Latent iron deficiency in utero is associated with abnormal auditory neural myelination in ≥ 35 weeks gestational age infants.
OBJECTIVE
To determine whether cord serum ferritin level is associated with auditory brainstem evoked response interpeak latencies, an index of auditory neural myelination, in infants at ≥ 35 weeks gestational age (GA).


METHODS
This prospective study compared auditory neural myelination in infants with latent iron deficiency (cord serum ferritin, 11-75 ng/mL) and infants with normal iron status (cord serum ferritin, >75 ng/mL) at birth. Our inclusion criteria were infants born at ≥ 35 weeks GA who had cord blood collected soon after birth and had 1 or more of the following risk factors for poor in utero iron status: maternal diabetes mellitus, pregnancy-induced hypertension, and intrauterine growth restriction. Cord serum ferritin level was measured using the chemiluminescence immunoassay method. Auditory brainstem evoked response was measured using 80-dB normal hearing level click stimuli at a rate of 69.9/second within 48 hours after birth to evaluate interpeak latencies, a measure of nerve conduction velocity or myelination.


RESULTS
Of the 45 infants studied, 12 had latent iron deficiency. On repeated-measures ANCOVA using interpeak latencies I-III, III-V, and I-V as multiple outcomes, infants with latent iron deficiency had significantly prolonged interpeak latencies (P = .01) compared with infants with normal iron status after controlling for confounders.


CONCLUSIONS
In utero latent iron deficiency is associated with abnormal auditory neural myelination at birth in infants born at ≥ 35 weeks GA.
Division of Neonatology, Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY. Electronic address: Sanjiv_Amin@urmc.rochester.edu.
Sanjiv B
SB
Amin
Mark
M
Orlando
Hongyue
H
Wang
D000704:Analysis of Variance; D018798:Anemia, Iron-Deficiency / Q000150:complications* / Q000175:diagnosis*; D003056:Cochlear Nerve / Q000473:pathology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D005293:Ferritins / Q000097:blood*; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay; D007231:Infant, Newborn; D008297:Male; D009186:Myelin Sheath / Q000378:metabolism*; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors
D005293:Ferritins
ABR; Auditory brainstem evoked response; GA; Gestational age