CORD BLOOD HAEMOGLOBIN, IRON AND FERRITIN STATUS IN MATERNAL ANAEMIA

ABSTRACT. Maternal and cord blood haemoglobin, serum iron, transferrin saturation and ferritin were studied in sets of 30 anaemic (haemoglobin <110 g/l) and 21 nonanaemic (haemoglobin ≧110 g/l) mothers. The cord serum iron, transferrin saturation and ferritin concentrations had significant correlation with maternal haemoglobin. The significant low levels of these parameters suggested that maternal anaemia adversely affected the iron status including iron stores of the newborns. The cord serum iron of 15.2±4.35 μmol/l and ferritin of 29.7±10.93 ng/ml seem to be effective to maintain cord haemoglobin levels. Thus, anaemic mothers with reasonably maintained ferritin and trasferrin saturation levels provide sufficient iron for maintenance of cord haemoglobin, although foetal iron stores are likely to be depleted.     

Serum transferrin receptor levels in the evaluation of iron deficiency in the neonate

Iron deficiency anemia (IDA) is a major global problem. Early onset of iron deficiency in developing countries makes it imperative to identify iron deficiency in neonates. Most conventional laboratory parameters of iron status fail to distinguish neonates with iron deficient erythropoiesis. Serum transferrin receptor (STFR) levels are a recent sensitive measure of iron deficiency and the present study was carried out to evaluate the usefulness of cord serum transferrin receptors in identifying iron deficient erythropoiesis in neonates. A complete hemogram, red cell indices, iron profile: serum iron (SI), percent transferrin saturation (TS%) and serum ferritin (SF) was carried out in 100 full-term neonates and their mothers at parturition. Cord and maternal STFR levels were estimated using a sensitive enzyme-linked immunosorbent assay (ELISA) technique. Anemic women had a significantly lower SI, their TS% and high STFR levels suggesting that iron deficiency was responsible for the anemia. In the neonates of iron deficient mothers, cord SI, TS% and cord ferritin were not significantly different from those of neonates born to non-anemic mothers. Cord STFR level correlated well with hemoglobin (Hb) and laboratory parameters of iron status, and its level was significantly higher in neonates born to anemic mothers than in those bom to non-anemic mothers. It was the only laboratory parameter to differentiate between neonates bom to anemic and non-anemic mothers. Therefore, STFR is a sensitive index of iron status in neonates and identifies neonates with iron deficient erythropoiesis.     

极低出生体重儿血清铁蛋白水平及影响因素

目的 分析极低出生体重儿(very low birth weight infants,VLBWI)的铁营养状况及影响其变化的因素.方法 收集2014年1月至12月我院收治的115例VLBWI,检测其基础血清铁蛋白及出院前末次血清铁蛋白水平,并对可能的影响因素如胎龄、出生体重、基础血红蛋白、住院期间累积输血量、累积失血量,孕母糖尿病、高血压及贫血等临床资料进行分析.结果 115例VLBWI的基础血清铁蛋白为100.8 ～210.3 μg/L,平均(140.32±13.21) μg/L;不同胎龄的VLBWI基础血清铁蛋白水平比较差异有统计学意义(F=14.367,P=0.000),胎龄＜32周的LBWI其基础血清铁蛋白最低[(124.5±31.3) g/L].母亲贫血程度越重,婴儿基础血清铁蛋白越低[无贫血:(230.9±68.7) μg/L,轻度贫血:(189.5 ±75.3) μtg/L,中度贫血:(133.5 ±88.1) μg/L,重度贫血:(122.2 ±56.8) μg/L;P ＜0.05].VLBWI基础血红蛋白水平越低,其基础血清铁蛋白水平越低(P＜0.05).同时VLBWI住院期间末次血清铁蛋白水平受累积输血量的影响差异有统计学意义(P＜0.05).结论 提高VLBWI基础血红蛋白水平对增加VLBWI体内铁储备是有益的,定期监测住院期间甚至出院后血清铁蛋白以指导VLBWI补铁治疗十分必要.     

