Predictors of serum ferritin and serum soluble transferrin receptor in newborns and their associations with iron status during the first 2 y of life

Iron optimisation in pregnancy: a Haematology in Obstetric and Women's Health Collaborative consensus statement

Anaemia is a well-recognised and widely accepted consequence of iron deficiency (ID); however, the two diagnoses are not synonymous with the effects of ID occurring long before the development of anaemia. In adults, ID can cause physical and neuropsychological symptoms, including lethargy, altered mood and poor concentration, reducing an individual's quality of life. Foetal and neonatal ID has been associated with impaired neurocognitive development with lasting effects despite iron replacement in early life. Obstetric ID is common, affecting up to 70% of Australian pregnancies. The impact, at both an individual and a population level, remains underappreciated and consensus on the identification and management of obstetric ID is lacking. This consensus statement was developed by the Haematology in Obstetrics and Women's Health (HOW) Collaborative and utilised the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to evaluate evidence and strength of recommendations. Recommendations are as follows: (i) Routine ferritin screening should be performed in all pregnant women (GRADE 1C) at booking and 24-28 weeks. Repeat testing should be performed at 36 weeks if clinically indicated or if the woman is previously unscreened. (ii) ID in pregnancy should be defined as a ferritin level <30 μg/L (GRADE 1D). (iii) An appropriate oral iron formulation should be offered as first-line therapy for obstetric ID (GRADE 1B). (iv) Alternate-day oral dosing can be considered to limit side effects in women with obstetric ID (GRADE 2B). (v) Intravenous iron should be offered to women with ID/ID anaemia who are intolerant of or refractory to oral iron or in the third trimester (GRADE 1B).

The interplay between maternal-infant anemia and iron deficiency

Iron deficiency anemia in pregnancy is a major public health problem known to cause maternal morbidity and adverse birth outcomes, and it may also have lasting consequences on infant development. However, the impact of the maternal hematological environment on fetal and infant hemoglobin and iron stores in the first year of life remains unclear. This review of the epidemiological evidence found that severe maternal iron deficiency anemia in pregnancy is associated with lower ferritin, and to a lesser degree hemoglobin levels, in infants at birth. Emerging data also suggests that severe anemia in pregnancy increases the risk of iron deficiency and anemia in infants 6-12 months of age, although longitudinal studies are limited. Effective anemia prevention in pregnancy, such as iron supplementation, could reduce the risk of infant anemia and iron deficiency during the first year of life; however, more evidence is needed to determine the functional impact of iron supplementation in pregnancy on infant hematological indices.

Impact and interactions between risk factors on the iron status of at-risk neonates

OBJECTIVE

Examine interactions between perinatal risk factors for congenital iron deficiency (ID) using two cohorts.

STUDY DESIGN

Iron status in a composite 767-member cord blood cohort and a NICU cohort of 257 infants < 33 weeks of gestation or small for gestational age (SGA). Risks for ID were examined. Cord ferritin levels < 84 µg/L defined congenital ID. Serum ferritin < 70 µg/L defined infantile ID at one-month.

RESULTS

31% of the cord cohort had congenital ID; risks summative (p < 0.0015). 16% of the NICU cohort had infantile ID; risks not summative. However, 32% had ID if the ferritin threshold was 100 µg/L. Being both preterm (p < 0.0001) and SGA (p < 0.05) negatively impacted cord iron status. Maternal hypertension was a novel predictor of iron status (p = 0.023 in preterm cord; p < 0.0025 in NICU).

CONCLUSION

Summing risks in term and understanding compounding risks in preterm infants can improve screening and management of ID in at-risk infants.

Smokeless Tobacco Exposure and Fetal Iron Status: An Analytical Study

Objectives:

To compare the cord serum ferritin and fetal iron status in newborns with and without maternal occupational smokeless tobacco exposure and determine the influencing factors.

Methods:

This cross-sectional study included mother–infant dyads with occupational tobacco exposure (exposed) and an unexposed group. Umbilical cord serum ferritin was compared in both groups. Fetal nicotine absorption was established by cord cotinine.

Results:

A total of 140 newborns each were analyzed in each group. There was no significant mean difference (MD) (P = 0.900) between the cord serum ferritin in the tobacco exposed and unexposed group. Fetal nicotine absorption was seen in 43.6% of the exposed group. Cord serum ferritin was 14.1 μg/L (95% confidence interval [(95% CI:-43.1, 14.9); P=0.338] lower in this group compared with the group without fetal nicotine absorption. A higher adjusted MD for ferritin was present for maternal hypertension (12.5 [95% CI: −75.5, 100.5]; P = 0.777) and gestational diabetes mellitus (21.4 [95% CI: −54.0, 96.9]; P = 0.571) in the group with fetal nicotine absorption. Fetal nicotine absorption exaggerated fetal iron depletion in maternal anemia [aOR 4.8 (95%CI: 1.2, 19.0); P=0.025].

Conclusion:

Cord serum ferritin and fetal iron status were comparable in tobacco exposed and unexposed groups. In those with fetal nicotine absorption, cord ferritin levels reflect the fetal inflammatory state.

Burden of anemia and its underlying causes in 204 countries and territories, 1990-2019: results from the Global Burden of Disease Study 2019

BACKGROUND

Anemia is a common disease which affects around 40% of children and 30% of reproductive age women and can have major health consequences. The present study reports the global, regional and national burden of anemia and its underlying causes between 1990 and 2019, by age, sex and socio-demographic index (SDI).

METHODS

Publicly available data on the point prevalence and years lived with disability (YLDs) were retrieved from the global burden of disease (GBD) 2019 study for 204 countries and territories between 1990 and 2019. The point prevalence, YLD counts and rates per 100,000 population were presented, along with their corresponding 95% uncertainty intervals.

RESULTS

In 2019, the global age-standardized point prevalence and YLD rates for anemia were 23,176.2 (22,943.5-23,418.6) and 672.4 (447.2-981.5) per 100,000 population, respectively. Moreover, the global age-standardized point prevalence and YLD rate decreased by 13.4% (12.1-14.5%) and 18.8% (16.9-20.8%), respectively, over the period 1990-2019. The highest national point prevalences of anemia were found in Zambia [49327.1 (95% UI: 46,838.5-51,700.1)], Mali [46890.1 (95% UI: 44,301.1-49,389.8)], and Burkina Faso [46117.2 (95% UI: 43,640.7-48,319.2)]. In 2019, the global point prevalence of anemia was highest in the 15-19 and 95+ age groups in females and males, respectively. Also, the burden of anemia was lower in regions with higher socio-economic development. Globally, most of the prevalent cases were attributable to dietary iron deficiency, as well as hemoglobinopathies and hemolytic anemias.

CONCLUSIONS

Anemia remains a major health problem, especially among females in less developed countries. The implementation of preventive programs with a focus on improving access to iron supplements, early diagnosis and the treatment of hemoglobinopathies should be taken into consideration.

Iron deficiency during the first 1000 days of life: are we doing enough to protect the developing brain?

