Periodontal diseases and adverse pregnancy outcomes

From last decade of the 20th century, numerous epidemiological studies and intervention trials have attempted to prove the relationships between maternal periodontal diseases and adverse pregnancy outcomes (APO). Periodontal diseases are considered a risk factor for APO, including preterm birth, fetal growth restriction, low birthweight, pre-eclampsia and gestational diabetes. However, the efficacy of periodontal treatment during pregnancy is controversial. Two pathogenic mechanisms might explain the potential effect of periodontal diseases on pregnancy outcomes. First, periodontal bacteria originating in the gingival biofilm directly affect the feto-placental unit subsequent to bacteremia. Second, inflammatory mediators secreted by the subgingival inflammatory site are carried to the feto-placental unit, where they then cause an inflammatory response. To elucidate these mechanisms, many researchers have been investigating the use of experimental animal models and in vitro models. In the present review, we summarize the current literature on the relationship between periodontal diseases and APO from epidemiological studies, animal models studies and in vitro studies, and speculate on the possible mechanism of periodontal diseases affecting pregnancy outcomes.