People at Increased Risk and How It Spreads

Anyone can get group B strep (GBS) disease, but some people are at greater risk for disease than others. Being a certain age or having certain medical conditions can put you at increased risk for GBS disease.

People at Increased Risk

Smiling pregnant women holding her belly with both hands

About 1 in every 4 pregnant women carry GBS bacteria in their body.

GBS disease is most common in newborns. There are factors that can increase a pregnant woman’s risk of having a baby who will develop GBS disease, including:

  • Testing positive for GBS bacteria late in pregnancy
  • Developing a fever during labor
  • Having 18 hours or more pass between when their water breaks and when their baby is born

Talk to your doctor or midwife to learn more and find out if you are at risk.

In adults, most cases of GBS disease are among those who have other medical conditions. Other medical conditions that put adults at increased risk include:

  • Diabetes
  • Heart disease
  • Congestive heart failure
  • Cancer or history of cancer
  • Obesity

Risk for serious GBS disease increases as people get older. Adults 65 years or older are at increased risk compared to adults younger than 65 years old.

How It Spreads

GBS bacteria commonly live in people’s gastrointestinal and genital tracts. The gastrointestinal tract is the part of the body that digests food and includes the stomach and intestines. The genital tract is the part of the body involved in reproduction and includes the vagina in women.

The bacteria do not spread through food, water, or anything that people might have come into contact with. How people get these bacteria or spread them to others is generally unknown.

However, experts know that pregnant women can pass the bacteria to their babies during delivery. Most babies who get GBS disease in the first week of life (early-onset) are exposed to the bacteria this way. Babies who develop GBS disease from the first week through three months of life have late-onset disease. It can be hard to figure out how babies who develop late-onset GBS disease got the bacteria. The bacteria may have come from the mother during birth or from another source.

Other people that live with someone who has GBS bacteria, including other children, are not at risk of getting sick.