Iron is essential for the functioning of all cells and organs, most critically for the developing brain in the fundamental neuronal processes of myelination, energy and neurotransmitter metabolism. Iron deficiency, especially in the first 1000 days of life, can result in long-lasting, irreversible deficits in cognition, motor function and behaviour. Pregnant women, infants and young children are most vulnerable to iron deficiency, due to their high requirements to support growth and development, coupled with a frequently inadequate dietary supply. An unrecognised problem is that even if iron intake is adequate, common pregnancy-related and lifestyle factors can affect maternal-fetal iron supply in utero, resulting in an increased risk of deficiency for the mother and her fetus. Although preterm birth, gestational diabetes mellitus and intrauterine growth restriction are known risk factors, more recent evidence suggests that maternal obesity and delivery by caesarean section further increase the risk of iron deficiency in the newborn infant, which can persist into early childhood. Despite the considerable threat that early-life iron deficiency poses to long-term neurological development, life chances and a country's overall social and economic progress, strategies to tackle the issue are non-existent, too limited or totally inappropriate. Prevention strategies, focused on improving the health and nutritional status of women of reproductive age are required. Delayed cord clamping should be considered a priority. Better screening strategies to enable the early detection of iron deficiency during pregnancy and early-life should be prioritised, with intervention strategies to protect maternal health and the developing brain.

The critical roles of iron during the journey from fetus to adolescent: Developmental aspects of iron homeostasis

Iron is indispensable for human life. However, it is also potentially toxic, since it catalyzes the formation of harmful oxidative radicals in unbound form and may facilitate pathogen growth. Therefore, iron homeostasis needs to be tightly regulated. Rapid growth and development require large amounts of iron, while (especially young) children are vulnerable to infections with iron-dependent pathogens due to an immature immune system. Moreover, unbalanced iron status early in life may have effects on the nervous system, immune system and gut microbiota that persist into adulthood. In this narrative review, we assess the critical roles of iron for growth and development and elaborate how the body adapts to physiologically high iron demands during the journey from fetus to adolescent. As a first step towards the development of clinical guidelines for the management of iron disorders in children, we summarize the unmet needs regarding the developmental aspects of iron homeostasis.

Soluble Transferrin Receptor during infancy and reference intervals for the Roche Cobas platform

INTRODUCTION

Infant iron status assessments may be difficult to interpret due to infections. The soluble transferrin receptor (sTfR) has been suggested as a biomarker mainly unaffected by the acute phase response. Reference intervals reflecting dynamics of infant growth first year in life are not well established.

METHODS

The sTfR and CRP concentrations were measured in samples from 451 term infants with the Roche Cobas platform in umbilical cord, at 48-96 hours, 4 and 12 months. Reference values were constructed as the 2.5th and 97.5th percentiles. The relationship between CRP concentrations >1 mg/L and sTfR was tested by Kendall correlation.

RESULTS

Reference intervals for girls and boys were 2.4-9.5 mg/L at birth, 2.9-8.4 mg/L at 48-96 hours, 2.6-5.7 mg/L at 4 months and 3.0-6.3 mg/L at 12 months. No differences between sexes were observed except for at 4 months. sTfR did not covariate with CRP concentrations >1 mg/L except in 48-96 hours samples.

CONCLUSION

This study reports reference intervals for sTfR from birth to 12 months of age in a large group of infants in a low-risk area for iron deficiency. sTfR might add value to infant iron status diagnostics since no covariation with CRP was found at birth, at 4 months or at 12 months.

Iron, iodine and vitamin D deficiencies during pregnancy: epidemiology, risk factors and developmental impacts

Micronutrient deficiency persists throughout the world, and although the burden is higher in low-resource settings, it is also prevalent in wealthy countries, a phenomenon termed 'hidden hunger'. Due to their high requirements for vitamins and minerals relative to their energy intake, young women and children are particularly vulnerable to hidden hunger. As they share several risk factors and impact on overlapping outcomes, we consider how deficiency of iron, iodine and vitamin D can have profound impacts on perinatal health and infant development. We review the epidemiology of these micronutrient deficiencies during pregnancy, including social, environmental and dietary risk factors. We identify the main challenges in defining nutritional status of these nutrients using validated diagnostic criteria linked with meaningful clinical outcomes. Public health strategies are urgently required to improve the overall health and nutritional status of women of reproductive age. Obesity prevention and early detection of malnutrition with standardised screening methods would detect pregnant women at increased risk of iron deficiency. Development of sensitive, individual biomarkers of iodine status is required to protect maternal health and fetal/infant brain development. Risk assessments of vitamin D requirements during pregnancy need to be revisited from the perspective of fetal and neonatal requirements. International consensus on standardised approaches to micronutrient assessment, analysis and reporting as well as sensitive, clinically validated infant and child neuro-behavioural outcomes will enable progression of useful observational and intervention studies.

Iron stores at birth in a full-term normal birth weight birth cohort with a low level of inflammation

Iron stores at birth are essential to meet iron needs during the first 4-6 months of life. The present study aimed to investigate iron stores in normal birth weight, healthy, term neonates. Umbilical cord blood samples were collected from apparently normal singleton vaginal deliveries (n=854). Subjects were screened and excluded if C-reactive protein (CRP) > 5 mg/l or α1-acid glycoprotein (AGP) > 1 g/l, preterm (<37 complete weeks), term < 2500g or term > 4000g. In total, 762 samples were included in the study. Serum ferritin, soluble transferrin receptor (sTfR), hepcidin, and erythropoietin (EPO) were measured in umbilical cord blood samples; total body iron (TBI) (mg/kg) was calculated using sTfR and ferritin concentrations. A total of 19.8% newborns were iron deficient (ferritin 35 μg/l) and an additional 46.6% had insufficient iron stores (ferritin < 76 μg/l). There was a positive association between serum ferritin and sTfR, hepcidin, and EPO. Gestational age was positively associated with ferritin, sTfR, EPO, and hepcidin. In conclusion, we demonstrate a high prevalence of insufficient iron stores in a Chinese birth cohort. The value of cord sTfR and TBI in the assessment of iron status in the newborn is questionable, and reference ranges need to be established.

Behavioral consequences at 5 y of neonatal iron deficiency in a low-risk maternal-infant cohort

BACKGROUND

Iron is critical to the developing brain, but fetal iron accretion is compromised by several maternal and pregnancy-related factors. Little consideration has been given to the long-term neurologic consequences of neonatal iron deficiency, especially in generally healthy, low-risk populations.

OBJECTIVE

We aimed to investigate the association between neonatal iron deficiency and neurologic development at 2 and 5 y of age.

DESIGN

We measured umbilical cord serum ferritin concentrations in the prospective maternal-infant Cork BASELINE (Babies after SCOPE: Evaluating the Longitudinal Impact Using Neurological and Nutritional Endpoints) Birth Cohort. Lifestyle and clinical data were collected from 15 weeks of gestation to 5 y of age. Standardized neurologic assessments were performed at 2 y [Bayley Scales of Infant Development/Child Behavior Checklist (CBCL)] and 5 y (Kaufman Brief Intelligence Test/CBCL).

RESULTS

Among 697 maternal-infant pairs, median (IQR) cord ferritin concentrations were 200.9 (139.0, 265.8) µg/L; 8% had neonatal iron deficiency (ferritin <76 µg/L). Using fully adjusted models, there was no association between neonatal iron deficiency and cognitive or behavioral outcomes at 2 or 5 y. We conducted an a priori sensitivity analysis in 306 high-risk children, selected using known risk factors for neonatal iron deficiency (smoking/obesity/cesarean section delivery/small-for-gestational age birth). In this high-risk subgroup, children with iron deficiency at birth (12%) had similar cognitive outcomes, but the behavioral assessments showed higher internalizing [9.0 (5.3, 12.0) compared with 5.0 (3.0, 10.0), P = 0.006; adjusted estimate (95% CI): 2.8 (0.5, 5.1), P = 0.015] and total [24.5 (15.3, 40.8) compared with 16.0 (10.0, 30.0), P = 0.009; adjusted estimate (95% CI): 6.6 (0.1, 13.1), P = 0.047] problem behavior scores at 5 y compared with those born iron sufficient.

