What is the recommended week‑by‑week screening and management plan for hepatitis B and hepatitis C in a pregnant woman, including timing of antiviral therapy, delivery considerations, and infant prophylaxis?

Week-by-Week Management of Hepatitis B in Pregnancy

Screen all pregnant women for hepatitis B surface antigen (HBsAg) at the first prenatal visit, measure HBV DNA and ALT at 26-28 weeks gestation in HBsAg-positive women, initiate tenofovir disoproxil fumarate at 28-32 weeks if HBV DNA exceeds 200,000 IU/mL, and ensure all exposed infants receive both hepatitis B vaccine and HBIG within 12 hours of birth. 1, 2, 3

First Trimester (Weeks 1-13)

Universal Screening

• Order HBsAg testing at the initial prenatal visit for every pregnant woman, regardless of prior vaccination status or previous negative test results. 4, 5
• The sensitivity and specificity of HBsAg immunoassays exceed 98%, making this the principal screening test for detecting maternal HBV infection. 4
• Consider triple-panel testing (HBsAg, anti-HBs, and anti-HBc) if immunity status has never been documented, as this identifies both infection and susceptibility. 3

If HBsAg-Positive

• Refer immediately to hepatology or infectious disease for case management and counseling about preventing transmission to household contacts and sexual partners. 4
• Counsel that breastfeeding will be safe after infant receives appropriate immunoprophylaxis. 1, 2

If HBsAg-Negative and Non-Immune

• Initiate hepatitis B vaccination series during pregnancy for all susceptible women, particularly those with risk factors (injection drug use, multiple sexual partners, HBsAg-positive partner, healthcare workers with blood exposure, or travel to endemic regions). 6, 3, 7

Second Trimester (Weeks 14-27)

Week 26-28: Critical Assessment Window

• Measure HBV DNA (viral load) and ALT levels at 26-28 weeks gestation in all HBsAg-positive women. 1, 2, 3
• This third-trimester viral load assessment is the single most important step for determining whether antiviral prophylaxis is needed to prevent perinatal transmission. 1
• Failing to check HBV DNA at this timepoint is a common and critical pitfall that leads to missed opportunities for prophylaxis in high-risk women. 1, 2

Invasive Prenatal Testing Considerations

• Strongly prefer non-invasive prenatal testing (NIPT) over amniocentesis in HBeAg-positive women or those with HBV DNA >200,000 IU/mL (>5.3 log₁₀ IU/mL). 1, 2
• If invasive testing is requested, counsel that amniocentesis data are more reassuring than chorionic villus sampling; avoid CVS in high-risk HBV infection. 1, 3

Third Trimester (Weeks 28-40)

Antiviral Prophylaxis Decision

• Initiate tenofovir disoproxil fumarate (TDF) 300 mg daily at 28-32 weeks gestation when maternal HBV DNA exceeds 200,000 IU/mL (≥5.3 log₁₀ IU/mL) or when the mother is HBeAg-positive. 1, 2, 3
• Tenofovir alafenamide (TAF) 25 mg daily is an acceptable alternative to TDF. 3
• TDF is the sole first-line oral agent for HBV treatment during pregnancy, with FDA safety data from ≥3,300 first-trimester exposures showing no increase in major birth defects. 1

Special Populations Requiring TDF Regardless of Viral Load

• Continue TDF throughout pregnancy in women with advanced fibrosis or cirrhosis, even if HBV DNA is below the 200,000 IU/mL threshold. 1, 2
• Switch from entecavir to TDF before or during pregnancy, as entecavir is FDA Category C (animal teratogenicity) while TDF is Category B. 1, 2

Delivery Planning

• Vaginal delivery is the preferred mode; do not perform cesarean section solely to reduce HBV transmission risk. 1, 2, 3
• The only narrow exception is Asian HBeAg-positive mothers with extremely high viral loads (>7 log₁₀ copies/mL) who did not receive antiviral therapy—cesarean may be considered in this specific scenario. 1
• Standard obstetric indications should guide all delivery mode decisions. 1, 2

Unknown HBsAg Status at Admission

• Test for HBsAg immediately upon hospital admission if maternal status is unknown or if the woman has new risk factors for acute HBV (injection drug use, recent STI evaluation). 4, 3

Delivery (Week 40+)

Neonatal Immunoprophylaxis: Time-Critical Intervention

• All infants born to HBsAg-positive mothers must receive both hepatitis B vaccine and HBIG within 12 hours of birth. 4, 1, 2, 3
• This dual immunoprophylaxis substantially reduces perinatal transmission risk and is the cornerstone of prevention. 4

Unknown Maternal Status at Delivery

• Administer hepatitis B vaccine within 12 hours of birth to infants of mothers with unknown HBsAg status. 4
• Add HBIG as soon as possible (but no later than 7 days after birth) if the mother subsequently tests HBsAg-positive. 4

Critical Pitfall to Avoid

• Never administer HBIG to the pregnant woman antepartum—maternal HBIG is completely ineffective at reducing transmission regardless of viral load. 1

Intrapartum Management

• Routine intrapartum care does not need alteration in HBsAg-positive women; neonatal immunoprophylaxis is the standard of care. 3

Postpartum Period

Maternal Antiviral Management

• Continue TDF through 12 weeks postpartum for women who started prophylaxis during pregnancy to prevent postpartum hepatitis flares. 1
• Monitor closely for viral reactivation and hepatitis flares after stopping antiviral therapy. 1, 2

Breastfeeding

• Breastfeeding is safe and should be strongly encouraged for all HBV-infected mothers, including those receiving TDF, as tenofovir levels in breast milk are low. 1, 2, 3
• The only contraindications are cracked or bleeding nipples in mothers with detectable HBV DNA and infants with oral ulcers. 1
• Discouraging breastfeeding is a common pitfall that contradicts current evidence showing safety with proper infant immunoprophylaxis. 1, 2

Infant Follow-Up

• Complete the hepatitis B vaccine series with the second dose at 1 month and third dose at 6 months of age. 1
• Perform serologic testing for anti-HBs at 9-12 months to confirm successful immunization. 1

Maternal Follow-Up and Case Management

• Refer HBsAg-positive mothers to the local Perinatal Hepatitis B Prevention Program for coordinated case management. 4, 1
• Establish effective systems for accurate and timely transfer of maternal HBsAg test results to labor, delivery, and newborn medical records. 4

Subsequent Pregnancies

• Screen in every subsequent pregnancy, even if prior tests were negative or the mother was vaccinated, to avoid missed infections. 4, 1

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Hepatitis C in Pregnancy: Key Distinctions

Do not treat hepatitis C during pregnancy; defer direct-acting antiviral (DAA) therapy to the postpartum period. 2, 8

Screening

• Screen women at increased risk for HCV by testing for anti-HCV antibodies at the first prenatal visit. 8
• Universal prenatal HCV screening is recommended as part of global elimination strategies. 2

Management

• No antiviral therapy is approved or recommended during pregnancy for HCV. 2, 8
• Avoid cesarean delivery solely for HCV prevention. 2, 8
• Breastfeeding is not contraindicated and should be encouraged. 2, 8
• Refer HCV-positive women to hepatology for DAA therapy postpartum. 2