In the course of clinical work and online consultation, we often encounter many women with chronic HBV infection who have been or plan to be pregnant asking about how to prevent their babies from being infected with hepatitis B. In the past, there were many disagreements and doubts about the understanding of this issue, but with the accumulation of a large amount of evidence-based medicine, the understanding has gradually matured. The following is a description of several issues of concern. 1, the main ways of mother-to-child transmission There are three main (1) intrauterine infection: most often occurs in late pregnancy, due to the aging of the placenta is damaged, the virus in the mother’s blood breaks through the placental barrier into the fetal blood circulation. (2) Natal infection: during labor and delivery, the newborn is inevitably exposed to maternal blood or secretions containing HBV, which is also the most important way of mother-to-child transmission. (3) Contact infection: newborns are infected by close contact with patients after birth. 2, how to block mother-to-child transmission (1) Hepatitis B immune globulin and hepatitis B vaccine combined immunization blockade: from the initial simple vaccine blockade to the later globulin and vaccine combined blockade, the success rate of each report varies. At present, China’s chronic hepatitis B prevention and treatment guidelines have clear recommendations, the specific method is to inject hepatitis B immunoglobulin (HBIG) as early as possible within 24 hours after birth, preferably within 12 hours, the earlier the better, the dose of not less than 100 IU, and at the same time, inoculate different parts of the recombinant yeast with 10 micrograms of recombinant yeast or 20 micrograms of hepatitis B vaccine against the oocytes of the hamster family of Chinese hamster (babies are born 1 and 6 months after the rise of). It is also recommended that infants should be vaccinated again with Hepatitis B vaccine, or HBIG should be injected again one month after birth. This method mainly focuses on the newborns without considering the maternal factor, because some pregnant women are inactive HBsAg carriers and the level of HBVDNA in the mother’s blood is very low, so it creates such a high success rate of blockage. The results may be discounted if a refined classification is done based on maternal HBVDNA levels. (2) Antiviral therapy during pregnancy The 2009 guidelines of the European Society of Hepatology recommend oral lamivudine (LAV) for pregnant women at the end of pregnancy with HBsAg(+),HBVDNA ≥10 to the 7th power IU/ml, and combined immunization measures are still required after the birth of the infant. China’s 2010 hepatitis B prevention and treatment guidelines consensus pointed out that: ① When pregnant women with elevated ALT and positive HBVDNA should be treated with antiviral therapy as early as possible, with the aim of preventing hepatitis flare-ups and hepatic decompensation, and at the same time reducing vertical transmission from mother to child. ② Pregnant women who are in the immune tolerance period may not need antiviral treatment in principle. ③ Pregnant women who have failed the combined blockade in the first pregnancy should receive timely antiviral treatment when they are pregnant again. ④ Pregnant women with active hepatitis should start antiviral therapy after 3 months of pregnancy. ⑤ The drugs for antiviral therapy in pregnant women can be lamivudine, telbivudine or tenofovir. ⑥ Pregnant women with normal ALT and HBVDNA greater than 7 times 10 can take oral antiviral drugs in late pregnancy, which can reduce the chance of infection if the virus is suppressed. (vii) Mothers with HBVDNA less than the 8th power of 10 have a success rate of greater than 90% with combined immunoblockade. (3) Safety of breastfeeding The current accepted view is that breastfeeding is possible after standardized combined immunization. 3, the current remaining controversy ⑴ late pregnancy pregnant women need to inject hepatitis B immunoglobulin Currently most of the evidence comes from the country, but the domestic studies are not randomized controlled trials (RCTs), lack of sufficient persuasive power, the World Health Organization and China’s Ministry of Health have no such recommendations. The main question is whether such a small dose of HBIG is sufficient to neutralize the virus in pregnant women? Will it lead to the creation of an immune escape strain of HBV? If this immune escape strain spreads in the population, it may affect the efficacy of the existing vaccine. Therefore, HBIG is not recommended for pregnant women! (2) Is it possible for pregnant women to take antiviral drugs to block and reduce mother-to-child transmission? It is a well-established fact that high viral loads in pregnant women are the main cause of failure of immune blockade. Therefore, some attempts have been made to have pregnant women take antiviral drugs prophylactically during the second trimester, but the results have been reported nationally and internationally with mixed results. The relatively accepted view is that pregnant women with HBVDNA greater than 10 to the 8th copy/ml can be treated with oral lamivudine and other drugs in the last 1-3 months of pregnancy. However, a few points to note are: how and when to stop the drug at the end of pregnancy, and does stopping the drug put the pregnant woman at risk of a disease flare? Is there an increased risk of drug resistance in pregnant women? Does it pose a risk for subsequent treatment? Therefore, physicians may recommend but first seek the consent of the patient and family. In conclusion, the interruption of vertical transmission from mother to child is of great importance, especially in a country like ours where mother-to-child transmission is the main route of infection, and it can be said to be of decisive significance to whether hepatitis B can be conquered and eliminated eventually.