Comparison of TAF and TDF in Preventing Mother-to-Child Transmission of HBV in Pregnancies With High Viral Loads

Inclusion criteria

• Pregnant women aged between 20 and 40 years old
• Pregnancy duration between 20 to 28 weeks (screening for eligible patients can start from the 20th week of gestation)
• Clinically diagnosed with compensated chronic hepatitis B, HBsAg positive for more than 6 months, with clinical history, signs, and test results consistent with compensated chronic hepatitis B
• HBsAg and HBeAg positive in maternal serum during screening
• PCR testing shows maternal serum HBV DNA levels exceeding 200,000 IU/mL
• Subjects voluntarily agree to undergo treatment according to the study design's drug treatment plan and all other research requirements, and patients consent to strictly avoid pregnancy within 28 weeks postpartum
• Patients and their husbands (the biological parents of the child) understand the risks and voluntarily participate in the study. The mother must participate voluntarily and sign a written informed consent document before participating in the study.

Exclusion criteria

• Creatinine clearance \< 100 mL/min (calculated using the Cockcroft-Gault method based on serum creatinine and ideal body weight), or hypophosphatemia (below normal range).
• History of adverse renal reactions induced by Adefovir or history of Adefovir resistance.
• Meeting one of the following criteria: hemoglobin \< 80 g/L, neutrophil count \< 1000/μL, ALT \> 5 times the upper limit of normal, total bilirubin \> 20 mg/L, albumin \< 25 g/L, abnormal levels of creatinine or urea nitrogen.
• Pregnant women with a history of miscarriage, history of giving birth to a child with congenital malformations, or history of fetal infection with hepatitis B virus.
• The biological father of the current pregnancy has chronic hepatitis B.
• The investigator assesses that the subject has significant kidney, cardiovascular, pulmonary, or neurological diseases that affect their participation in the study.