What is the management algorithm for Hepatitis B (HB) in pregnancy?

Management Algorithm for Hepatitis B in Pregnancy

Initial Screening and Assessment

All pregnant women should be screened for HBsAg at the first prenatal visit, and HBsAg-positive women must have HBV DNA and ALT levels measured at 26-28 weeks of gestation to determine the need for antiviral prophylaxis. 1, 2

• Screen all pregnant women for HBsAg in the first trimester regardless of vaccination history or prior testing 2, 3
• For HBsAg-positive women, obtain baseline HBV DNA and ALT levels 1
• Repeat HBV DNA and ALT testing at 26-28 weeks of gestation in all HBsAg-positive mothers 1, 2

Antiviral Therapy Decision Algorithm

High Viral Load (HBV DNA >200,000 IU/mL or >10^6 IU/mL)

Women with HBV DNA >200,000 IU/mL should receive tenofovir disoproxil fumarate starting at 28-32 weeks of gestation and continuing through 4 weeks postpartum to prevent vertical transmission. 1, 2

• Initiate tenofovir disoproxil fumarate 300 mg daily at 28-32 weeks 2, 3, 4
• Continue therapy through delivery and for 4 weeks postpartum 1
• This reduces vertical transmission from 2.8% to essentially 0% despite standard infant immunoprophylaxis 1

Advanced Liver Disease (Cirrhosis or Advanced Fibrosis)

Women with chronic HBV and advanced fibrosis or cirrhosis should continue tenofovir throughout the entire pregnancy regardless of viral load. 2

• Do not discontinue antiviral therapy in women with cirrhosis or advanced fibrosis 2
• The maternal benefit of preventing hepatic decompensation outweighs minimal fetal risk 1

Women Already on Antiviral Therapy

Pregnant women taking entecavir should be switched to tenofovir disoproxil fumarate before or during pregnancy. 1, 2

• Switch from entecavir to tenofovir (pregnancy category B) 1, 2
• Women on tenofovir can continue without interruption 2, 5
• Women with mild liver disease not requiring long-term therapy may discontinue treatment before conception and restart in third trimester if viral load is elevated 1

Lower Viral Load or Mild Disease

Women with HBV DNA <200,000 IU/mL and no advanced fibrosis can defer antiviral therapy but require close monitoring. 1

• Monitor HBV DNA and ALT every 12 weeks during pregnancy 1
• Initiate therapy if viral load rises above threshold or ALT flares occur 1

Drug Selection

Tenofovir disoproxil fumarate is the first-line agent for HBV treatment in pregnancy due to superior safety data and efficacy. 2, 5, 3

• Tenofovir disoproxil fumarate 300 mg daily (pregnancy category B) 1, 2, 5
• Alternative: Telbivudine (pregnancy category B) 1
• Lamivudine is acceptable but has higher resistance rates and should be avoided for long-term use 1
• Never use entecavir during pregnancy 1, 2

Monitoring During Pregnancy

HBsAg-positive mothers require monitoring every 12 weeks during pregnancy and at 4-6 weeks postpartum for hepatitis flares. 1

• Check HBV DNA and ALT every 12 weeks throughout pregnancy 1
• Some experts recommend monitoring every 4-6 weeks in the third trimester to detect flares early 1
• Monitor at 4-6 weeks postpartum for hepatitis flares, especially in women who discontinue therapy 1, 2

Delivery Management

Vaginal delivery is recommended, and cesarean section should not be performed solely to reduce HBV transmission. 2, 3

• Mode of delivery should follow standard obstetric indications only 2, 3
• Cesarean delivery does not reduce vertical transmission risk when infant immunoprophylaxis is administered 1, 2, 3

Invasive Prenatal Testing

Non-invasive prenatal testing is strongly preferred over amniocentesis in HBeAg-positive women or those with HBV DNA >5.3 log₁₀ IU/mL. 2

• Avoid amniocentesis when possible in highly viremic mothers 2
• If invasive testing is necessary, perform only after informed discussion of transmission risks 3

Neonatal Management

All infants born to HBsAg-positive mothers must receive both hepatitis B vaccine and HBIG within 12 hours of birth, regardless of maternal antiviral therapy. 1, 2, 3

• Administer HBIG within 12 hours of birth 1, 2
• Give first dose of HBV vaccine at birth, then at 1 month and 6 months 1
• This combination prevents 90% of perinatal infections, but 4-10% still fail despite proper immunoprophylaxis 1
• Test infant for HBsAg and anti-HBs at 9-12 months to confirm protection 4

Breastfeeding

Breastfeeding is safe and should be encouraged in HBsAg-positive mothers, including those on tenofovir therapy. 2, 5, 3

• Breastfeeding does not increase transmission risk when infant receives proper immunoprophylaxis 2, 3, 6
• Do not discourage breastfeeding unless mother has cracked/bleeding nipples with detectable HBV DNA or infant has oral ulcers 2
• Tenofovir is present in breast milk but breastfeeding benefits outweigh theoretical risks 5

Postpartum Monitoring

Women who discontinue antiviral therapy postpartum require close monitoring for hepatitis flares and viral reactivation. 1, 2

• Monitor ALT every 1-3 months for 6 months after delivery 1, 4
• Check HBV DNA if ALT elevation occurs 1
• Hepatitis flares are common due to immune reconstitution postpartum 1
• Restart antiviral therapy if ALT flare occurs or if patient meets standard treatment criteria 1

Common Pitfalls to Avoid

• Failing to check viral load at 26-28 weeks leads to missed opportunities for prophylaxis in high-risk women 1, 2
• Using lamivudine for long-term therapy increases resistance risk; tenofovir is superior 1, 2
• Continuing entecavir during pregnancy when tenofovir is the evidence-based choice with better safety data 1, 2
• Discouraging breastfeeding contradicts current evidence showing safety with proper infant immunoprophylaxis 2, 3
• Performing cesarean delivery solely for HBV provides no transmission benefit and increases maternal morbidity 2, 3
• Stopping postpartum monitoring misses hepatitis flares that commonly occur after delivery or therapy discontinuation 1, 4