Group B streptococcus, also referred to as 'beta strep' or 'GBS', is a common, naturally occurring bacteria found in the intestines or gastrointestinal tract, which can move into the vagina and/or rectum.

It is possible that the bacteria are in your system for a short period of time; however, you might always carry it, or it could come and go.

GBS is not a sexually transmitted disease, nor is it transmitted through food or water. And although it has the word 'strep' in it, it is not related to the bacteria that causes strep throat.

As ominous as this sounds, GBS is usually harmless in adults. The greater danger is to babies born through vaginal deliveries to mothers who are carriers. According to the Centers for Disease Control and Prevention (CDC), group B strep is the most common cause of life-threatening infections in newborns.

How Common Is It?

Approximately 1 in 4 women carry the GBS bacteria. (Being a carrier does not mean that you have the disease, but it does mean that you can pass it along to your baby during delivery.)

Am I at Risk for Group B Strep?

Anyone (male or female) can be a carrier for GBS. However, you're at increased risk of an infection from the bacteria if you have a weakened immune system from a condition like diabetes or a disease like HIV.

What are the Symptoms?

Most carriers don't know they have the bacteria and don't show any symptoms. Women carriers will likely only find out if they are tested during a pregnancy. If the bacteria cause an infection, you might develop a urinary tract infection (bladder infection) or a uterine infection (called chorioamnionitis if developed before delivery). Chorioamnionitis could cause a fever, tenderness of the uterine area, and an increased heart rate in your baby. Your health care provider can treat you with antibiotics that are safe for your baby.

How Do I Know if I am a Group B Strep Carrier?

The CDC recommends that pregnant women be screened between the 35th and 37th week of pregnancy. Since the bacteria can come and go, testing any earlier wouldn't be a good indication of whether or not the bacteria would be present during labor.

Screening for GBS is relatively simple: your health care practitioner will swab your vaginal and rectal area. Results should be back within 1 – 2 days.

What Happens if I Test Positive?

Testing positive for GBS only means that you're a carrier. If, during your pregnancy, you develop complications due to GBS, your doctor can give you an oral antibiotic that is safe for your baby.

During a vaginal delivery, your baby can come into contact with the bacteria in the vagina, increasing his chances of contracting GBS. To prevent this from happening, GBS carriers are routinely given antibiotics (via an IV) during delivery. Make sure to remind your delivery team that you are a carrier.

Antibiotics reduce your baby's risk of GBS from 1 in 200 to 1 in 4,000. (If you are allergic – or strongly opposed - to antibiotics during delivery, talk to your healthcare provider; there are alternative medications, including herbal and homeopathic options, which you can explore.)

Note that the following symptoms put you in the 'high risk' category for delivering a baby with group B strep. Antibiotics can greatly reduce this risk:

  • A urinary tract infection (as a result of GBS) during pregnancy
  • Going into labor (or rupturing your membrane) before week 37
  • Rupture of membrane 18 hours or more before delivery
  • Fever during labor
  • Having had a baby with group B strep

If you were not screened before you go into labor and you have any of the above following symptoms, you will be treated during delivery with antibiotics – as a precaution for your baby.

What are Potential Complications for my Baby?

Depending on which reports you consult, GBS infection happens between 1 in every 2,000 babies and 1 in every 3,000 babies. It is the most common cause of blood infections (sepsis) and meningitis (an infection of the fluid and lining surrounding the brain and spinal cord).

However, being a carrier does not mean that your baby will have the infection. In fact, of the babies whose mothers who tested positive – and were given antibiotics during delivery -- 98% - 99% will not become infected.

For babies that do contract the infection, there are two types of group B strep: early and late onset. Conditions brought on by either early or late onset group B strep are:

  • Sepsis
  • Pneumonia
  • Meningitis (less likely in early onset GBS)

Early Onset GBS

This is the more common form of GBS. It is also more serious. 15% of babies with early onset GBS will not survive. Babies born prematurely are at higher risk than full-term babies.

Signs of infection will be shown as early as 6 hours of birth and as late as seven days after birth. These signs – or symptoms- include:

  • Fever
  • Difficulty feeding
  • Irritability
  • Lethargy
  • Breathing problems
  • Heart and blood pressure instability
  • Gastrointestinal and kidney problems

Late Onset GBS

Less common, this form of GBS appears within a week to a few months after birth. Half of these illnesses are not related to the mother being a carrier of GBS, but by the baby being in contact with another person who is a carrier (a hospital worker, for example). Babies with late onset GBS have a higher survival rate than those with early onset GBS.

Signs of infection include:

  • Fever
  • Difficulty feeding
  • Lethargy
  • Upper respiratory infection
  • Seizures

If an infection is suspected, sample of the baby's blood or spinal fluid will be taken and analyzed.

How Can My Baby Be Treated?

If your baby develops early onset or late onset group B strep, he will be given antibiotics (via an IV) to fight the bacteria. If necessary, additional steps will be taken to treat the infection, including oxygen and/or additional medications.

Can Group B Strep Be Prevented in Adults?

While a vaccine is currently being researched, it is not yet available. Since GBS can come and go, it is important that you are tested in each pregnancy — even if you tested negative in the past.

This article has been reviewed by Anthony Chin, MD, an OB/GYN in Beverly Hills, California.