The main diagnosis of hepatitis B virus (HBV) infection is based on HBsAg positivity. Mother-to-child transmission is the main cause of chronic HBV infection in China, so prevention of infants and children is emphasized. All pregnant women need prenatal screening for hepatitis B serological markers (commonly known as hepatitis B two-and-a-half). If a pregnant woman is HBsAg positive, her newborn is at high risk of HBV infection and must be given hepatitis B immunoglobulin (HBIG) within 12h of birth in addition to hepatitis B vaccination. In order to standardize the preventive measures for mother-to-child transmission of HBV in China and to reasonably prevent HBV infection in newborns, experts in epidemiology and obstetrics have jointly developed this guideline based on recognized research findings at home and abroad and with reference to relevant information from other countries. I. Clinical diagnosis of HBV infection Chronic HBV infection is defined as HBsAg positivity lasting for more than 6 months. If the liver function is normal, it is called chronic HBV carriage; if the liver function is abnormal and other causes are excluded, the diagnosis is chronic hepatitis B. Chronic HBV carriers need to review liver function and other necessary tests every 6 to 12 months. Mother-to-child transmission of HBV, in which HBsAg-positive mothers transmit HBV to their offspring, occurs mainly during and after delivery, whereas vertical transmission (intrauterine infection before delivery) has an infection rate of <3% [1], mostly in HBeAg-positive pregnant women. Detection of hepatitis B serologic markers, namely HBsAg, hepatitis B surface antibody (anti-HBs), HBeAg, hepatitis B e antibody (anti-HBe), and hepatitis B core antibody (anti-HBc), can determine the presence or absence of infection or immunity, and the significance of their clinical diagnosis is shown in Table 1. Table 1 HBV serologic markers and their clinical diagnostic significance HBsAg anti-HBs HBeAg anti-HBe anti-HBe anti-HBc Clinical significance + - + - +/- HBV infection, highly infectious + - - +/- + HBV infection, infectious + - - + - - HBV infection, infectious + + +/- +/- +/- HBV infection, infectious, possible mutation of HBV + - - - - - HBV infection latency, infectious previous - + - +/- + HBV infection recovered, protected previous - + - + - HBV infection recovered, protected vaccinated or previous - + - - HBV infection recovered, protected previous - - +/- + HBV infection recovered, unprotected previous - - + - HBV infection recovered, unprotected previous no - - - HBV infection, susceptible HBsAg positive, indicates virus is replicating, has HBeAg positive is a sign of active viral replication and high viral load, highly infectious. Anti-HB. is a neutralizing antibody, serum anti-HBs level ≥ lO mIU/ml is protective. Fluorescence real-time quantitative PCR technique detects HBV DNA level, which can reflect the level of viral load. However, about 30% of pregnant women who are HBsAg-positive and HBeAg-negative (commonly known as minor triplets), or even a few HBeAg-positive (commonly known as major triplets), have HBV DNA below the lower limit of detection, which is called "HBV DNA negative", but still have HBV in their blood and are infectious. Therefore, when a pregnant woman is HBsAg positive, regardless of her HBV DNA level, or even "negative", her newborn will have the possibility of infection if she does not take immunoprophylaxis. Second, the management of chronic HBV-infected patients during pregnancy 1, the timing of pregnancy: chronic HBV-infected women planning pregnancy, it is best to be assessed by a specialist in infection or hepatology liver function. Infected patients whose liver function is always normal can have a normal pregnancy; those with abnormal liver function can have a pregnancy if they return to normal after treatment and are rechecked normal for more than 6 months after stopping medication. Pregnancy during antiviral therapy must be done with caution. Interferon can inhibit fetal growth and contraception must be used during its use. Among the nucleoside (acid) analogues, adefovir and entecavir have adverse effects on fetal development or teratogenic effects [2] and are contraindicated in the first 6 months of pregnancy and during pregnancy. Tenofovir and telbivudine belong to pregnancy drug class B [2] and have no significant effect on the fetus when used in mid- to late pregnancy. Lamivudine belongs to class C drugs but does not increase neonatal birth defects when used in early, mid and late pregnancy to prevent mother-to-child transmission of HIV [3]. Nevertheless, if pregnancy occurs during the use of any antiviral drug, the patient must be informed of the various risks of the drug used and a consultation with the relevant physician must be requested to decide whether to interrupt the pregnancy or whether to continue antiviral therapy. 