Even women who acquire genital herpes during the first two trimesters of pregnancy are usually able to supply sufficient antibody to help protect the fetus.
Babies born prematurely may be at a slightly increased risk, however, even if the mother has a long-standing infection.
If you are a man with either oral or genital herpes and your partner is uninfected and pregnant, you can do even more to protect the baby.
Since the highest risk to an infant comes when the mother contracts HSV-1 or 2 during pregnancy, you can take steps to ensure that you don't transmit herpes during this crucial time.
To put this in greater perspective, an estimated 20-25% of pregnant women have genital herpes, while less than 0.1% of babies contract an infection.
But on the other hand, the risk is extremely low, experts agree especially for women with known, long-standing infections.
The chances of transmission are highest when a woman acquires genital herpes late in pregnancy.
Unfortunately, when infants do contract neonatal herpes, the results can be tragic.
If the mother's infection is a true primary (she has no previous antibodies to either HSV-1 or HSV-2), and she seroconverts (becomes HSV positive) at the end of pregnancy, the risk of transmission can be as high as 50%, according to research by Brown and others.
The risk is also high if she has prior infection with HSV-1 but not HSV-2.