An assessment of cord ferritin concentration and its predictors among a cohort of Canadian preterm and term infants.

Abstract

Low iron stores at birth may adversely influence child cognitive and motor development. The aims of this study were to assess cord blood iron levels and explore maternal and neonatal factors associated with iron status. Cord blood specimens (n=46) were obtained from the BC Children's Hospital BioBank in Vancouver, Canada. The primary outcome was cord plasma ferritin, measured using sandwich-ELISA. Predictors of interest included maternal age, gestational age, gravidity, infant sex, birth weight, and delivery method. Median (IQR) maternal age and gestational age at delivery was 33.5 (29.3-35.8) years and 36.5 (30.0-39.0) weeks, respectively, and 44% of infants were female. Median (IQR) cord ferritin was 100.4 (75.7-128.9) µg/L, and 26% had low iron status (ferritin <76 µg/L). Among preterm deliveries, a 1-week increase in gestational age was associated with a 6.22 (95% CI [1.10, 9.52]) µg/L increase in median cord ferritin. However, among term deliveries, a negative trend was observed (-2.38 µg/L per week of gestation [95% CI: -34.8, 0.78]), indicating a potential non-linear relationship between gestational age and cord ferritin. Female term infants had higher cord ferritin compared to males (β [95% CI]: 30.3 [18.4, 57.9] µg/L), suggesting sex-specific differences in iron transfer, acquisition and utilization. Cord ferritin was higher with vaginal deliveries compared to cesarean sections (β [95% CI]: 39.1 [29.0, 51.5] µg/L). Low iron status may be a concern among infants in Canada; however, further research is needed to inform appropriate thresholds to define optimal iron status in cord blood.