Effects of intrauterine latent iron deficiency on auditory neural maturation in full-term newborns.

OBJECTIVE: This study analyzed the relationship between latent iron deficiency evaluated by ferritin, and the myelination of the central nervous system evaluated through the brainstem evoked response audiometry test. METHOD: A total of 109 full-term newborns, born without anemia and risk factor for hearing deficiency, were enrolled. After delivery, umbilical cord blood was collected to determine ferritin and hematocrit levels. The brainstem evoked response audiometry test was carried out in the first 28 days of life. Analysis was performed between the control group (n=71) with ferritin greater than 75ng/mL, and the latent iron deficiency group (n=38) with ferritin between 11 and 75ng/mL. Results were presented as mean±standard deviation. Statistical analysis was performed using GraphPad prism7 and SPSS with a significance level of 5%. RESULTS: A significant higher V-wave (p=0.02) and interpeak intervals I-III (p=0.014), I-V (p=0.0003), and III-V (p=0.0002) latencies were found in the latent iron deficiency group, as well as a significant inversely proportional correlation between ferritin and the same wave and intervals (p=0.003, p=0.0013, p=0.0002, p=0.009, respectively). Multiple correlation analysis showed a significant correlation of latent iron deficiency with all interpeak intervals, even taking into account newborn gestational age. CONCLUSION: Iron deficiency anemia is a prevalent pathology; this study showed auditory delayed maturation associated to intrauterine iron deficiency, even in its latent form. This reinforces the importance of adopting effective measures, on a global scale, to prevent and treat this pathology in different life periods, especially in the most vulnerable population.