Hepatitis B virus (HBV) can be transmitted from an infected mother to her baby during childbirth. The presence of HBV does not influence whether the delivery method is vaginal or via cesarean section. Infants who are infected with hep B are at high risk for serious complications including liver damage, liver cancer and even death. Fortunately, nearly all cases of infant-acquired hep B can be avoided if established prevention measures are followed.

When prevention measures are not taken, roughly 40 percent of infants born to HBV-infected mothers will develop chronic hepatitis B infection. Infants who are born with hep B often have no symptoms. Infants who are infected have a 90 percent chance of developing chronic HBV; one in four of these will die from chronic liver disease.

Vaccination Hepatitis B vaccination is recommended for everyone in the United States. The vaccination is usually given in a series of two or three shots. The CDC recommends giving the first dose within 24 hours of birth. Pregnant women who have been vaccinated against hep B are unable to transmit HBV to their infants. Note: In some cases, additional doses of HBV vaccine may be necessary. Your doctor will advise you.

Testing Pregnant women are routinely tested for hepatitis B infection. Women who had hep B in the past and resolved the infection are immune and cannot transmit HBV to their infants. Women who are not immune to hepatitis B are offered the vaccination in order to prevent them from acquiring HBV. It is safe to be vaccinated during pregnancy. Preventive measures are taken to protect infants whose mothers are infected with HBV at the time of pregnancy.

Perinatal Prevention of Hep B Transmission Fortunately, medical interventions can protect infants whose mothers are infected with HBV at the time of pregnancy. These include vaccination and hepatitis B immune globulin (HBIG) administered to the baby at birth. HBIG is a human protein that causes temporary immunity and prevents the development of hepatitis B. The HBIG and first dose of HBV vaccine are given within 12 hours of birth. Two or three additional vaccine shots are given to help prevent hepatitis B, usually when the infant is one to six months.

Hep B Treatment The American Association for the Study of Liver Diseases (AASLD) recommends antiviral treatment for pregnant women who are HBsAG positive with an HBV DNA level >200,000 IU/mL. To date, the only HBV medications that have been studied in pregnant women are Epivir-HBV (lamivudine) and Viread (tenofovir). Tyzeka (telbivudine) was also studied, but this drug will no longer be available after  2016. Antiviral therapy is not recommended for pregnant women who are HBsAG positive with an HBV DNA level ≤200,000 IU/mL.

Breast Feeding Mothers with HBV may breast-feed without risk of infecting their infants. There is not much data regarding the safety of breast feeding while taking antiviral medications. The AASLD states that breast-feeding while taking HBV antivirals is not contraindicated.

Last Reviewed: March 4, 2019