Postnatal Impairments of Auditory Acuity and Neural Transmission Times Induced by Maternal Iron Deficiency

Iron deficiency (ID) is believed to affect central nervous system (CNS) on several aspects such as myelinogenesis, neurotransmitter synthesis and brain fatty acid metabolism. While most findings in humans investigated ID during post natal periods, our study aimed to evaluate consequences of moderate maternal ID on CNS development in guinea pig offspring. We used auditory brainstem response (ABR) to assess neurophysiologic auditory function and neural transmission times (NTT). Females were fed an iron sufficient (IS) or deficient (ID) diet during the gestation and lactation periods. ID appeared in the third trimester of pregnancy for the ID group. On post natal day 9 (PND9), an IS diet was introduced to wean offspring from both groups. ABR was measured on PND24 using descending intensities and various frequencies (2 to 32 kHz). ID pups had significantly elevated ABR thresholds (hearing loss) at 2, 16 and 32 kHz. NTT seemed to demonstrate shorter inter peak latencies for offspring born to ID dams. A delay in the appearance of the first neural nucleus is likely to be the explanation, whereas later relays did not differ among the two groups. Our study demonstrates that a moderate maternal ID adversely impairs the auditory functions of pups born to ID females. These results suggest that maternal ID may alter the CNS myelinogenesis in the progeny. Support: Canadian Institutes of Health Research and the Canada Research Chairs.