Periodontitis Induced Changes in the Gut Microbiome and Pregnancy Outcomes

Objectives: The effect of periodontitis on adverse birth outcomes is equivocal and few studies have examined potential changes to the gut microbiome potentially caused by an increase in Gram negative oral pathogens.
Aim. To determine whether induced periodontitis in pregnant mice leads to changes in the gut microbiome that may result in adverse pregnancy outcomes.


Methods: Periodontitis was induced in pregnant mice using an inoculum of Fusobacterium nucleatum and Porphyromonas gingivalis. At day 18 of gestation, pregnancy outcomes were recorded and the presence of F. nucleatum and P. gingivalis was assessed by PCR, inflammatory mediators were assessed by multiplex analysis and alveolar bone loss was assessed using micro-CT. Sections from both the jejunum and colon were with stained with H&E to assess inflammation.
Genomic DNA from caecum contents and faeces were extracted and amplicon metagenomics targeting the V4 region of the 16S rRNA was performed on the Illumina MiSeq platform.


Results: Induction of periodontitis was confirmed by an increased distance between the cemento-enamel junction and alveolar bone crest. Both foetuses and placentas from mothers with induced periodontitis were significantly heavier compared to controls.
Microbial composition analysis revealed that both induction of periodontitis and pregnancy status alter the gut microbiota. Periodontitis in pregnant mice was associated with a significant change in the proportions of 21 genera compared to controls.
Increased levels of inflammation of the jejunum and colon were also observed in the periodontitis groups irrespective of pregnancy.

Conclusions: The gut microbiome was significantly altered at both the phylum and genus levels following induction of periodontitis and was associated with a significant increased inflammation of the gastrointestinal tract. This study also found significant changes in pregnancy outcomes after the induction of periodontal disease in mice.