Which of the following hepatitis viruses is most commonly associated with fulminant hepatic failure in pregnant women, particularly in the third trimester?

Explanation

## Hepatitis E Virus (HEV) — Fulminant Hepatic Failure in Pregnancy **Key Point:** Hepatitis E virus causes fulminant hepatic failure (FHF) in pregnant women with a mortality rate of 15–25%, compared to <1% in the general population. This is the most distinctive and clinically significant feature of HEV infection in pregnancy. **High-Yield:** The increased severity in pregnancy is: - Unique to HEV among all hepatitis viruses - Highest in the **third trimester** - Associated with high viral loads and rapid disease progression - Leads to maternal mortality and fetal loss **Clinical Pearl:** The mechanism of increased severity in pregnancy remains incompletely understood but may involve: - Altered immune response (Th2 shift) - Hormonal factors (estrogen, progesterone) - Increased viral replication - Impaired interferon response **Mnemonic:** **HEV = Hazard in prEgnancy** — Remember HEV for fulminant disease in pregnant women. ### Hepatitis Viruses and Pregnancy Outcomes | Virus | Acute Infection in Pregnancy | Fulminant Hepatic Failure Risk | Vertical Transmission | Chronic Infection | | --- | --- | --- | --- | --- | | **HAV** | Mild-moderate | Rare (<1%) | No | No | | **HBV** | Mild-moderate | Rare | Yes (high if acute 3rd trimester) | Yes (10–15% if acute in pregnancy) | | **HCV** | Mild-moderate | Rare | Yes (5%) | Yes (80%) | | **HEV** | **Severe** | **15–25%** | **Yes (high)** | No (except immunocompromised) | ### Clinical Features of HEV in Pregnancy 1. **Timing:** Usually manifests in 2nd–3rd trimester 2. **Severity:** Rapid progression to encephalopathy and coagulopathy 3. **Outcomes:** - Maternal mortality: 15–25% - Fetal loss: 20–30% - Preterm delivery: common 4. **Transmission:** Vertical transmission occurs in ~30% of infected pregnancies **Warning:** HEV should be specifically screened in any pregnant woman presenting with acute hepatitis, particularly in endemic regions (South Asia, Africa, Central America). [cite:Harrison 21e Ch 297]