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Am J Perinatol
DOI: 10.1055/a-2806-3017
Original Article

Iron Deficiency Screening with Reticulocyte–Hemoglobin Content and 2-Year Neurodevelopmental Outcomes in Extremely Low Birth Weight Infants

Authors

  • Whitley N. Hulse 

    1   Division of Neonatology and Newborn Nursery, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States
    2   Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, United States

  • Timothy M. Bahr 

    2   Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, United States
    3   Department of Neonatology, Intermountain Healthcare, Salt Lake City, Utah, United States

  • Betsy Ostrander

    4   Division of Pediatric Neurology, Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, United States

  • Sarah Winter

    5   Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, United States

  • Robin K. Ohls

    2   Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, United States

  • Tara L. DuPont

    2   Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, United States
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Abstract

Objective

The objective of this study is to assess reticulocyte–hemoglobin (RET–He) and daily iron dosing with 2-year cognitive outcomes.

Study Design

A multicenter retrospective cohort study of 78 infants born between 2014 and 2018 at less than 28 weeks' gestation or less than 1,250 g birth weight throughout level III or IV neonatal intensive care units (NICUs). RET–He measurement, iron supplementation, and the Bayley Scales of Infant and Toddler Development-III (Bayley-III) test were analyzed using multiple linear regression models.

Results

For every 1 mg/kg increase in mean total daily iron supplementation, the Bayley-III cognitive score increased by 2.9 points (95% confidence interval [CI]: 0.4–5.4, p = 0.023). No associations were identified between minimum or maximum RET–He and Bayley-III cognitive outcomes. Infants with a RET–He value < 29 pg tended to be 2.53 times more likely to have a Bayley-III language score below 70 (odds ratio: 2.53, 95% CI: 0.92–6.95, p = 0.071). Thirty-eight out of 78 (38.4%) infants were iron-deficient during their NICU hospitalization, with at least one RET–He < 29 pg.

Conclusion

An association was identified between a higher mean daily iron dose and improved cognitive outcomes for infants, but not between the iron index RET–He and neurodevelopmental outcomes. Iron deficiency remains common among NICU patients undergoing follow-up, suggesting that standard iron dosing may be inadequate for high-risk neonates.

Key Points

  • Higher daily iron dose improves cognitive outcomes.

  • Reticulocyte–hemoglobin level is not associated with neurodevelopmental outcomes.

  • Iron deficiency is common in very low birth weight infants, affecting 38.4%.

Keywords

iron - reticulocyte–hemoglobin - preterm infant - neurodevelopmental outcomes

Data Availability Statement

These data are original and have not been previously published. Data are not available for sharing outside of the institution.


Contributors' Statement

W.N.H.: Conceptualization, data curation, formal analysis, investigation, methodology, project administration, writing—original draft, writing—review and editing. T.M.B.: Formal analysis, writing—original draft, writing—review and editing. B.O.: Conceptualization, methodology, writing—original draft, writing—review and editing. S.W.: Conceptualization, methodology, writing—original draft, writing—review and editing. R.K.O.: Conceptualization, methodology, writing—original draft, writing—review and editing. T.L.D.: Conceptualization, formal analysis, methodology, project administration, supervision, writing—original draft, writing—review and editing.




Publication History

Received: 12 June 2025

Accepted: 04 February 2026

Article published online:
20 February 2026

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