New UNC, Duke study shows periodontal treatment doesn't reduce preterm birth risk

The study, involving researchers from the University of North Carolina at Chapel Hill and Duke University Medical Center, is one of the largest randomized trials to date to look at the link between the two conditions.

Dr. David Couper

Gillings School of Global Public Health researchers David Couper, Ph.D., and Dawn Stewart, M.S. worked with lead investigator Steven Offenbacher, D.D.S., Ph.D., from the UNC School of Dentistry, and a host of other researchers from the School of Dentistry, Duke University and other universities in Texas and Alabama. Couper is a research associate professor in the Department of Biostatistics.

Previous research had suggested that gum disease was associated with very preterm deliveries (defined as less than 32 weeks gestation). That led insurance policies and health-care providers to recommend scaling and root planing, sometimes referred to as “deep cleaning,” in pregnant women. It was thought that such care had the potential to reduce preterm delivery risk.

These new findings, based on a randomized trial of 1,800 pregnant women with periodontal disease, indicate that routine gum treatments do not reduce the risk of early delivery.

“I’m always asked whether we should mandate dental treatment for all pregnant women,” said Amy Murtha, M.D., director of obstetrics research at Duke University Medical Center, who presented the findings at the annual meeting of the Society for Maternal-Fetal Medicine in San Diego. “The biggest implication of this study is that this level of standard periodontal care will not affect the birth outcome.”

That’s not to say pregnant women should not get dental exams and treatment as needed; they should, Murtha added. “Our study emphasizes that treating periodontal disease during pregnancy is safe, but that standard periodontal care is not enough.”

Progression, or worsening of periodontal disease occurs in about 25 percent of pregnancies, said Steven Offenbacher, D.D.S., Ph.D., the study’s lead investigator and director of the UNC-Chapel Hill School of Dentistry-based Center for Oral and Systemic Diseases. The disease is a bacterial infection that attacks the teeth-supporting tissues below the gum line. Left untreated, it can lead to tooth loss, as well as a host of other problems.

This study, conducted at Duke, the University of Alabama at Birmingham and the University of Texas at San Antonio, was overseen by the UNC-Chapel Hill School of Dentistry. Approximately 1,800 pregnant women with periodontal disease were randomly assigned to two groups: one received periodontal treatment before 23 weeks gestation; the other did not. Overall, no significant differences were reported regarding obstetric or neonatal outcomes when the two groups were compared.

Despite the findings, Murtha said much remains unknown about the relationship between the two conditions. “Periodontal disease and poor pregnancy outcomes travel together, but we don’t know why.”

Nor do researchers understand how or why pregnancy appears to jumpstart the onset and progression of the disease. Murtha said it may be that preterm birth and periodontal disease share a common underlying trait, such as an exaggerated inflammatory response, but more studies are needed to fully explain the connection.

Additional research is also needed to determine whether more intensive periodontal care during pregnancy might make a difference. “Although we did not reduce the risk of preterm births, the level of periodontal care provided in this study was not as effective as compared to earlier studies,” Offenbacher said. It may be that a more aggressive approach to periodontal disease management could have a different outcome, he added.

The study was funded by the National Institute of Dental and Craniofacial Research. James D. Beck, Ph.D., associate dean for research and a Kenan professor within the UNC-Chapel Hill School of Dentistry, is the study’s co-principal investigator. Other UNC-Chapel Hill School of Dentistry researchers include Luisito Mendoza, D.D.M., and Sally Mauriello, Ed.D. UNC-Chapel Hill Gillings School of Global Public Health researchers include David Couper, Ph.D., and Dawn Stewart, M.S. Researchers David Cochran, D.D.S., Ph.D., and Donald Dudley, M.D., are with the University of Texas Health Science Center at San Antonio. Researchers Michael Reddy, D.M.D., D.M.Sc., Nicolaas Geurs, D.D.S., and John Hauth, M.D., are with the University of Alabama at Birmingham. Heather Jared, M.S., formerly with the UNC-Chapel Hill School of Dentistry, also contributed to this research.

UNC Gillings School of Global Public Health contact: Ramona DuBose, director of communications, (919) 966-7467 or ramona_dubose@unc.edu.