Although obstetricians generally consider dental care safe for pregnant women, supporting clinical trial evidence has been lacking.

The researchers randomly assigned 823 pregnant women with periodontitis -- a severe form of gum disease -- to receive scaling and root planing and 351 of the women completed all recommended treatment. Throughout the trial, obstetric nurses reviewed medical records to monitor subjects for serious adverse events -- pregnancies ending in a non-live birth and other events that did not result in pregnancy termination including hospitalizations, fetal, or congenital anomalies and neonatal deaths.

The study, published in The Journal of the American Dental Association, finds periodontal treatment and essential dental treatment, administered at a time between 13 and 21 weeks' gestation, did not significantly increase the risk of any adverse outcome evaluated.

"Use of topical and local anesthetics for scaling and root planing also was not associated with an increased risk of experiencing these adverse events and outcomes," the study authors say in a statement.