A 28-year-old woman from Mumbai attends the antenatal clinic at 20 weeks gestation. Routine screening for blood-borne viruses is performed. Her serology shows: HBsAg positive, anti-HBc IgG positive, anti-HBc IgM negative, HBeAg negative, anti-HBe positive, anti-HBs negative. She has no history of jaundice or liver disease. Liver function tests are normal. What is the most likely diagnosis and what is her risk of vertical transmission?

Explanation

## Interpretation of HBeAg-Negative Chronic HBV ### Serological Pattern Recognition **Key Point:** The combination of HBsAg+ with anti-HBc IgG+ and anti-HBc IgM− indicates chronic hepatitis B. The presence of anti-HBe (with HBeAg−) indicates low viral replication and low infectivity. ### HBeAg Status and Viral Replication | Marker | HBeAg+ (High Replication) | HBeAg− (Low Replication) | |--------|---------------------------|------------------------| | **HBV DNA level** | >10^5 copies/mL | <10^4 copies/mL | | **Infectivity** | Very high | Low | | **Vertical transmission risk** | >90% (if HBeAg+) | <10% (if HBeAg−) | | **Chronic progression** | Faster | Slower | | **Anti-HBe** | Negative | Positive | **High-Yield:** HBeAg status is the strongest predictor of vertical transmission risk in pregnant women. HBeAg+ mothers have >90% risk; HBeAg− mothers have <10% risk. ### Clinical Significance in Pregnancy **Clinical Pearl:** This patient is HBeAg−/anti-HBe+, indicating: 1. Low HBV DNA levels (low viral load) 2. Low infectivity to contacts and neonate 3. Slower progression of liver disease 4. Still requires neonatal prophylaxis (HBV vaccine + HBIG) but risk is substantially lower **Warning:** Do not assume all HBsAg+ pregnant women have high transmission risk. HBeAg status must be checked. HBeAg− mothers can still transmit, but the risk is much lower. ### Management Implications - Neonatal vaccination and HBIG are still recommended for all HBsAg+ mothers - Breastfeeding is safe if infant receives appropriate prophylaxis - Antiviral therapy during pregnancy is NOT routinely indicated for HBeAg− mothers with normal LFTs - Follow-up serology and HBV DNA quantification should be performed postpartum