2. Pregnancy follow-up: After pregnancy, liver function must be reviewed regularly in chronic HBV-infected patients, especially in the early and late stages of pregnancy. If the liver function is normal in the first test, and if there are no clinical symptoms of hepatitis, it should be rechecked once every l-2 months; if the alanine transferase (ALT) is elevated but does not exceed 2 times the normal value (<80u>80U/L), or if the bilirubin level is elevated, it is necessary to consult a relevant professional physician, and if necessary, hospitalization, and in serious cases, termination of pregnancy. 3, the application of HBIG in late pregnancy has no role in preventing mother-to-child transmission: some scholars have proposed that HBIG applied to HBV-infected pregnant women in late pregnancy can prevent intrauterine infection in the fetus, but the following problems exist in the relevant studies: (1) the protection rate of neonates in the control group after immunoprophylaxis is only 55%-85%, which is significantly lower than the accepted protection rate, suggesting that there is no formal prevention in the control group; (2) the diagnostic criteria are incorrect and exaggerated the rate of intrauterine infection; (3) some studies had contradictory results before and after themselves. In addition, there was no anti-HBS in newborns after HBIG in pregnant women [4]; gorilla experiments and studies on prevention of reinfection after liver transplantation in HBV-infected patients suggest that HBIG injections of 200-400 U every 4 weeks during late pregnancy are unlikely to reduce HBV viral load [5]; and it has also been reported in China that this regimen does not reduce mother-to-child transmission [6-7]. Therefore, it is not necessary to apply HBIG to HBV-infected pregnant women in late pregnancy. 4, the problem of antiviral therapy during pregnancy: high levels of HBV in pregnant women are the main risk factor for the occurrence of mother-to-child transmission, and reducing the amount of virus can reduce mother-to-child transmission. When pregnant women are HBsAg positive but HBeAg negative, their newborns have been 98% to 100% protected by regular prophylaxis [7-9]. Therefore, there is no need to use antiviral therapy to prevent mother-to-child transmission in HBeAg-negative infected pregnant women. Chronic HBV infection still occurs in 5%-15% of newborns of HBeAg-positive pregnant women after formal prophylaxis [7-9]. Although, treatment with lamivudine or telbivudine in mid- and late pregnancy has been reported to reduce mother-to-child transmission [10-12], some of these studies had a small number of cases [IO], and some control neonates may not have been formally prophylactic [11], or mother-to-child transmission still occurred after treatment [10-11,13]. Therefore, HBeAg-positive pregnant women cannot be routinely treated with antiviral therapy as an indication to reduce mother-to-child transmission at this time. The following factors are also reasons for caution in anti-HBV therapy in pregnant women: (1) nucleoside (acid) analogs do not clear the virus, and after discontinuation, the virus will return to its original level or even higher, even inducing severe liver function damage; (2) long-term medication will increase the financial burden and cause the virus to mutate and develop drug resistance as well as other side effects; (3) 85%-95% of HBeAg-positive pregnant women are treated with anti-HBV therapy even if they are not anti (3) 85%-95% of HBeAg-positive pregnant women can be protected after regular prophylaxis even without anti-HBV treatment; (4) anti-HBV treatment usually starts in mid- and late pregnancy and is not effective for intrauterine infection in early and mid-pregnancy. In conclusion, more rigorously designed, rigorously controlled, large sample, multicenter studies are needed to determine whether anti-HBV therapy is needed to reduce mother-to-child transmission in HBeAg-positive pregnant women. In addition, abnormal liver function during pregnancy in HBV-infected patients does not increase the risk of mother-to-child transmission of HBV [8-9], and most pregnant women will return to normal liver function after delivery. Therefore, routine anti-HBV therapy cannot be administered to those with abnormal liver