Does pregnancy have an impact on the subgingival microbiota?

Objective: The prevalence of pre-term birth is increasing. Periodontitis has been associated with a higher risk for pre-term birth. We investigated the clinical and subgingival microbiological changes during pregnancy. Methods: Consecutive consenting pregnant women, 18 years of age or older, were enrolled. Subgingival and tongue bacterial samples were collected at the 12th, 28th, 36th week of pregnancy and at 4 - 6 weeks post-partum. Bacterial samples were processed by the checkerboard DNA-DNA hybridization method assaying 40 species. Clinical periodontal data were collected at the 12th week and at the post-partum examination.

Results: A total of 22 consecutive cases were enrolled. The mean % of BOP at week 12 and post-partum was 40.1% (S.D. ± 18.2) and 27.4% (S.D. ± 12.5) respectively. At the post-partum examination 15 subjects (68.2%) presented with evidence of having periodontitis. A reduction over the study period among 17/40 species was found at the p<0.001 level for: Staphylococcus aureus, Streptococcus intermedius, Streptococcus oralis, Streptococcus sanguinis, Streptococcus mutans, Streptococcus anginosus, Capnocytophaga ochracea, Capnocytophaga sputigena, Fusobacterium nucleatum polymorphum, Fusobacterium nucleatum naviforme, Parvimonas micra, Prevotella intermedia, Eubacterium saburreum, Leptotrichia buccalis, Neisseria mucosa, Prevotella melaninogenica and Selenomonas noxia. Over the study period, no significant changes were found for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. Conclusions: A natural decrease in gingival inflammation and a reduction of 17/40 species occurred during pregnancy. This change did not occur for all bacteria such as Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola.