Group B Strep in Pregnancy

• Group B strep is a naturally occurring bacteria in the human body. 
• Most pregnant women should test for it as it puts them and their unborn child at an elevated risk for other diseases.
• This bacterial infection is commonly treated with antibiotics.

Group B streptococcus (strep) is typically not one of the primary bacteria that comes to mind when associated with bacteria and infections, except for care around maternal and neonatal patient types. Group B strep (GBS) is most talked about during pregnancy and delivery because of the potential risks associated with the newborn.  

Multiple questions arise around the GBS impact between healthcare providers, patients, and even with families. Be sure to educate patients on the risks of GBS disease, indications for maternal antibiotic prophylaxis, and risks to the newborn. Reassuring patients that Group B Strep is not a form of a sexually transmitted disease is important because this is a common misconception.   

What Is Group B Strep?

Group B Streptococcus, also known as group B strep (GBS) is a form of bacteria that can come and go naturally in the body. The naturally forming bacteria typically colonize the gastrointestinal tract or genital tract regions of the body. This bacterium is common and considered a normal finding with around 25% of pregnant women being positive for GBS.  

Who Needs a Group B Strep Test?

With evidence-based research, there have been universal screening guidelines implemented for all pregnant patients. Screening is performed through culture testing from a vaginal-rectal swab that is collected between 35-37 weeks gestation.  

The only exceptions for screening are for patients who have had GBS bacteriuria during the current pregnancy or who previously gave birth to a neonate with invasive GBS disease.  

How Does Group B Strep Affect Pregnancy?

The majority of patients that are positive for GBS are asymptomatic. Pregnant patients can be susceptible to several infections during the antepartum, intrapartum, and postpartum periods.

For patients who are positive for group b strep, it can place them at an elevated risk for those infections. These infections can include:  

• Urinary tract infection  
• Upper genital tract infections  
• Post-cesarean wound infections  
• Postpartum endometritis  
• Pneumonia  
• Sepsis  
• Bacteremia  

How Does Group B Strep Affect Pregnancy?

Upon arrival to labor and delivery, the GBS status of a patient will be reviewed. Patients will be identified with either a positive, negative, or an unknown GBS status.  

Intrapartum antibiotic prophylaxis is performed when indicated with Penicillin as the first-line antibiotic and Ampicillin used as an acceptable alternative. Patients with a history of a Penicillin allergy may receive Cefazolin, Clindamycin, Erythromycin, or Vancomycin based on clinical opinion. 

Prompt IV access should be prioritized when intrapartum antibiotic prophylaxis is indicated in patients in order to achieve antibiotic prophylaxis before delivery. Successful antibiotic prophylaxis is obtained when one course of antibiotics is administered at least 4 hours before delivery.   

Intrapartum antibiotic prophylaxis indicated:  

-GBS culture collected after 35 weeks gestation is positive  

-Previous infant with invasive GBS disease  

-GBS bacteriuria during any trimester of the current pregnancy  

-Unknown GBS status  

No intrapartum antibiotic prophylaxis indicated:  

– Negative GBS culture after 35 weeks gestation  

-C-section prior to rupture of membranes or active labor

What Are the Consequences Without Treatment?

The most critical component with a positive or unknown GBS patient is the concern for the newborn during delivery when Group B Strep is not effectively treated.  

Infection can be acquired through vertical transmission during delivery from the mother to the newborn. The severity of the infection in newborns can depend on various factors including gestational age, birth weight, and disease onset.  

Newborns are at risk for developing sepsis, meningitis, epilepsy, cerebral palsy, respiratory conditions, genitourinary problems, and death. Newborns can experience signs and symptoms that include hypotension, apnea, seizures, neutropenia, thrombocytopenia, developmental difficulty, feeding issues, blood sugar instability, and difficulty with thermoregulation.  

The Bottom Line

Group B strep is a bacterial infection that affects the pregnant mother and the newborn. There are both tests and medical treatment available, so no one need suffer. 

In most cases, a course of antibiotics is all that’s needed.  

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