Group B Streptococcus (GBS) Symptoms & Causes

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In-Depth

What is group B streptococcus?

GBS is a bacterium that can be found in the digestive tract, urinary tract and genital area of adults. Although GBS usually does not cause problems in healthy women before pregnancy, it can cause serious illness for the mother and baby during pregnancy and after delivery.

What causes group B streptococcus?

The bacterium that causes GBS may live in an adult's body for years and not cause any problems. The only time it becomes an issue is when a woman gets pregnant.

  • Newborns can contract GBS during pregnancy, or from the mother's genital tract during labor and delivery.
  • GBS is the most common cause of life-threatening infections in newborns, including pneumonia and meningitis
  • In a pregnant woman, GBS infection may cause chorioamnionitis (a severe infection of the placental tissues) and postpartum (after birth) infection. Urinary tract infections caused by GBS can lead to preterm labor and birth.
  • Although it is rare, GBS may also develop in babies one week to several months after birth. Only about half of late-onset GBS disease among newborns comes from a mother who is a GBS carrier. The source of infection for others with late-onset GBS disease is unknown.

Is group B streptococcus common?

One out of every four or five pregnant women carries GBS in her rectum or vagina.

  • About one out of every 100 to 200 babies whose mothers carry GBS develop symptoms of GBS disease.
  • Nearly 75 percent of the cases of GBS disease among newborns occur in the first week of life, called early-onset disease.
  • Premature babies are more susceptible to GBS infection than full-term babies.

What are the symptoms of group B streptococcus?

Most newborns with GBS infection have symptoms in the first few hours after birth. Symptoms are related to the body systems that are affected by the infection. The symptoms for early-onset GBS can also seem like other problems. If you think your newborn is sick, call your doctor immediately. Some symptoms may include:

  • breathing problems
  • changes in blood pressure
  • neurologic problems such as seizures
  • fever
  • difficulty feeding
  • irritability
  • lethargy (limpness or hard to wake up the baby)

Can you preventgroup B streptococcus?

Yes. The Centers for Disease Control and Prevention recommends that all pregnant women be tested for GBS in her vagina and rectum when she is 35 to 37 weeks pregnant. GBS can be cultured with a swab during a pelvic examination or from a mother's urine. If you are a carrier, you should be given antibiotics through the vein (IV) at the time of labor or when their water breaks.

It's important to understand that, in spite of testing and treatment, some babies still develop GBS disease. Research is ongoing to develop vaccines to prevent GBS disease. In the future, women who are vaccinated against GBS may make antibodies that cross the placenta and protect the baby during birth and early infancy.

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