What is Group B Strep (GBS)?
Group B Streptococcus (GBS) is a type of bacteria that is found in the lower intestine of 10-35% of all healthy adults and in the vagina and/ or lower intestine of 10-25% of all healthy, adult women. Group B Strep should not be confused with Group A Strep, which causes strep throat. A person whose body carries Group B strep bacteria but who does not show signs of infection is said to be “colonized” with Group B strep. GBS colonization is not contagious. GBS bacteria are a normal part of the commonly found bacteria in the human body. Normally, the presence of GBS does not cause problems. In certain circumstances, however, Group B Strep bacteria can invade the body and cause serious infection; this is referred to as Group B Strep disease.
Who May be Affected by Group B Strep disease?
15,000 to 18,000 newborns and adults in the United States will contract serious GBS disease each year, resulting in bloodstream, respiratory, and other devastating infections.
About half of all GBS disease occurs in newborns and is acquired during childbirth when a baby comes into direct contact with the bacteria carried by the mother.
GBS causes infections in pregnant women – in the womb, in amniotic fluid, in incisions following cesarean sections, and in the urinary tract. Each year there are over 50,000 cases of such infections in pregnant women.
35-40% of GBS disease occurs in the elderly or in adults with chronic medical conditions.
How common is GBS disease in newborns?
Approximately 8,000 babies in the United States contract serious GBS disease each year. Up to 800 of these babies may die from it, and up to 20% of the babies who survive GBS-related meningitis are left permanently handicapped.
In newborns, GBS is the most common cause of sepsis (infection of the blood) and meningitis (infection of the fluid and lining surrounding the brain) and is a frequent cause of newborn pneumonia. GBS disease is more common than other, better known newborn problems such as rubella, congenital syphilis, and spina bifida. Some babies that survive, especially those who develop meningitis, may develop long-term medical problems, including hearing or vision loss, varying degrees of physical and learning disabilities, and cerebral palsy.
How Do Babies Get Sick from GBS Disease?
Typically, babies are exposed to Group B Strep during labor and delivery; they may also be exposed after the mother’s membranes rupture (“water breaks”). Babies can come into contact with Group B Strep if the bacteria travel upward from the mother’s vagina into the uterus. Babies may also be exposed while passing through the birth canal. The babies become infected when they swallow or inhale the bacteria. There is also evidence that GBS may cross intact membranes to expose the baby while it is still in the womb. There it may cause preterm births, stillbirths, or miscarriages. However, these problems may be caused by a variety of other factors as well – other infections, stress, and genetic defects for example.
Are Certain Babies More Vulnerable to GBS Disease?
Premature babies, with their less-developed bodies and immune systems, are more vulnerable to the effects of GBS infection than older infants. Premature babies infected with GBS are at higher risk for long-term complications and/or death. Since most babies are born full-term, however, full term babies account for 70% of the cases of GBS disease in newborns.
The majority (80%) of the cases of GBS disease among newborns occur in the first week of life. The is called early onset disease. Most of these babies are ill within a few hours after birth. Babies who develop early onset disease may have one or more of the following symptoms:
- Problems with temperature regulation
- Grunting sounds
- Fever
- Seizures
- Breathing problems
- Unusual change in behavior
- Stiffness
- Extreme limpness
GBS disease may also develop in infants one week to several months after birth. This is called late onset disease. Meningitis is more common with late onset GBS disease. About half of late onset GBS disease can be linked to a mother who is colonized with GBS; the source of infection for other babies with GBS disease is unknown. A baby who develops late onset GBS disease may exhibit the following signs:
Stiffness (this could be the entire body or just the arms and legs)
- Limpness or floppy
- Inconsolable screaming
- Fever
- Refusal to feed
- Grunting sounds or difficult breathing
- Breathing irregularities
- Temperature regulation difficulty
How is GBS transmitted? Is GBS a sexually transmitted disease?
GBS is a naturally occurring bacterium in the human body of both women and men. Since it is commonly found in the vagina, some people wonder whether GBS is a sexually transmitted disease. The answer is No. GBS bacteria usually do not cause genital symptoms or discomfort and are not linked with increased sexual activity. Women found to carry GBS do not need to change their sexual practices.
Can pregnant women be checked for GBS colonization?
Our practice will do a vaginal culture for the presence of GBS bacteria on all pregnant women between 35-37 weeks gestation. Knowing your culture result before you go into labor can help protect your baby’s life. The test involves collecting a swab or swabs from the lower vaginal and rectum and culturing the sample.
What does a positive GBS result mean for me and my baby?
A positive result means that the mother is colonized with GBS. It does not mean that she has Group B Strep disease or that her baby will become ill. Rather, a positive test means that we need to plan for your labor and delivery with this test result in mind. The results of GBS cultures should be available at delivery. If they are not available, you should not hesitate to tell a doctor or nurse your results as soon as you arrive at Labor and Delivery.
How can GBS disease in newborns and mothers be prevented?
Giving antibiotics (such as Penicillin) through a vein during labor and delivery to women who have a positive GBS test or who have certain risk factors effectively prevents most GBS infections in women and their newborns. For best protection, the mother should receive intravenous antibiotics at least 4 to 6 hours before delivery. However, the earlier the administration of antibiotics the better once a risk factor has been identified.
If a woman’s labor begins or her membranes rupture before 37 weeks of pregnancy (before a culture is collected) she should be offered IV antibiotics.
Cesarean sections are not likely to prevent GBS disease.
All women should be tested for GBS with each pregnancy to ensure that the very best available protection is provided for their babies.
Should Women Who Have Had a Previous GBS Positive Baby Have More Children?
Women who have had problems due to GBS in the past should inform their prenatal care provider and pediatrician. GBS infections can be prevented and managed in subsequent pregnancies so that babies are protected and born healthy and free of GBS.
