Association of third-trimester maternal lipid levels with adverse pregnancy outcomes in women with gestational diabetes mellitus: a retrospective single-center study using intrapartum data

Objectives This study investigates the relationships between maternal factors and gestational diabetes mellitus (GDM), as well as third‑trimester maternal lipids and adverse pregnancy outcomes among GDM patients.Methods This study enrolled 3,973 pregnant women, divided into a control group (n = 3166) and a GDM group (n = 807). The GDM group was further divided into well-controlled (n = 152) and poorly controlled subgroups (n = 655). Univariate and multivariate logistic regression analyses were performed to evaluate factors associated with GDM risk. Baseline clinical/laboratory characteristics were compared across groups via parametric, nonparametric, and chi‑square tests to assess associations of third‑trimester maternal lipid levels with adverse pregnancy outcomes. Receiver operating characteristic analyses evaluated the predictive values of body mass index (BMI) and third‑trimester maternal lipid levels.Results Age (OR = 1.069, 95% CI:1.050–1.087, p < .001), overweight (OR = 1.678 95% CI:1.396–2.013, p < .001), and obesity (OR = 2.018, 95% CI:1.511–2.677, p < .001) are key risk factors for GDM. Significant differences existed in age (p = .001), BMI (p < .001), fasting blood glucose (FBG, p < .001) and 2-hour postprandial plasma glucose (2hPPG, p = .001) across subgroups, as well as triglycerides (TG, p < .001), high-density lipoprotein cholesterol (HDL-C, p = .001), and free fatty acids (FFAs, p < .001) among the three groups. Subgroup analysis by lipid levels showed TG predominantly affected delivery mode (p = .031), neonatal birth weight (p = .005), and quantitative blood loss (QBL, p = .019) in GDM, while HDL-C mainly influenced fetal growth curve (p = .004) and neonatal birth weight (p = .002). Subgroup analysis by triglyceride-glucose index (TyG index) revealed significant differences in glycemic control (p = .002), delivery mode (p = .002), neonatal weight (p = .005), and QBL (p = .005). The area under the curve of pre-pregnancy BMI for GDM complicated by hypertensive disorders of pregnancy was 0.738, third-trimester BMI 0.720, and 0.709 for macrosomia prediction in non-advanced-age women with GDM.Conclusion Age, overweight, and obesity are independent risk factors for GDM. Among women with GDM, third-trimester lipid levels are associated with adverse pregnancy outcomes. Therefore, lipid levels should be considered in GDM clinical management, rather than focusing exclusively on glycemic control.