function, and the indications for anti-HBV therapy should be strictly controlled. Cesarean delivery cannot reduce mother-to-child transmission It was previously believed that the contraction of the uterus during natural delivery “squeezes” the placenta, which encourages the virus in the mother to enter the fetus and cause intrauterine infection, so theoretically cesarean delivery can reduce mother-to-poppy transmission of HBV [14]. However, recent studies have demonstrated that there is no statistically significant difference between the rate of HBV infection in neonates delivered by curettage and those delivered spontaneously after formal prophylaxis in chronically infected pregnant women (P>0.05) [15], indicating that curettage does not reduce the mother-to-child transmission of HBV. Therefore, cesarean delivery cannot be chosen for the purpose of interrupting mother-to-child transmission of HBV [16]. IV. Prevention of mother-to-child transmission of HBV Vaccination against hepatitis B is the most effective measure to prevent HBV infection, and the active ingredient of hepatitis B vaccine is HBsAg, which induces the body to function by actively producing anti-HBs. After the first dose of vaccine, most anti-HBs are still negative or below the lower limit of detection; anti-HBs turn positive only about l week after the second dose [17], i.e., immunity to HBV 35-40 d after the start of vaccination; pressing the third dose can lead to a significant increase in anti-HBs level and prolong the years of protection. The positive conversion rate of anti-HBs after full vaccination of neonates is as high as 95%-100% [8,18], and the protection period can be more than 22 years [19]. After the human body actively produces anti-HBs, it has immune memory, and even if anti-HBs turn negative, the body can produce anti-HBs within a short period of time when exposed to HBV again [19]; therefore, booster vaccination against hepatitis B is not needed for non-high-risk groups. Table 2: Immunoprophylaxis of hepatitis B in newborns Category Vaccine type Dose Volume Vaccination protocol Follow up Full-term newborns Maternal HBsAg (-) Yeast 5 μg or 0, 5 ml 3-dose regimen: i.e., 1 injection each at 0, 1, and 6 months No follow-up required 10 μg CHO 10 μg 1 ml Maternal HBsAg (+) Yeast 10 μg 1 ml HBIG 100-200 U; 3-dose regimen: i.e., 1 injection each at 0, 1, and 6 months Follow-up at 7 to 12 months of age Preterm neonates with birth mass < 2000 g 2000g< p=""> Maternal HBsAg (-) Yeast 5μg 0, 5 ml 4-shot regimen: i.e. 1 injection each at 1~2, 2~3, 6~7 months when birth mass ≥ 2000g May not follow up or 1~6 months after the last injection CHO 10μg or 1 ml Maternal HBsAg (+) Yeast 10μg 1 ml HBIG 100~200U within 12h of birth 200U, repeat 1 time after 3~4 weeks; vaccine line 4-dose regimen; i.e. 1 injection within 24h of birth, 3~4 weeks, 2~3 months, 6~7 months CHO 20μg 1 ml 1~6 months after the last dose Note: GBIG: B immunoglobulin; CHO Chinese hamster oocytes When pregnant women are positive for HBsAg, regardless of whether HBeAg is positive or negative, newborns must be promptly HBIG injection and full vaccination against hepatitis B (3-dose regimen at 0, 1 and 6 months). HBIG needs to be administered within 12h after birth (theoretically the earlier the better), its active ingredient is anti-HBs, which starts to work 15~30min after intramuscular injection, and protective anti-HBs can be maintained for at least 42~63d, when anti-HBs are already actively produced in the body, so there is no need for the 2nd injection of HBIG. If the results of HBsAg in pregnant women are unknown, it is better to give HBIG to newborns if possible. After taking the above-mentioned formal preventive measures, the protection rate of newborns of HBsAg-positive and HBeAg-negative pregnant women is 98%-100%, and the protection rate of newborns of both HBsAg and HBeAg-positive pregnant women is 850/0-95% [7-9]. 95% [7-9], and if HBIG is not used and only vaccine prophylaxis is applied, the overall protection rate is only 55%-85%. 