Premature Birth Can Damage Brain

Boys Brains Particularly Affected by Early Birth

From the WebMD Archives

Aug. 9, 2004 -- Premature birth can cause long-lasting brain damage -- especially in boys, a study shows.

MRI brain scans of 8-year-old boys and girls show that those born prematurely have smaller-than-normal brains. The findings, reported in the Journal of Pediatrics, come from a comparison of 65 preterm and 31 normal-term kids.

The results point to lingering effects of too-early birth. The lower the child's birth weight, the more severe the problem, notes study leader Allan Reiss, MD, director of the Stanford University Psychiatry Neuroimaging Laboratory.

"It's fascinating," Reiss says in a news release. "It's as though we're seeing echoes of the 'big bang' of preterm birth at 8 years of age."

It's well-known that preterm boys don't do as well as preterm girls. They have much more trouble with language and speech, and have a harder time in social situations than girls do.

Brain scans show the preterm kids have smaller brains than normal-term kids. Most of this difference was found in boys. Most striking was the difference in white matter -- the areas of the brain that handle more complex functions.

"When we divided the preterm group by gender we found, bingo, the females had normal or preserved white matter volume, but the males' volumes were reduced compared to their full-term peers," Reiss says.

Reiss and colleagues suggest that the preterm child's brain is not yet equipped to thrive outside the womb. Girls, because they have two X chromosomes, may have redundant features that help protect them. They may also get protection from female hormones, Reiss speculates.

Certain parts of the brain appear to be more vulnerable than others. Reiss notes that the temporal lobe -- one of the seats of language -- is particularly affected in preterm males.

"We should try to figure out a way to stimulate white matter growth in the brain of a preterm baby or develop a partially protective agent," Reiss suggests.

The researchers found that the earlier the children were born -- and the lower their birth weight -- the smaller their brains.

SOURCES: Reiss, A.L. Journal of Pediatrics, August 2004; vol 145: pp 242-249. News Release, Stanford University Medical Center.