Hepcidin Status at 2 Months in Infants Fed Breast Milk Compared with Formula

Non Breast-Milk-Fed Very Preterm Infants Are at Increased Risk of Iron Deficiency at 4-6-Months Corrected Age: A Retrospective Population-Based Cohort Study

Iron supplementation is routinely recommended for breast-milk-fed preterm infants. However, the Canadian Pediatric Society recommends no additional iron supplementation for preterm infants fed primarily with iron-rich formula. Other pediatric societies don't provide specific guidance on supplemental iron for formula-fed preterm infants. This study investigated how feeding type influences iron status of very preterm infants at 4-6-months corrected age (CA). A retrospective cohort study was conducted using a population-based database on all very preterm infants (<31 weeks gestational age) born in Nova Scotia, Canada from 2005-2018. Information about feeding type, iron intake from formula, supplemental iron therapy and iron status at 4-6-months CA was extracted. Iron deficiency (ID) was defined as serum ferritin <20 and <12 µg/L at 4-and 6-months CA, respectively. Of 392 infants, 107 were "breast-milk-fed" (exclusively or partially) and 285 were "not breast-milk-fed" (exclusively fed with iron-rich formula) at 4-6-months CA. Total daily iron intake was higher in the non-breast-milk-fed group (2.6 mg/kg/day versus 2.0 mg/kg/day). Despite this, 36.8% of non-breast-milk-fed infants developed ID versus 20.6% of breast-milk-fed infants. ID is significantly more prevalent in non-breast-milk-fed infants than breast-milk-fed infants despite higher iron intake. This suggests the need to revisit recommendations for iron supplementation in non-breast-milk-fed preterm infants.

Postdischarge Iron Status in Very Preterm Infants Receiving Prophylactic Iron Supplementation after Birth

OBJECTIVE

To determine postdischarge iron status and associated factors in very preterm infants.

STUDY DESIGN

A retrospective cohort study was conducted through a provincial database on all very preterm infants born in Nova Scotia between 2005 and 2018. As a standard of care, all infants received prophylactic iron supplements starting at 2-4 weeks of chronological age and were tested for iron deficiency at 4 or 6 months corrected age. Iron deficiency was defined as serum ferritin <20 g/L at 4 months or <12 g/L at 6 months. Multivariate logistic regression analysis identified factors associated with iron deficiency.

RESULTS

Among 411 infants, 132 (32.1%) had iron deficiency and 11 (2.7%) had iron deficiency anemia. The prevalence of iron deficiency decreased over time, from 37.6% in 2005-2011 to 25.8% in 2012-2018. Gestational hypertension in the mother (P = .01) and gestational age <27 weeks (P = .02) were independent risk factors for iron deficiency. In addition, the odds of iron deficiency were lower in the mixed-fed group (ie, with breast milk and formula combined) compared with the exclusive formula-fed group (P = .01).

CONCLUSIONS

Iron deficiency was prevalent in 32% of the very preterm infants despite early iron prophylaxis. These results demonstrate the importance of monitoring iron stores during preterm follow-up. Information about risk factors is important to mitigate iron deficiency in very preterm infants.

Iron deficiency in infancy: current insights

PURPOSE OF REVIEW

Iron deficiency is the most common micronutrient deficiency and infants are at particular risk. The purpose of this review is to summarize recent studies that explored the metabolism of iron in infants as well as the risks and benefits of iron supplementation in different populations.

RECENT FINDINGS

The ability of infants to regulate iron homeostasis is not fully known but most likely different from adults. Reducing iron deficiency has beneficial effects on neurodevelopment but iron overload may have adverse functional effects including diarrhea and even poor neurodevelopment. Recent studies have confirmed benefits of delayed cord clamping and supplementation of infants in risk groups while iron supplementation to pregnant women has shown limited effect in the offspring with regard to iron status and neurodevelopment. Further support is given to the recommendation that exclusive breast feeding, without supplementation, is safe for normal birth weight infants until 6 months whereafter an iron-rich diet should be given.

SUMMARY

Iron deficiency negatively impacts global health but efforts to identify optimal interventions are progressing. Yet, questions remain, particularly regarding long-term risks, benefits and optimal interventions for low birth weight infants as well as the level of iron fortification in infant formula.