Background: Reports show that more than 20 million infants world-wide are born prematurely with 95% of all pre-term births occurring in developing countries. Oral colonization of gram-negative anaerobes has been implicated as a risk factor for preterm delivery of low birth weight infants.
Materials and methods: This study comprised 200 women admitted to the department of obstetrics and gynecology of the teaching hospital of Butare in Rwanda. Gingival crevicular fluid was collected from each quadrant of the mother's mouth (using paper points) within 24 hours of delivery. A dichotomous score of presence or absence of gingival inflammation was recorded for each patient along with demographic data such as age, marital status etc. Samples were examined by PCR for the presence of Aggregatibacter actinomycetemcomitans and selected members of the red and orange complexes described by Socransky et al., (1998), and their presence associated with age, gingival inflammation and pregnancy outcomes.
Results: Association of bacterial species with the risk of periodontal disease and thus the risk of preterm delivery was only observed when they occurred in pairs or groups of three or more. Aa appeared to be a necessary co-factor for significant associations of bacterial groups with the variables recorded.