Many factors influence children’s grades in school, from the involvement of their parents and the quality of their diet, to whether they can keep the proverbial dog from chowing down on their homework assignments.
Researchers have now found one factor that probably doesn’t have an impact on school performance: x-ray exposure in utero.
Providers have made dose reduction a priority in recent years to protect the health of children, infants and fetuses. Children’s hospitals are eschewing CT for modalities involving less ionizing radiation, but even low doses are cause for concern.
Previous studies of low-dose radiation exposure in utero or in infancy have been inconsistent as to whether the exposure impacts cognitive ability or school performance later in life, explained A.C. Nordenskjöld, MD, PhD, of the Karolinska Institute in Stockholm, and colleagues.
To test whether children exposed in utero to x-ray pelvimetry—performed to assess the birth canal—fared worse than their peers in school, Nordenskjöld and colleagues conducted a population-based cohort study and published their findings in the August issue of Clinical Radiology.
More than 46,000 children born in the Swedish county of Östergötland from 1980 through 1990 were included in the study, with 1,536 children who were exposed to x-ray pelvimetry exams in utero compared against other children born in the same county and against their unexposed siblings.
Univariate analysis showed children exposed to x-ray pelvimetry in utero had slightly higher school grades compared with unexposed children, though this difference was not statistically significant in a multivariate analysis that included sex, birth order, birth position and the mother’s education and income level.
No statistical difference was present in either univariate or multivariate analysis when comparing exposed children with their siblings.
“It has been generally conceived that there are no risks of cognitive impairment after in utero doses below 100 mGy,” wrote Nordenskjöld and colleagues. “More recent studies have put this concept in question, and there is an ongoing debate as to whether there is a threshold below which cognitive impairment does not occur. The present study cannot address the issue of a threshold, as the range of exposure was narrow.”
The authors continued: “Fetal exposure to pelvimetry in the 1980s, when doses were much higher than they are today, did not have any measurable effect on school performance 16 years later.”