Definition of Birth-acquired herpes:

Birth-acquired herpes is a herpes virus infection that an infant gets (acquires) at the time of birth.

Causes, incidence, and risk factors:

Newborn infants can become infected with herpes virus:

• In the uterus (intrauterine herpes -- this is very rare)
• Passing through the birth canal (birth-acquired herpes, the most common method of infection)
• Right after birth (postpartum) from kissing or having other contact with someone who has herpes mouth sores

If the mother has an active genital herpes infection at the time of delivery, the baby is more likely to become infected during birth. Some mothers may not be aware they have internal (inside the vagina) herpes sores.

Some people have had herpes infections in the past, but were not aware of it. These people, not knowing that they have herpes, may pass it to their baby.

Herpes type 2 (genital herpes) is the most common cause of herpes infection in newborn babies, but herpes type 1 (oral herpes) can also occur.