CONCLUSIONS

We have demonstrated lasting behavioral consequences of neonatal iron deficiency in high-risk children from our generally healthy, low-risk maternal-infant cohort. Although larger investigations are warranted, this study provides strong association data to suggest that interventions and strategies targeting the fetal and neonatal period should be prioritized for the prevention of iron deficiency and associated neurologic consequences.

Association of cesarean delivery on maternal request with neonatal iron stores at birth

BACKGROUND

Cesarean has been suggested to decrease neonatal iron stores at birth. However, few studies have differentiated the effect induced by cesarean operation from that related to medical indications.

OBJECTIVES

We aimed to estimate the association of cesarean delivery on maternal request (CDMR), a subtype of cesarean without any medical indications, with a spectrum of indicators reflecting iron stores at birth.

METHODS

This prospective cohort study involved 288 term singleton neonates born to women without any complications by CDMR or spontaneous vaginal delivery (SVD). Measured hematological iron-related indicators in cord blood included serum ferritin (SF), hemoglobin (Hb), red blood cell (RBC), and hematocrit (Hct). Blood flow volume (BFV) of cord vein when clamping was measured to reflect placental transfusion status during birth. Quantile regression was used to assess the association between delivery mode and the iron store indicators.

RESULTS

CDMR (n = 154) versus SVD group (n = 134) had lower conditional median cord blood SF (-34.80; 95% CI -64.70, -4.90 μg/L; P = 0.02), Hb (-10.67; 95% CI -18.87, -2.47 g/L; P = 0.01), RBC (-0.30; 95% CI -0.48, -0.12 ×10¹²/L; P = 0.002), and Hct (-3.06; 95% CI -6.08, -0.04 %; P = 0.047). The BFV was higher in CDMR than SVD group at the 25th centile (0.51; 95% CI 0.19, 0.82 ml/cm³; P = 0.002), median (0.49; 95% CI 0.04, 0.95 ml/cm³; P = 0.03) and the 75th centile (0.54; 95% CI 0.06, 1.03 ml/cm³; P = 0.03).

CONCLUSIONS

The cesarean operation per se likely hampered placental transfusion from mother to neonate and decreased iron stores at birth.

Newborn micronutrient status biomarkers in a cluster-randomized trial of antenatal multiple micronutrient compared with iron folic acid supplementation in rural Bangladesh

BACKGROUND

Daily antenatal multiple micronutrient (MM) compared with iron folic acid (IFA) supplementation from early pregnancy improved birth outcomes and maternal micronutrient status in rural Bangladesh, but effects on newborn status are unknown.

OBJECTIVE

We examined cord blood micronutrient biomarkers in relation to antenatal MM and IFA supplementation and maternal gestational micronutrient status in rural Bangladeshi newborns.

DESIGN

In a double-blinded, cluster-randomized trial of antenatal IFA or MM (with the same IFA content), we analyzed cord blood plasma from 333 singleton births, and corresponding maternal plasma at 32.5 ± 2.6 wk of gestation, for ferritin (iron stores), folate, cobalamin (vitamin B-12), retinol (vitamin A), 25-hydroxyvitamin D [25(OH)D, vitamin D status], α-tocopherol (vitamin E), zinc, thyroglobulin, and free thyroxine (iodine status). Intervention effects and associations were determined using linear regression, exploring maternal status as a mediator of intervention effects on cord biomarkers.

RESULTS

The MM intervention increased cord ferritin (mean: +12.4%; 95% CI: 1.3, 24.6%), 25(OH)D (mean: +14.7%; 95% CI: 4.8, 25.6%), and zinc (mean: +5.8%; 95% CI: 1.0, 10.8%). Cord folate (mean: +26.8%; 95% CI: 19.6, 34.5%), cobalamin (mean: +31.3%; 95% CI: 24.6, 38.3%), 25(OH)D (mean: +26.7%; 95% CI: 23.2, 30.3%), α-tocopherol (mean: +8.7%; 95% CI: 3.6, 13.7%), zinc (mean: +2.3%; 95% CI: 0.5, 4.2%), thyroglobulin (mean: +20.1%; 95% CI: 9.0, 32.2%) and thyroxine (mean: +1.5%; 95% CI: 0.0, 3.0%) increased per 1-SD increment in maternal status (all P < 0.05); ferritin and retinol changed by +2.0%; 95% CI: -8.9, 14.3%; P = 0.72; and +3.5%; 95% CI: -0.4, 7.3%; P = 0.07, respectively. Ferritin, folate, cobalamin, zinc, and thyroglobulin averaged 1.57-6.75 times higher and retinol, α-tocopherol, and 25(OH)D 0.30-0.84 times lower in cord than maternal plasma, suggesting preferential maternal-fetal transfer of iron, folate, cobalamin, and zinc; limited transfer of fat-soluble vitamins; and high fetal iodine demand.

CONCLUSIONS

Antenatal MM supplementation increased newborn ferritin, 25(OH)D, and zinc, while maternal and newborn folate, vitamins B-12, D, and E, zinc, and iodine biomarkers were positively related. Despite limited effects of MM, better maternal micronutrient status was associated with improved micronutrient status of Bangladeshi newborns. This trial was registered at clinicaltrials.gov as NCT00860470.

Contribution of iron status at birth to infant iron status at 9 months: data from a prospective maternal-infant birth cohort in China

BACKGROUND/OBJECTIVES

The contribution of iron status at birth to iron status in infancy is not known. We used a physiologic framework to evaluate how iron status at birth related to iron status at 9 months, taking iron needs and sources into account.

SUBJECTS/METHODS

In a longitudinal birth cohort in China, iron status measures in cord blood and venous blood in infancy (9 months) and clinical data were prospectively collected in 545 healthy term maternal–infant dyads. We used structural equation modeling (SEM) to create a 9-month iron composite and to assess direct and indirect contributions of multiple influences on 9-month iron status. Logistic regression was used to calculate odds ratios (OR) for iron deficiency (ID), iron deficiency anemia (IDA), and anemia.

RESULTS

Approximately 15% (78/523) of infants were born with cord SF<75 μg/l, suggesting fetal-neonatal ID. At 9 months, 34.8% (186/535) and 19.6% (105/535) of infants had ID and IDA, respectively. The following factors were independently associated with poorer 9-month iron status: higher cord zinc protoporphyrin/heme (ZPP/H) (adjusted estimate −0.18, P< 0.001) and serum transferrin receptor (sTfR) (−0.11, P=0.004), lower cord hemoglobin (Hb) (0.13, P=0.004), lower birth weight (0.15, P< 0.001), male sex (0.10, P=0.013), older age at testing (−0.26, P<0.001), higher 9-month weight (−0.12, P=0.006) and breastfeeding (0.38, P<0.001). Breastfeeding at 9 months showed the strongest association, adjusting for all other factors. Compared to formula-fed infants, the odds of IDA were 19.1 (95%CI: 6.92, 52.49, P< 0.001) and 3.6 (95%CI: 1.04, 12.50, P=0.043) times higher in breastfed and mixed-fed infants, respectively.

CONCLUSIONS

Indicators of iron status at birth, postnatal iron needs, and iron sources independently related to iron status at 9 months. Sex was an additional factor. Public health policies to identify and protect infants at increased risk of ID should be prioritized.

