TDF was more effective than the placebo in reducing vertical transmission in HBeAg-positive chronic hepatitis B (CHB) pregnancies with high serum HBV-DNA levels (OR = 0.21, 95% CI = 0.07–0.61) at 4–12 months, infant HBV DNA seropositivity at delivery (OR = 0.16, 95% CI = 0.07–0.37), and a severe flair in maternal alanine aminotransferase (ALT) levels (OR = 0.43, 95% CI = 0.19–0.95) during pregnancy. This evidence concerns the gene GPT and chronic hepatitis B virus infection.