Group B streptococcus (GBS), also known as group B strep, Streptococcus agalactiae, Strep B, or Beta Strep, is a type of bacteria that is naturally found in the digestive and lower reproductive tracts of both men and women.
About 1 in 4 pregnant individuals "carry" or are "colonized" with group B strep (GBS). Carrying GBS does not mean that you are unclean or have poor hygiene. Carrying GBS or testing GBS+ does not mean you are infected, but it can potentially cause an infection in your baby. Anyone can carry GBS. GBS is not considered to be a sexually transmitted disease or infection as it can occur on its own even in someone with no prior sexual experience. However, bacteria can be passed between sexual partners, including through oral contact. (For more info on this, please read the medical articles on our website under Sex & GBS.)
Unfortunately, babies can be infected by group B strep before birth through several months of age due to their underdeveloped immune systems. These infections have been known as "GBS disease" with a newer terminology of "invasive GBS disease (iGBS)" being introduced. "GBS" refers to the type of bacteria while "iGBS" refers to an invasive infection (disease) caused by GBS.
GBS most commonly causes invasive infection in the blood (sepsis), the fluid and lining of the brain (meningitis), and lungs (pneumonia). GBS can also cause invasive bone and joint infections. Some iGBS survivors experience handicaps such as blindness, deafness, and mental challenges, and/or cerebral palsy. Only a few babies who are exposed to GBS become infected, but iGBS can cause babies to be miscarried, stillborn, or become very ill and sometimes die after birth.
There are three types of perinatal invasive GBS disease, each with their own prevention challenges:
WHO CAN CARRY GBS? Anyone can carry GBS. GBS is naturally found in the digestive and lower reproductive tracts of both men and women. About 1 in 4 pregnant women "carry" or are "colonized" with GBS.
WHO CAN BE INFECTED BY GBS? Babies can be infected by GBS before birth through several months of age due to their underdeveloped immune systems. According to the US Centers for Disease Control & Prevention (CDC), most cases of iGBS disease in adults are among those who have other medical conditions. Other medical conditions that puts adults at increased risk include:
Diabetes
Heart disease
Congestive heart failure
Cancer or history of cancer
Obesity
Risk for serious iGBS also increases as people get older. Adults 65 years and older are at increased risk compared to adults under 65 years old.
HOW DO YOU GET GBS? Group B strep (GBS) is a type of bacteria that is naturally occurring in the digestive and lower reproductive tracts of both men and women. GBS colonization is not considered to be a sexually transmitted disease or infection as it can occur on its own even in someone with no prior sexual experience. However, bacteria can be passed between sexual partners, including through oral contact. Carrying GBS is not a sign of poor hygiene and illness.
Anyone can carry GBS. However, those at the most risk for iGBS are infants, adults with some chronic medical conditions and the elderly.
IS MY BABY AT RISK OF A GBS INFECTION? iGBS in your baby from birth through the first six days of life is more likely if:
You tested GBS positive in your urine or GBS swab test during this pregnancy
Your baby was born before 37 weeks (preterm)
Your water has been broken 18+ hours without delivering
You have a fever during labor
You previously had a baby who developed iGBS
These steps can help reduce the risk of early-onset iGBS:
Have your urine cultured early in pregnancy for GBS as well as other bacteria and, if GBS- in your urine, have a swab test for GBS during your 36th or 37th week of pregnancy
If you are GBS+ in either your urine or swab test, or have previously had a baby with a GBS infection, having IV antibiotics for GBS when your water breaks or your labor starts (unless you are having a C-section done before your water breaks and your labor starts).
Currently, there are no proven prevention methods for prenatal and late-onset iGBS, so being aware of the signs of iGBS can make a difference!
HOW CAN MY BABY BECOME INFECTED BY GBS? Carrying GBS or testing GBS+ does not mean you are infected, but it can potentially cause an infection in your baby.