Association of maternal hemoglobin and iron stores with neonatal hemoglobin and iron stores

Background

One of the commonest causes of anemia in pregnancy is iron deficiency. This study aims at understanding and exploring the association between fetal and maternal iron status. Predelivery maternal hemoglobin (Hb) and iron stores, serum iron, ferritin, and soluble transferrin receptor (sTfR), were assessed and compared to the cord blood Hb and iron stores with an attempt to identify the level of maternal Hb and ferritin at which the fetal iron stores reduce, helping to identify the neonates who will require earlier iron supplementation.

Method

Four hundred eight participants were enrolled, and maternal and cord blood was collected at the time of delivery and tested for Hb and iron parameters. The results were statistically analyzed.

Results

Of all mothers, 27.2% mothers were anemic (Hb less than 11 g/dl). Of all newborns, 15.4% newborns had Hb less than 14 g/dl. There was a significant association between the maternal and cord blood iron, ferritin, sTfR and sTfR/log ferritin index. Eighty-five percent of the babies with cord blood Hb <14 g/dl had maternal serum ferritin (SF) <50 μg/L. Maternal SF <10 μg/l was associated with a significant number of babies with cord blood SF <75 μg/l (77.7%). One hundred sixty six neonates had sTfR 2 μg/ml or more. Of these, 80.7% had maternal SF <50 μg/l. Of the 115 newborns with a high sTfR/log ferritin index (>1.5), 56.5% had raised maternal sTfR (>2μg/ml).

Conclusion

In view of a significant association between maternal and neonatal Hb and iron stores, newborns of mothers with iron deficiency anemia (IDA) during pregnancy should be monitored and followed up after birth for development of IDA and early iron supplementation.

Iron Deficiency and Iron Deficiency Anemia: Implications and Impact in Pregnancy, Fetal Development, and Early Childhood Parameters

A normal pregnancy consumes 500-800 mg of iron from the mother. Premenopausal women have a high incidence of marginal iron stores or iron deficiency (ID), with or without anemia, particularly in the less developed world. Although pregnancy is associated with a "physiologic" anemia largely related to maternal volume expansion; it is paradoxically associated with an increase in erythrocyte production and erythrocyte mass/kg. ID is a limiting factor for this erythrocyte mass expansion and can contribute to adverse pregnancy outcomes. This review summarizes erythrocyte and iron balance observed in pregnancy; its implications and impact on mother and child; and provides an overview of approaches to the recognition of ID in pregnancy and its management, including clinically relevant questions for further investigation.

Maternal Prenatal Psychosocial Stress and Prepregnancy BMI Associations with Fetal Iron Status

BACKGROUND

Iron accrued in utero is critical for fetal and infant neurocognitive development. Psychosocial stress and obesity can each suppress fetal iron accrual. Their combined effects and differences by fetal sex are not known. In an observational pregnancy cohort study in Mexico City, we investigated associations of maternal prenatal life stressors, psychological dysfunction, and prepregnancy BMI with fetal iron status at delivery.

OBJECTIVES

We hypothesized that greater maternal prenatal psychosocial stress and prepregnancy overweight and obesity are associated with lower cord blood ferritin and hemoglobin (Hb), with stronger associations in boys than girls.

METHODS

Psychosocial stress in multiple domains of life stress (negative life events, perceived stress, exposure to violence) and psychological dysfunction symptoms (depression, generalized anxiety, and pregnancy-specific anxiety) were assessed with validated questionnaires during pregnancy. Prepregnancy BMI was predicted with a validated equation and categorized as normal/overweight/obese. Cord blood ferritin and Hb associations with prenatal psychosocial stress and BMI were modeled in multivariable linear regressions adjusted for maternal age, socioeconomic status, child sex, and prenatal iron supplementation. Interactions with child sex and 3-way stress-overweight/obesity-sex interactions were tested with product terms and likelihood ratio tests.

RESULTS

In 493 dyads, median (IQR) cord blood ferritin and Hb concentrations were 185 µg/L (126-263 g/dL) and 16 g/dL (14.7-17.1 g/dL), respectively. Ferritin was lower in infants of mothers with higher prenatal perceived stress (-23%; 95% CI: -35%, -9%), violence exposure (-28%; 95% CI: -42%, -12%), anxiety symptoms (-16%; 95% CI: -27%, -4%), and obesity (-17%; 95% CI: -31%, 0.2%). Interaction models suggested sex differences and synergism between maternal stress and overweight/obesity. No associations were observed between stress or BMI and Hb.

CONCLUSIONS

Multiple prenatal psychosocial stressors and excess prepregnancy BMI were each inversely associated with fetal iron status at birth. Pregnancies and infants at elevated risk of impaired fetal iron accrual may be identifiable according to observed synergism between maternal stress and obesity and differential associations with fetal iron status by infant sex.

Cord Blood-Derived Exosomal CNTN2 and BDNF: Potential Molecular Markers for Brain Health of Neonates at Risk for Iron Deficiency

Maternal iron deficiency anemia, obesity, and diabetes are prevalent during pregnancy. All are associated with neonatal brain iron deficiency (ID) and neurodevelopmental impairment. Exosomes are extracellular vesicles involved in cell–cell communication. Contactin-2 (CNTN2), a neural-specific glycoprotein, and brain-derived neurotrophic factor (BDNF) are important in neurodevelopment and found in exosomes. We hypothesized that exosomal CNTN2 and BDNF identify infants at risk for brain ID. Umbilical cord blood samples were measured for iron status. Maternal anemia, diabetes, and body mass index (BMI) were recorded. Cord blood exosomes were isolated and validated for the exosomal marker CD81 and the neural-specific exosomal marker CNTN2. Exosomal CNTN2 and BDNF levels were quantified by ELISA. Analysis of CNTN2 and BDNF levels as predictors of cord blood iron indices showed a direct correlation between CNTN2 and ferritin in all neonates (n = 79, β = 1.75, p = 0.02). In contrast, BDNF levels inversely correlated with ferritin (β = −1.20, p = 0.03), with stronger association in female neonates (n = 37, β = −1.35, p = 0.06), although there is no evidence of a sex-specific effect. Analysis of maternal risk factors for neonatal brain ID as predictors of exosomal CNTN2 and BDNF levels showed sex-specific relationships between infants of diabetic mothers (IDMs) and CNTN2 levels (Interaction p = 0.0005). While male IDMs exhibited a negative correlation (n = 42, β = −0.69, p = 0.02), female IDMs showed a positive correlation (n = 37, β = 0.92, p = 0.01) with CNTN2. A negative correlation between BNDF and maternal BMI was found with stronger association in female neonates (per 10 units BMI, β = −0.60, p = 0.04). These findings suggest CNTN2 and BNDF are respective molecular markers for male and female neonates at risk for brain ID. This study supports the potential of exosomal markers to assess neonatal brain status in at-risk infants.

Maternal anemia type during pregnancy is associated with anemia risk among offspring during infancy

BACKGROUND

We evaluated the association between etiology of maternal anemia and iron status throughout infancy.

METHODS

Samples from a study designed to examine Praziquantel treatment during pregnancy were used (n = 359). All women were infected with schistosomiasis and randomized to Praziquantel or placebo at 16 ± 2 weeks' gestation. Hemoglobin, serum ferritin (SF), soluble transferrin receptor (sTfR), hepcidin, C-reactive protein, and interleukin-6 were measured in maternal and infant blood. The relationship between both maternal Praziquantel treatment and etiology of anemia and infant iron status was evaluated.

