U of M study shows treatment of periodontal disease does not decrease risk for preterm birth

Research shows no direct link between periodontal disease and preterm birth

Researchers at the University of Minnesota School of Dentistry have found treatment of periodontal (gum) disease in pregnant women does not significantly alter rates of preterm birth, low birth weight, or fetal growth restriction.

The Obstetrics and Periodontal Therapy Trial (OPT), published in the Nov. 2, 2006, issue of the New England Journal of Medicine, concluded that while treatment for periodontal disease during pregnancy is safe and effective, it does not directly affect a woman's risk for preterm birth or having a baby of low birth weight.

Past research has associated maternal periodontal disease (periodontitis) with an increased risk of preterm birth, low birth weight, infant mortality, and the risk for long-term health problems, including cerebral palsy, blindness, and learning disabilities. Scientists suspected that bacteria from infected gums could enter the bloodstream and cause the immune system to provoke changes in tissues and organs elsewhere in the body, leading to premature labor.

"But, this research does not show a direct cause and effect relationship between periodontal disease and preterm birth," said Bryan Michalowicz, D.D.S., M.S., lead author and associate professor in the Division of Periodontology at the University of Minnesota School of Dentistry. "A common, nonsurgical treatment for periodontitis delivered between weeks 13 and 21 of pregnancy did not reduce the rate of preterm birth or low birth weight. This could suggest that in the future, researchers focus on testing other means to reduce rates of preterm birth."

Periodontal disease is a bacterial infection that affects the tissues that support the teeth at and below the gumline. In its mildest form, known as gingivitis, the gums will redden, swell, and bleed. Untreated, bacteria build up and produce toxins that irritate the gums and stimulate an inflammatory response that breaks down the gum tissue. As the tissues are damaged, gums begin to separate from the teeth, forming "pockets" between the teeth. Eventually, the attachment of the tooth and its support system is destroyed teeth can then loosen and have to be removed.

Symptoms of periodontal disease include reddened, puffy, and bleeding gums. Unlike gingivitis, periodontal disease cannot be diagnosed by visual examination alone. It is diagnosed with a probe that is inserted into the space between the tooth and gumline.

Although periodontal disease is not caused by pregnancy, pregnant women often experience an increase in gingival bleeding, which is thought to be caused by increased levels of female hormones that favor the growth of certain oral bacteria.

More than 800 women who had early-to-moderate periodontitis participated in the study. Half of the women were randomly assigned to receive nonsurgical periodontal treatment during their second trimester of pregnancy. The other half was monitored closely through the trial and received periodontal treatment after giving birth.

"Although treatment for periodontal disease didn't have a direct impact on risk of pre-term birth, expectant mothers should continue to visit their dentists and maintain good oral health." said Michalowicz. "This study showed that dental checkups and treatment are safe and effective at the appropriate times during pregnancy."


The phase III, multi-center clinical trial was sponsored by a three-year, $7.5 million grant from the National Institute of Dental and Craniofacial Research (NIDCR). Other centers participating in the study include Hennepin County Medical Center in Minneapolis, University of Kentucky in Lexington, University of Mississippi Jackson Medical Mall, and Harlem Hospital Columbia University.

Last reviewed: By John M. Grohol, Psy.D. on 30 Apr 2016
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