Prenatal Iron Deficiency and Auditory Brainstem Responses at 3 and 10 Months: A Pilot Study

Purpose: To examine whether prenatal iron deficiency delays auditory brainstem response (ABR) maturation in infancy.

Methods: One hundred and fifteen full-term healthy Chinese infants with maternal and cord blood haemoglobin and serum ferritin determinations were recruited into this study. Forty-eight infants received ABR testing at 3 months, and 45 infants were tested at 10 months. Comparison of the ABR variables were made between infants with and those without evidence of prenatal iron deficiency (maternal 3rd trimester haemoglobin <110 g/L, cord blood ferritin <75 μg/L); or anaemia at 10 months (haemoglobin <110 g/L).

Results: Latencies for wave V and wave III-V and I-V intervals were prolonged at 3 months in infants of anaemic mothers (effect sizes 1.02-1.19 SD). At 10 months, infants with low cord blood serum ferritin (indicating low iron stores at birth) showed longer wave I latency and possibly wave V latency also, besides demonstrating a smaller wave V amplitude (effect sizes 0.58-0.62 SD). Infants with low ferritin at birth and anemia at 10 months had longer wave III-V latency than other groups.

Conclusion: In full-term healthy infants, prenatal iron deficiency appears to have adverse effects on the developing central nervous system and auditory system as assessed by ABRs at 3 and/or 10 months.