RESULTS

Maternal iron-deficiency anemia was associated with increased risk of infant anemia at 6 months of age. Infants of mothers with the lowest levels of circulating hepcidin during gestation, likely a marker for iron deficiency, had higher sTfR:SF levels and lower hemoglobin levels, particularly at 12 months of age. Maternal non-iron-deficiency anemia (NIDA) did not impact infant anemia risk or iron status. Maternal treatment for schistosomiasis had no effect on infant hematologic status.

CONCLUSIONS

Maternal iron deficiency anemia was associated with an increased risk for anemia or iron deficiency during late infancy. We did not observe an association between maternal NIDA and increased risk for iron deficiency during infancy.

Maternal and Early Life Iron Intake and Risk of Childhood Type 1 Diabetes: A Danish Case-Cohort Study

BACKGROUND

Iron overload has been associated with diabetes. Studies on iron exposure during pregnancy and in early life and risk of childhood type 1 diabetes (T1D) are sparse. We investigated whether iron supplementation during pregnancy and early in life were associated with risk of childhood T1D.

METHODS

In a case-cohort design, we identified up to 257 children with T1D (prevalence 0.37%) from the Danish National Birth Cohort through linkage with the Danish Childhood Diabetes Register. The primary exposure was maternal pure iron supplementation (yes/no) during pregnancy as reported in interview two at 30 weeks of gestation (n = 68,497 with iron supplement data). We estimated hazard ratios (HRs) using weighted Cox regression adjusting for multiple confounders. We also examined if offspring supplementation during the first 18 months of life was associated with later risk of T1D.

RESULTS

Maternal iron supplementation was not associated with later risk of T1D in the offspring HR 1.05 (95% CI: 0.76⁻1.45). Offspring intake of iron droplets during the first 18 months of life was inversely associated with risk of T1D HR 0.74 (95% CI: 0.55⁻1.00) (ptrend = 0.03).

CONCLUSIONS

Our large-scale prospective study demonstrated no harmful effects of iron supplementation during pregnancy and in early life in regard to later risk of childhood T1D in the offspring.

Inadequate iron stores in early term neonates

OBJECTIVE

To characterize neonatal iron stores depending on gestational age (GA) at term.

STUDY DESIGN

Participants were 751 mother-newborn pairs from the placebo arm of a randomized clinical trial of prenatal iron-folate supplementation in China. We compared mean cord serum ferritin (SF) by weeks GA and, following the general linear model, assessed whether maternal iron deficiency (ID) influenced relations between GA and cord SF.

RESULTS

Controlling for covariates, cord SF increased between 37 and 41 weeks (ps < 0.05-0.01). Cord SF was lower in infants of ID vs. non-ID mothers (geometric mean 96.3 [95% CI: 91.3-101.6] µg/L vs. 115.9 [95% CI: 105.0-127.8] µg/L, effect size = 0.33 SD, p = 0.0012). There was no significant increase with GA among infants of ID mothers. For non-ID mothers, cord-blood SF increased sharply with GA until 38 5/7 weeks, after which it plateaued.

CONCLUSIONS

The findings emphasize that neonates at 37-38 weeks, although considered term, are not fully mature.

Excess iron: considerations related to development and early growth

What effects might arise from early life exposures to high iron? This review considers the specific effects of high iron on the brain, stem cells, and the process of erythropoiesis and identifies gaps in our knowledge of what molecular damage may be incurred by oxidative stress that is imparted by high iron status in early life. Specific areas to enhance research on this topic include the following: longitudinal behavioral studies of children to test associations between iron exposures and mood, emotion, cognition, and memory; animal studies to determine epigenetic changes that reprogram brain development and metabolic changes in early life that could be followed through the life course; and the establishment of human epigenetic markers of iron exposures and oxidative stress that could be monitored for early origins of adult chronic diseases. In addition, efforts to understand how iron exposure influences stem cell biology could be enhanced by establishing platforms to collect biological specimens, including umbilical cord blood and amniotic fluid, to be made available to the research community. At the molecular level, there is a need to better understand stress erythropoiesis and changes in iron metabolism during pregnancy and development, especially with respect to regulatory control under high iron conditions that might promote ineffective erythropoiesis and iron-loading anemia. These investigations should focus not only on factors such as hepcidin and erythroferrone but should also include newly identified interactions between transferrin receptor-2 and the erythropoietin receptor. Finally, despite our understanding that several key micronutrients (e.g., vitamin A, copper, manganese, and zinc) support iron's function in erythropoiesis, how these nutrients interact remains, to our knowledge, unknown. It is necessary to consider many factors when formulating recommendations on iron supplementation.

Protecting the Newborn and Young Infant from Infectious Diseases: Lessons from Immune Ontogeny

Infections in the first year of life are common and often severe. The newborn host demonstrates both quantitative and qualitative differences to the adult in nearly all aspects of immunity, which at least partially explain the increased susceptibility to infection. Here we discuss how differences in susceptibility to infection result not out of a state of immaturity, but rather reflect adaptation to the particular demands placed on the immune system in early life. We review the mechanisms underlying host defense in the very young, and discuss how specific developmental demands increase the risk of particular infectious diseases. In this context, we discuss how this plasticity, i.e. the capacity to adapt to demands encountered in early life, also provides the potential to leverage protection of the young against infection and disease through a number of interventions.

Iron status, body size, and growth in the first 2 years of life

Rapid growth in infancy has been shown to adversely affect iron status up to 1 year; however the effect of growth on iron status in the second year of life has been largely unexplored. We aimed to investigate the impact of growth and body size in the first 2 years on iron status at 2 years. In the prospective, maternal-infant Cork BASELINE Birth Cohort Study, infant weight and length were measured at birth, 2, 6, 12, and 24 months and absolute weight (kg) and length (cm) gain from 0 to 2, 0 to 6, 0 to 12, 6 to 12, 12 to 24, and 0 to 24 months were calculated. At 2 years (n = 704), haemoglobin, mean corpuscular volume, and serum ferritin (umbilical cord concentrations also) were measured. At 2 years, 5% had iron deficiency (ferritin < 12 μg/L) and 1% had iron deficiency anaemia (haemoglobin < 110 g/L + ferritin < 12 μg/L). Weight gain from 6 to 12, 0 to 24, and 12 to 24 months were all inversely associated with ferritin concentrations at 2 years but only the association with weight gain from 12 to 24 months was robust after adjustment for potential confounders including cord ferritin (adj. estimate 95% CI: -4.40 [-8.43, -0.37] μg/L, p = .033). Length gain from 0 to 24 months was positively associated with haemoglobin at 2 years (0.42 [0.07, 0.76] g/L, p = .019), only prior to further adjustment for cord ferritin. To conclude, weight gain in the second year was inversely associated with iron stores at 2 years, even after accounting for iron status at birth. Further examinations of iron requirements, dietary intakes, and growth patterns in children in the second year of life in high-resource settings are warranted.

Impact of maternal, antenatal and birth-associated factors on iron stores at birth: data from a prospective maternal-infant birth cohort

BACKGROUND/OBJECTIVES

Low serum ferritin concentrations at birth, which reflect neonatal iron stores, track through to early childhood and have been associated with poorer neurodevelopmental outcomes. We aimed to identify maternal, antenatal and birth-associated factors that influence iron stores at birth in a prospective maternal-infant birth cohort.

