Even though the biological mechanism involved behind the association between periodontitis and GDM remain to be elucidated, the release of inflammatory mediators [including, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and C-reactive protein (CRP)] from inflamed periodontal tissues that are known to interfere with glucose metabolism by inducing insulin resistance, has biological plausibility [19, 20]. This evidence concerns the gene TNF and periodontitis.