GBS in Pregnancy: Your Guide to a Safe Birth

Caring for your health during pregnancy involves more than just ultrasound scans; it also includes simple diagnostics that provide vital protection for your baby. One of the key tests in the third trimester is the GBS (Streptococcus agalactiae) swab. Although the name sounds serious, proper knowledge and procedures ensure that the presence of this bacteria does not threaten your peace of mind.

What is GBS?

GBS stands for Group B Streptococcus – a bacterium naturally found in the bodies of many healthy people.

• It is not an infection: The presence of GBS in a pregnant woman is called colonization, not a disease. It is estimated to affect 10% to 30% of women.

• Natural flora: This bacterium typically resides in the digestive and reproductive tracts without causing any symptoms or affecting your well-being.

  
  

Why do we perform this test?

While GBS is harmless to you, it can be passed to the baby during a vaginal birth. In a small percentage of newborns, this can lead to infections (such as pneumonia or sepsis). This test allows us to identify which mothers should receive prophylactic antibiotics, reducing the risk of infection in the baby by over 80%.

When and how is the swab collected?

According to Polish perinatal care standards and international guidelines:

• Timing: The test is performed between the 35th and 37th week of pregnancy.

• EBM Fact: The latest American guidelines (ACOG) suggest a window of 36 0/7 – 37 6/7 weeks to ensure the result is as current as possible at the time of delivery.

• Method: It is a quick and painless test. A swab is used to collect a sample from the vaginal introitus and the rectum (this is crucial, as the bacteria originate in the digestive tract).

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What does a positive GBS(+) result mean?

If your result is positive – stay calm. It does not mean that you or your baby are ill.

• No treatment during pregnancy: Oral antibiotics are not administered before labor because the bacteria would simply return. Treatment only begins once labor starts.

• Intrapartum prophylaxis: When contractions begin or your water breaks, you will receive intravenous antibiotics (usually penicillin) at the hospital. This is the most effective method of protecting your baby.

• Planned C-section: If you have a planned Cesarean section before the rupture of membranes and the start of labor, GBS prophylaxis is usually not necessary.

  
  

Exceptional Situations (Proceeding without a result)

If labor begins before the test is performed or if your result is unknown, doctors will implement "just in case" prophylaxis if risk factors occur, such as:

• Preterm labor (before 37 weeks).

• Prolonged rupture of membranes (>18 hours before delivery).

• Maternal fever during labor (≥38°C).

  
  

Summary for the Mother-to-be

GBS status is simply logistical information for your midwife and doctor. By knowing your status, we can give your baby the best possible start. Remember to pack your test result (the original lab report) in your hospital bag!

EBM-based Sources:

• PTGiP Recommendations for the prevention of GBS infections.

• ACOG Guidelines: Prevention of Group B Streptococcal Early-Onset Disease.

• RCOG Patient Information: Group B Streptococcus (GBS) in pregnancy and newborn babies.

• Swab collection standards - Gov.pl.