Antenatal prevention General measures (1) Pre-birth evaluation; (2) Protecting the integrity of the placental barrier: avoiding abdominal collision and extrusion and amniocentesis during pregnancy; (3) Avoiding expired pregnancies, the prolongation of gestational age at delivery increases the risk of failure of intrauterine blockade with highly potent hepatitis B immune globulin (HBIG); and (4) Cesarean section as soon as possible after the occurrence of preterm labor. Passive immunity Injection of HBIG activates the complement system, enhances humoral immunity, and reduces viral load, and its effectiveness in blocking mother-to-child transmission has been reported inconsistently, with most believing that the effect is unequivocal, but there is no consensus on whether to apply it routinely.Shi et al[1] systematically reviewed a randomized controlled trial of nearly 6,000 patients with HBIG from January 1990 to December 2008, and concluded that there was a high degree of highly infectious HBV carrier mothers were effectively and safely prevented intrauterine transmission of HBV by multiple injections of HBIG during the second trimester of pregnancy. Huang Y et al [2] divided 172 neonates delivered by HBV-positive pregnant women into three groups: group A pregnant women and their neonates used HBIG in combination; group B used HBIG only in the neonates; and group C pregnant women and their neonates did not use HBIG. neonates of all three groups were injected with intramuscular Hepatitis B vaccine after birth at 016 months of age. at 7 months of age, the rate of infants in group A who were positive for HBsAg was (1.72%) was lower than that of group B (11.11%), and the difference was statistically significant, suggesting that HBsAg-positive pregnant women and newborns were better immunized with HBIG than non-users. Whereas Han Zhonghou et al [3] concluded that HBsAg-positive mothers were ineffective for mother-to-child blockade with HBIG injections in late pregnancy, Sinha et al [4] concluded that there was no reliable evidence-based medicine that could confirm that maternal HBIG injections given in late pregnancy could reduce mother-to-child transmission of HBV. Antiviral therapy High viral load is a major risk factor for failure of mother-to-child blockade of hepatitis B. Nucleoside antivirals have received attention in recent years as a complementary blockade to passive immunization of the pregnant woman and active-passive immunization of the newborn at birth, with a view to reducing the incidence of intrauterine transmission. Indications for maternal antiviral therapy [4] include all those with cirrhosis, those with HBV DNA >107 copies/ml in late pregnancy, and those with a previous history of delivery of HBV-positive infants with HBVDNA >106 copies/ml require antiviral therapy. The conclusions of studies on the use of lamivudine and telbivudine antiviral in pregnant women with hepatitis B at home and abroad to block mother-to-child transmission were optimistic.Jiang[5] and Zhu Meiqin et al[6] reviewed the relevant literature on the use of lamivudine antiviral during the period of 1996-2009 and conducted Meta-analysis, a total of 1,005 patients who had a combined pregnancy with chronic hepatitis B. The results showed that the use of lamivudine in pregnancy at different times of the pregnancy The results showed that with lamivudine at different times during pregnancy, the HBsAg positivity rate of newborns was significantly lower than that of the non-lamivudine group (9.7% vs 29.8%), and the use of lamivudine from the 24th and 32nd weeks of pregnancy was effective in increasing the rate of blockade of HBV intrauterine infections; there was no statistical significance in the comparison of the use of lamivudine from the 36th week of pregnancy with that of the blank group; and the use of lamivudine in the late stages of pregnancy, when compared with HBIG, showed that the effect of the blockade of HBV intrauterine infections had a trend of superiority over HBIG. This indicates that lamivudine is effective and safe in reducing mother-to-child transmission of HBV.Xu et al [7] reported that a randomized, double-blind, multicenter, placebo-controlled clinical study showed that maternal lamivudine treatment given in the 32nd week of pregnancy significantly reduced neonatal HBV infection. Korea Rong et al [8] reported that 120 pregnant women with HBVDNA ≥107 copies/ml and HBeAg-positive pregnancy were given tibivudine 600 mg/d from weeks 20 to 32, and 100 in the control group were not antiviral, and on the basis of primary-passive immunization given to the newborns, (followed up to 7 months of age) the newborns delivered by patients in the treatment group were less likely to develop perinatal The probability of infection was lower than that of the control group, 0 and 8% respectively (P=0.002), and no adverse events occurred. Zhang Liju et al [9] reported 61 patients with chronic