Low birth weight linked to low IQ in teens

Adolescents with a low birth weight, defined as less than 4.4 lbs., have lower IQ scores than other teens and are also more likely to have movement problems, according to a report in the Archives of Pediatrics and Adolescent Medicine.

The findings support previous reports suggesting that low birth weight is not only a risk factor for major disabilities, such as cerebral palsy and mental retardation, but also for subtler movement and brain impairments.

The findings are based on an analysis of data for 474 low birth weight adolescents who were born in a three-county region during a 3-year period. All of the subjects underwent IQ and movement assessment at home using standard tests.

Movement problems were more common in the study group than in normal comparison subjects, Dr. Agnes H. Whitaker, from Columbia University Medical Center in New York, and colleagues found.

The IQ scores of the low birth weight subjects were within the normal range, but were still significantly lower than population norms, the authors point out.

Further analysis showed that male gender, brain injury seen during newborn ultrasound imaging, and days on a ventilator predicted movement problems. Predictors of lower IQ scores included social disadvantage, poor fetal growth, and brain injury on ultrasound, the report indicates.

"Taken together, these findings suggest that enhanced maternal-fetal and neonatal care have the potential to substantially improve" brain and movement outcomes for low birth weight adolescents, the authors conclude.

SOURCE: Archives of Pediatrics and Adolescent Medicine, October 2006.