Release Date: February 2010

DentistryIQ recently had the privilege of interviewing Dr. Yiping Han, a researcher from the Department of Periodontics at Case Western Reserve University School of Dental Medicine, who reported the first documented link between a mother with pregnancy-associated gingivitis and the death of her fetus.

DentistryIQ: Please explain the significance of your lab work involving Fusobacterium nucleatum and preterm labor/stillbirths and the recent case of the 35-year-old mother who delivered a stillborn child in Santa Monica, Calif.

Dr. Yiping Han: My lab has been working to understand the pathogenesis mechanism of Fusobacterium nucleatum for nearly 10 years. Our work encompasses basic science work on host-pathogen interactions, animal studies, to translational studies in humans. With regard to preterm birth and stillbirth, we first established a pregnant mouse model and showed that when oral F. nucleatum was injected into the bloodstream of the pregnant mice, it colonizes and proliferates in the placenta and causes localized, rather than systemic, infection and inflammation confined within the feto-placental unit leading to fetal death. This was a rather significant finding, because it showed that oral bacteria can translocate to the pregnant uterus through hematogenous transmission. As we know, transient bacteremia occurs during periodontal infections and treatments. This study indicates that transient bacteremia, if not controlled well, may have detrimental consequences. The recent case of the California mother who delivered a stillborn child provides the first direct human evidence in support of this hypothesis. The human case corroborated very well with what we observed in mice in terms of the likely duration of infection, pattern of infection, and birth outcome.

DentistryIQ: How did you come across the case initially?

Dr. Han: The patient’s friend contacted me via e-mail shortly after the stillbirth occurred. I have been contacted by patients or obstetricians regarding stillbirths or miscarriages caused by F. nucleatum both before and after this case. Unfortunately, in most cases, either the incidence occurred a while ago, thus no samples were saved for analysis, or it happened in a different country, which made sample collection difficult. I really want to thank this California patient and our wonderful team because had it not been for the patient’s prompt contact of me and total cooperation from her and everyone else, this study would not have been possible.