SUBJECTS/METHODS

In a population-based, longitudinal, birth cohort in Ireland, 413 maternal-infant dyads with prospectively collected lifestyle and clinical data from 15 weeks' gestation had umbilical cord serum ferritin concentrations measured. Regression models were developed to identify independent factors associated with cord ferritin concentrations.

RESULTS

Median (IQR) cord ferritin concentrations were 185.7 (131.7, 385.5) μg/l, and 8% (n=33) of infants had low iron stores (ferritin <76 μg/l) at birth. Maternal obesity (BMI ⩾30 kg/m²) at 15 weeks' gestation (adj. estimate (95% confidence interval (CI)): -66.4 (-106.9, -25.9) μg/l, P<0.0001) and delivery by caesarean section (-38.8 (-70.2, -7.4) μg/l, P=0.016) were inversely associated with cord ferritin concentrations. In addition, maternal smoking at 15 weeks' gestation (adj. odds ratio (95% CI): 2.9 (1.2, 7), P=0.020) and being born small-for-gestational age (3.4 (1.3, 8.9), P=0.012) were associated with an increased risk of low iron stores (ferritin <76 μg/l) at birth.

CONCLUSIONS

We have identified a number of potentially modifiable lifestyle factors that influence iron stores at birth, with the important role of overall maternal health and lifestyle during pregnancy highlighted. Public health policies targeting women of child-bearing age to improve nutrition and health outcomes should be prioritised for the health of the next generation.

Early deterioration of iron status among a cohort of Bolivian infants

Iron deficiency (ID) and iron deficiency anemia (IDA) are major contributors to infant and maternal morbidity worldwide. There is limited longitudinal data on iron status in young infants and on methods to adjust iron biomarkers for inflammation. We aimed to quantify the prevalence of inflammation-adjusted ID, anemia, and IDA over the first year in a cohort of Bolivian infants and their mothers. Healthy mother-infant dyads were recruited from two peri-urban hospitals. Infants provided three blood draws (2, 6-8, and 12-18 months; N = 160); mothers provided two blood draws (1 and 6-8 months postpartum [plus third anemia measurement at 12-18 months]; N = 250). Blood was analyzed for hemoglobin, ferritin, soluble transferrin receptor, C-reactive protein (CRP), and alpha(1)-acid glycoprotein (AGP). Iron biomarkers were adjusted for inflammation using CRP and AGP; hemoglobin cutoffs were adjusted for altitude. Inflammation (elevated CRP or AGP) was 17% among toddlers 12-18 months of age. ID (inflammation-adjusted ferritin) increased with age (<1%, 56%, and 79% at each blood draw), as did anemia and IDA (anemia: 70%, 76%, and 81%; IDA: <1%, 46%, and 68%). Maternal ID declined from the first to second assessment (39% vs. 27%). Inflammation-adjusted ID prevalence was up to 15 percentage points higher than unadjusted estimates. The high prevalence of ID, anemia, and IDA in this cohort of Bolivian infants beginning at 6-8 months of age suggests that early interventions may be necessary in vulnerable populations.

Correlation between hemoglobin levels of mothers and children on exclusive breastfeeding in the first six months of life

OBJECTIVE

To evaluate the correlation between hemoglobin levels of mothers and their children on exclusive breastfeeding in the first six months of life.

METHODS

Cross-sectional study with 221 binomials (mother-child) enrolled in a breastfeeding support program, who were stratified into six groups according to the children's age group. The sample consisted of children born at term with normal weight, with no neonatal complications and whose mothers did not have anemia or infectious disease at the time of data collection. Interviews were carried out with the mothers, blood was collected by peripheral venipuncture from mothers and children, and children's anthropometric data were assessed. Pearson's correlation coefficients between the hemoglobin levels of mothers and children were calculated. Six multiple linear regression models were adjusted with regression coefficient estimates, considering as statistically significant associations with p≤0.05.

RESULTS

The correlation coefficients of hemoglobin levels of mothers and children ranged from 0.253, at three months, to 0.601, at five months. The hemoglobin level of mothers was correlated with the hemoglobin level of their children at four months (r=0.578) and at five months (r=0.601). In the adjusted multiple linear regression, the regression coefficients were higher at four months (β=1.134; p=0.002) and at five months (β=0.845; p<0.001).

CONCLUSION

These findings allow for the conclusion that there is a correlation between the hemoglobin of mothers and the hemoglobin of their children on exclusive breastfeeding in the first six months of life.

The placenta: the forgotten essential organ of iron transport

Optimal iron nutrition in utero is essential for development of the fetus and helps establish birth iron stores adequate to sustain growth in early infancy. In species with hemochorial placentas, such as humans and rodents, iron in the maternal circulation is transferred to the fetus by directly contacting placental syncytiotrophoblasts. Early kinetic studies provided valuable data on the initial uptake of maternal transferrin, an iron-binding protein, by the placenta. However, the remaining steps of iron trafficking across syncytiotrophoblasts and through the fetal endothelium into the fetal blood remain poorly characterized. Over the last 20 years, identification of transmembrane iron transporters and the iron regulatory hormone hepcidin has greatly expanded the knowledge of cellular iron transport and its regulation by systemic iron status. In addition, emerging human and animal data demonstrating comprised fetal iron stores in severe maternal iron deficiency challenge the classic dogma of exclusive fetal control over the transfer process and indicate that maternal and local signals may play a role in regulating this process. This review compiles current data on the kinetic, molecular, and regulatory aspects of placental iron transport and considers new questions and knowledge gaps raised by these advances.

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

BACKGROUND

Little is known about anemia and iron status in US newborns because screening for anemia is typically not undertaken until 1 y of age. This study was undertaken to characterize and identify determinants of iron status in newborns born to pregnant adolescents.

METHODS

Pregnant adolescents (≤ 18 y, n = 193) were followed from ≥ 12 wk gestation until delivery. Hemoglobin, ferritin, soluble transferrin receptor, serum iron, hepcidin, erythropoietin (EPO), IL-6, and C-reactive protein were assessed in maternal and cord blood.

RESULTS

At birth, 21% of the neonates were anemic (Hb < 13.0 g/dl) and 25% had low iron stores (ferritin < 76 µg/l). Cord serum ferritin concentrations were not significantly associated with gestational age (GA) at birth across the range of 37-42 wk. Neonates born to mothers with ferritin < 12 µg/l had significantly lower ferritin (P = 0.003) compared to their counterparts. Hepcidin and IL-6 were significantly (P < 0.05) higher in neonates born to mothers with longer durations of active labor.

CONCLUSION

Given the importance of the iron stores at birth on maintenance of iron homeostasis over early infancy, additional screening of iron status at birth is warranted among those born to this high risk obstetric population.

The prevalence of anemia and iron deficiency is more common in breastfed infants than their mothers in Bhaktapur, Nepal

Background/Objectives:

Iron deficiency anemia is a widespread public health problem, particularly in low- and middle-income countries. Maternal iron status around and during pregnancy may influence infant iron status. We examined multiple biomarkers to determine the prevalence of iron deficiency and anemia among breastfed infants and explored its relationship with maternal and infant characteristics in Bhaktapur, Nepal.

Subjects/Methods:

In a cross-sectional survey, we randomly selected 500 mother–infant pairs from Bhaktapur municipality. Blood was analyzed for hemoglobin, ferritin, total iron-binding capacity, transferrin receptors and C-reactive protein.

