• Location:臺灣
• Date: 2019/12/23
• Update Date:2020/07/20
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The hepatitis B virus (HBV) can be spread to the baby via vertical transmission during delivery. However, as long as the newborn receives a hepatitis B immune globulin (HBIG) injection and regular hepatitis B vaccines, breastfeeding will not increase the likelihood of him or her being infected with HBV.

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Transmission of Hepatitis B Virus (HBV)

Modes of HBV transmission vary, as the prevalence of carriers differs. In high-endemic areas (including East Asia, South Asia, and Sub-Saharan Africa), the transmission mainly takes place during the perinatal period from the mother to her newborn, or via intimate contact between children (horizontal transmission). In Asia, 40% of female HBV carriers of reproductive age are hepatitis B-e antigen (HBeAg) positive, and these women have a 70–90% chance of infecting their newborns during the perinatal period. The perinatal infection mainly happens during or after giving birth, when the baby is exposed to the mother’s blood and other body fluids. Perinatal transmission accounts for 25–30% of the carrier population. Outside of Asia, 10% of female HBV carriers of reproductive age are hepatitis B-e antigen (HBeAg) positive, and perinatal transmission is a less significant factor in carrier population increase. In low-endemic areas (including Western Europe and North America), perinatal transmission is less common, and the virus is mainly transmitted among adults via sexual contact or exposure to blood. However, most industrialized countries screen every pregnant woman to see if she has Hepatitis B surface antigens (HBsAg), and they treat the babies of carrier mothers with hepatitis B immune globulin (HBIG) and hepatitis B vaccines.

Risk of HBV Transmission Via Breastfeeding

Breastfeeding was once considered a way for babies to be infected with HBV for a small amount of HBsAg can be found in some breast milk. However, there is no evidence breastfeeding increases the risk of mother-to-child transmission. A study in Taiwan tracked 147 children born to a HBV carrier mother and found the 92 breastfed children had the same chances of getting hepatitis B as the other 55 formula-fed children (4). A British study (5) of 126 targets also suggested that breastfeeding by a HBV carrier mother would not increase the risk of her baby getting hepatitis B. This study examined HBeAg in mothers and found it uncorrelated with the transmission rate. These studies strongly suggested that the risk of breast milk transmission can be overlooked compared with the high risk of perinatal transmission with the baby’s exposure to the mother’s blood and body fluids. However, some hepatitis experts worry that the baby might be exposed to enough HBV for infection when there are pathological changes in the mother’s breasts, such as a bleeding nipple.

Prevention of Vertical and Horizontal Transmission of HBV

HBV vaccine can effectively prevent vertical and horizontal transmission of HBV. Getting vaccinated can prevent 70-90% of babies born to a carrier mother from becoming a carrier, and it can also prevent 95% of horizontal transmission. Injection of HBIG along with first shot of hepatitis B vaccine within 24 hours after birth can increase the protection rate of babies born to a carrier mother by 85-90%. However, it is not feasible to screen all pregnant women for HBV or use HBIG in developing countries; thus, it is suggested to let all newborns receive hepatitis B vaccine. If it is possible, the first shot should be given within 48 hours after birth, and the rest should be given regularly afterwards. It is likely to vaccinate babies born in a hospital or a clinic, but it will be difficult for those born at home. Giving newborns first shot of hepatitis B vaccine after birth is especially important in Asia, where perinatal transmission is rather common. It is safe to breastfeed newborns that have received their first shot of hepatitis B vaccine.

In areas without hepatitis B vaccine being given regularly, more attention needs to be paid to breast milk from wet nurses and donors. Most non-carrier mothers in high endemic area have been infected with HBV, recovered and transmitted the hepatitis B surface antibody to their babies via placenta, which can protect the babies from being infected for 6 months. In many industrialized countries, breast milk from wet nurses and donors is screened for hepatitis B antigens, and their milk can only be used to feed their own babies if it tests positive. However, this kind of screening might be difficult to do in developing countries. Newborns that have received hepatitis B vaccine will not be infected with HBV from breast milk from wet nurses and donors.

Recommendations:

World Health Organization (WHO) recommends all newborns to receive hepatitis B vaccine with first shot given within 48 hours after birth if possible. This can reduce vertical transmission and eliminate any risk of breastfeeding transmission. Getting vaccinated can also prevent all other modes of HBV transmission.

WHO and United Nations Children's Fund (UNICEF) recommends all babies to be completely breastfed for 4-6 months, and continue being breastfed with addition of proper solid food until age 2 or older. Unbreastfed babies will have higher sickness and death rate. There is no evidence breastfeeding increases the risk of transmission to babies, even the unvaccinated ones, for HBV carrier mothers. Therefore, breastfeeding is still recommended for babies even in high endemic areas and areas without hepatitis b vaccine being given.

If you want to learn more about issues related to hepatitis B and breastfeeding, please go to the I-Baby Information Service Website/Health Education/Delivery/Breastfeeding/ Hepatitis B and Breastfeeding