Salivary biomarkers in hyperglycemia in pregnancy: a scoping review

Timely detection and low-burden assessment of hyperglycemia in pregnancy (HIP), particularly gestational diabetes mellitus (GDM), are clinically important. Saliva permits non-invasive repeated sampling, but the scope, consistency, and translational potential of salivary biomarkers in HIP remain unclear. This scoping review mapped the available comparative evidence, characterized the principal biomarker domains and reported discriminatory performance, and identified priorities for further validation. This scoping review was conducted in accordance with the JBI methodology and reported in accordance with PRISMA-ScR. Eight databases were searched in September 2026 for English- or Chinese-language studies published through August 31, 2026. Original comparative studies reporting biomarkers in directly collected saliva from women with HIP and normoglycemic pregnant women were eligible. Two reviewers independently screened records and charted data. Critical appraisal was performed using design-specific JBI tools. Thirty-one reports from nine countries were included; several arose from the same or potentially overlapping study populations, and most used cross-sectional or case–control designs and focused on GDM. Both studies of salivary glucose found higher postprandial or post-load values in GDM and positive blood–saliva correlations; one reported an AUC of 0.865 (95% CI 0.765–0.966) for 2-h postprandial unstimulated saliva. Oxidative stress findings highlighted MDA as a candidate, although results were not uniform; one study reported an AUC of 0.812 (95% CI 0.694–0.929). Selected adipokines showed study-specific discriminatory performance, with AUCs of 0.705 (95% CI 0.574–0.836) for visfatin and 0.641 (95% CI 0.520–0.761) for resistin. Inflammatory findings varied with periodontal context. Microbiome reports identified taxon-specific differences; one study internally validated saliva-only classification models, while another examined early-pregnancy microbial patterns in a separate cohort. Methodological heterogeneity, limited control of confounding, and the absence of external validation for reported diagnostic-performance estimates constrained interpretation. Findings for salivary glucose, MDA, and selected adipokines support further investigation in HIP, particularly GDM, but their diagnostic utility remains unestablished. Reported discriminatory performance is study-specific and requires confirmation through prospective studies with standardized collection and assay methods, appropriate consideration of periodontal status, and validation in independent cohorts. Not applicable.