FRIDAY, Feb. 22 (HealthDay News) -- Poor growth among children born with heart defects may be due to abnormalities in growth regulation rather than nutrition problems, a new study suggests.

Discrepancies in weight between these children and those without heart defects peaked at 4 months of age, the researchers found. Weight and other size differences were still evident when the children reached the age of 3 years.

"When compared with their healthy peers, children with congenital heart disease have impaired growth, as measured in weight, length and head circumference," senior study author Dr. Meryl Cohen, a pediatric cardiologist at the Children's Hospital of Philadelphia cardiac center, said in a hospital news release. "We investigated patterns of poor growth in these children, as a starting point in guiding us toward more effective treatments."

The researchers compared the medical records of two groups of children up to the age of 3: one group included 856 children who were born with heart defects ("congenital heart disease"), and the other group included over 7,600 similar children who did not have heart defects. The study revealed that significant deficits in weight, length and head circumference had developed among the children with congenital heart defects just weeks after they were born.

Of the children with heart defects, 248 needed surgery. These children, the investigators found, were at much greater risk for being below the third percentile in weight, length and head circumference as infants, and were still smaller than other children at 3.

The other 608 children with heart defects who did not have surgery were also smaller than other children their own age, but the differences were less significant, the study showed.

Although poor nutrition can restrict a child's growth, in those cases weight is typically affected before length and head circumference, the researchers pointed out.

"The fact that all three parameters [weight, length and head circumference] changed simultaneously rather than sequentially supports the idea that impaired growth in children with heart disease is affected at least in part by factors unrelated to nutrition," Cohen explained.

She added that more research is needed to determine how growth hormones and other factors that affect growth regulation in children with congenital heart defects come into play.

The study was published in a recent online edition of the journal Pediatrics.

More information

Visit the U.S. Centers for Disease Control and Prevention to learn more about living with a congenital heart defect.