2, immunoprophylaxis of preterm infants: preterm infants have immature immune systems and usually require 4 doses of hepatitis B. Preterm infants of HBsAg-negative pregnant women, if their vital signs are stable and their birth mass is ≥2000 g, can be vaccinated according to the 3-dose protocol at O, 1, and 6 months of age, and it is best to reinforce l doses at 1~2 years of age; if the vital signs of preterm infants are unstable, they should first deal with related diseases and wait for If the vital signs of preterm infants are unstable, they should first be treated for relevant diseases and then be vaccinated according to the above protocol after stabilization. If the preterm infant is <2000g, the 1st vaccination should be given after the body mass reaches 2000g (if the body mass does not reach 2000g before discharge, the 1st vaccination should be given before discharge); the 3-dose regimen at o, 1, and 6 months should be re-administered after l-2 months [16]. HBIG must be administered intramuscularly within 12 h after birth to preterm infants of HBsAg-positive pregnant women, regardless of their physical condition, and another injection is required after an interval of 3-4 weeks. If the vital signs are stable, there is no need to consider the body mass and the 1st dose of vaccine is given as soon as possible; if the vital signs are unstable, the 1st dose will be given as soon as possible after stabilization; after 1 to 2 months or after the body weight reaches 2000 g, the vaccination will be given again according to the 3-dose protocol for 0, 1 and 6 months (ix). 3, HBV-infected pregnant women's newborn breastfeeding: Although, HBsAg and HBV DNA feet can be detected in the milk of HBV-infected pregnant women], and some scholars believe that cracked nipples, excessive sucking or even biting of nipples by infants may transmit the virus to infants, but these are theoretical analysis, the lack of evidence-based medical evidence. Even without immunoprophylaxis, the infection rate of breastfed and artificially fed newborns is almost the same as in the old days". There is more evidence that breastfeeding does not increase the risk of infection even if the pregnant woman is HBeAg positive. Therefore, after formal prophylaxis, regardless of whether the pregnant woman is HBeAg positive or negative, her newborn can be breastfed without testing for HBV DNA in the breast milk. 4. Follow-up of newborns of HBsAg-positive pregnant women: The newborns of healthy pregnant women do not need to be regularly checked for hepatitis B serological markers. The purpose is to determine whether immunoprophylaxis has been successful, whether there is HBV infection, and whether booster immunization is needed. Testing for HBsAg and HBeAg in cord blood or newborn Jhgl,week blood, a negative result does not exclude mother-to-child transmission because of the long latency period of HBV infection; a positive result also does not confirm the diagnosis of intrauterine infection or perinatal infection because HBsAg, HBeAg and related antibodies can enter the fetus through the placenta. In addition, serum HBsAg positivity can also occur in newborns within 2-3 weeks after vaccination...Therefore, testing for HBV serum markers before 6 months of age is not recommended for newborns without symptoms of hepatitis. The appropriate time for follow-up is from 1 month (7 months of age) to 12 months of age after the third vaccination; if not, follow-up is still needed after 12 months of age. 7 months of age is when the body has the strongest response to hepatitis B vaccine and the highest anti-HBs titer, with the following results: (1) HBsAg negative, anti-HBs positive and >100 mU/ml, indicating successful prophylaxis and good response without special (2) HBsAg negative, anti-HBs positive, but <100 mU/ml, indicating successful prevention, but weak response to the vaccine, can be booster vaccination at the age of 2-3 years to extend the years of protection; (3) HBsAg and anti-HBs negative (or <10 mU/m1), indicating no HBV infection, but no response to the vaccine (3) HBsAg and anti-HBs are negative (or <10 mU/m1), indicating no HBV infection, but no response to the vaccine, requiring another full vaccination (3-dose regimen) followed by a review; (4) HBsAg is positive and anti-HBs is negative, highly suggestive of immunoprophylaxis failure; HBsAg is still positive on review after 6 months, confirming prevention failure and chronic HBV infection. After successful prevention, annual follow-up is not required. For children of HBeAg-positive mothers, review every 2 to 3 years; if the anti-HBs drops below 10 mU/ml, it is better to receive a booster vaccination; follow-up is generally not necessary after 10 years of age. 5. Other matters for prevention of mother-to-child transmission of HBV: If women of childbearing age are negative for serological markers of hepatitis B in pre-pregnancy screening, it is best to receive hepatitis B vaccine (10 or 20 dougs) before pregnancy. If pregnancy occurs during vaccination, no special treatment is required and the full course of vaccination can be completed because the hepatitis B vaccine has