In some cases, group B strep is able to cross intact membranes reaching the baby in the womb (prenatal-onset). It is thought that babies are most often infected with GBS as they pass through the birth canal (early-onset). Once born, iGBS can be caused by sources other than the birthing parent (early or late-onset). Exactly how this can happen is unclear and not well-studied. However, it is good practice to have everyone wash their hands before handling your baby. It is speculated that a few late-onset and recurrent GBS infections are possibly associated with infected breast milk, but be aware that breastfeeding can supply your baby with important antibodies to fight infection. It is currently thought that the health benefits of breastfeeding outweigh any potential risk of exposure to GBS.
There are currently no prevention protocols in place to help prevent prenatal and late-onset iGBS. However, being able to recognize the signs of iGBS in babies is imperative in getting prompt medical treatment to help optimize outcomes.
I’M PREGNANT – HOW DO I KNOW IF I HAVE GBS? Although most people do not have any symptoms, GBS can cause vaginal burning/irritation and/or unusual discharge. GBS can also cause bladder infections. Consult your healthcare provider if any of these symptoms occur.
Your provider should do a urine culture for GBS and other bacteria at the first prenatal visit. GBS in your urine means that you may be heavily colonized. If you have a significant level of GBS in your urine or urinary symptoms, your provider should prescribe oral antibiotics at the time of diagnosis. If your urine tests positive, your provider should consider you as “GBS colonized” for this pregnancy. It is now the standard of care in several countries for all pregnant individuals to be routinely tested for GBS with a vaginal/rectal swab test during the 36th or 37th week during each pregnancy unless their urine already cultured positive in the current pregnancy.
WHAT IS THE GBS SWAB TEST? It is a culture of a swab that has been inserted in both the vagina and rectum. Inform your provider if you are using antibiotics and/or vaginal medications which may cause false negative results.
WHAT IF I TEST NEGATIVE? It’s important to know that: 1) A pregnant individual may test negative if their GBS colonization level at the time of the test was below the level of detection. 2) A pregnant individual's GBS status can change so a person could test negative but be colonized later in pregnancy. 3)Test results are only considered to accurately (95%-98%) predict a pregnant individuals colonization status at delivery if they deliver within 5 weeks of their test. 4) A pregnant individual may need to be retested if they have not yet given birth within 5 weeks of being tested. 5) Once born, a baby can become infected with GBS by sources other than the birthing parent. Learn more.
WHAT IF I TEST POSITIVE? If your urine or swab tests are positive, your provider should consider you as “GBS colonized” for this pregnancy so that you receive IV antibiotics for GBS when labor starts or your water breaks. Plan ahead if you have short labors or live far from the hospital. The IV antibiotics you receive in labor generally take 4 hours to be optimally effective. Ask your provider to not strip your membranes if you test positive for GBS, as it may push bacteria closer to your baby.
It is also important to know the signs of infection in unborn babies and of preterm labor! Learn more.
CAN MY GBS STATUS CHANGE? Yes, GBS colonization can be transient which means that a pregnant person could test negative, but be colonized later in pregnancy and vice versa. It is possible for your GBS status to change between testing and the time you go into labor although test results are considered to accurately (95%-98%) predict a pregnant person's colonization status at delivery if they deliver within 5 weeks of the test.
WHAT ARE THE SYMPTOMS THAT I HAVE GBS? Most people do not have any symptoms. Although, GBS can cause vaginal burning/irritation and/or unusual discharge which may be mistaken for a yeast infection and treated incorrectly. If you have “vaginitis” symptoms, see your care provider promptly for an exam and possible GBS testing. GBS can also cause bladder infections, with or without symptoms.
Because most do not experience symptoms, pregnant women should get tested for GBS in their urine early in pregnancy and also tested with a vaginal/rectal swab test during the 36th or 37th week if the current pregnancy’s urine culture was negative.
CAN GBS CAUSE BABIES TO BE MISCARRIED OR STILLBORN? Yes. Is it rare? For many years, the prevailing thought has been that GBS-caused miscarriages and stillbirths are rare or very rare. However, there wasn’t surveillance data to support that until recently. According to one study, an estimated 57,000 fetal infections/stillbirths occur each year. Another study found that GBS causes up to 12.1% of stillbirths, but more research is needed. According to the World Health Organization (WHO), an estimated 2.6 million stillbirths occur annually worldwide.