Effect of delayed cord clamping on iron stores in infants born to anemic mothers: a randomized controlled trial

OBJECTIVE:To study the effects of cord clamping on iron stores of infants born to anemic mothers at 3 months of age. DESIGN: Randomized controlled trial. SETTING: Teaching hospital. METHODS: Infants born to mothers with hemoglobin (Hb)<100 g/L were randomized at delivery to either immediate cord clamping (early group) or cord clamping delayed till descent of placenta into vagina (delayed group). The outcome measures were infant's hemoglobin and serum ferritin 3 months after delivery. RESULTS: There were 102 neonates randomized to early (n = 43) or delayed cord clamping (n = 59). The groups were comparable for maternal age, parity, weight and supplemental iron intake, infant s birth weight, gestation and sex. The mean infant ferritin and Hb at 3 months were significantly higher in the delayed clamping group (118.4 microg/L and 99 g/L) than in the early clamping group (73 microg/L and 88 g/L). The mean decrease in Hb (g/L) at 3 months adjusted for co-variates was significantly less in the delayed clamping group compared to the early clamping group (-1.09, 95% CI-1.58 to -0.62, p >0.001). The odds for anemia (<100 g/L) at 3 months was 7.7 (95% CI 1.84-34.9) times higher in the early compared to the delayed clamping group. CONCLUSION: Iron stores and Hb in infancy can be improved in neonates born to anemic mothers by delaying cord clamping at birth.     

Measurement of reticulocyte hemoglobin content to diagnose iron deficiency in Saudi children

Iron deficiency and iron deficiency anemia are common conditions in children, especially in developing countries. It is often difficult for the pediatrician to know which indices should be used in the diagnosis of these conditions in children. Reticulocyte hemoglobin (Hb) content (CHr) has been shown to be an accurate indicator of anemia, however whether its use suits the situation in developing countries or not is unclear. The aim of this study was to evaluate the value and effectiveness of using CHr as a method to diagnose iron deficiency and iron deficiency anemia in Saudi children. The samples for the study were collected from 305 children suspected to have anemia. Complete blood count, transferrin saturation (Tfsat), ferritin, circulating transferrin receptor (TfR) and CHr were measured. Three groups were defined, iron deficiency (Tfsat <20%, Hb >11 g/dL; n=120), iron deficiency anemia (Tfsat <20%, Hb <11 g/dL; (n=73) and controls (Tfsat >20%; n=112). The anemic group had significantly lower macrocytic anemia (MCV), mean corpuscular hemoglobin (MCH) and CHr. All of the variables in the anemia group were significantly lower than those of the control group except for the ferritin level. Compared to the control group, the iron deficiency group also showed significantly lower values except for transferrin receptor and the ferritin levels. CHr levels of <26 pg correlated well with anemic states. CHr together with a complete blood count may provide an alternative to the traditional hematologic or biochemical panel for the diagnosis of iron deficiency and iron deficiency anemia in young children and is cost-effective in developing countries. A CHr cut-off level of 26 pg is considered to be a reasonable indicator of anemic states.     

Relationship between newborn and maternal iron status and haematological indices.

The haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin, haematocrit, serum iron and total iron binding capacity, and serum ferritin concentrations in umbilical cord blood samples taken from 96 appropriate-for-gestational age infants delivered at term were measured and compared to the respective maternal values measured at 36 weeks' gestation. All the values were higher in cord blood. Only maternal mean corpuscular volume and mean corpuscular haemoglobin were correlated with cord serum iron. Cord blood haematological indices were not correlated with either gestation at delivery or birth weight. However, newborn serum ferritin was positively correlated with gestation at delivery, while the maternal:newborn ferritin ratio was inversely correlated with gestation and birth weight. The results suggest that maternal haematological and iron indices are not predictive of the haemoglobin or iron status of the newborn, and that the fetus continues to take up iron from the mother until delivery.     

Iron deficiency in an Eskimo village. The value of serum ferritin in assessing iron nutrition before and after a three-month period of iron supplementation.

The serum ferritin concentration, a new means of assessing iron nutrition, was utilized in conjunction with the hematocrit value, serum iron concentration, and total iron binding capacity to determine the effect of a three-month period of iron supplementation in a group of 146 Eskimo children in Chevak, Alaska. Before treatment, 41% of the children had concentrations of serum ferritin below normal, 18% had a subnormal serum transferrin saturation, and 26% were anemic. After supplementation, only 6% had a subnormal serum ferritin concentration. Despite this evidence of improved iron stores in the group as a whole, the prevalence of low serum transferrin saturation and of anemia remained high, 15% and 17%, respectively. These results could be explained by a high incidence of infection, which, like iron deficiency, is associated with anemia and a low serum transferrin saturation. We conclude that the serum ferritin determination reflected an improvement in iron nutrition that was not as readily apparent by other measurements, and that factors other than iron deficiency also played an important role in the mild anemia that was prevalent in Chevak.     

