Heart Defects Can Delay Baby's Brain Development

(Page 3)

"Although we don't know the exact cause of delayed brain development, it is likely to relate to the way blood flows to the brain in fetal life. In babies with the two types of heart disease that we studied, the brain receives blood with lower oxygen," said McQuillen.

But questions remain, Garg said. Even though the study confirms that brain development delays exist prior to surgery, it does not settle the question of cause and effect, he said.

It's possible for heart defects and brain abnormalities to exist in the same population but not necessarily be related to each other, Garg argued.

"In the paper, they describe the abnormalities that have been seen. The question is whether [heart defects are] related to that. It's an association. Also, the kids have these abnormalities on MRI, but does this lead to later abnormalities? Further studies need to be done in terms of linking the two brain abnormalities," said Garg.

The researchers said further investigation is needed to find ways of minimizing brain development delays in utero and as a result of heart surgery.

Garg acknowledged that the new information may help physicians protect babies' brains before and during heart surgery, but those steps could have hazards of their own.

"We do a lot of interventions that can lead to neurologic problems. You have multiple hits, so how do you know what caused the developmental delay? That's what's tricky about it," Garg said.

The researchers did not compare the infants' brain development to that of other infants who are ill at birth, he added, and long-term studies of the impact of these brain abnormalities are needed.

"Babies with a fetal diagnosis may also be studied with MRI to learn more about how the brain develops when there is congenital heart disease. This will be especially important as cardiologists begin to consider interventions to treat heart conditions before birth -- something that is only being studied at this time," said McQuillen.

The researchers stressed that both of the congenital heart defects in the study required surgery. Parents who have been told their child has a heart murmur but does not need surgery should not worry about related developmental delays, McQuillen and Miller said.

More information

There's more on congenital heart defects at the American Heart Association.