HOW IS GBS TREATED DURING PREGNANCY? It is not standard to treat individuals for GBS during pregnancy unless found at a significant level in their urine or GBS is causing urinary or vaginitis symptoms.
In some cases, if a pregnant person is heavily colonized or has had a baby previously infected by GBS, they may be treated with oral antibiotics during pregnancy, although this is not a standard routine.
IF I’VE HAD GBS IN A PAST PREGNANCY, WHAT SHOULD I DO IN A CURRENT OR FUTURE PREGNANCY? If you have already had a baby with iGBS or have had GBS in your urine in this pregnancy, you should receive IV antibiotics for GBS during labor and delivery even if you later test negative for GBS in your urine or in a vaginal/rectal swab test for GBS in a current or future pregnancy. Please note that once you have tested positive in your urine during this pregnancy, your provider may not do a routine vaginal/rectal swab test for you later in this pregnancy since you should already be considered "GBS colonized."
Whether or not you have had a baby with iGBS, please check with your provider about having your urine cultured for GBS early in this pregnancy (not standard in all countries). ACOG issued new guidance in 2019 regarding Bacteriuria (GBS in urine) in regards to early-onset disease prevention. Studies have also shown that treating asymptomatic bacteriuria can reduce the risks of preterm birth.
If you have not had a baby with GBS disease, you should ask to have a vaginal/rectal swab test for GBS during the 36th or 37th week of gestation (also not standard in all countries) regardless of any past pregnancy results for GBS. (Please note that once you have tested positive in your urine during this pregnancy, your provider may not do a routine vaginal/rectal swab test for you later in this pregnancy since you should already be considered "GBS colonized.")
Plan ahead if you have short labors or live far from the hospital. Avoid unnecessary, frequent, or forceful internal exams which may push GBS closer to your baby.
WHAT ARE THE SIGNS MY BABY MAY HAVE PRENATAL-ONSET GBS DISEASE (POGBSD)? POGBSD can cause babies to be miscarried, stillborn, or born very sick. Know the signs of infection in unborn babies! Contact your provider immediately if you experience any of these signs. Reasons to contact your provider immediately:
Decreased or no fetal movement after your 20th week
Frenzied fetal movement
You have any unexplained fever
Any signs of preterm labor or your water breaks before your 37th week
WHAT ARE THE SIGNS OF PRETERM LABOR? GBS can cause preterm labor as well as cause a woman's water to break too soon, also known as preterm premature rupture of membranes (PPROM). It's important to know the warning signs and symptoms of preterm labor. Call your healthcare provider right away if you experience any of the following:
Your water breaks
You have more vaginal discharge than usual or your vaginal discharge changes
Vaginal bleeding
Increased pressure in your pelvis or vagina
Cramping in your lower abdomen or period-like cramps
Nausea, vomiting, or diarrhea
Dull lower backache
Regular or frequent contractions
HOW IS GBS TREATED DURING LABOR & DELIVERY? GBS is treated with antibiotics through the vein (also called IV for intravenous). When your water breaks or labor starts, remind your care provider of your GBS status and report any fever. If you have already had a baby with iGBS or have had GBS in your urine in this pregnancy, you should receive IV antibiotics regardless of this pregnancy’s GBS test results. Go to the hospital immediately when your water breaks or your labor starts if you should receive IV antibiotics. The antibiotics you receive generally take 4 hours to be optimally effective.
If you are having a planned C-section, talk to your provider about the risks vs. benefits of starting IV antibiotics well before your incision. C-sections may not completely prevent GBS infection although, according to the CDC, the risk of early-onset infection for a full term baby during a planned C-section is extremely low if performed before your labor starts and before your water breaks. The current American College of Obstetrician and Gynecologist (ACOG) guidelines state that IV antibiotics for GBS are not indicated before a planned C-section performed before onset of labor on a woman with intact amniotic membranes, regardless of GBS colonization status or gestational age.
WHAT IF I DID NOT RECEIVE THE RECOMMENDED AMOUNT OF ANTIBIOTICS? If you give birth before you have had 4 hours of antibiotics, the hospital may culture your baby and/or observe him or her for 36-48 hours.
