Association between triglyceride-glucose index (TyG) as a surrogate marker of insulin resistance and risk of gestational diabetes mellitus (GDM): updated systematic review and meta-analysis.

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title: "First-Trimester TyG Index and Gestational Diabetes Risk: A Meta-Analysis"

description: "A systematic review and meta-analysis of 14 cohorts links an elevated first-trimester triglyceride-glucose index to higher odds of later gestational diabetes, but diagnostic accuracy is only moderate."

study: "Association between triglyceride-glucose index (TyG) as a surrogate marker of insulin resistance and risk of gestational diabetes mellitus (GDM): updated systematic review and meta-analysis"

pubmed: "42924394"

evidenceTier: "B"

TL;DR

A first-trimester triglyceride-glucose (TyG) index above typical levels was associated with roughly 2.35 times higher odds of developing gestational diabetes mellitus (GDM) in a pooled analysis of observational cohorts . The index shows only moderate accuracy as a screening test, so it is best understood as a possible risk-stratification signal rather than a diagnostic tool.

What the study found

Gestational diabetes mellitus is a form of glucose intolerance first recognized during pregnancy. Because insulin resistance rises across pregnancy, researchers have looked for simple, inexpensive markers that could flag women at higher risk early. The TyG index, calculated from fasting triglyceride and glucose levels, is one such surrogate marker of insulin resistance that is already used in non-pregnant populations.

This systematic review and meta-analysis, registered in PROSPERO (CRD420251125511), searched six databases from inception through August 12, 2025. The authors included 14 observational cohorts covering 462,233 pregnant women, of whom 30,875 (about 7%) developed GDM. Twelve studies contributed adjusted association estimates, which were pooled using random-effects models with REML estimation and Hartung-Knapp adjustment.

The central finding was that elevated first-trimester TyG was associated with higher odds of GDM, with a pooled odds ratio of 2.35 (95% CI 1.88 to 2.94). Heterogeneity across studies was high (I² = 92%). When the authors excluded influential studies, the estimate barely changed (OR 2.36, 95% CI 1.91 to 2.90) and heterogeneity fell substantially (I² = 30.6%). The association was also reported as consistent in Asian populations and in studies rated at low risk of bias, though the authors note that non-Asian evidence is limited.

Diagnostic performance was moderate. The pooled sensitivity was 0.62 (95% CI 0.54 to 0.69), specificity was 0.64 (95% CI 0.60 to 0.69), and the area under the curve was 0.67. An AUC in this range means the index discriminates better than chance but misclassifies a substantial share of women in both directions. The authors conclude that the TyG index may support early risk stratification but should not be used as a standalone screening test.

Several limitations temper these results. All included studies were observational, so the findings describe association rather than causation. The TyG thresholds used across studies varied, which complicates clinical translation. The authors also flag that the evidence base is weighted toward Asian cohorts. Taken together, the findings are a reasonable basis for further research and for considering TyG alongside established risk factors, but they do not establish a clinical screening standard. Current evidence for GDM screening remains based on established glucose testing protocols.

What this means for you

Study details

Sources

1. Association between triglyceride-glucose index (TyG) as a surrogate marker of insulin resistance and risk of gestational diabetes mellitus (GDM): updated systematic review and meta-analysis. *Revista Brasileira de Ginecologia e Obstetrícia*. PubMed. https://pubmed.ncbi.nlm.nih.gov/42924394/

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