Hemoglobin and serum ferritin levels in mothers and infants at birth

Hemoglobin levels and serum ferritin concentrations were measured in cord blood and maternal blood taken a few hours before birth. Maternal serum ferritin levels were 29.1±18.6 g/l which is lower than values given for normal adult women. Serum ferritin levels in cord blood were 144.4±73.2 g/l which is higher than levels in normal adult men. No correlation was found between newborn hemoglobin and serum ferritin levels, or between newborn birth weight and serum ferritin levels.     

SERUM FERRITIN IN ASSESSMENT OF IRON NUTRITION IN HEALTHY INFANTS

ABSTRACT. We followed up 238 infants on 7 occasions during their first year of life. The diets of the infants were systematically either supplemented or not supplemented with iron. Developmental changes in serum ferritin were determined from a group with adequate intake of iron and without evidence of iron deficiency by three laboratory criteria: hemoglobin, mean corpuscular volume and transferrin saturation. The data indicate that the average level of serum ferritin correlates well with iron nutrition within groups of infants since the developmental changes are in accordance with the known changes in storage iron, the level of serum ferritin correlates with iron intake, and low ferritin levels are associated with lower transferrin saturation. The usefulness of serum ferritin as the sole criterion of iron deficiency in individual infants is limited, suggesting the use of more than one indicator to refine the diagnosis of iron deficiency without anemia.     

Serum transferrin receptor in children: usefulness for determinating the nature of anemia in infection

OBJECTIVES: To know the variations of serum transferrin receptor (sTfR) and its indices depending on the status of body iron and the presence of infection in children, to evaluate their usefulness for recognizing the nature of anemia in infection, and to know the role of erythropoietic activity in these conditions. DESIGN AND METHODS: Three hundred and sixty-eight children between 1 and 10 years were included: 206 healthy children; 60 iron deficient anemic children (IDA); 102 with anemia and infectious disease, 58 of them meeting criteria for IDA. We measured hemoglobin, red cell indices, reticulocytes, transferrin saturation, serum ferritin, erythrocyte protoporphyrin, serum erythropoietin, and sTfR. Statistic method: ANOVA test, multiple linear regression, and ROC curve. RESULTS: sTfR, sTfR/ferritin ratio, and sTfR-logferritin index values were found to increase significantly in IDA children. These values were significantly lower in infectious anemia than iron deficiency states. Serum erythropoietin only was elevated significantly in iron deficiency states. In children without infection, mean corpuscular hemoglobin, erythrocyte protoporphirin, erythropoietin logarithm, and total-iron-binding-capacity logarithm predicted 81% of sTfR variability. sTfR and its indices showed a very high sensitivity and specificity for recognizing iron deficiency states. In children with IDA and infection sensitivity for sTfR/ferritin ratio was low (area under the curve: 0.71; 95% confidence interval: 0.64-0.88). For discriminating the nature of anemia in infection the cut-off point obtained for sTfR, sTfR/ferritin ratio, and sTfR-F index were 3, 70, and 1.8, respectively, and their sensitivity and specificity were also very high. CONCLUSIONS: sTfR, sTfR/ferritin ratio, and sTfR-F index are useful parameters for recognizing iron deficiency and the nature of anemia in infection. In IDA+infection, sTfR/ferritin ratio should not be recommended in the diagnosis of iron deficiency. In iron deficiency, erythropoietic activity has a secondary role as predictor factor of sTfR levels.     

The diagnosis of iron deficiency by erythrocyte protoporphyrin and serum ferritin analyses

Free erythrocyte protoporphyrin (FEP) and serum ferritin have been determined in 57 healthy children and in 25 children with varying degrees of iron deficiency. FEP was found to be inversely correlated to the concentration of hemoglobin (r = -0.80) as well as to serum ferritin (r=-0.64). Elevated FEP was found in children with hemoglobin less than 12.5 g/dl, or serum ferritin less than 8 microgram/l. In a group of apparently hematologically normal children between the age of 10--14 years (hemoglobin greater than 12.5 g/dl), a 2-month-trial of iron medication resulted in an increase in hemoglobin and ferritin, and a decrease in FEP, indicating suboptimal supply of iron for hemoglobin synthesis before iron medication. In a patient with iron deficiency (FEP 15.3 mumole/l, hemoglobin 5.2 g/dl), iron therapy was followed by a rapid fall in FEP before any changes in hemoglobin, serum iron transferrin saturation and ferritin could be detected. The rapid fall in FEP during start of treatment in iron deficiency makes FEP a sensitive biochemical parameter on iron homeostasis in iron deficiency anemia.     

