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Updated: Jan 12, 2026
Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
In utero lead exposure and auditory neural myelination in premature infants
Radhika S Amin1, Mark S Orlando2, Sanjiv B Amin3
1Case Western Reserve University School of Medicine, 9501 Euclid Ave, Cleveland, OH, 44106, USA.
Insights
Low-level prenatal lead exposure did not impact auditory neural myelination in premature infants. This study found no association between cord blood lead levels and auditory brainstem response measures in preterm newborns.
Area of Science:
- Neuroscience
- Environmental Health
- Neonatology
Background:
- Prenatal low-level lead exposure is linked to neurodevelopmental issues in term infants, specifically affecting auditory neural myelination (ANM).
- Premature infants may exhibit heightened susceptibility to lead-associated neurotoxicity, necessitating further investigation.
Purpose of the Study:
- To determine if low-level in-utero lead exposure is associated with developmental neurotoxicity in premature infants.
- To evaluate the impact of prenatal lead exposure on auditory neural myelination (ANM) in preterm neonates.
Main Methods:
- A prospective observational study included singleton infants with gestational ages between 24-33 weeks.
- Cord blood lead levels were quantified using Inductively Coupled Plasma Mass Spectrometry.
- Auditory brainstem evoked response (ABR) was conducted on both ears at 35 weeks post-menstrual age to assess inter-peak latencies (IPLs) as a measure of ANM.
Main Results:
- The study analyzed 103 premature infants with a mean gestational age of 29.3 weeks.
- Mean cord blood lead levels were 0.54 μg/dL (range: 0.065-5.30 μg/dL).
- Statistical analysis revealed no significant association between cord blood lead levels and auditory neural myelination (IPLs) in either ear, even after controlling for confounding factors.
Conclusions:
- In-utero exposure to low-level lead (≤5.30 μg/dL) does not appear to adversely affect auditory neural myelination in preterm infants.
- These findings suggest that ANM, assessed at 35 weeks post-menstrual age, is not a sensitive indicator for detecting neurodevelopmental effects of low-level prenatal lead exposure in infants born at or before 33 weeks gestational age.
Background:
In studies of term infants, in-utero low level lead exposure was associated with developmental neurotoxicity, including abnormal auditory neural myelination (ANM). However, this association has not been well-studied in premature infants who may be more susceptible to lead associated developmental neurotoxicity.
Aim:
To evaluate if low level in-utero lead exposure is associated with developmental neurotoxicity as evaluated by ANM in premature infants.
Methods:
A prospective observational study was performed in singleton infants 24-33 weeks gestational age (GA). Cord blood lead level was measured using Inductively Coupled Plasma Mass Spectrometry. Auditory brainstem evoked response (ABR) was performed in each ear at 35 weeks post-menstrual age (PMA) to evaluate inter-peak latencies (IPL), a measure of ANM.
Results:
A total of 103 infants were studied. The mean (standard deviation) GA was 29.3 (1.8) weeks. The mean (range) cord blood lead level was 0.54 (0.065-5.30) ug/dL. On multiple linear regression analyses, controlling for confounders, cord lead levels were not associated (p > 0.05) with right ear IPLs (beta coefficients, 95 % confidence intervals): I-III (-0.001, -0.014-0.012), III-V (0.005, -0.007-0.018), or I-V (0.002, -0.015-0.020). There was also no association (p > 0.05) with left ear IPLs: I-III (-0.002, -0.017-0.012), III-V (-0.003, -0.015-0.008), or I-V (-0.006, -0.026-0.013).
Conclusion:
Our findings suggest that in-utero low level lead exposure of ≤5.30 μg/dL is not associated with adverse effects on ANM when evaluated at 35 weeks PMA in infants ≤33 weeks GA.
