Question

Maximum chance of transmission to the baby during delivery is seen with which infection?

• A. HSV (Herpes simplex virus)
• B. CMV (Cytomegalovirus)
• C. VZV (Varicella zoster virus)
• D. Rubella

Hint:

Which virus infects the baby by contact in the birth canal rather than across the placenta?

Answer 1

The Correct Option is A

Step 1: The question asks which infection is transmitted maximally at the time of delivery, that is, by the intrapartum or perinatal route rather than across the placenta.

Step 2: Herpes simplex virus is the answer. Transplacental spread of HSV is uncommon. The neonate is infected mainly by contact with virus shed from the cervix and lower genital tract during passage through the birth canal at vaginal delivery, giving the highest risk of intrapartum transmission.

Step 3: Why the others are wrong. CMV and rubella are classic transplacental (intrauterine) infections, so their main risk is before delivery, not during it. Varicella zoster also spreads mainly transplacentally, causing congenital varicella when contracted early or severe neonatal varicella when maternal rash appears around term, but the dominant route is not contact in the birth canal.

Step 4: Because HSV is acquired chiefly during passage through an infected genital tract, the maximum chance of transmission during delivery is with HSV.