How can vertical transmission of Hepatitis B (HB) from mother to newborn be prevented?

Prevention of Vertical Transmission of Hepatitis B Virus

All infants born to HBsAg-positive mothers should receive both hepatitis B vaccine (first dose) and HBIG (0.5 mL) within 12 hours of birth, administered at different injection sites, to prevent vertical transmission of HBV. 1, 2

Prenatal Screening and Management

Maternal Screening

• All pregnant women must be tested for HBsAg during early prenatal care (first trimester), regardless of previous vaccination or testing status 1, 2
• Women not screened prenatally should be tested at admission for delivery, especially those with high-risk behaviors or clinical hepatitis 1
• All laboratories should use FDA-licensed HBsAg tests with confirmatory testing of initially reactive specimens 1

Management of HBsAg-Positive Pregnant Women

• HBV DNA quantification should be performed in all HBsAg-positive pregnant women 2
• Women with viral loads >200,000 IU/mL should receive antiviral therapy with tenofovir starting at 28-32 weeks gestation 2, 1
• Tenofovir disoproxil fumarate is the preferred antiviral agent (FDA pregnancy category B) 2
• Antiviral therapy should be continued until 12 weeks postpartum 2
• Maternal HBsAg status must be clearly documented and communicated to the delivery facility 1, 2

Infant Prophylaxis Protocol

For Infants Born to HBsAg-Positive Mothers

1. Administer HBIG (0.5 mL) within 12 hours of birth 1, 2, 3
2. Administer first dose of hepatitis B vaccine within 12 hours of birth (at a different injection site from HBIG) 1, 2
3. Complete the vaccine series according to the recommended schedule, with doses at 1-2 months and 6 months 1
4. The final dose should not be administered before age 24 weeks (164 days) 1

For Preterm Infants (<2,000g) Born to HBsAg-Positive Mothers

• The initial vaccine dose (birth dose) should not be counted as part of the vaccine series 1
• Administer 3 additional doses of vaccine (for a total of 4 doses) beginning when the infant reaches age 1 month 1
• Studies show lower seroprotection rates in infants with birth weights <2000g (93% versus 98% for ≥2000g infants) 4

For Infants Born to Mothers with Unknown HBsAg Status

• Administer hepatitis B vaccine within 12 hours of birth 1, 2
• Test mother for HBsAg immediately 1
• If mother tests positive, administer HBIG (0.5 mL) as soon as possible (within 7 days of birth) 2

Efficacy and Follow-up

• Combined passive-active prophylaxis with HBIG and hepatitis B vaccine is 85-95% effective in preventing perinatal HBV infection 1, 2
• Research shows that even a reduced dose of 100 IU HBIG combined with the HepB series might be sufficient for preventing mother-to-child transmission of HBV 5
• Postvaccination testing for anti-HBs and HBsAg should be performed at age 9-18 months (after completion of the vaccine series) 1, 2
• Testing should not be performed before age 9 months to avoid detection of anti-HBs from HBIG administered during infancy 1

Additional Considerations

Breastfeeding

• Breastfeeding is safe and should not be discouraged for HBsAg-positive mothers 2
• Exception: If mothers with detectable HBV DNA have cracked nipples or if the infant has oral ulcers, breastfeeding should be avoided 2

Delivery Method

• Cesarean section is not recommended solely to prevent HBV transmission 2
• Vaginal delivery is appropriate for HBsAg-positive women, even with high viral loads, if they received antiviral prophylaxis 2

System-Level Implementation

• All delivery hospitals should implement policies and procedures to ensure identification of infants born to HBsAg-positive mothers and initiation of immunoprophylaxis 1
• Case-management programs should be established to ensure that all pregnant women are tested for HBsAg and that infants born to HBsAg-positive women receive recommended care 1

Pitfalls to Avoid

• Delaying HBIG administration beyond 48 hours significantly decreases efficacy 3
• Failing to complete the full hepatitis B vaccine series may leave the infant vulnerable to infection
• Not testing infants for HBsAg and anti-HBs after vaccination series completion may miss breakthrough infections
• Neglecting to document and communicate maternal HBsAg status to the delivery facility can lead to missed prophylaxis opportunities
• Failing to identify and provide antiviral therapy to pregnant women with high viral loads (>200,000 IU/mL) increases transmission risk 1, 2

The combination of timely HBIG administration, complete hepatitis B vaccination series, and maternal antiviral therapy when indicated has dramatically reduced the rate of vertical HBV transmission and is critical to the global goal of HBV eradication 6.