no significant adverse effects on either the pregnant woman or the fetus.241 For women who were not screened for HBsAg during pregnancy, or when it is not possible to determine whether the pregnant woman is HBsAg positive or negative, it is best to administer HBIG to the newborn; if there is a family history of hepatitis B, HBIG to the newborn is strongly recommended. pregnant women HBsAg negative, but the father of the newborn is HBsAg positive, he is usually in close contact with the newborn due to caring for him, increasing his risk of infection; therefore, HBIG for the newborn is preferable; semen cannot cause HBV infection in the fetus. similarly, other family members who are HBsAg positive are preferable to HBIG for the newborn if they are in close contact with the newborn. HBIG is a blood product and is best administered before Informed consent is completed and signed before delivery to avoid delays in its use. It is advisable to have HBIG available in obstetrics and gynecology wards so that high-risk newborns born at night, on weekends, or during holidays13 can receive timely formal prophylaxis. HBV is likely to be present on the skin surface of newborns of HBV-infected mothers, and it is important to wash and adequately disinfect the skin before any skin-damaging treatment and to administer HBIG before any other injectable treatment, etc. Amniocentesis of HBV-infected pregnant women does not increase the risk of mother-to-child transmission of HBV in newborns if HBeAg is negative Uglyworm, if HBeAg is positive, does it increase the risk of fetal infection The risk of fetal infection is less studied, and further research is needed. V. Key points of immunoprophylaxis for neonatal hepatitis B 1. Pregnant women need to be tested for serological markers of hepatitis B before delivery: HBsAg positive, indicating HBV infection and infectious; HBeAg positive, highly infectious; anti-HBs positive, immune to hepatitis B. 2. 2, HBsAg negative pregnant women: newborns are vaccinated with hepatitis B vaccine according to the 3-dose program at 0, 1 and 6 months, i.e. 1 dose at 1 month and 6 months respectively within 24 h of birth; no need to inject HBIG again. 3, HBsAg positive pregnant women: newborns are injected with 1 dose of HBIG intramuscularly within 12 h of birth; at the same time, they are vaccinated with hepatitis B vaccine according to the 3-dose program at 0, 1 and 6 months. 4.Breastfeeding of HBsAg-positive pregnant women: after formal prevention of newborns, breastfeeding is feasible regardless of whether the pregnant women are HBeAg-negative or positive. 5, mode of delivery and mother-to-child transmission: cesarean delivery cannot reduce the rate of mother-to-child transmission of HBV. 6, preterm infants: when the birth mass ≥ 2000 g, no special treatment. If the body mass < 2000 g, the first vaccination should be given after the body mass reaches 2000 g, and then after an interval of 1-2 months according to the 3-dose program for 0, 1 and 6 months. If the pregnant woman is HBsAg-negative and the premature baby is in good health, treat as above; if the health condition is not good, treat the related disease first and wait for recovery before vaccination. If the pregnant woman is HBsAg positive, regardless of the health condition of the premature baby, one injection of HBIG will be given intramuscularly within 12 hours, and another injection will be required after an interval of 3-4 weeks; vaccination will be given within 24 hours, 3-4 weeks, 2-3 months and 6-7 months of age, and follow-up will be conducted. 7, other family members HBsAg positive: If the newborn is in close contact with HBsAg positive members, it must be injected with HBIG; without close contact, it is not necessary to inject. 8.Follow-up of newborns of HBsAg-positive pregnant women: at 7-12 months, test for serological markers of hepatitis B. If HBsAg negative and anti-one HBs positive, prevention is successful and resistant; if HBsAg negative and anti. HBs negative, prevention is successful but requires another 3 doses of vaccination program; if HBsAg positive, prevention fails and becomes chronic infected. 9, other precautions: before any operation that damages the skin mucosa, it must be fully cleaned and disinfected before proceeding. 10.Whether anti-HBV treatment should be performed in HBsAg-positive pregnant women to reduce the rate of mother-to-child transmission: when HBeAg-negative, no antiviral is needed; when HBeAg-positive, whether anti-HBV treatment should be performed is inconclusive and requires a rigorous multi-center controlled study.