There are some infections that can be transmitted to a baby during the birth process. Most important among these is Group B streptococcus (GBS). Generally, you will be screened for GBS just before labor, in order to prevent transmission to your newborn.
GBS is a type of bacteria that can cause serious infections in pregnant women and newborns. GBS (part of the normal bacteria found in healthy individuals) is often found in the mouth and throat, lower-intestinal tract, and vagina of healthy women. Pregnancy increases the risk of GBS infection to both mother and baby due to several factors that may create an imbalance in the body's bacterial makeup.
Herpes is a sexually transmitted viral infection that can be transmitted from mother to baby during delivery. If you have a history of herpes, and feel that an outbreak may be imminent, then you may be visually screened for lesions before or during labor.