Results:

The altitude-adjusted prevalence of anemia was 49% among infants 2–6-month-old (hemaglobin (Hb) <10.8 g/dl) and 72% among infants 7–12-month-old (Hb <11.3 g/dl). Iron deficiency anemia, defined as anemia and serum ferritin <20 or <12 μg/l, affected 9 and 26% of infants of these same age groups. Twenty percent of mothers had anemia (Hb <12.3 g/dl), but only one-fifth was explained by depletion of iron stores. Significant predictors of infant iron status and anemia were infant age, sex and duration of exclusive breastfeeding and maternal ferritin concentrations.

Conclusions:

Our findings suggest that iron supplementation in pregnancy is likely to have resulted in a low prevalence of postpartum anemia. The higher prevalence of anemia and iron deficiency among breastfed infants compared with their mothers suggests calls for intervention targeting newborns and infants.

Identification, prevention and treatment of iron deficiency during the first 1000 days

Iron deficiency is a global problem across the life course, but infants and their mothers are especially vulnerable to both the development and the consequences of iron deficiency. Maternal iron deficiency during pregnancy can predispose offspring to the development of iron deficiency during infancy, with potentially lifelong sequelae. This review explores iron status throughout these "first 1000 days" from pregnancy through two years of age, covering the role of iron and the epidemiology of iron deficiency, as well as its consequences, identification, interventions and remaining research gaps.

Iron stores of breastfed infants during the first year of life

The birth iron endowment provides iron for growth in the first months of life. We describe the iron endowment under conditions of low dietary iron supply. Subjects were infants participating in a trial of Vitamin D supplementation from 1 to 9 months. Infants were exclusively breastfed at enrollment but could receive complementary foods from 4 months but not formula. Plasma ferritin (PF) and transferrin receptor (TfR) were determined at 1, 2, 4, 5.5, 7.5, 9 and 12 months. At 1 month PF ranged from 38 to 752 µg/L and was only weakly related to maternal PF. PF declined subsequently and flattened out at 5.5 months. PF of females was significantly higher than PF of males except at 12 months. TfR increased with age and was inversely correlated with PF. PF and TfR tracked strongly until 9 months. Iron deficiency (PF < 10 µg/L) began to appear at 4 months and increased in frequency until 9 months. Infants with ID were born with low iron endowment. We concluded that the birth iron endowment is highly variable in size and a small endowment places infants at risk of iron deficiency before 6 months. Boys have smaller iron endowments and are at greater risk of iron deficiency than girls.

Iron, human growth, and the global epidemic of obesity

Iron is an essential nutrient utilized in almost every aspect of cell function and its availability has previously limited life. Those same properties which allow iron to function as a catalyst in the reactions of life also present a threat via generation of oxygen-based free radicals. Accordingly; life exists at the interface of iron-deficiency and iron-sufficiency. We propose that: (1) human life is no longer positioned at the limits of iron availability following several decades of fortification and supplementation and there is now an overabundance of the metal among individuals of many societies; (2) this increased iron availability exerts a positive effect on growth by targeting molecules critical in regulating the progression of the cell cycle; there is increased growth in humans provided greater amounts of this metal; and indices of obesity can positively correlate with body stores of iron; and (3) diseases of obesity reflect this over-abundance of iron. Testing potential associations between iron availability and both obesity and obesity-related diseases in populations will be difficult since fortification and supplementation is so extensively practiced.

Impact of multiple prenatal risk factors on newborn iron status at delivery

BACKGROUND

Maternal anemia and several complications of pregnancy can affect fetal iron acquisition.

AIM

Because it is unknown whether the effects of demographic and maternal risk factors (RF) are summative, we examined cord iron status in newborns with multiple RF for acquiring iron deficiency.

METHODS

Cord blood indices from healthy control newborns with and without RF for newborn or infant iron deficiency were studied.

RESULTS

Newborns with greater RF had poorer erythrocyte and storage iron status. Poorest status was seen if mothers with comorbid obesity and diabetes delivered large-for-gestation newborns. Findings highlight the importance of identifying RF.

Prenatal maternal stress predicts cord-blood ferritin concentration

AIM

To examine the relationship between maternal stress in early pregnancy and cord-blood ferritin concentration.

METHODS

The sample consisted of 140 pregnant women who lived in a region that was under rocket attack during a military operation (December 2008 to January 2009). Mothers in the stress group (n=63) were in their first trimester during this period. Mothers in the control group (n=77) became pregnant 4-5 months after the attacks ended. Maternal subjective stress was reported retrospectively. Cord-blood ferritin concentration was compared between stress and control groups, and was the dependent variable in a hierarchical multiple regression analysis.

RESULTS

The mean cord-blood ferritin concentration was lower in the stress group compared to the control group (145.7±62.0 vs. 169.3±85.4 ng/mL, P<0.05). The cumulative distribution of cord-blood ferritin showed a shift to the left for the stress group. Hierarchical multiple regression analysis revealed that maternal subjective stress was a predictor for cord-blood ferritin concentration (hierarchical regression: β=-0.18, P<0.05), especially in the stress group (simple slope analysis: β=-0.32, P<0.01).

CONCLUSION

Maternal stress during the first trimester of pregnancy is associated with lower cord-blood ferritin concentration.

Maternal serum ferritin concentration is positively associated with newborn iron stores in women with low ferritin status in late pregnancy

Iron deficiency (ID) is common in pregnant women and infants, particularly in developing countries. The relation between maternal and neonatal iron status remains unclear. This study considered the issue in a large sample of mother-newborn pairs in rural southeastern China. Hemoglobin (Hb) and serum ferritin (SF) were measured in 3702 pregnant women at ≥37 wk gestation and in cord blood of their infants born at term (37-42 wk gestation). Maternal anemia (Hb <110 g/L) was present in 27.5% and associated with maternal SF <20 μg/L in 86.9%. Only 5.6% of neonates were anemic (Hb <130 g/L) and 9.5% had cord-blood SF <75 μg/L. There were low-order correlations between maternal and newborn iron measures (r = 0.07-0.10 for both Hb and SF; P ≤ 0.0001 due to the large number). We excluded 430 neonates with suggestion of inflammation [cord SF >370 μg/L, n = 208 and/or C-reactive protein (CRP) >5 mg/L, n = 233]. Piecewise linear regression analyses identified a threshold for maternal SF at which cord-blood SF was affected. For maternal SF below the threshold of 13.6 μg/L (β = 2.4; P = 0.001), cord SF was 0.17 SD lower than in neonates whose mothers had SF above the threshold (167 ± 75 vs. 179 ± 80 μg/L). The study confirmed that ID anemia remains common during pregnancy in rural southeastern China. Despite widespread maternal ID, however, iron nutrition seemed to meet fetal needs except when mothers were very iron deficient. The impact of somewhat lower cord SF on iron status later in infancy warrants further study.

The use of cluster and principal component analysis in the estimation of iron status in term newborns

OBJECTIVE

To assess the relationship between parameters of iron homeostasis in infants and clinical features characterizing newborns and their mothers.

METHODS

The goal of the present work was to determine nine iron status parameters, i.e. hepcidin, prohepcidin, soluble transferrin receptor, ferritin, total iron binding capacity, unsaturated iron binding capacity, transferrin saturation, erythropoietin and total iron concentration, in the cord blood of 57 term newborns as well as to determine the complete blood count in their mothers. Moreover, an appraisal of the relationships between all of the iron parameters, the mothers' hematological factors and 12 clinical attributes was carried out using both cluster analysis (CA) and principal component analysis (PCA).

