Maternal pregnancy weight gain and cord blood iron status are associated with eosinophilia in infancy

OBJECTIVE: Allergic disease is multifactorial in origin. Because iron nutrition affects immune responses and maternal pregnancy weight gain impairs fetal iron delivery while increasing fetal demands for growth, the study examined maternal pregnancy weight gain, newborn iron status and an index of atopic disease, infant eosinophilia. STUDY DESIGN: Within a larger prospective study of healthy newborns at risk for developing iron deficiency anemia, umbilical cord iron indicators were compared to infant eosinophil counts. RESULT: Infants who developed eosinophilia exhibited higher cord reticulocyte-enriched zinc protoporphyrin/heme ratio, P < 0.05 and fewer cord ferritin values in the highest (best) quartile, P < 0.05. If cord ferritin was in the upper three quartiles, the negative predictive value for infant eosinophilia was 90%. High maternal pregnancy weight gain predicted infant eosinophil counts, P < 0.04, and contributed to cord ferritin predicting eosinophilia, P < 0.003. CONCLUSION: Poor fetal iron status may be an additional risk factor for infant eosinophilia.