Beta Strep Infection during Pregnancy

What is group B streptococcus (beta strep)?

Group B streptococcus (also called beta strep, or GBS), is a very common type of bacteria. Ten to thirty percent of pregnant women carry GBS bacteria. Most often the bacteria are in the vagina or rectum. GBS bacteria are different from the type of bacteria that cause strep throat.

Healthy adults carrying GBS may not have any symptoms or problems. However, sometimes the bacteria can cause an infection in the uterus, bladder, or kidneys. These infections in adults are usually not serious and can be treated with antibiotics. But a baby can get very sick and even die if the mother has untreated GBS.

How does it occur?

Both women and men may have GBS. The bacteria often live in the mouth, bowel, bladder, vagina, and rectum. A woman who carries GBS can pass it to her baby during labor or delivery.

How is it diagnosed?

GBS can be found by testing urine or swabbing the vagina or rectum. The samples of fluid are cultured in a lab. A test result is positive if beta strep bacteria are found in the culture. The test is negative if the bacteria are not found. The Centers for Disease Control (CDC) recommends that all pregnant women have a GBS culture in the 35th to 37th weeks of pregnancy.

A rapid test for GBS may be done when you go to the hospital to deliver your baby. The results of this test can be known in 2 to 3 hours. However, it is less accurate than cultures and is rarely used earlier in a pregnancy.

How is it treated?

If your tests for beta strep are positive, you will probably not be treated until you are in labor. During labor you will be given intravenous (IV) antibiotics. If you were treated earlier in the pregnancy, the bacteria could come back again before the baby is born. The one exception is when a urine culture, done at any time during pregnancy, shows that GBS is causing a bladder infection. In this case your health care provider will probably prescribe an oral antibiotic to treat the infection.

Because infection of the baby can cause serious problems, you may be treated during labor if you have any risk factors for beta strep infection, even if your test results are negative. The risk factors are:

• preterm labor (labor that starts before 37 weeks of pregnancy)
• premature rupture of membranes (water breaking before 37 weeks of pregnancy)
• membranes ruptured for longer than 18 hours
• a previous child with beta strep infection
• fever (higher than 100.4°F, or 38.0°C) during labor.

Treatment with IV antibiotics during labor is usually very effective. Babies rarely develop the serious side effects of GBS infection with this treatment.

If a newborn develops any signs or symptoms of GBS infection, the baby is treated with IV antibiotics and watched very closely. The baby may stay in a special intensive care unit.

How long will the effects last?

A woman who has GBS does not usually have any symptoms of illness or long-lasting effects. The main risk is that the newborn will become sick. GBS infection can affect the baby's blood, brain, spinal cord, or lungs. The baby may have long-term problems that affect hearing, vision, or learning abilities if the brain is infected. The baby might die.

How can I help prevent GBS infection of the baby?

Getting tested for GBS and being treated with antibiotics during labor, if necessary, greatly reduces the risk that your baby will be infected with GBS.