Latent iron deficiency at birth influences auditory neural maturation in late preterm and term infants

Background: In utero latent iron deficiency has been associated with abnormal neurodevelopmental outcomes during childhood. Its concomitant effect on auditory neural maturation has not been well studied in late preterm and term infants. Objective: The objective was to determine whether in utero iron status is associated with auditory neural maturation in late preterm and term infants. Design: This prospective cohort study was performed at Sir Ganga Ram Hospital, New Delhi, India. Infants with a gestational age >= 34 wk were eligible unless they met the exclusion criteria: craniofacial anomalies, chromosomal disorders, hemolytic disease, multiple gestation, third-trimester maternal infection, chorioamnionitis, toxoplasmosis, other infections, rubella, cytomegalovirus infection, and herpes simplex virus infections (TORCH), Apgar score <5 at 5 min, sepsis, cord blood not collected, or auditory evaluation unable to be performed. Sixty consecutive infants with risk factors for iron deficiency, such as small for gestational age and maternal diabetes, and 30 without risk factors for iron deficiency were enrolled. Absolute wave latencies and interpeak latencies, evaluated by auditory brainstem response within 48 h after birth, were measured and compared between infants with latent iron deficiency (serum ferritin <= 75 ng/mL) and infants with normal iron status (serum ferritin >75 ng/mL) at birth. Results: Twenty-three infants had latent iron deficiency. Infants with latent iron deficiency had significantly prolonged wave V latencies (7.10 +/- 0.68 compared with 6.60 +/- 0.66), III-V interpeak latencies (2.37 +/- 0.64 compared with 2.07 +/- 0.33), and I-V interpealc latencies (5.10 +/- 0.57 compared with 4.72 +/- 0.56) compared with infants with normal iron status (P < 0.05). This difference remained significant on regression analyses after control for confounders. No difference was noted between latencies I and III and interpeak latencies I-III. Conclusion: Latent iron deficiency is associated with abnormal auditory neural maturation in infants at >= 34 wk gestational age.