What are the implications of hepatitis B (HBV) in pregnancy?

From the Guidelines

Hepatitis B screening is essential for all pregnant women, and those testing positive for hepatitis B surface antigen (HBsAg) should receive appropriate management to prevent mother-to-child transmission, including antiviral therapy with tenofovir disoproxil fumarate for women with high viral loads, as recommended by the American Association for the Study of Liver Diseases 1. The management of hepatitis B in pregnancy involves several key steps, including:

• Screening for HBsAg at the first prenatal visit, with HBV-DNA testing performed if positive 1
• Administering hepatitis B vaccine and hepatitis B immune globulin (HBIG) to the infant within 12 hours of birth to prevent vertical transmission 1
• Considering antiviral therapy with tenofovir disoproxil fumarate for pregnant women with high viral loads (HBV DNA >200,000 IU/mL), starting at 28-32 weeks of pregnancy and continuing through delivery 1
• Monitoring liver function and viral load regularly during pregnancy, and referring patients to specialists in liver disease or infectious disease for comprehensive care 1
• Allowing women with chronic hepatitis B to breastfeed safely, as the virus is not transmitted through breast milk 1 It is also important to note that cesarean delivery has not been shown to reduce the risk of mother-to-child transmission of hepatitis B, and should only be performed for obstetrical indications 1. Additionally, antiviral therapy with tenofovir disoproxil fumarate is generally safe during pregnancy, and can be continued through delivery to further reduce transmission risk 1.

From the FDA Drug Label

5.1 Severe Acute Exacerbation of Hepatitis B in Individuals with HBV Infection All individuals should be tested for the presence of chronic hepatitis B virus (HBV) before or when initiating emtricitabine and tenofovir disoproxil fumarate tablets Severe acute exacerbations of hepatitis B (e.g., liver decompensation and liver failure) have been reported in HBV-infected individuals who have discontinued emtricitabine and tenofovir disoproxil fumarate tablets.

The FDA drug label does not answer the question about hepatitis B in pregnancy.

From the Research

Hepatitis B in Pregnancy

• Hepatitis B virus (HBV) infection is a significant health concern during pregnancy, as it can be transmitted from mother to child 2.
• Pregnant women with an elevated viral load of HBV have a risk of transmitting infection to their infants, despite the infants' receiving hepatitis B immune globulin (HBIG) and hepatitis B vaccine 3.
• The administration of tenofovir disoproxil fumarate (TDF) to pregnant women with HBV has been shown to reduce the risk of mother-to-child transmission (MTCT) of HBV 3, 4.

Prevention of Mother-to-Child Transmission

• The standard care for preventing MTCT of HBV in highly viremic mothers consists of maternal antiviral prophylaxis beginning at gestational week 28, combined with an HBV vaccine series and HBIG at birth 4.
• However, a randomized clinical trial found that initiating TDF at gestational week 16, combined with HBV vaccinations for infants, was noninferior to the standard care of TDF at gestational week 28, combined with HBV vaccinations and HBIG for infants, in preventing MTCT in mothers with HBV and high levels of viremia 4.
• HBIG is used to provide immediate passive protection against HBV infection, and its principal indications include mother-to-infant transmission, as well as other scenarios such as acute percutaneous exposure to HBV and non-responders to hepatitis B vaccine 5.

Hepatitis B Vaccine and HBIG

• The hepatitis B vaccine is currently made by recombinant DNA technology using baker's yeast, and preexposure vaccination results in protective antibody levels in almost all infants and children, as well as healthy adults younger than 40 years of age 2.
• The co-administration of HBIG with the hepatitis B vaccine can delay and reduce responses to the vaccine, regardless of the site of administration, although the initial circulating levels of HBIG can prevent infection despite an impaired response to the vaccine 6.
• A comprehensive hepatitis B vaccination policy is recommended, including routine infant vaccination, catch-up vaccination of high-risk individuals, and prevention of perinatal HBV infection 2.