Study boosts suspected link between mothers' gum disease and both premature birth, low birth weight

March 13, 2002
As much as 18 percent of preterm deliveries are due to gum disease, according to researchers.

Mothers who suffer from gum disease are significantly more likely to deliver their babies prematurely than women without that illness, which also is known as periodontal disease, a new University of North Carolina at Chapel Hill study shows. Such women also are more likely than others to deliver babies whose weight is less than normal.

The study, done in collaboration with Duke University scientists, supports results of earlier investigations at UNC and elsewhere that suggested a link, said Dr. Steven Offenbacher, professor at the UNC School of Dentistry.

Offenbacher, director of the Center for Oral and Systemic Diseases, presented his group's findings in San Diego on Thursday (March 7) at the annual meeting of the International Association for Dental Research.

In the five-year study, researchers evaluated periodontal disease in more than 850 women before and after they gave birth and divided the women into groups representing healthy gums, mild disease and moderate-to-severe disease. They then adjusted for risk factors affecting birth timing and weight such as age, race, food stamp eligibility, marital status, previous pre-term births, smoking and other health problems.

"This prospective study confirms our earlier case-control studies showing that both periodontal disease and periodontal disease progression during pregnancy have an effect on the fetus," Offenbacher said. "It increases the risk of pre-term delivery two-fold or greater depending on whether there is fetal exposure during pregnancy. This is complemented with new information suggesting that some organisms from mothers' periodontal tissues actually get in the bloodstream and target the fetus."

In other words, he said, babies developing in women's wombs are being adversely affected by germs growing in their mothers' mouths such that they are born early or at lower than normal weight. Scientists find antibodies to specific organisms in placental blood at the time of delivery.

"One in 10 babies in the United States is born too small or too early, which is a major cause of sickness and mortality," Offenbacher said. "This work is very important because it confirms a new and potentially modifiable risk factor that we should be able to reduce."

Gum disease may be responsible for up to 18 percent of pre-term deliveries, he said the new study suggests. The size of gum disease's effect appears to be as strong as smoking or alcohol abuse.

"It's not just that periodontal disease is a surrogate marker for poor oral hygiene or other socioeconomic factors just sort of jumbled together," the scientist said. "The fact that we're finding specific organisms that can cause growth and delivery problems opens up a whole new avenue for preventive care."

UNC co-authors are Drs. Susan Lieff and Rosemary G. McKaig, research assistant professors of dental ecology; Kim Boggess, assistant professor of obstetrics-gynecology at the UNC School of Medicine; Phoebus N. Madianos, research assistant professor of periodontology; Catherine Champagne, research assistant professor of dental research; research dental hygienist Heather L. Jared, Sally M. Mauriello, associate professor of dental ecology; and James D. Beck, professor of dental ecology.

Duke authors are Drs. Amy Murtha, assistant professor of maternal and fetal medicine; Richard L. Auten, assistant professor of neonatology; and William Herbert, professor of obstetrics and gynecology, now at the University of Virginia.

The National Institute of Dental and Craniofacial Research supports the continuing gum disease studies.

New research is under way at UNC and Duke to determine if treating pregnant women's gum disease cuts their risk of pre-term delivery.

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Note: Offenbacher can reached through the San Diego Convention Center, (619) 525-6418 or 525-5000, and the Hyatt Hotel, where he is staying, (619) 232-1234

School of Dentistry contact: Alice Lockhart, (919) 966-4563