RESULTS

We found that hepcidin is not correlated with its precursor, but it is strongly positively correlated with the total iron concentration. The CA divided all of the 24 parameters into three clusters and showed that certain clinical features, e.g. the APGAR score, mother's age or parity are related to the hepcidin and prohepcidin concentration.

CONCLUSION

We demonstrated that CA and PCA are efficacious methods for assessing the relationship between iron metabolism parameters in cord blood and large amounts of clinical characteristics.

Timing of umbilical cord clamping: effect on iron endowment of the newborn and later iron status

The optimal timing of umbilical cord clamping has been debated in the scientific literature for at least the last century, when cord clamping practices shifted from delayed towards immediate clamping. Recent research provides evidence for the beneficial effect of delayed cord clamping on infant iron status. The present review describes the physiological basis for the impact of cord clamping time on total body iron at birth and the relationship between birth body iron, as affected by cord clamping time, and iron status later in infancy. This research is discussed in the context of current clamping practices, which tend towards early cord clamping in most settings, as well as the high levels of anemia present in young infants in many countries worldwide.

Iron supplementation of breastfed infants

Reported here are three studies performed with the objective of finding ways to improve the iron status of breastfed infants and to prevent iron deficiency (ID). Participating infants were exclusively breastfed until 4 months of age; thereafter, they could receive complementary foods and, in some studies, supplemental formula. In the first study, infants were given medicinal iron between the ages of 1 and 5.5 months. During this period, iron status improved and ID was prevented; however, these benefits did not continue after the intervention ceased. In the second study, infants received medicinal iron or an equivalent amount of iron from an iron-fortified cereal between the ages of 4 and 9 months. Again, iron supplementation largely prevented ID from occurring, while non-anemic ID and ID anemia occurred in the control group as well as in the intervention groups before the intervention began. In the third study, infants received dry cereals fortified with electrolytic iron or with ferrous fumarate between the ages of 4 and 9 months. The cereals were equally effective in providing relative protection from ID. The results of these three studies indicate it is possible to protect breastfed infants from ID and IDA.

Folate and cobalamin status in relation to diet in healthy 2-y-old children

BACKGROUND

Limited data exist on sources of folate and cobalamin in the toddler diet.

OBJECTIVE

We examined the influence of diet on folate and cobalamin status in healthy toddlers in an unfortified population.

DESIGN

Dietary intake was assessed in 178 children, aged 24 mo, by using 7-d food records and related to serum folate and cobalamin status in 155 children.

RESULTS

Median (25th-75th percentile) daily intakes of folate and cobalamin were 87 μg (74-104 μg) and 3.1 μg (2.4-3.8 μg), respectively. Thirty-five percent of subjects had a folate intake below the Norwegian recommendations (80 μg folate/d), but only 5.8% of subjects had low serum folate concentrations (<10 nmol/L). All children reached the recommended cobalamin intake (0.8 μg cobalamin/d). Median (25th-75th percentile) serum concentrations were as follows: folate, 19 nmol/L (14-24 nmol/L); cobalamin, 410 pmol/L (334-521 pmol/L); holotranscobalamin, 94 pmol/L (67-121 pmol/L); holohaptocorrin, 315 pmol/L (241-409 pmol/L); methylmalonic acid, 0.16 μmol/L (0.13-0.20 μmol/L); and total homocysteine, 5.0 μmol/L (4.2-5.7 μmol/L). Folate intake correlated with serum folate concentrations (ρ = 0.25, P < 0.01), and cobalamin intake correlated with serum holotranscobalamin concentrations (ρ = 0.21, P < 0.05). In multivariate models, serum folate concentrations were significantly positively associated with the consumption of fruit and berries and grain products; however, this was not the case with dairy products, which was the food group that contributed most to folate intake. Cobalamin status was associated with dairy products (cobalamin and holotranscobalamin), cobalamin supplements (cobalamin and holohaptocorrin), and liver pâté (holotranscobalamin).

CONCLUSIONS

In this unfortified toddler population, folate status was associated with intakes of fruit and berries and grain products. Cobalamin status was associated with intakes of dairy, liver pâté, and supplements. In the assessment of vitamin sources, vitamin availability must be considered.

Association of maternal anemia with increased wheeze and asthma in children

BACKGROUND

Increasing interest has focused on maternal nutrition and micronutrient status during pregnancy and respiratory disease development in the offspring.

OBJECTIVE

To examine the relationship between maternal anemia in pregnancy with wheeze and asthma in early childhood.

METHODS

The cohort included children of women followed through pregnancy and recontacted when the child was 6 years of age to evaluate respiratory health. Exposure was assessed using maternal anemia diagnosis and hemoglobin (Hgb) < 11 during delivery hospitalization. Study outcomes include wheezing in early childhood; patterns of wheeze from birth to age 6 (early-onset transient wheeze; late-onset wheeze; early-onset persistent wheeze); and diagnosis of childhood asthma.

RESULTS

Maternal anemia was reported by 11.9% of mothers and was associated with recurrent infant wheeze in the first year (adjusted odds ratio [ORa] = 2.17, 95% confidence interval [CI] 1.18, 4.00), wheezing before age 3 (Ora = 2.42, 95% CI 1.38, 4.23), and early-onset transient and early-onset persistent wheeze patterns (Ora = 2.81, 95%CI 1.38, 5.72, and Ora = 2.07, 95% CI 1.02, 4.22), respectively. Among children of mothers with asthma, maternal anemia was associated with recurrent wheeze in year 1 (Ora = 4.22, 95% CI 1.65, 10.80) and wheeze before age 3 (Ora = 2.73, 95% CI 1.17, 6.35). Offspring of mothers with asthma also had increased odds of asthma diagnosis (Ora = 2.53, 95% CI 1.04, 6.17) and current asthma (Ora = 3.46, 95% CI 1.45, 8.26).

CONCLUSIONS

Maternal anemia during pregnancy is associated with infant respiratory health outcomes. If this observation is replicated, maternal anemia may be a target for intervention and future research.

Maternal folate and cobalamin status predicts vitamin status in newborns and 6-month-old infants

Our aim in this longitudinal study was to determine predictors of folate and cobalamin status in infancy. Data were collected from 364 mother-infant pairs with blood measurements from pregnancy ( approximately 18 wk; n = 149), newborns (cord serum; n = 361), and 6-mo-old partially or exclusively breast-fed children (n = 221). Serum/plasma folate, cobalamin, holotranscobalamin (holoTC), holohaptocorrin (holoHC), methylmalonic acid (MMA) and total homocysteine (tHcy) at birth and 6 mo were related to maternal vitamin status, parity, lifestyle variables, and anthropometry. In multivariate analyses, the strongest predictors of folate at birth and 6 mo were maternal folate and cord folate, respectively (P < 0.01). Maternal holoTC best predicted cobalamin status at birth (positively associated with cord cobalamin, holoTC, and holoHC; inversely with MMA and tHcy; P < or = 0.001), whereas maternal and cord holoHC were the strongest predictors of cobalamin status at 6 mo (positively associated with cobalamin, holoTC, holoHC; inversely with tHcy; P < 0.05). The association between cobalamin status and parity was negative at birth but positive at 6 mo. Birth weight, female sex, and smoking were associated with low cobalamin or high tHcy at birth but showed no or opposite associations at 6 mo. In conclusion, maternal folate and cobalamin status exerts a long-term positive effect on infant vitamin status. The effect of smoking, parity and female sex on cobalamin status did not persist beyond the newborn period. Maternal holoTC was the superior predictor of newborn cobalamin status, while holoHC could be a valuable marker for predicting cobalamin status later in infancy.