Second-trimester triglyceride-glucose (TyG) indices that incorporate adiposity measures showed stronger performance than the conventional TyG index for identifying macrosomia risk in gestational diabetes mellitus (GDM). In a study published in Diabetes Metabolic Syndrome and Obesity, TyG-body mass index (TyG-BMI) and TyG-waist circumference (TyG-WC) provided better discrimination than TyG alone.

The analysis assessed TyG, TyG-BMI, TyG-WC, and TyG-waist-to-height ratio (TyG-WHtR) at 24 to 28 weeks of gestation. Binary logistic regression and restricted cubic spline analyses examined associations with macrosomia. Predictive performance was compared using receiver operating characteristic curves, integrated discrimination improvement (IDI), and net reclassification improvement (NRI). Subgroup analyses were also performed.

Women in the highest tertile had 3.458-fold higher risk of macrosomia for TyG-BMI and 3.718-fold higher risk for TyG-WC compared with the lowest tertile. Restricted cubic spline analyses showed dose-response relationships for all indices (all P for overall <0.001). Compared with TyG alone (AUC, 0.596), TyG-BMI (AUC, 0.682) and TyG-WC (AUC, 0.681) performed significantly better (P<0.01), with superiority also supported by significant IDI and NRI values (P<0.01).

Associations were more pronounced in primiparous women younger than 35 years. The findings suggest that TyG-BMI and TyG-WC may offer useful supplementary markers for macrosomia risk stratification in GDM.