Triglyceride-glycaemic index: Insights into predicting fetal macrosomia and its interaction with gestational diabetes mellitus: A cohort study of Chinese pregnant women

Objective: This study investigates the association between a new insulin resistance indicator, the triglyceride-glucose (TyG) index, and the risk of macrosomia. Design: This is a prospective cohort study. Methods: This study included 1332 women who delivered at Peking University International Hospital between October 2017 and August 2019. Participants were divided equally into three groups based on the TyG index. Logistic regression and restricted cubic spline (RCS) analyses were used to evaluate the relationship between the TyG index and macrosomia and conducted subgroup analyses. The TyG index's ability to predict macrosomia was assessed using the receiver operating characteristic (ROC) curve. Results: Multivariable logistic regression analysis revealed that the TyG index is an independent risk factor for macrosomia (Odds ratio [OR] 1.84, 95% confidence interval [CI] 1.02-3.30, p < .05). RCS analysis indicates that the risk of macrosomia increases with the rise of the TyG index (p for nonlinearity <.001) when the TyG index is >6.53. Subgroup analysis showed a synergistic additive interaction between the TyG index and gestational diabetes mellitus (GDM) of macrosomia. The area under the ROC curve for the predictive model was 0.733 (95% CI 0.684, 0.781), with a sensitivity of 76.4% and specificity of 66.9%. Incorporating the TyG index alongside traditional risk factors notably enhances macrosomia prediction (p < .05). Conclusions: The TyG index independently predicts macrosomia, and exhibits an additive interaction with GDM in its occurrence. Integrating the TyG index with traditional risk factors improves the prediction of macrosomia.