Differential prevalence of periodontal pathogens in pregnant women with gestational diabetes mellitus and periodontitis: A cross-sectional microbiological study

Background Gestational diabetes mellitus (GDM), characterized by pregnancy-induced insulin resistance, and periodontal disease, a chronic inflammatory condition of the periodontium, are intricately linked and may collectively amplify the risk of adverse maternal and fetal outcomes. This study aimed to evaluate periodontal microbial associations in periodontitis in relation to GDM. Methods An observational cross-sectional study was conducted among 80 pregnant women with periodontitis, stratified into GDM (Group A; n = 40) and non-GDM (Group B; n = 40) groups. Clinical parameters, including Plaque Index, Oral Hygiene Index–Simplified, Modified Sulcular Bleeding Index, and Probing Pocket Depth (PPD), along with glycemic parameters (OGTT), were recorded. Subgingival plaque samples were analyzed using real-time Polymerase Chain Reaction for key periodontal pathogens ( Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Selenomonas sputigena, Treponema denticola, and Tannerella forsythia ). Pearson correlation analysis assessed associations between clinical and glycemic parameters and pathogens, followed by multiple linear regression to determine the independent effects of predictors on the outcomes ( p < 0.05). Results Group A demonstrated significantly lower Ct values (higher bacterial load) for P. gingivalis , S. sputigena, P. nigrescens, T. denticola, and F. nucleatum (p ≤ 0.005). Strong positive correlations in the overall population were observed between P. gingivalis and probing pocket depth (r = 0.79, p = 0.001) and clinical attachment loss (r = 0.73, p = 0.010), followed by S. sputigena (r = 0.64, p = 0.01). Multiple regression analysis identified MSBI, PPD, and CAL as significant predictors of P. intermedia and P. gingivalis in both groups ( p < 0.05), with OGTT-1h emerging as an additional predictor of P. gingivalis . In contrast, F. nucleatum and S. sputigena demonstrated significant inverse associations with these parameters ( p < 0.05). Conclusion The results of the present study demonstrate that GDM is associated with an increased periodontal pathogenic burden, with clinical and glycemic parameters emerging as significant independent determinants, highlighting the intricate interplay between metabolic dysregulation and periodontal disease.