The CMA-A2, based on SVM models, a combination of 12 genes, namely, C10orf142, STX6, CORO1C, RCOR3, ITGB7, DUSP6, GSE1, RAB8A, KLC3, UBE2M, MCAT, and GLE1, was the optimal gene combination to predict macrosomia, with the best performance and the highest prediction accuracy in 84.26% of the studied population (AUC, 0.8298, 95% CI: 0.7675–0.8921). This evidence concerns the gene STX6 and Large for gestational age.