Everything you need to know about Group B Streptococcus (GBS) during pregnancy and in general

What is GBS?

GBS is short for a bacteria called Group B Streptococcus. This bacteria is sometimes also referred to as Streptococcus Agalactiae.

Where does GBS originate? Is it only found in pregnant women?

Remember how the human body hosts millions of bacteria? Well, in approximately 20% of the general population, this bacteria is simply part of the natural flora found in the intestines. Therefore, GBS can be one of many bacteria that live in our bodies naturally and cause absolutely no harm.

So, the answer to this question is that GBS is not only found in pregnant women but also in a large proportion of the general population.

How does one catch this bacteria?

This bacteria is often naturally found in some people’s gastrointestinal system, where it is part of the delicate balance of bacteria in their intestines. A person can carry this bacteria in their body either temporarily, for a short period of time, or for longer periods.

What can GBS cause?

GBS can cause several different types of invasive infections in people of various age groups, regardless of whether or not they are pregnant, ranging from infancy to adulthood. Some of these infections are mild (such as urinary tract infections), while others are invasive (such as sepsis and meningitis).

The majority of morbidity occurs in infants who are 1 week old and whose mothers are GBS carriers.

Is carrying the bacteria during pregnancy dangerous?

This is an important point to understand. The bacteria is not inherently dangerous during the pregnancy itself, but it poses a threat to the baby if it is passed on during delivery. There is a concern that the neonate could become infected as they pass through the birth canal, which may increase their risk of developing early sepsis during the first week of life.

For neonates, this infection is associated with severe morbidity, short-term mortality, and a risk of neurodevelopmental complications in the long run.

Is it important to identify this bacteria and treat pregnant women who test positive for GBS?

Absolutely! The guidelines for pregnant women in most countries include screening for GBS and treating those who test positive prior to delivery.

So, how can we tell if a woman is positive for GBS?

According to national guidelines in most countries, pregnant women must undergo screening for GBS between the 35th and 37th weeks of gestation.

How is this screening performed?

Since the bacteria is carried in the intestines, a cotton swab is used to collect a sample from both the rectum and the vagina.

Where can this test be done?

Pregnant women can perform this test themselves using a cotton swab. The cotton swab can be kept at room temperature but must be sent for culture within 24 hours. Most obstetrics/gynecology practices or family practices can provide the swab for testing.

How long does it take to get the results?

This can vary depending on your practice, but it typically takes about 2-3 days for the culture results to come back. The result will be either positive or negative for the bacteria.

Are there women who do not need to take this test?

Yes. Women who have had a urine test and urine culture during pregnancy and were found positive for GBS, as well as those who have had a child who suffered from an invasive GBS infection in their first week of life, do not need to take the test. In both cases, it is assumed that the woman is already positive for GBS.

Why? The reasoning is that if the woman had a urinary tract infection caused by GBS during her current pregnancy, it is assumed she is carrying a significant amount of the bacteria, and therefore, there is no need to screen her again. The same logic applies to women who have had a child with an invasive GBS infection.

If results indicate that I am positive for GBS, do I need to start antibiotics immediately?

No, immediate treatment is not necessary. However, intravenous antibiotic treatment is required during delivery, and it is important to receive at least one dose of antibiotics 4 hours before delivery. Therefore, you should make sure to arrive at the hospital early when contractions begin or as soon as your water breaks.

What happens if a woman misses her screening test?

There are two options, depending on where you plan to deliver.
For women who have not been tested, some birth centers can perform PCR tests that provide results within an hour.
Another option is to treat women who are at increased risk of infection but have an unknown GBS status with antibiotics.
Factors that increase risk for infection include:
• Preterm delivery before 37 weeks’ gestation.
• Prolonged rupture of membranes for more than 18 hours.
• Women with a fever of 38 degrees Celsius or higher during labor.

Are antibiotics also required for caesarean delivery?

The concern about infection transmission is during passage through the birth canal. In cesarean deliveries, where there has been no rupture of membranes (when the woman’s water does not break), the neonate does not pass through the birth canal. Therefore, there is no need for preventive antibiotic treatment, even if the woman is GBS positive.

I am scheduled for a caesarean section; do I still need to get screened for GBS?

According to national guidelines, a culture should be taken even in women scheduled for a cesarean section because they may go into spontaneous labor before the scheduled delivery date.

What type of antibiotics are given to women who are found positive for GBS?

Treatment typically includes an antibiotic from the penicillin family, usually ampicillin. The treatment is always administered intravenously. Of course, there are alternative treatment options for women who are allergic to penicillin. You can read more about penicillin allergy here.
Please note that treatment for the prevention of GBS in the neonate must be administered intravenously. Oral medication administered prior to labor is ineffective for this purpose.

If I was positive for GBS in my previous pregnancy but am negative in my current pregnancy, do I still need to be treated?

If a woman was positive for GBS in her previous pregnancy but is negative in her current pregnancy, there is no need for treatment.
Exceptions to this rule include cases such as having a urinary tract infection caused by GBS during the current pregnancy or having had a previous child who suffered an invasive GBS infection after birth.

What if I should have received antibiotics but did not receive them on time?

This can sometimes happen. Keep in mind that the chances of transmitting the infection to the neonate are quite small to begin with, even without preventive antibiotic treatment. However, if the mother hasn’t received treatment and is a carrier of the bacteria, the pediatric team will need to monitor the infant closely for any signs of infection and treat them accordingly, as needed.

In summary, this is a very important topic that everyone should be aware of, especially pregnant women. It’s crucial to get screened and receive preventive antibiotic treatment if needed.

Good luck everyone!