 predicted morbidity best (sensitivity 82%, specificity 96%). Presence of morbidity and BW were prime determinants of death (r=0.42, p!0.01). CONCLUSION: Simple daily NRBC counts provide clinical information equivalent to more complicated methods. The importance of prematurity and growth are emphasized, but elevated NRBC counts beyond Day 3, are prognostically relevant independent predictors of adverse outcome.