The effectiveness of mother-to-child block of CHB in pregnant women in the middle and later stages of pregnancy has been recognized by the guidelines. TAF, as a newly marketed antiviral drug, has not been conclusively concluded in terms of its efficacy and postpartum safety in preventing mother-to-child transmission in pregnant women.Our purpose is to explore the TAF for CHB the curative effect of pregnant and postnatal security.

After diagnosis at the infection clinic of the Third Affiliated Hospital of Sun Yat-sen University, the eligible patients were enrolled into the group.Each person will sign the informed consent prior to enrollment.

Inclusion Criteria:

• 25 pregnant women with HBeAg (+), HBV DNA ≥ 2*10^6IU/mL who met the diagnostic criteria in the guidelines for the prevention and treatment of chronic hepatitis B were pregnant women at 24-28 weeks of pregnancy.
• 25 non-pregnant women with HBeAg (+), HBV DNA ≥ 2*10^6IU/mL who met the diagnostic criteria in the guidelines for the prevention and treatment of chronic hepatitis B.
• The enrolled patients were all newly admitted patients without treatment, and if they did not meet the standard after completing the relevant examination, they would be removed.

Exclusion Criteria:

• Coinfection with HAV, HCV, HDV, HEV or HIV;
• A history of antiviral therapy or concurrent treatment with immunoregulatory drugs, antitumor drugs, cytotoxic drugs or immunosuppressive steroids;
• Three-dimensional ultrasonography showed fetal malformation;
• The spouse is infected with HBV;
• History of decompensated liver disease (e.g., decompensated liver disease with coagulation disorders, hyperbilirubinemia, hepatic encephalopathy, hypoalbuminemia, ascites and esophageal varicose bleeding), history of liver cancer or other chronic liver disease (e.g., autoimmune hepatitis) or clinical symptoms;
• History of immune diseases;
• A history of serious cardiovascular disease;
• Other reasons the researchers considered it inappropriate to participate in the trial.