What is the management approach for hepatitis B in pregnancy?

Management of Hepatitis B in Pregnancy

All pregnant women with chronic hepatitis B and HBV DNA >200,000 IU/mL (>5.3 log₁₀ IU/mL) should receive tenofovir disoproxil fumarate starting at 28-32 weeks of gestation through 2-12 weeks postpartum to prevent mother-to-child transmission, in addition to standard neonatal immunoprophylaxis. 1, 2, 3

Universal Screening

• Screen all pregnant women for HBsAg at the initial prenatal visit, regardless of vaccination history or prior testing 1, 2, 3
• For women with previously documented negative triple-panel testing, repeat HBsAg screening alone at the first prenatal visit 3
• Test women with unknown HBsAg status on any presentation for care, including at admission to the birthing facility 1, 3

Third Trimester Assessment

• Measure HBV DNA and ALT levels at 26-28 weeks of gestation in all HBsAg-positive women to determine need for antiviral prophylaxis 1, 2
• This timing allows for initiation of therapy before the critical period of vertical transmission risk 1

Antiviral Therapy Indications

For Prevention of Mother-to-Child Transmission

• Initiate tenofovir disoproxil fumarate (300 mg daily) or tenofovir alafenamide (25 mg daily) at 28-32 weeks in women with HBV DNA >200,000 IU/mL (>10⁶ IU/mL) 1, 2, 3
• Continue therapy through delivery and for 2-12 weeks postpartum 1, 2
• This reduces transmission risk from 7-10% to 0-2% when combined with neonatal immunoprophylaxis 1

For Maternal Liver Disease

• Women with advanced fibrosis or cirrhosis should continue tenofovir throughout pregnancy regardless of viral load 1
• For women with active liver disease (elevated ALT, significant fibrosis), treatment should follow standard chronic hepatitis B guidelines, with tenofovir as the preferred agent 1

Drug Selection and Safety

Tenofovir disoproxil fumarate is the first-line agent for all pregnant women requiring HBV treatment due to its pregnancy category B classification, extensive safety data, superior resistance profile, and proven efficacy 1, 2

Switching Medications

• Women on entecavir should be switched to tenofovir before or immediately upon pregnancy recognition 1, 4
• Entecavir is pregnancy category C with limited safety data in pregnancy 1, 4
• Women on lamivudine may continue if already pregnant, but tenofovir is preferred for new starts due to lower resistance risk 1

Alternative Agents

• Telbivudine (pregnancy category B) and lamivudine (category C with HIV safety data) are acceptable alternatives but inferior to tenofovir due to resistance concerns with long-term use 1

Monitoring During Pregnancy

• Monitor HBsAg-positive women every 12 weeks during pregnancy for hepatitis flares due to immunologic changes 1
• Some experts recommend monitoring HBV DNA and ALT every 4-6 weeks in the third trimester to detect severe flares early 1
• Monitor closely at 4-6 weeks postpartum for hepatitis flares, particularly in women who discontinue antivirals 1, 2

Neonatal Immunoprophylaxis

All infants born to HBsAg-positive mothers must receive both hepatitis B vaccine and HBIG within 12 hours of birth, regardless of whether maternal antiviral therapy was administered 1, 2, 5, 3

• This passive-active immunization prevents 90-95% of perinatal infections 1
• Complete the vaccine series at 1 and 6 months of age 1
• The 4-10% failure rate occurs almost exclusively in mothers with high viral loads, which is why antiviral prophylaxis is recommended 1

Delivery Management

Vaginal delivery is recommended; cesarean section should not be performed solely to reduce HBV transmission 2, 5, 3

• Mode of delivery does not affect transmission rates when neonatal immunoprophylaxis is administered 1, 5, 3
• Base delivery decisions on standard obstetric indications only 2, 5, 3

Invasive Prenatal Testing

• Non-invasive prenatal testing is strongly preferred over amniocentesis in women with HBV DNA >200,000 IU/mL (>5.3 log₁₀ IU/mL) 2, 3
• If invasive testing is necessary, counsel patients that transmission risk may increase with high viral loads (>7 log₁₀ IU/mL), though the absolute risk remains low 2, 5, 3
• Perform invasive procedures only when results will change clinical management 3

Breastfeeding

Breastfeeding is safe and should be encouraged in all HBsAg-positive mothers, including those on tenofovir therapy, as long as the infant receives immunoprophylaxis at birth 1, 2, 5, 3

• HBsAg can be detected in breast milk, but breastfeeding does not increase transmission risk when proper infant immunization is given 1
• Tenofovir concentrations in breast milk are minimal with limited oral bioavailability 1
• The only contraindication is cracked/bleeding nipples with detectable maternal HBV DNA or infant oral ulcers 2

Postpartum Antiviral Management

Women Treated for Transmission Prevention Only

• Antivirals may be discontinued at delivery or within 2-12 weeks postpartum in women without maternal treatment indications 1, 2
• Stopping at delivery avoids any theoretical concerns about breastfeeding, though tenofovir is considered safe 1
• Monitor ALT every 1-3 months for 6 months after discontinuation to detect hepatitis flares 1, 2, 6

Women with Maternal Treatment Indications

• Continue tenofovir indefinitely in women with advanced fibrosis, cirrhosis, or other standard treatment indications 1

Common Pitfalls and How to Avoid Them

Failing to check viral load at 26-28 weeks leads to missed opportunities for prophylaxis in high-risk women—this is a critical step that must not be omitted 1, 2

Using lamivudine for long-term therapy increases resistance risk significantly; tenofovir has a superior resistance profile and should be the default choice 1

Continuing entecavir during pregnancy when tenofovir is the evidence-based, safer choice with more extensive pregnancy data 1, 4

Discouraging breastfeeding based on outdated guidance contradicts current evidence showing safety with proper infant immunoprophylaxis 1, 2, 5, 3

Performing cesarean delivery to prevent transmission is not supported by evidence and exposes women to unnecessary surgical risks 2, 5, 3

Administering HBIG to pregnant women is ineffective at reducing transmission regardless of viral load—only neonatal HBIG is beneficial 2

Inadequate postpartum monitoring after antiviral discontinuation can miss hepatitis flares that may cause significant liver damage 1, 2, 6