ARE THERE VIABLE ALTERNATIVE TREATMENTS? “Alternative medicine” treatments such as garlic or tea tree oil have not been proven to prevent your baby from becoming infected. Some alternative treatments are unsafe. Yoghurt and probiotics are known to have health benefits, but the exact impact on GBS colonization is not yet known. Learn more about current research on probiotics in regards to GBS colonization.
WHAT IF I AM HAVING A PLANNED C-SECTION? If you are having a planned C-section, talk to your provider about the risks vs. benefits of starting IV antibiotics well before your incision. C-sections may not completely prevent a GBS infection although, according to the CDC, the risk of early-onset infection for a full term baby during a planned C-section is extremely low if performed before your labor starts and before your water breaks. The current AGOG guidelines state that IV antibiotics for GBS are not indicated before a planned C-section performed before onset of labor on a pregnant person with intact amniotic membranes, regardless of GBS colonization status or gestational age.
Be aware that your womb and/or C-section wound can become infected by GBS.
SHOULD I HAVE MY MEMBRANES STRIPPED? Ask your provider to not strip your membranes if you test positive for GBS. GBS can cross even intact membranes and procedures such as stripping membranes may push bacteria closer to your baby.
According to the ACOG guidelines, "Although current evidence is limited, membrane sweeping does not appear to be associated with adverse outcomes in women colonized with GBS." However, "Because of the hypothetical concern of bacterial seeding during the procedure, some practitioners may choose not to sweep the membranes in women colonized with GBS." (The referenced study included 135 women who were known to be GBS positive.)
ARE WATER BIRTHS SAFE? The current US GBS guidelines issued by the American College of Obstetricians and Gynecologists (ACOG) explain that water births with GBS+ pregnant people are not well studied. International guidelines suggest that GBS colonization is not a reason to advise against immersion in water during labor or birth as long as the pregnant individual is offered the appropriate IV antibiotics and there aren't other reasons present to avoid water immersion.
WHAT ARE THE SIGNS & SYMPTOMS MY BABY COULD BE INFECTED WITH GBS? During pregnancy you experience:
Decreased or no fetal movement after your 20th week
Frenzied movement has also been linked to fetal distress
Any unexplained fever
After birth (early and late-onset)
Sounds - High-pitched cry, shrill moaning, whimpering, inconsolable crying, constant grunting or moaning as if constipated or in distress
Breathing - Fast, slow, or difficult breathing
Appearance of skin - Blue, gray, or pale skin, blotchy or red skin, tense or bulging fontanel (soft spot on a baby's head), infection (pus/red skin) at base of umbilical cord or in puncture on head from internal fetal monitor
Eating and Sleeping Habits - Feeding poorly, refusing to eat, not waking for feedings, sleeping too much, difficulty being aroused
Behavior- Marked irritability, projectile vomiting, reacting as if skin is tender when touched, not moving an arm or leg, listless, floppy, blank stare, body stiffening, uncontrollable jerking
Body Temperature - Fever or low or unstable temperature, hands and feet may feel cold even with a fever
IS IT SAFE TO BREASTFEED? Breastfeeding can supply your baby with important antibodies to fight infection. However, it is speculated that a few late-onset and recurrent GBS infections are possibly associated with infected breast milk. It is currently thought that the health benefits of breastfeeding outweigh any potential risk of exposure to GBS.
WHAT IS RECURRENT GBS? Recurrent GBS is when a baby has had a GBS infection, been treated successfully, and is later infected by GBS, again.
ARE THERE LASTING EFFECTS FROM GBS DISEASE? A little over half of survivors will have no long term effects. While there needs to be more research on the lasting effects of invasive GBS sepsis, the lasting effects of invasive GBS meningitis depend on the severity of the infection. A mild-to-moderate infection can lead to neurological or functional impairment, while a severe infection can cause blindness, hearing loss, cerebral palsy, and significantly delayed development.
Dr. Morven Edwards says that with early developmental evaluation, "problems can be identified early and addressed even before the child actually starts school so that the child has the best chance to fulfill their potential." Learn more
Recognize the symptoms of infection! GBS is a fast-acting type of bacteria so it is imperative that everyone who takes care of your baby knows the symptoms of possible GBS infection in babies and how to respond.
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