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Preparing for Birth - Group Beta Strep

What is Group Beta Strep?

Group Beta Strep (GBS) Is a bacteria that lives in the intestines and vaginal canal. It is common to be in the lower half of the body. GBS is transient and can move. Aggressive Strains of GBS may ascend into the bladder or the uterus. Approximately 20–30% of pregnant women are colonized in the vagina and/or rectum.

How does GBS affect my body and my baby?

GBS may cause a urinary tract infection (UTI) if it ascends in through the urethra and into the bladder. This bacteria doesn't usually cause UTI have symptoms in pregnancy. It is common to test for UTI throughout pregnancy to detect if GBS is present. The prescense of GBS can weaken the amniotic fluid sac and cause the water to break before labor. This may lead to the need for more intervention.

GBS can cross the placental barrier into the amniotic fluid. When this occurs, the baby will breathe the amniotic fluid in as they practice breathing movements. GBS may be present in your baby's lungs once baby is born. Once baby takes their first breath, it will create a dark and warm environment where GBS can grow and multiply. This can create GBS aquired infection that is similar to pnemonia.

Another way of colonization occurs a baby descends into the vaginal canal. GBS is normal to be in our lower digestive tract but not in our respiratory tract. As baby comes into the vaginal canal, GBS can ascend into the nasal cavity, sinus passages, and into the lungs.

Is GBS dangerous?

According to studies, 50-70% of babies born to mothers who test GBS positive become colonized without infection or symptoms. 1-2% of infants devleop GBS acquired infection.

GBS is the leading cause of invasive neonatal infection worldwide. Babies born prematurely make up 28% of all GBS aquired infection cases. Of those preterm infants, fatality rates are higher, 19%. Of the 72% of term GBS aquired infection cases, fatality rates are 2%.

Early onset GBS

Early-onset GBS disease is when an infant is positive to GBS aquired infection within 6 days of birth. GBS symptoms and illness typically presents within 12 to 24 hours after delivery.

Late onset GBS

Late-onset GBS disease is when an infant is postive with GBS aquired sinfection within one week to three months of age. Late onset GBS is caused by hospital inquired infection usually from a care provider. GBS menegitis accounts for 31% of cases.

Screening for GBS in Pregnancy

American College of Gynecology (ACOG) recommends that all pregnant women have antenatal testing for GBS colonization with a vaginal-rectal culture at 36 to 37 weeks of pregnancy. This vaginal-rectal culture is completed either by your health provider. If you are planning a birth with a birth center or homebirth midwives, you will most likely do the vaginal sawb yourself.

Screening is also recommended for any woman with preterm labor or if water breaks before 37 weeks of pregnancy. If urine is positive for GBS, you will be considered automatically GBS positive. Due to the transient nature of GBS, even with a negative test, a baby can still be born to a woman with a negative test. Early-onset GBS occurs in infants born to mothers with negative screening in approximately 8% of cases.

Treatment for GBS

Antibiotics are recommended throughout labor to reduce the bacterial count and reduce infection. Antibiotics in labor temporarily decreases vaginal GBS colonization, reducing the chance baby may come in contact with GBS in the vaginal canal. Newborn bloodstream antibiotic levels also exceed the minimum inhibitory concentration for GBS.

Treatment is considered completed upon receiving two doses of antibiotics spaced 4 hours apart and provided throughout the entirty of labor. For women allergic to penicillin who are at high risk of allergic reaction, clindamycin is usually provided. For women colonized with clindamycin-resistant GBS or who are allergic to penicillin and at high risk of a reaction, vancomycin is recommended.

Risks and Benefits for Treatment of Antibiotics

Potiential Benefits:

Treating you with antibiotics before your labor begins does not reduce the chance of your baby developing GBS infection. Antibiotics are provided during labor by IV. These antibiotics reduce the risk of your baby developing a GBS infection in their first week of life from around 1 in 400 to 1 in 4000. This reduction in risk is not a prevention method.


  • Antibiotics can cause allergic reaction, this allergic reaction may be severe. Even without previous reaction to antibiotics.

  • Antibiotics causes reduction of good bacteria in the gut for mom and baby.

    • For Mom:

    • disruption of gut bacteria that leads to increased risk of infection and illness

    • Increased risk of yeast infection including yeast in breast milk ducts leading to thrush and vaginal yeast

    • For Baby:

    • Increased risk of developing necrotizing enterocolitis (NEC)

    • Increased risk in developing autoimmune disease later in life, exposure to antibiotics was associated with a 28% increased risk for autoimmune diseases

    • Increased risk of childhood illness and infection

What are symptoms of GBS aquired infection?

  • Difficulty feeding

  • Fever

  • Irritability or lethargy (limpness or baby is hard to wake up)

  • Difficulty breathing

  • Blue-ish color to skin

What happens if my baby has GBS aquired infection?

Treatment for babies with GBS aquired infection are antbiotics. GBS infection is treated promptly and aggressively. Your baby will recieve high doses of IV antibiotics for at least 7 days or 14 days if meningitis is present. With antibiotics, the majority of babies with GBS infection can be treated successfully with antibiotics. Babies who are treated for GBS aquired infection will be treated in the neonatal itensive care unit (NICU).

Even with full intensive care, neonatal mortality rates are approximately one out of every 16 infected babies and around 5% of babies with early-onset and around 8% with late-onset GBS infection.

The Take Away:

GBS testing is offered to every pregnant woman at 36-37 weeks of pregnancy. The testing is faulty, it only tests if GBS is present on that day. GBS is transient, it may be there one day and not another. As a midwife we watch every baby as if they can develop GBS acquired infections. With local hospital policies, the question has been asked:

If I do not want to test for GBS, do I really need to test?

Generally most hospitals will automatically consider a woman who has not tested as positive for GBS. They will offer antbiotics in labor. If you are giving birth in a birth center or at home, the only time it may become an issue is if the family transfers to the hospital. In the event that a woman chooses not to test or take antibiotics in labor, the hospital will require a blood culture to confirm the baby does not have GBS in their blood stream that may lead to infection. This may prolong a stay at hospital. In the event that GBS is found in the blood stream or baby shows symptoms of GBS aquired infection, the baby will be admitted into the NICU for treatment of antibiotics.

Choosing to test or not is a very personal choice, as is the decision to choose antibiotics. Informed decision making is important, knowing all the risks and benefits so families feel they have made the best choice for their health and the health of their baby.

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