Elevated ALT levels directly affect neonatal birth weight (β = 0.0291, 95% CI: 0.0100–0.0635), while GDM has an indirect effect (β = 0.0025, 95% CI: 0.0012–0.0056), with GDM accounting for 8.1% of the mediation effect. This evidence concerns the gene GPT and gestational diabetes.