Effects of latent iron deficiency on auditory neural maturation during early infancy in infants above 35 weeks' gestation
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Updated: Aug 26, 2025
Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
Ajoy Kumar Garg1, Satish Saluja1, Manoj Modi1
1Sir Ganga Ram Hospital, New Delhi, India.
Insights
Latent iron deficiency (LID) in newborns did not affect auditory brainstem response (ABR) latencies at birth or 4-6 months. However, LID infants showed a higher risk of iron deficiency later.
Area of Science:
- Neonatal studies
- Neuroscience
- Pediatric iron status
Background:
- Latent iron deficiency (LID) at birth is linked to delayed neural maturation, indicated by prolonged auditory brainstem response (ABR) latencies.
- This study investigates the impact of LID on ABR in neonates.
Purpose of the Study:
- To compare ABR wave and inter-peak latencies at birth and 4-6 months in infants with and without LID.
- To assess the association between LID at birth and iron status at 4-6 months.
Main Methods:
- Screened neonates ≥35 weeks gestation for LID (cord ferritin ≤75 ng/mL) versus normal iron status (NIS; >75 ng/mL).
- Performed ABR within 48 hours of birth and reassessed latencies at 4-6 months.
- Measured hemoglobin and serum ferritin at follow-up.
Main Results:
- No significant differences in ABR latencies were observed at birth or 4-6 months between LID and NIS groups.
- Small-for-gestational-age neonates with LID showed longer inter-peak latencies (I-III, I-V) at birth.
- 24.3% of LID infants remained iron-deficient at 4-6 months, compared to none in the NIS group.
Conclusions:
- Latent iron deficiency at birth does not impact ABR latencies in neonates ≥35 weeks gestation.
- Infants with LID at birth have an increased risk of developing iron deficiency by 4-6 months of age.
Background:
Latent iron deficiency (LID) at birth is associated with prolonged latencies in auditory brainstem response (ABR), a surrogate for neural maturation. This study aimed to compare wave and inter-peak latencies of ABR at birth and at 4-6 months of age in infants ≥35 weeks of gestation with normal iron status (NIS) and LID.
Methods:
Neonates born at ≥35 weeks were screened. Cord ferritin value ≤ 75 ng/mL and >75 ng/mL were classified as LID and NIS, respectively. ABR was performed within 48 h of birth. The absolute latencies of waves I, III, and V, and inter-peak latencies I-III, III-V, and I-V were computed. Infants were reassessed at 4-6 months of age for hemoglobin, serum ferritin levels, and ABR latencies.
Results:
In total, 160 neonates were enrolled. The mean (SD) birth weight and gestational age of the study population were 2843 (384) g and 38.3 (1.1) weeks, respectively. Approximately 122 infants completed follow-up until 4-6 months of age: 37 in the LID group and 85 in the NIS group. Overall, the wave and interpeak latencies in both groups at birth were comparable. At 4-6 months, the absolute latencies of waves I, III, and V, and inter-peak latencies I-III, III-V, and I-V were decreased and were comparable in both groups. Among small-for-gestational-age neonates, inter-peak latencies in I-III and I-V at birth were significantly longer in the LID group than in the NIS group. Nine (24.3%) infants in the LID group and none in the NIS group were iron-deficient at 4-6 months of age.
Conclusion:
There was no difference in wave or inter-peak latencies at birth and at 4-6 months of age in neonates aged ≥35 weeks with or without LID. However, infants with LID at birth have a significant risk of iron deficiency at 4-6 months of age. CTRI/2017/08/009379 (www.ctri.nic.in).
