Oral Microbiome Signatures and Salivary Biomarkers Associated with Gestational Diabetes Mellitus and Maternal–Fetal Outcomes: A Systematic Review
Ridwan Abdullah Putra, Wiku Andonotopo, Arief Setiawan, Aloysius Suryawan, Theresia Monica Rahardjo, Rizna Tyrani Rumanti, Roland Frederik Lengkey, Muhammad Adrianes BachnasBackground:
Gestational diabetes mellitus (GDM) is one of the most common metabolic complications of pregnancy and contributes significantly to maternal and fetal morbidity. Increasing evidence indicates that the oral cavity functions as a dynamic biological interface where microbial dysbiosis, inflammatory mediators, and metabolic alterations may reflect systemic changes associated with GDM. Oral microbiome signatures and salivary biomarkers have therefore emerged as promising noninvasive candidates for disease detection and monitoring.
Objective:
To systematically synthesize the available primary evidence evaluating oral microbiome signatures, salivary biomarkers, periodontal characteristics, and their associations with GDM and maternal–fetal outcomes.
Methods:
A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Comprehensive electronic searches were performed in PubMed/MEDLINE, Scopus, and Web of Science. Original observational and clinical studies investigating oral microbiome alterations, salivary biomarkers, periodontal parameters, or oral inflammatory markers in relation to GDM were included. Systematic reviews, meta-analyses, narrative reviews, expert reviews, and clinical guidelines were excluded from the formal qualitative synthesis to avoid duplication of primary evidence and were retained only for contextual interpretation. Methodological quality and risk of bias were assessed qualitatively.
Results:
Seventeen original primary studies fulfilled the predefined eligibility criteria. The included evidence consistently demonstrated alterations in oral microbial diversity and composition, increased salivary glucose concentrations, dysregulated adipokines, elevated inflammatory mediators, oxidative stress, and periodontal inflammatory changes among women with GDM. Several studies also suggested that maternal GDM influences neonatal oral microbial colonization. Despite methodological heterogeneity across study populations, biomarker platforms, and microbiome assessment techniques, the collective evidence supports an association between oral biological alterations and the metabolic and inflammatory disturbances accompanying GDM. However, the current evidence remains predominantly observational and does not establish causal relationships.
Conclusions:
The available primary evidence suggests that oral microbiome dysbiosis and salivary biomarkers are associated with GDM and adverse maternal–fetal outcomes, highlighting their potential as future noninvasive tools for early risk stratification and disease monitoring. Nevertheless, standardized biomarker assessment, multicenter prospective studies, mechanistic investigations, and external validation are required before these biomarkers can be incorporated into routine clinical practice.