hepatitis B in the second trimester of pregnancy, 31 were given tibivudine 600mg orally once/d, and 30 were controls without antiviral drugs. The results showed that the maternal HBV DNA level in the tibivudine group decreased significantly compared with that before taking the drug, and was significantly lower than that in the control group (P<0.01). The prevalence of HBV infection at 7 months of age in newborns of the two groups was 0 and 13.3%, respectively. The 2009 European Association of Hepatology (EASL) guideline affirms the safety of nucleoside analogs such as lamivudine and tebivudine in pregnancy [10], and the use of lamivudine, tebivudine, and tenofovir in class B drugs can be used in the presence of hepatitis B flare-ups or high viral loads in pregnancy [4] in order to interrupt mother-to-child transmission, and there is also a consensus in the Chinese Guidelines for the Prevention and Control of Chronic Hepatitis B (2010) [11]. Entecavir and adefovir are classified in category C for their proven embryonic and fetal toxicity in animal studies and are usually not used; interferon should be contraindicated during pregnancy due to its antiproliferative effects. Timing and duration of antiviral therapy: In patients with cirrhosis, antiviral therapy should be started before pregnancy and continued throughout pregnancy and for a long time after delivery [4]. For non-cirrhotic patients, antiviral therapy should be started at 32 or 34 weeks of gestation and continued until delivery, or up to 4 weeks postpartum, depending on the condition of the patient [4,5,7]. Intrapartum prophylaxis Measures to reduce transmission during labor include reducing neonatal birth injuries and amniotic fluid aspiration, shortening the duration of labor, and strict aseptic practices. The effect of mode of delivery on mother-to-child transmission is inconclusive, and there is a tendency to advocate vaginal delivery. Most of the existing studies [4] concluded that cesarean section is not an effective measure to interrupt mother-to-child transmission of HBV. Wang Hui-Hua et al [12] conducted a Meta-analysis of a total of 1435 study participants from seven publications on delivery methods to assess the effect of delivery methods of infants with active and passive combined immunization against hepatitis B on the prevalence of HBV infection in infants. Results In the natural delivery group, 831 infants were infected with HBV-positive rate of 7.34%; in the cesarean section group, 604 infants were infected with HBV-positive rate of 4.80%. There was no statistically significant difference in HBV infection rates between the two groups of infants. Zhang Weili et al [13] also concluded that the mode of delivery and liver function status of pregnant women had no effect on HBV mother-to-child transmission.Yang et al [14] concluded that cesarean section was effective in reducing HBV mother-to-child transmission compared with vaginal delivery (10.5% vs. 28%,P<0.01), but the lack of randomization and blinding of subgroups made the role of cesarean section in preventing HBV mother-to-child transmission uncertain. Postnatal prophylaxis The active and passive immunization of newborns currently adopted to minimize perinatal infections and breastfeeding infections is the most effective way to prevent hepatitis B infection. A consensus has been reached in China [6]. For newborns of HBsAg-positive mothers, HBIG should be injected as early as possible within 24 h after birth (the dose should be ≥100 IU), and at the same time, hepatitis B vaccine should be administered sequentially in different parts of the body, which can significantly improve the effect of blocking mother-to-child transmission. Liu Chongbai [15] reported that to block perinatal transmission, the blockage rate of hepatitis B vaccine alone was 70% ~80%; HBIG blocked up to 90% ~95%.André et al. [16] believed that postnatal hepatitis B vaccination or combined active-passive immunization could block 90% of mother-to-child transmission, and that HBIG only blocked the entry of HBV into the cells in body fluids, and that the vaccination procedure that is most effective in preventing transmission The most effective vaccination program to prevent transmission is to vaccinate as early as possible within 24h after birth, so the time of injection is critical. The mechanism of mother-to-child transmission of hepatitis B is still not completely clear. Preventive measures currently reach a consensus that each HBsAg-positive mother's neonate should be immunized with combined active-passive immunization as soon as possible after birth, and pregnant women who are double-positive for HBsAg and HBeAg or who have a high load of HBVDNA (≥2×106IU/ml) can receive antiviral therapy with ticlopidine tenofovir in the last trimester of gestation [4] in order to improve the rate of blockade .. There is no consensus on whether to administer HBIG passive immunization during pregnancy.