Group B streptococcus, also called group B strep, is bacteria that causes infection that’s usually not serious for adults. How does group B strep affect pregnancy?

Published: December 3, 2021

Group B streptococcus, also called group B strep (GBS), is bacteria that causes infection. Many people carry group B strep bacteria without knowing it because they usually don’t have symptoms. The condition isn’t considered serious for adults but can be harmful to babies. What do expectant parents need to know about group B strep?

What is group B strep and how does it spread?

Group B strep bacteria live in the intestines as well as the urinary and genital tract. The strep bacteria occur naturally. Group B strep is not something one can catch from eating, drinking or sexual intercourse. Sometimes it can invade the body and cause GBS disease, which is infections such as:

• Bacteremia (bloodstream infection)
• Bone and joint infections
• Meningitis (tissue infection of the brain and spinal cord)
• Pneumonia
• Sepsis (body’s extreme response to an infection)
• Skin and soft-tissue infections

Group B strep affects newborns much more than it does adults. A baby can become infected during birth.

Group B strep symptoms in mothers and newborns

The pregnant patient usually does not appear sick or have symptoms of GBS. However, a baby experiencing GBS can have:

• Difficulty feeding
• Difficulty breathing
• Blue tint to skin
• Fever
• Irritability or limp appearance

These symptoms are similar to other health issues newborns can experience. Babies who have GBS in the first week of life are diagnosed with early onset GBS disease. Many times, these babies show symptoms at birth. However, children who develop the condition later, after appearing healthy at birth, are diagnosed with late-onset GBS disease. These conditions are the leading cause of meningitis and bloodstream infections in the first three months of life for newborns in the U.S.

How to protect baby from group B strep

About 1 in 4 pregnant patients carry group B strep bacteria, according to the Centers for Disease Control and Prevention (CDC). Babies are at risk of developing GBS disease if the pregnant patient:

• Tests positive for group B strep late during pregnancy
• Develops fever during labor
• Has 18 hours or more pass between the water breaking and when baby is born

To help protect children, OB/GYNs test patients for group B strep between the 36th and 37th week of pregnancy. If the patient tests positive, they can be given intravenous (IV) antibiotics during labor to prevent early onset GBS disease in the child. According to the CDC, a patient who receives IV antibiotics during delivery has a 1 in 4,000 chance of delivering a child who develops GBS disease. However, in cases where the pregnant patient does not receive the IV medication, the chance increases to 1 in 200. Antibiotics during pregnancy don’t work as a preventive, because the bacteria grow back quickly; the best defense is to receive the antibiotics during labor. Because of testing and prevention methods for GBS, there are low rates of early onset and late-onset GBS disease.