Influence of maternal diabetes mellitus on fetal iron status

OBJECTIVE: To determine the effects of maternal diabetes on fetal iron status using serum transferrin receptors (STfR) and their ratio to ferritin (TfR-F index) in cord blood. METHODS: Iron, ferritin, erythropoietin, STfR and haemoglobin concentration were measured and TfR-F index calculated in 97 maternal/cord blood pairs. Forty-nine women had type 1 diabetes (diagnosed before pregnancy) and these were compared with forty-eight non- diabetic controls. The women with type 1 diabetes were recruited consecutively from attendance at the joint antenatal endocrine clinic while the control group of women was recruited from consecutive attendance at the remaining antenatal clinics. RESULTS: The infants of the diabetic women had significantly lower levels of ferritin (47 vs 169 mug/l; p<0.01) and higher STfR (17.4 vs 12.9 mg/l; p<0.01) and TfR-F index (10.4 vs 5.8; p<0.01) than controls. They were also significantly more acidotic at birth (7.25 vs 7.30; p<0.01), were born at an earlier gestation (36.7 vs 39.7 weeks; p<0.01) and had higher z Scores for weight (0.53 vs 0.02; p = 0.016). CONCLUSIONS: Maternal diabetes causes depletion of fetal iron stores and is associated with higher fetal iron demands as indicated by higher STfR level and TfR-F index in cord blood.     

THE DIAGNOSIS OF IRON DEFICIENCY BY ERYTHROCYTE PROTOPORPHYRIN AND SERUM FERRITIN ANALYSES

ABSTRACT. Free erythrocyte protoporphyrin (FEP) and serum ferritin have been determined in 57 healthy children and in 25 children with varying degrees of iron deficiency. FEP was found to be inversely correlated to the concentration of hemoglobin (r=-0.80) as well as to serum ferritin (r=-0.64). Elevated FEP was found in children with hemoglobin less than 12.5 g/dl, or serum ferritin less than 8 μg/l. In a group of apparently hematologically normal children between the age of 10–14 years (hemoglobin≥ 12.5 g/dl), a 2-month-trial of iron medication resulted in an increase in hemoglobin and ferritin, and a decrease in FEP, indicating suboptimal supply of iron for hemoglobin synthesis before iron medication. In a patient with iron deficiency (FEP 15.3 μmole/l, hemoglobin 5.2 g/dl), iron therapy was followed by a rapid fall in FEP before any changes in hemoglobin, serum iron transferrin saturation and ferritin could be detected. The rapid fall in FEP during start of treatment in iron deficiency makes FEP a sensitive biochemical parameter on iron homeostasis in iron deficiency anemia.     

THE ANEMIA OF FAMILIAL MEDITERRANEAN FEVER DISEASE

The aim of this study was to evaluate the incidence of anemia detected in familial Mediterranean fever (FMF) and the effect of disease activity and colchicine therapy along with inteleukins to laboratory tests, including serum transferrin receptor (TfR), in the diagnosis of anemia seen in FMF in children. After detecting anemia in 63.4% of 172 FMF patients followed up by our rhematology outpatient polyclinics, it was decided to study 3 groups of patients: group 1, 17 newly diagnosed FMF patients; group 2, 36 FMF patients on colchicine therapy; and group 3, 17 healthy children as control for the symptom of anemia. All 3 groups of patients were investigated for their hematological parameters, iron status, including soluble transferrin receptor (sTFR) concentrations and sTFR index, and IL-6 levels. Anemia ratio was 9/17, 53%; 11/36, 31%; and 1/17, 5% in the groups 1, 2 and 3, respectively. There was a significant difference between hemoglobin (Hb) values in the first group and the second (patients who were on colchicine therapy). Furthermore, in the second group there was a significant difference between the Hb concentrations at the time of diagnosis and after colchicine therapy (p =. 003). There was a positive correlation between Hb and plasma iron and transferrin saturation in group 1 and disease beginning age, iron, transferrin saturation, and erythrocyte sedimentation rate (ESR) in the second group. In the first group the anemic patients' iron and transferrin saturation were significantly lower than normal, while ferritin levels were higher. In the second group, a good correlation was found with ESR and Hb levels; the higher ESR values were detected in patients with lower Hb values. Of the anemic and nonanemic patients of the first and second groups, values for interleukin 6 and iron parameters, including sTFR, were found similar. Anemia detected in FMF patients was found related to iron status more than interleukins. Colchicine therapy had a positive effect on anemia as well as on disease activity. Resolution of symptoms of FMF occurred with correction of the anemia, if the patient ESR values also decreased on colchicine therapy.     

