Inclusion Criteria:
* Between the ages of 20 and 40
* HBsAg positive for \>= 6 months
* 0-24 week of pregnancy
* Meets the indications for antiviral therapy in the 2022 version of the guidelines for the prevention and treatment of chronic hepatitis B
* It is planned to use TAF or TDF antiviral therapy until the end of delivery or long-term administration, and follow-up will be carried out in this research institution
* Signed informed consent for medication
Exclusion Criteria:
* Previous use of anti-hepatitis B virus drugs (e.g., entecavir, tenofovir, tenofovir alafenol, emintenofovir, adefovir dipoproxil, telbivudine, etc.)
* Concomitant viral hepatitis A, C, E or other hepatotropic virus infection or AIDS
* Concomitant cirrhosis, liver cancer or other chronic liver diseases (e.g., alcoholic liver, autoimmune liver disease, G6PD deficiency, etc.)
* Patients with heart (such as coronary heart disease, myocardial infarction, heart failure, etc.), lung (such as: lung cancer, chronic obstructive pulmonary disease, tuberculosis, etc.), kidney (such as: renal failure, elevated creatinine, nephritis, nephrotic syndrome, etc.) and other important organ diseases
* Chronic diseases such as autoimmune diseases (such as systemic lupus erythematosus, rheumatoid arthritis, anticoagulant antibody syndrome), hypertension, diabetes, thyroid disease, etc
* Patients with previous pregnancy complications (such as: gestational hypertension, gestational diabetes, gestational eclampsia, etc.)
* Those who have had fetal or neonatal growth and development defects in previous pregnancies
* Previous or ongoing use of nephrotoxic medications, glucocorticoids, nonsteroidal anti-inflammatory drugs, cytotoxic drugs, or immunomodulators
* Premedication ultrasound showed fetal malformations, fetal development abnormalities, placental abnormalities, threatened abortion, etc
