Association between reticulocyte hemoglobin content (RetHe) and neurodevelopmental outcomes in preterm infants

Objective Investigate the impact of reticulocyte hemoglobin content (RetHe) on neurodevelopment in preterm infants. Study Design Retrospective cohort of infants born ≤36 6/7 weeks gestational age (GA) with neurodevelopmental testing post-discharge. Associations between neurodevelopment and average RetHe, lowest RetHe, and exposure time to low RetHe ( < 29 pg) were described and stratified by GA. RetHe over time and test Z-scores were assessed using multivariable linear regression. Results 52% of 381 infants ( N = 199) had at least 1 low RetHe. Infants with abnormal development had lower average and minimum RetHe, and longer exposure to low RetHe (all p ≤ 0.003 ). RetHe was highest in infants born 32–33 weeks GA. Higher RetHe during postnatal weeks 1-5 was associated with higher Test of Infant Motor Performance Z-scores ( p = 0.0048 ), with diminishing effect over time, but decreasing 12-month Bayley cognitive Z-scores ( p = 0.0064 ). Conclusion RetHe is associated with neurodevelopment and potentially has differential effects based on GA and postnatal age.