Neonatal nucleated red blood cells in infants of overweight and obese mothers

Objective: The perinatal outcome of the infant of obese mother is adversely affected and in theory, may involve fetal hypoxia. We hypothesized that an index of fetal hypoxia, the neonatal nucleated red blood cell (NRBC) count, is elevated in infants of overweight and obese mothers. Study Design: Absolute NRBC counts taken during the first 12 hours of life in 41 infants of overweight and obese mothers were compared to 28 controls. Results: Maternal body mass index and infant birthweight were significantly higher in the overweight and obese group (P < 0.01). Hematocrit, corrected white blood cell and lymphocyte counts did not differ between groups. The absolute NRBC count was higher (P = 0.01), and the platelet count lower (P = 0.05) in infants of overweight and obese mothers than in controls. In stepwise regression analysis, the absolute NRBC count in infants of overweight and obese mothers remained significantly higher even after taking into account birthweight or gestational age and Apgar scores (P < 0.02). Conclusion: Infants of overweight and obese mothers have increased nucleated red blood cells at birth compared with controls. We speculate that even apparently healthy fetuses of overweight and obese mothers are exposed to a subtle hypoxemic environment.