Males born prematurely tend to fare worse than "preemie" females, and a new study offers an explanation for the difference.
When Allan Reiss et al. compared MRI brain scans of 65 eight-year-old children born prematurely to scans of a matched group of children born at full term, the researchers found marked reductions in brain volume in the children with a history of prematurity. "In the preterm group as a whole," Reiss says, "we found the volumes of both gray matter and white matter were reduced." Girls born prematurely showed normal white matter volume, while the boys exhibited significant reductions not just in gray matter, but in white matter as well.
In particular, boys showed reductions in the temporal lobe and the deep cerebral region of the brain. Reiss notes that these areas are involved in language, emotion, attention, and reading, all of which are areas in which children born prematurely often show impairment.
"It's fascinating," says Reiss. "It's as though we're seeing echoes of the 'big bang' of preterm birth at eight years of age."
"Sex differences in cerebral volumes of 8-year-olds born preterm," A. Reiss, S. Kesler, B. Vohr, C. Duncan, K. Katz, S. Pajot, K. Schneider, R. Makuch, and L. Ment, Journal of Pediatrics, Vol. 145, No. 2, August 2004. Address: Allan L. Reiss, Dept. of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd., Stanford, CA 94305.