The anemia of familial Mediterranean fever disease

The aim of this study was to evaluate the incidence of anemia detected in familial Mediterranean fever (FMF) and the effect of disease activity and colchicine therapy along with inteleukins to laboratory tests, including serum transferrin receptor (TfR), in the diagnosis of anemia seen in FMF in children. After detecting anemia in 63.4% of 172 FMF patients followed up by our rhematology outpatient polyclinics, it was decided to study 3 groups of patients: group 1, 17 newly diagnosed FMF patients; group 2, 36 FMF patients on colchicine therapy; and group 3, 17 healthy children as control for the symptom of anemia. All 3 groups of patients were investigated for their hematological parameters, iron status, including soluble transferrin receptor (sTFR) concentrations and sTFR index, and IL-6 levels. Anemia ratio was 9/17, 53%; 11/36, 31%; and 1/17, 5% in the groups 1, 2 and 3, respectively. There was a significant difference between hemoglobin (Hb) values in the first group and the second (patients who were on colchicine therapy). Furthermore, in the second group there was a significant difference between the Hb concentrations at the time of diagnosis and after colchicine therapy (p = .003). There was a positive correlation between Hb and plasma iron and transferrin saturation in group 1 and disease beginning age, iron, transferrin saturation, and erythrocyte sedimentation rate (ESR) in the second group. In the first group the anemic patients' iron and transferrin saturation were significantly lower than normal, while ferritin levels were higher. In the second group, a good correlation was found with ESR and Hb levels; the higher ESR values were detected in patients with lower Hb values. Of the anemic and nonanemic patients of the first and second groups, values for interleukin 6 and iron parameters, including sTFR, were found similar. Anemia detected in FMF patients was found related to iron status more than interleukins. Colchicine therapy had a positive effect on anemia as well as on disease activity. Resolution of symptoms of FMF occurred with correction of the anemia, if the patient ESR values also decreased on colchicine therapy.     

Iron status with different infant feeding regimens: relevance to screening and prevention of iron deficiency

The objective of this study was to evaluate the benefit of screening for anemia in infants in relation to their previous diet. The iron status of 854 nine-month-old infants on three different feeding regimens and on a regimen including iron dextran injection was determined by analysis of hemoglobin, serum ferritin, and erythrocyte protoporphyrin levels and of serum transferrin saturation. Infants were categorized as having iron deficiency if two or three of the three biochemical test results were abnormal and as having iron deficiency anemia if, in addition, the hemoglobin level was less than 110 gm/L. The prevalence of iron deficiency was highest in infants fed cow milk formula without added iron (37.5%), intermediate in the group fed human milk (26.5%), much lower in those fed cow milk formula with added iron (8.0%), and virtually absent in those injected with iron dextran (1.3%). The corresponding values for iron deficiency anemia were 20.2%, 14.7%, 0.6%, and 0%, respectively. The use of iron supplements is therefore justified in infants fed cow milk formula without added iron, even when there is no biochemical evidence of iron deficiency. The low prevalence of iron deficiency in the group fed iron-fortified formula appears to make it unnecessary to screen routinely for anemia in such infants. These results also support the recommendation that infants who are exclusively fed human milk for 9 months need an additional source of iron after about 6 months of age.     

Free erythrocyte protoporphyrin as an index of perinatal iron status

The relationship between free erythrocyte protoporphyrin and conventional indices of iron status was studied in 49 mothers and their infants. Maternal venous blood samples were collected at 34 weeks gestation and at delivery. The corresponding infant blood samples were collected from the umbilical cord and at age 6 weeks. In each case free erythrocyte protoporphyrin, serum iron, total iron binding capacity, and serum ferritin were determined. Cord free erythrocyte protoporphyrin was negatively correlated with maternal ferritin at 34 weeks gestation (p = 0.016) and at delivery (p = 0.014), and with transferrin saturation at delivery (p = 0.026). The infants' haemoglobin concentrations at 6 weeks were significantly negatively related to maternal free erythrocyte protoporphyrin at 34 weeks (p = 0.026) and at delivery (p = 0.026). Cord free erythrocyte protoporphyrin is an index of maternal iron status in the last trimester. Maternal free erythrocyte protoporphyrin in the last trimester predicts the magnitude of physiological anaemia of the infant at age 6 weeks.     

