Inflammatory mediators linking periodontal disease and gestational diabetes mellitus: biological plausibility and clinical implications

Periodontal disease is a chronic inflammatory condition that may contribute to systemic inflammatory burden, while gestational diabetes mellitus (GDM) is a pregnancy-specific metabolic disorder characterised by insulin resistance and low-grade inflammation. Evidence from predominantly observational studies suggests an association between periodontal disease and GDM, supported by overlapping inflammatory pathways; however, causality remains unestablished and may be influenced by shared risk factors such as obesity and baseline metabolic inflammation. This narrative review synthesises current evidence on inflammatory mediators reported in both periodontal disease and GDM, including tumour necrosis factor-α (TNF-α), interleukins (IL-1β, IL-6, IL-8), C-reactive protein (CRP), and matrix metalloproteinases (MMP-8 and MMP-9). These mediators are discussed in the context of shared inflammatory mechanisms that may link periodontal disease with metabolic dysregulation during pregnancy. Available evidence is examined in light of important limitations, including non-specificity of inflammatory mediators, heterogeneity in periodontal and GDM case definitions, confounding by pregnancy-related inflammation, and variability in study design. Elucidating shared inflammatory pathways between periodontal disease and GDM may improve mechanistic understanding of their association and inform the design of future longitudinal and interventional studies, supporting more integrated oral–systemic perspectives in maternal health research.