Vertical mother-to-child transmission is the main mode of transmission of hepatitis B virus (HBV) infection in China. Mother-to-child transmission of HBV includes 3 levels: in utero infection, infection during delivery, and postpartum close contact infection. High viral (HBV-DNA) load and maternal preterm delivery during pregnancy are risk factors for in utero infection. The rate of vertical mother-to-child transmission is greatly reduced by the current use of standard high-valent hepatitis B immunoglobulin combined with hepatitis B vaccine immunization for newborns, but some data show that maternal serum HBV-DNA >108copies/ml, and the rate of mother-to-child transmission is still as high as 8.5% even with standard combined immunoprophylaxis for newborns after birth. Therefore, antiviral therapy during pregnancy is particularly critical. Here is a brief overview of how to select antiviral therapy for women of childbearing age with chronic hepatitis B virus infection. I. Current HBV drug options available for pregnant women: The U.S. Food and Drug Administration (FDA) recognizes telbivudine and tenofovir as class B anti-HBV drugs for pregnancy. Given the increasing safety data on lamivudine in anti-HIV (HIV) and hepatitis B virus (HBV) clinical applications, the National Institutes of Health (NIH) currently upgrades lamivudine to a class B drug for pregnancy The NIH has upgraded lamivudine to a pregnancy class B drug, i.e., pregnancy class B drugs are lamivudine, telbivudine, and tenofovir. Second, the treatment principles of chronic hepatitis B patients of childbearing age: patients of childbearing age with chronic hepatitis B who plan to become pregnant should complete antiviral therapy before pregnancy as far as possible; for patients who become pregnant unexpectedly during antiviral therapy, the decision can be made according to the severity of liver disease whether to discontinue or apply lamivudine, tenbivudine or tenofovir therapy throughout pregnancy; chronic HBV carriers with high viral load should apply lamivudine, tenbivudine, tenofovir at the end of pregnancy The use of lamivudine, tenbivudine, tenofovir antiviral therapy at the end of pregnancy is still controversial. 1, antiviral therapy before pregnancy: HBV-infected patients of childbearing age should try to get pregnant as early as possible if their condition allows, delaying antiviral therapy until after pregnancy, optimizing the choice of interferon or any of the nucleoside (acid) analogues. The course of interferon is relatively exact compared to nucleoside (acid) analogs, so suitable patients may prefer interferon, but it has anti-proliferative effects and pregnancy must be considered 6 months after discontinuation of the drug. 2, antiviral therapy in the course of antiviral therapy for patients with unintended pregnancy: antiviral therapy in the course of unintended pregnancy of HBV-infected patients, for patients with mild hepatitis, serious rebound or less risk of disease progression, can consider temporary discontinuation of drugs, the whole pregnancy to monitor HBV-DNA and liver function levels, the third stage of pregnancy and then decide whether antiviral therapy according to the specific circumstances; for patients with heavy disease, prone to Patients with severe disease and prone to serious rebound should not easily discontinue the drug, and in the case of unintended pregnancy during interferon therapy, the pregnancy should be terminated immediately. For patients treated with entecavir and adefovir, if the pregnancy is unintended, the need to terminate the pregnancy can be determined according to the preciousness of the fetus: if it is a precious child (advanced maternal age, those who are not easily conceived), continue treatment after replacing the drug with lamivudine or tebivudine on the basis of adequate information with the patient. If a patient treated with lamivudine, telbivudine or tenofovir has an unplanned pregnancy, the original antiviral treatment can be applied throughout the pregnancy on the basis of full information with the patient. 3, antiviral treatment for HBV infected patients found during pregnancy: HBsAg positive patients found during pregnancy, first assess the severity of liver disease, if the course of the disease is chronic hepatitis B, liver function and HBV-DNA should be tested every 3 months during pregnancy. if there is a 4-fold or more elevation of ghrelin, consider antiviral treatment, if there is no significant change, continue to observe until the end of pregnancy, and after the birth of the fetus give the standard combination of Immunization. 4, antiviral therapy for high viral load carriers at the end of pregnancy: the application of antiviral drugs to reduce maternal high HBV-DNA load in chronic HBV carriers at the end of pregnancy can reduce HBV intrauterine infection, but the evidence of treatment benefits and risks is far from adequate, and some scholars currently recommend the application of lamivudine, telbivudine, tenofovir therapy starting at 32 weeks of gestation. 5. Antiviral therapy after the end of pregnancy: HBV-DNA levels should continue to be monitored after the end of pregnancy, and the decision to continue oral antiviral therapy should be made on a case-by-case basis. If the mother is not on antiviral therapy, regardless of whether the mother is HBeAg positive or negative, the newborn can receive breastfeeding as long as he or she receives standard co-immunization within 12 hours of birth. However, if the mother is on antiviral therapy, the decision to breastfeed needs to be made with caution, as the safety of these drugs for the newborn during lactation exposure has not been proven.