Oral colonization of Gram-negative anaerobes as a risk factor for preterm delivery

BACKGROUND: Preterm birth significantly impacts on neonatal morbidity and mortality and is apparently increasing world-wide. Several studies have attempted to define a causative role for periodontal disease in adverse pregnancy outcomes but few have focused on the microbiology of periodontal disease in relation to these outcomes. RESULTS: The evidence for a positive correlation is strong, supported by microbiological and immunological findings. Conflicting results are often associated with uncontrolled confounding factors. MATERIALS AND METHODS: A literature search was conducted in order to establish whether or not a role exists for oral Gram-negative bacteria in adverse pregnancy outcomes. Association and intervention studies are summarized along with pathogenic potential of the Gram-negative bacteria most frequently implicated in periodontal disease.