Objective This study aimed to systematically evaluate the association between the Metabolic Score for Insulin Resistance (METS-IR) and the risk of gestational diabetes mellitus (GDM). Methods A systematic search was conducted in PubMed, Embase, Web of Science, and the Cochrane Library up to March 2026. Two independent reviewers completed study screening, data extraction, and quality assessment. Cohort studies were evaluated with the Newcastle-Ottawa Scale, and cross-sectional studies were assessed with the Agency for Healthcare Research and Quality checklist. Meta-analyses were performed using Stata 16.0 and Review Manager 5.4.1. Heterogeneity was examined using the Cochrane Q-test and I 2 statistic, and a random-effects model was used to pool effect sizes. Subgroup analyses stratified by country, study design, and sample size were conducted to explore sources of heterogeneity. Sensitivity analysis was used to validate the robustness of pooled estimates, and publication bias was assessed using funnel plots and Egger’s test. Results A total of 6 studies involving 93,995 pregnant women were included. The overall pooled odds ratio (OR) for GDM risk in the highest versus lowest METS-IR category was 2.53 (95% CI: 2.14–3.00, I 2 = 57%, p 0.001). Subgroup analyses showed: Chinese populations had a significant positive association (OR = 2.58, 95% CI: 2.19–3.03, I 2 = 61%, p 0.001), while the association in American populations was marginally non-significant (OR = 2.80, 95% CI: 0.94–8.31, I 2 = 71%, p = 0.06); Prospective cohorts (OR = 2.13, 95% CI: 1.27–3.59, I 2 = 83%, p = 0.004) and retrospective cohorts (OR = 2.75, 95% CI: 2.31–3.28, I 2 = 23%, p 0.001) both showed significant positive associations, with no significant between-subgroup differences ( p = 0.66); Large-sample studies (≥5,000 participants) had a stable, significant association (OR = 2.63, 95% CI: 2.41–2.88, I 2 = 12%, p 0.001), while small-sample studies (5,000 participants) also showed a significant association (OR = 2.78, 95% CI: 1.41–5.47, I 2 = 78%, p = 0.003). Sensitivity analyses confirmed the stability of the pooled results, and no significant publication bias was detected. Conclusion Elevated METS-IR is significantly associated with increased GDM risk. As a noninvasive and cost-effective insulin resistance marker, METS-IR may serve as a reliable early predictor for GDM and support early screening in high-risk pregnant women. Further large-scale, multi-ethnic prospective studies are needed to validate these findings. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420261355910 , CRD420261355910.
Dai et al. (Thu,) studied this question.