Reduced hemoglobin values in children and young adults with hemophilia

Mild leukopenia and thrombocytopenia are common in multitransfused hemophiliacs. Because little attention has previously been directed to measurements of erythropoiesis in these patients, we prospectively examined hemoglobin concentration and RBC indices in 94 children and young adults with hemophilia during comprehensive clinic visits. Additional studies performed in many included serum transferrin saturation, ferritin, haptoglobin, and free erythrocyte protoporphyrin measurements. Hemoglobin concentrations were recorded as age-related percentile values. Hemophiliacs of all ages and degrees of severity often had lower than average values for hemoglobin; 31% had values less than the third percentile, 46% less than the tenth percentile, and 83% less than the mean value. Reduced hemoglobin percentile values were unrelated to age, severity of disease, or human immunodeficiency virus antibody status. Only five patients had an obvious cause for anemia. Serum ferritin, transferrin saturation, and erythrocyte protoporphyrin values were usually normal, indicating that iron deficiency and anemia of chronic disease were uncommon. Although serum haptoglobin was reduced in 44% of the patients, reticulocyte count was infrequently increased. We conclude that hemoglobin values are frequently less than the mean normal values for age in hemophiliacs. Although frank anemia is common, it is usually mild and without obvious cause. Hemophiliac individuals with slightly reduced hemoglobin values probably do not routinely require detailed investigation for occult blood loss, iron deficiency, or inflammation.     

PLASMA FERRITIN CONCENTRATIONS IN PRETERM INFANTS IN CORD BLOOD AND DURING THE EARLY ANAEMIA OF PREMATURITY

Abstract. Hågå, P. (Department of Paediatrics and Paediatric Research Institute, National Hospital of Norway, and Department of Paediatrics, Oslo City Hospital, Ullevål, Oslo, Norway). Plasma ferritin concentrations in preterm infants in cord blood and during the early anaemia of prematurity. Acta Paediatr Scand, 69: 637, 1980.—Ferritin concentrations in cord blood were determined in 22 normal term and 32 preterm infants (birth weights 600–2000 g). Eight of the preterms were SGA infants. AGA preterm infants had significantly lower concentrations than term infants, and the SGA preterm newborn had even lower levels. Plasma ferritin in cord blood of the term and AGA preterm infants correlated positively with plasma iron and transferrin saturations, but not with the transferrin level, while plasma iron and transferrin concentrations correlated positively. In a longitudinal study, 17 AGA preterm infants (birth wights 850–1500 g) were followed during the early anaemia of prematurity. Iron was supplemented from 4 weeks of age. Plasma ferritin rose rapidly during the first days after birth, peak levels being reached at 1–4 weeks. Thereafter linear falls (semilog) occurred with similar slopes in different infants. Transferrin concentrations showed a slow progressive increase from 0–8 weeks. Plasma ferritin, after reaching the peak value, correlated negatively with weight gain. No infant had low ferritin values indicating iron deficiency during the early anaemia.     

Iron status at 9 months of infants with low iron stores at birth

OBJECTIVE: To determine the 9-month follow-up iron status of infants born with abnormally low serum ferritin concentrations.Study design: Ten infants of >34 weeks' gestation with cord serum ferritin concentrations <5th percentile at birth (<70 microg/L) and 12 control infants with cord serum ferritin concentrations >80 microg/L had follow-up serum ferritin concentrations measured at 9 +/- 1 month of age. The mean follow-up ferritins, incidences of iron deficiency and iron-deficiency anemia, and growth rates from 0 to 12 months were compared between the two groups. RESULTS: At follow-up, the low birth ferritin group had a lower mean ferritin than the control group (30 +/- 17 vs 57 +/- 33 microg/L; P =.03), but no infant in either group had iron deficiency (serum ferritin <10 microg/L) or iron-deficiency anemia. Both groups grew equally well, but more rapid growth rates were associated with lower follow-up ferritin concentrations only in the low birth ferritin group (r = -0.52; P =.05). Both groups were predominantly breast-fed without iron supplementation before 6 months. CONCLUSIONS: Infants born with serum ferritin concentrations <5th percentile continue to have significantly lower ferritin concentrations at 9 months of age compared with infants born with normal iron status, potentially conferring a greater risk of later onset iron deficiency in the second postnatal year.