Low birth weight infants who receive iron supplements have a lower risk of developing ADHD (attention deficit hyperactivity disorder) and other behavioral problems later on, researchers from Umeå University, Sweden, and the Karolinska Institute, also in Sweden, reported in Pediatrics (January 2013 issue).

Health professionals and researchers have long known that infants who are born with a low body weight are more likely to have long-term health risks. Children with a low birth weight are more likely to develop behavioral and cognitive problems.

The authors added that babies born with a low body weight are more likely to suffer from iron deficiency. Iron deficiency has been shown to be linked to neurodevelopmental problems.

Previous research found a link between low birth weight and psychiatric problems in kids, while another report indicated that low birth weight infants have a higher chance of developing kidney disease, diabetes, and heart disease.

In this latest study, the team set out to determine whether iron supplements could lower behavioral issues and improve cognitive scores of LBW (low birth weight) infants.

They carried out a randomized, controlled trial involving 285 LBW infants (they weighed between 2,000 and 2,500 grams or about 4.4 to 5.5 pounds at birth). They were all given 0, 1, or 2 mg/kg of iron supplements each day from when they were 6 weeks to 6 months old.

When the children were 3.5 years old, along with 95 infants who had normal birth weight (control group), they were given:

  • A psychometric test – Wechsler Preschool and Primary Scale of Intelligence
  • A questionnaire of behavioral problems – Child Behavior Checklist; CBCL

Results showed that between the low birth weight groups and the control group of normal weight, there were no notable differences in IQ.

However, taking iron supplements had a significant impact on behavioral problems, including ADHD.

The scientists discovered that 12.7% of the LBW infants who were not given any iron supplements displayed signs of behavioral problems, compared to:

  • 2.9% of the kids in the 1-mg group
  • 2.7% of the kids in the 2-mg group
  • 3.2% of the control group

The authors concluded that the cognitive functions of low birth weight infants at 3.5 years of age are not affected by early iron supplementation. However, iron supplementation does notably lower the chances of development behavioral issues later on.

The findings indicate that there is a causal link between a child’s iron deficiency and behavioral problems later in life. Nevertheless, this study has also shown that LBW infants will receive long-term health benefits from receiving iron supplements early in life.

In an Abstract in the same journal, the authors wrote:

“Early iron supplementation of marginally LBW infants does not affect cognitive functions at 3.5 years of age but significantly reduces the prevalence of behavioral problems. The study suggests a causal relation between infant iron deficiency and later behavioral problems.”

Written by Sarah Glynn