Prenatal prevention: General measures: 1. pre-birth assessment; 2. protection of the integrity of the placental barrier: avoid abdominal collision and extrusion during pregnancy and avoid invasive operations such as amniocentesis; 3. avoid overdue pregnancy, the prolongation of gestational age at delivery increases the risk of failure of intrauterine blockade with high-valent hepatitis B immunoglobulin (HBIG); 4. cesarean section should be performed as soon as possible after the occurrence of preterm labor. Passive immunization: HBIG injection activates the complement system, enhances humoral immunity, and reduces the amount of virus. Its effectiveness in blocking mother-to-child transmission has been reported differently; most believe that the effect is clear, but whether it is routinely applied has not yet reached a consensus and is controversial. This regimen is now generally considered largely ineffective and has been abandoned in recent years in China. Antiviral therapy: High viral load is a major risk factor for failure of mother-to-child blockade of hepatitis B. As a complementary blockade to passive immunization of pregnant women and active-passive immunization of newborns at birth, nucleoside antivirals have received attention in recent years in an effort to reduce the incidence of intrauterine transmission. The findings of domestic and international studies on the use of lamivudine, telbivudine and tenofovir antiviral blockade of mother-to-child transmission in pregnant women with hepatitis B are optimistic. The 2009 European Academy of Liver Diseases (EASL) guidelines affirm the safety of nucleoside analogues such as lamivudine and telbivudine in pregnancy and the use of lamivudine, telbivudine, and tenofovir in class B drugs in pregnancy with hepatitis B exacerbations or high viral load [4] to block mother-to-child transmission, and there is a consensus in the Chinese guidelines for the prevention and treatment of chronic hepatitis B (2010). Entecavir and adefovir are classified as category C for embryonic and fetal toxicity confirmed in animal studies and are usually not used; interferon should be contraindicated during pregnancy due to its anti-proliferative effect. Duration of antiviral therapy: For patients with cirrhosis, antiviral therapy should be started before pregnancy (i.e., full treatment) and should be continued throughout pregnancy and for a longer period after delivery. For non-cirrhotic patients, antiviral therapy should be started at 32 or 34 weeks of gestation (i.e. late pregnancy) and continued until delivery, or until 4 weeks after delivery, depending on the condition. (Please consult your physician for specific medications.) Intrapartum prevention: Measures to reduce intrapartum transmission include: reducing neonatal birth injuries and amniotic fluid aspiration, shortening the duration of labor, and strict aseptic practice. The impact of mode of delivery on mother-to-child transmission is inconclusive, and there is a tendency to promote vaginal delivery. Most existing studies have concluded that cesarean delivery is not an effective measure to interrupt mother-to-child transmission of HBV. It has also been reported that cesarean delivery before contractions may reduce the rate of infection, but there is no expert consensus. Postnatal prophylaxis: Active and passive immunization of newborns, which is currently adopted mainly to minimize perinatal infection and lactation, is the most effective way to prevent hepatitis B infection. A consensus has been formed in China. For newborns of HBsAg-positive mothers, HBIG should be injected as early as possible within 6h after birth (the dose should be ≥100 IU, and the earlier the better is generally required, 0 hours is better), and hepatitis B vaccine should be administered sequentially at different sites at the same time, which can significantly improve the effect of interrupting mother-to-child transmission. Summary: The mechanism of mother-to-child transmission of hepatitis B is not yet fully understood. The current consensus on prevention and treatment measures is that the newborn of each HBsAg-positive mother should receive combined active-passive immunization as soon as possible after birth, and pregnant women who are double positive for HBsAg and HBeAg or have a high HBVDNA load (≥1×106IU/ml) can receive antiviral treatment with tipifudin and tenofovir in the last 3 months of pregnancy to improve the interruption rate by nearly 97%. Antiviral therapy in the second trimester is also recommended for mothers with positive virus but less than 106u/ml. There is no consensus on whether to administer HBIG passive immunization during pregnancy, including the need for blockade therapy between father and infant, and it is generally not recommended.