Researchers at Umeå University studied 285 marginally low birth weight infants with 95 infants who had normal birth weight.
Children with low birth weight were given 0, 1, or 2mg/kg of iron supplements a day from six weeks of age to six months of age.
The research showed babies who received no iron supplements were significantly more likely to experience behavioural problems, as reported by their parents. Some of the behavioural issues reported in the study include problems managing emotional reactions, anxiety and depression as well as sleep and attention problems.
Results of the study showed that low birth weight babies who weren't given iron supplements were 4.5 times more likely to show signs of behavioural problems at age 3 compared with other low-birth-weight babies who received iron supplements during early infancy.
The findings suggest that iron deficiency in infancy may be a direct cause of behavioral problems later in life, the researchers wrote in the study published in the journal of Pediatrics.
Co-researchers Dr. Magnus Domellof of Umea University told Reuters that the latest finding "further solidifies the evidence that it's a very good idea to give these (marginally low birth-weight) children iron supplements."
He said that he did not see any delayed growth or stomach problems that could be linked to the use of iron supplements.
Previous studies have found that giving young children who aren't deficient excessive iron may stunt their growth.
"Here's where an ounce of prevention is worth a pound of cure," Dr. Michael Georgieff, a child development researcher at the University of Minnesota in Minneapolis who had reviewed the study as part of Berglund's dissertation committee, told Reuters.
He recommended parents know their baby's iron requirements when they leave the hospital.