Logistic regression analysis demonstrated that decreased LDL-C levels were associated with an elevated risk of GDM when the high-LDL-C subgroup was used as a reference, with pre-pregnancy BMI, gestational age at sampling, maternal age, fasting insulin, fasting glucose, and HOMA-IR as covariates (OR = 1.372, 95% CI: 1.050–1.794, P = 0.021 for the medium-LDL-C subgroup; OR = 1.672, 95% CI: 1.219–2.294, P = 0.001 for the low-LDL-C subgroup). This evidence concerns the gene INS and gestational diabetes.