Antepartum Dental X-Rays Inhibit Fetal Growth

Antepartum Dental X-Rays Inhibit Fetal Growth

Here is surprising news about a risk for low birth weight.

Ionizing radiation inhibits growth in many situations. To determine whether local irradiation to the mother's head and neck affects fetal growth, investigators compared the dental records of 1117 women who delivered low-birth-weight (LBW) infants with the records of 4468 maternal controls; the women were members of the same dental insurance plan.

Investigators found diagnostic dental x-rays to be an independent risk factor for delivery of an LBW infant. After adjustment for all dental procedures, receiving a thyroid radiation dose of greater than 0.4 mGy significantly increased risk for LBW and term LBW (odds ratios, 2.54 and 3.54, respectively). Each cumulative 1-mGy increase in thyroid radiation dose increased the OR by 2.59 for term LBW. More than two thirds of antepartum maternal dental radiography occurred in the first trimester, and exposure during this period was associated with a very high risk for LBW (OR, 5.49).

Comment: Women should not have diagnostic dental x-rays during pregnancy or while trying to conceive. The risk for delivering a term LBW infant after undergoing first-trimester dental radiography is striking. As the authors point out, these data were obtained from an affluent, homogeneous, insured population that may not be representative of other populations. Nonetheless, if these findings are broadly applicable, elimination of dental diagnostic x-rays during pregnancy might reduce the prevalence of term LBW in the U.S. by as much as 5%.

— F. Bruder Stapleton, MD

Published in Journal Watch Pediatrics and Adolescent Medicine June 14, 2004