Study: Dental X-Ray May Be Bad for Baby

April 28 -- As if anyone needed another excuse not to go to the dentist, researchers now suggest pregnant women getting dental X-rays are more likely to have underweight babies.

Dentists already know not to take unnecessary X-rays of pregnant patients, since certain forms of radiation have been linked to pre-term labor and low-birth weight. But a new study is the first to link dental X-rays with low birth weight and full-term babies.

Study authors say they were surprised by the results, published in the Journal of the American Medical Association on Tuesday. Researchers previously assumed only direct radiation to the uterus or fetus would be harmful. The authors speculate the finding may have something to do with radiation effects on the thyroid gland or other hormonal systems in the head and neck region.

An examination of the records for more than 5,500 patients in the state of Washington showed pregnant women exposed to very low-dose radiation at the dentist's office, equivalent to a diagnostic X-ray series done for first-time patients, were twice as likely to have a low birth weight baby as those who didn't receive dental X-rays.

For full-term infants only, those born of mothers receiving dental X-rays during pregnancy were more than three times as likely to be of low birth weight.

Keep Your Appointments With the Dentist

Both the study authors and other experts agree the finding shouldn't discourage expectant mothers to cancel their dental appointments.

"The study certainly does show an association with X-rays, but this should not be mistaken to be a definite cause-and-effect situation," says Dr. Douglass Benn, professor of radiology and director of oral diagnostic systems at University of Florida College of Dentistry in Gainesville. Benn was not involved in the study.