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Investigators of a new study published in JAMA Pediatrics found that daily low-dose iron supplementation among exclusively or predominantly breastfed infants was ineffective at improving psychomotor development.¹

Iron deficiency is associated with suboptimal development according to the study authors, who wrote, “In Europe and the [United States], approximately 20% of children have iron deficiency and up to 5% develop iron deficiency anemia before age 3 years.”¹ The American Academy of Pediatrics recommends exclusive breastfeeding “for about the first [6] months,” and supports continued breastfeeding after solid foods are introduced.²

Since iron content is low in breast milk, prolonged breastfeeding is known to have associations with iron deficiency, also in part because of often insufficient iron intakes from complementary foods.¹

In a randomized, double-blind, placebo-controlled trial, investigators sought to assess if daily iron supplementation at 1 mg / kg, given between 4 and 9 months of age in breastfed infants improved psychomotor development at 12 months. The trial was conducted from December 2015 to May 2020, with follow-up conducted through May 2023 in a Poland and Sweden outpatient setting.¹

Inclusion criteria included¹:

· Healthy singleton infants born between 37 to 42 weeks’ gestation with a birth weight greater than 2500 g

· Exclusively or predominantly breastfed (>50% of daily feedings)

· Did not have anemia (>10.5 g/dL; to convert to g/L, multiply by 10) at age 4 months.

Exclusion criteria included¹:

· Major illness

· Congenital anomaly

· Food allergy

· Difficulty communicating with caregivers

The primary outcome of the study was psychomotor development at age 12 months, assessed by motor score of Bayley Scales of Infant and Toddler Development, adjusted for gestational age, sex, and maternal education. Secondary outcomes included “cognitive and language scores at 12 months; motor, cognitive, and language scores at 24 and 36 months; iron deficiency (serum ferritin <12 ng/mL), and iron deficiency anemia (iron deficiency and hemoglobin <10.5 g/dL) at 12 months,” the study authors wrote.¹

The trial featured 221 infants randomized infants, of which 111 were female. Of the 221 infants, 200 were included in the intend-to-treat analysis, with a mean (SD) age of 12.4 months (0.8). Following analysis, the investigative team observed that iron supplementation given to 104 infants, compared to placebo (n = 95), had no effect on psychomotor development for motor score (mean difference [MD], –1.07 points; 95% CI, –4.69 to 2.55). Similarly, there was no effect for cognitive score (MD, −1.14; 95% CI, −4.26 to 1.99), or language score (MD, 0.75; 95% CI, −2.31 to 3.82) at 12 months of age.¹

Risk for iron deficiency was not reduced (relative risk [RR], 0.46; 95% CI, 0.16 to 1.30), nor was risk reduced for iron deficiency anemia (RR, 0.78; 95% CI, 0.05 to 12.46) at 12 months at 12 months of age.¹

“We found no statistically significant effect of early iron supplementation on developmental scores at 24 and 36 months,” the investigative team wrote. “At age 12 months, iron deficiency was present in 5 children (6%) in the iron group and 9 (13%) in the placebo group (relative risk [RR], 0.46; 95% CI, 0.16 to 1.30). One child in the iron group and 1 in the placebo group developed iron deficiency anemia (RR, 0.78; 95% CI, 0.05 to 12.46)… We did not detect a significant effect of the iron intervention compared to placebo on hemoglobin and serum ferritin levels at 12 months in either the intention-to-treat or per-protocol analyses.”¹

The authors concluded there is no benefit of daily, low-dose iron supplementation between the ages of 4 to 9 months related to psychomotor development, iron deficiency, or iron deficiency anemia in the profiled patient population.¹

Related: Patient-centered approach to updated AAP breastfeeding guidelines

Allison Scott, DNP, CPNP-PC, IBCLC.

Allison Scott, DNP, CPNP-PC, IBCLC, reviews the updated breastfeeding guidelines from the American Academy of Pediatrics.

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References:

1. Svensson L, Chmielewski G, Czyżewska E, et al. Effect of Low-Dose Iron Supplementation on Early Development in Breastfed Infants: A Randomized Clinical Trial. JAMA Pediatr. Published online May 13, 2024. doi:10.1001/jamapediatrics.2024.1095
2. Feldman-Winter L. Breastfeeding: AAP policy explained. The American Academy of Pediatrics. Updated July 18, 2022. Accessed May 14, 2024. https://www.healthychildren.org/English/ages-stages/baby/breastfeeding/Pages/Where-We-Stand-Breastfeeding.aspx#:~:text=The%20American%20Academy%20of%20Pediatrics,for%202%20years%20or%20beyond.