**Core Concept:** Foetal varicella syndrome (FVS) is a severe complication of maternal varicella (chickenpox) infection during pregnancy. It can lead to severe birth defects and infant mortality. Prevention of FVS is crucial through timely vaccination and avoidance of exposure to varicella.

**Why the Correct Answer is Right:**

The correct answer, **Option C: Varicella-Zoster Immune Globulin (VZIG)** is used to prevent FVS. VZIG is a human immunoglobulin product containing specific antibodies against Varicella-Zoster virus (VZV). When administered within 96 hours after exposure to VZV, it can reduce the risk of FVS by neutralizing the virus in the mother's bloodstream and thereby protecting the fetus from infection.

**Why Each Wrong Option is Incorrect:**

A. **Option A: Acetaminophen (Paracetamol)** is a pain reliever and fever reducer, but it does not provide immunity against VZV infection. It is not a preventive measure against FVS.

B. **Option B: Oral Acyclovir (antiviral)** is a medication commonly prescribed for treating herpes simplex virus (HSV) infections and not VZV. It does not prevent FVS and is not recommended for use in this context.

D. **Option D: Pregnancy termination (abortion)** is an extreme measure not recommended for preventing FVS. Instead, prompt administration of VZIG is the safer and more appropriate way to reduce the risk of FVS.

**Clinical Pearl:**

To prevent foetal varicella syndrome, it is crucial to administer Varicella-Zoster Immune Globulin (VZIG) within the first 96 hours after potential VZV exposure. Early intervention can significantly reduce the risk of FVS and protect the developing fetus from severe complications.

In summary, the correct method to prevent FVS is administering VZIG, while acetaminophen, oral acyclovir, and pregnancy termination are incorrect options for this prevention. Always seek medical advice promptly after potential VZV exposure to ensure the best course of action for both the mother and fetus's wellbeing.