Prevention of Mother-to-Child HBV Transmission: Goals and Guidelines

Prevention of mother-to-child transmission is a part of the WHO’s core strategy to achieve worldwide elimination of HBV infection by 2030. All international guidelines recommend universal screening of pregnant women for HBV infection, as it poses a serious risk to infants at birth and can have long-term health consequences. Without postexposure immunoprophylaxis, approximately 40% of infants born to mothers with HBV develop chronic HBV infection; approximately 25% of those infected eventually die from related complications, particularly hepatocellular carcinoma.

Postexposure Preventive Measures in Infants
An effective way to prevent perinatal HBV transmission from mothers with HBV infection is by providing hepatitis B immunoglobulin and HBV vaccination to their newborns within 12 hours after birth. After completion of the vaccine series (between 9 and 18 months of age), infants should be tested for hepatitis B surface antibody to evaluate their response to the vaccine and for hepatitis B surface antigen (HBsAg) to rule out infection. Despite these preventive measures, a small percentage of women with high viremia may still transmit HBV infection to their child.

Maternal Antiviral Treatment and Prophylaxis
Several studies have shown that in addition to preventive measures for the newborn, the use of antiviral prophylaxis in HBsAg-positive mothers with HBV DNA > 200,000 IU/mL can fully avert HBV transmission to the child. Screening for HBV should be completed in the first trimester of pregnancy, allowing enough time to start maternal antiviral prophylaxis in the third trimester and reduce HBV DNA levels prior to birth. Pregnant women who test HBsAg positive should also have HBV DNA and HBsAg levels measured and be linked to care for additional testing, including assessment of ALT levels and a hepatic ultrasound. These results will help to determine if there is an immediate need to start antiviral therapy for the mother’s health or if antiviral therapy for the purpose of prophylaxis is needed during the last trimester of pregnancy only. The suggested cutoffs for starting maternal antiviral prophylaxis are HBV DNA > 200,000 IU/mL and/or HBsAg > 4 log₁₀ IU/mL, as women with these laboratory values have the highest likelihood of HBV transmission to their infants. Tenofovir disoproxil fumarate (TDF) is recommended for both antiviral treatment during pregnancy and as prophylaxis for those who do not otherwise meet indications for HBV treatment for their own health because of its high antiviral potency, high genetic barrier to resistance, and demonstrated safety during pregnancy (no teratogenicity).

Discontinuing Maternal Antiviral Prophylaxis
The duration of maternal antiviral prophylaxis remains an open question. There is no agreement on whether prophylaxis should stop at delivery (or soon after) or continue for up to 12 weeks after delivery, as the EASL guidelines have suggested. Another important factor to consider is that of breastfeeding. In both untreated women with HBV infection and those receiving TDF, breastfeeding is not contraindicated. The AASLD guidance recommends that pregnant women with HBV infection who are not receiving treatment or who discontinue prophylaxis at or soon after delivery should be monitored closely for hepatitis flares and seroconversion for up to 6 months following delivery. Long-term maternal monitoring should also be continued following delivery to assess the need for future therapy due to the dynamic nature of HBV infection. Finally, we should always ensure that all family members are screened for HBV and that those with no signs of infection are vaccinated.

Your Thoughts?
What challenges do you encounter when caring for pregnant women with HBV infection? Please share your experiences and thoughts in the comment box below.