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Group B streptococcus basics

Take steps to prevent this serious infection.

Pregnant women can do a lot to make sure their baby is healthy. Screening for group B streptococcus (GBS) should be on the list.

GBS is a common cause of life-threatening infection in newborns, says the Centers for Disease Control and Prevention (CDC).

Yet a few simple steps can usually prevent it.

What is it?

GBS is a bacterium that lives in the gastrointestinal system. In women, it's usually found in the vagina or rectum.

GBS usually isn't a problem for a woman. But for pregnant women, it may increase the chances of:

  • Bladder infections.
  • Uterine infections.
  • Stillbirth.

It can also infect a baby. This can happen during childbirth.

In most cases GBS won't make a baby sick. But when it does, it can infect the:

  • Lungs.
  • Blood.
  • Brain.
  • Spinal cord.

Early GBS infections occur within a week of birth. They usually happen on the first day.

Late GBS infections occur after the first week of life. Late infections can come from the mom. They can also come from other sources, such as people who carry the bacteria.

Some GBS infections have lasting effects. These may include:

  • Hearing loss.
  • Vision loss.
  • Learning disabilities.

About 5% of babies who get sick from GBS don't survive, according to the March of Dimes.

How common is it?

About 25% of pregnant women have GBS, says CDC.

Can it be prevented?

Women should be screened for GBS between weeks 36 and 38 of pregnancy, says the American College of Obstetricians and Gynecologists.

Women who test positive for GBS need medicine. So do women who are at high risk for passing on GBS. Both these groups should take antibiotics during labor and delivery.

Women who have had GBS found in their urine during their current pregnancy are high risk. So are women who have passed on GBS to a baby in an earlier pregnancy.

Antibiotics should also be given to women whose GBS status isn't known and who have:

  • Premature labor (before the 37th week of pregnancy).
  • A rupture of membranes 18 hours or more before delivery.
  • A fever of 100.4 degrees or higher during labor.

Researchers are also working on several vaccines to prevent GBS.

Reviewed 5/23/2024

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