What are the management and testing strategies for a Hepatitis B (HBV) surface antigen positive mother to prevent perinatal transmission?

Management of Hepatitis B Surface Antigen Positive Mothers to Prevent Perinatal Transmission

All HBsAg-positive pregnant women should be tested for HBV DNA levels during pregnancy, and those with viral loads >200,000 IU/mL should receive antiviral therapy with tenofovir starting at 28-32 weeks gestation, while all infants born to HBsAg-positive mothers must receive both hepatitis B vaccine and HBIG within 12 hours of birth. 1, 2

Screening and Testing Protocol

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 tested prenatally, those with clinical hepatitis, or those with high-risk behaviors should be tested at admission for delivery 1
• Ensure that maternal HBsAg status is clearly documented in medical records and communicated to the delivery facility 2

Additional Testing for HBsAg-Positive Mothers

• HBV DNA quantification to guide antiviral therapy decisions 1, 2
• HBeAg status to help predict transmission risk 2
• Liver function tests (ALT/AST, bilirubin, albumin, prothrombin time) at baseline and each trimester 2
• Repeat HBV DNA quantification at 24-28 weeks of gestation to assess need for antiviral therapy 2

Antiviral Therapy for Pregnant Women

Indications for Antiviral Therapy

• HBV DNA levels >200,000 IU/mL at 24-28 weeks gestation 1, 2
• Advanced fibrosis or cirrhosis, regardless of viral load 2

Antiviral Regimen

• Tenofovir disoproxil fumarate (TDF) 300 mg daily is the preferred agent (pregnancy category B) 2
• Start at 28-32 weeks gestation 2
• Continue until 12 weeks postpartum 2
• Monitor for hepatic flares 3 months postpartum, which occur in 3.5-25% of women 2

Infant Prophylaxis

Standard Protocol for All Infants Born to HBsAg-Positive Mothers

• Hepatitis B vaccine (first dose) within 12 hours of birth 1, 2
• Hepatitis B immune globulin (HBIG) 0.5 mL within 12 hours of birth 1, 2
• Complete the full HBV vaccination series according to schedule 2
  • Second dose at 1-2 months of age
  • Third dose at 6 months of age

Efficacy of Prophylaxis

• Combined passive-active prophylaxis with HBIG and hepatitis B vaccine is 85-95% effective in preventing perinatal HBV infection 1, 2
• The risk of mother-to-child transmission is negligible (0.04%) when maternal HBV DNA is <200,000 IU/mL with proper infant immunoprophylaxis 2
• Research shows that even a reduced dose of HBIG (100 IU) combined with hepatitis B vaccine may be effective in preventing transmission 3, but standard practice remains using 0.5 mL HBIG 1

For Infants Born to Mothers with Unknown HBsAg Status

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

Follow-Up Testing

Infant Testing

• Test infants born to HBsAg-positive mothers for HBsAg and anti-HBs at 9-15 months of age (3-9 months after completing vaccination) 1
• Testing determines success of prophylaxis and identifies infants who may require revaccination or who have become HBV carriers 1

Maternal Follow-Up

• Refer all HBsAg-positive pregnant women to appropriate case-management programs 1
• Reassess need for long-term HBV treatment postpartum based on standard criteria 2

Additional Considerations

Breastfeeding

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

Counseling for HBsAg-Positive Mothers

• Provide information about modes of transmission
• Discuss perinatal concerns and breastfeeding safety
• Emphasize importance of infant prophylaxis and completion of vaccine series
• Recommend hepatitis B vaccination for household, sexual, and needle-sharing contacts
• Discuss substance abuse treatment if appropriate
• Explain the need for medical evaluation and possible treatment of chronic hepatitis B 1

Common Pitfalls to Avoid

• Failing to document and communicate maternal HBsAg status to the delivery facility
• Delaying HBIG and hepatitis B vaccine beyond 12 hours after birth
• Not testing HBV DNA levels to determine need for antiviral therapy
• Missing the opportunity to start antiviral therapy when indicated (HBV DNA >200,000 IU/mL)
• Neglecting to complete the full infant vaccination series
• Forgetting to test infants at 9-15 months to confirm prevention of infection