Group B Strep: FAQs

Group B Streptococcus (group B strep) is a type of bacteria that causes illness in newborn babies, pregnant women, the elderly, and adults with other illnesses, such as diabetes or liver disease. Group B strep is the most common cause of life-threatening infections in newborns.

Question: How common is group B strep disease in newborns?

Answer: Group B strep is the most common cause of sepsis (blood infection) and meningitis (infection of the fluid and lining around the brain) in newborns. Group B strep is a frequent cause of newborn pneumonia and is more common than other, more well-known, newborn problems such as rubella, congenital syphilis, and spina bifida.

In the year 2001, there were about 1,700 babies in the U.S. less than one week old who got early-onset group B strep disease. More detailed information about group B strep disease rates can be found at

Question: How does group B strep disease affect newborns?

Answer: About half of the cases of group B strep disease among newborns happen in the first week of life ("early-onset disease"), and most of these cases start a few hours after birth. Sepsis, pneumonia (infection in the lungs), and meningitis (infection of the fluid and lining around the brain) are the most common problems. Premature babies are more at risk of getting a group B strep infection, but most babies who become sick from group B strep are full-term.

Group B strep disease may also develop in infants one week to several months after birth ("late-onset disease"). Meningitis is more common with late-onset group B strep disease. Only about half of late-onset group B strep disease among newborns comes from a mother who is a group B strep carrier; the source of infection for others with late-onset group B strep disease can be hard to figure out. Late-onset disease is slightly less common than early-onset disease.

Question: Can group B strep disease among newborns be prevented?

Answer: Yes! Most early-onset group B strep disease in newborns can be prevented by giving pregnant women antibiotics (medicine) through the vein (IV) during labor. Antibiotics help to kill some of the strep bacteria that are dangerous to the baby during birth. The antibiotics help during labor only -- they can't be taken before labor, because the bacteria can grow back quickly. Any pregnant woman who had a baby with group B strep disease in the past, or who now has a bladder (urinary tract) infection caused by group B strep should receive antibiotics during labor. Pregnant women who carry group B strep (test positive during this pregnancy) should be given antibiotics at the time of labor or when their water breaks.

Question: What are the symptoms of group B strep in a newborn?

Answer: The symptoms for early-onset group B strep can seem like other problems in newborns. Some symptoms are fever, difficulty feeding, irritability, or lethargy (limpness or hard to wake up the baby). If you think your newborn is sick, get medical help right away.

Question: How is group B strep disease diagnosed and treated in babies?

Answer: If a mother received antibiotics for group B strep during labor, the baby will be observed to see if he or she should get extra testing or treatment. See the newborn management section of the CDC’s revised prevention guidelines to learn more.

If the doctors suspect that a baby has group B strep infection, they will take a sample of the baby’s sterile body fluids, such as blood or spinal fluid. Group B strep disease is diagnosed when the bacteria are grown from cultures of those fluids. Cultures take a few days to grow. Group B strep infections in both newborns and adults are usually treated with antibiotics (e.g., penicillin or ampicillin) given through a vein (IV).

Question: How will I know if I need antibiotics to prevent passing group B strep to my baby?

Answer: You should get a screening test late in pregnancy to see if you carry group B strep. If your test comes back positive, you should get antibiotics through the vein (IV) during labor.