A Review of Cord Blood Concentrations of Iron Status Parameters to Define Reference Ranges for Preterm Infants

Abstract

Background: Iron plays an essential role in various tissue functions, and hence the reliable assessment of iron nutrition status of preterm infants appears to be mandatory. Objectives: To summarize available data on cord blood concentrations of iron status parameters as surrogate reference ranges for preterm infants until term-equivalent age. Methods: Review of the literature searching PubMed for cord blood values of hemoglobin, mean corpuscular volume, ferritin, soluble transferrin receptor, ferritin index, transferrin saturation, reticulocyte hemoglobin content, zinc protoporphyrin/heme ratio, and hepcidin and comparison with reference ranges established for adults. Results: Gestational age-specific cord blood concentration ranges at term were computed as weighted mean for hemoglobin [15.9 g/dl (13.3-18.4)], mean corpuscular volume [108.1 fl (97.8-118.5)] and transferrin saturation [61.2% (31.5-90.9)] and listed for ferritin, soluble transferrin receptor, ferritin index, zinc protoporphyrin/heme ratio, reticulocyte hemoglobin content and hepcidin. These surrogate reference ranges were markedly different from adult values. Conclusion: Reference ranges of iron status parameters established for adults are probably not suitable to define iron status in preterm infants. If iron supplementation in preterm infants should be individually adjusted based on iron status parameters, it may be necessary to aim for cord blood concentration ranges to enable optimal growth and development.

Prevalence of anemia and associations between neonatal iron status, hepcidin, and maternal iron status among neonates born to pregnant adolescents

“…Direct comparison of these values is challenging because the US reference data were obtained from a mixture of capillary, venous, and arterial blood, and Hb concentrations are known to vary between these sources (22). To better control for variability due to site of sampling, our data were compared to weighted mean cord Hb concentrations published in a review of nine studies (15.9 g/dl, n = 1,538) (23). Using this reference value, mean cord Hb concentrations of neonates in our study remained on average 1.8 g/dl lower than expected.…”

Assessment of Neurodevelopment, Nutrition, and Inflammation From Fetal Life to Adolescence in Low-Resource Settings

“…89,90 However, there are no universally accepted methods for accounting for inflammation in estimating micronutrient status, which can lead to incorrect diagnosis of individuals, as well as over-or underestimation of the prevalence of deficiency in a population. 7,47,87,91 To address these challenges in the assessment of nutrition status, a collaborative research group called Biomarkers Reflecting Inflammation and Nutrition Determinants of Anemia has been formed to pool and analyze data from populationbased nutrition surveys and answer priority research questions related to the assessment of micronutrient status in settings of inflammation. 79 Preliminary findings suggest a strong relationship between CRP and AGP and both iron (ferritin, soluble transferrin receptor) and vitamin A (retinol binding protein) biomarkers.…”

Zinc protoporphyrin/heme ratio as parameter of iron status in moderately preterm infants: natural course and associations in the first 4 months

“…23 The higher ZnPP/H levels in our study population might be a reflection of intrauterine growth restriction, intrauterine hypoxia and maternal conditions that can lead to impaired placental function with decreased mother-to-fetus iron supply. Insufficient iron supply to the fetus stimulates erythropoiesis and increases ZnPP/H levels.…”

“…Insufficient iron supply to the fetus stimulates erythropoiesis and increases ZnPP/H levels. 15,16 In the study by Lorenz et al, 23 infants who were exposed to these prenatal conditions were excluded.…”

“…High growth velocity has been reported as a risk factor for ID and IDA, 1,23 because an increase in weight and subsequently expanding blood volume increases the requirement of iron for erythropoiesis. 12,21 We found lower ZnPP/H levels in the infants of mothers with pregnancy-induced hypertension.…”