SUPERStudy: Intrapartum Group B Streptococcus (GBS) Antibiotic Prophylaxis

By usmlevideoss

Introduction: Intrapartum Group B Streptococcus (GBS) antibiotic prophylaxis is a preventive treatment given during labor to reduce the risk of neonatal GBS infection. Group B Streptococcus is a common bacterium that colonizes the genital and gastrointestinal tracts of women and can be transmitted to the neonate during delivery, potentially causing sepsis, pneumonia, or meningitis.

Epidemiology: Group B Streptococcus (GBS) asymptomatically colonizes between 10% and 30% of pregnant women, but perinatal transmission can result in a severe and potentially fatal neonatal infection. 

Perform universal GBS screening at 35 to 37 weeks of pregnancy

Indications for GBS Prophylaxis:

1.Positive GBS Screening (at 35-37 weeks of gestation): Vaginal-rectal swab tests positive for GBS colonization.

2.Previous Infant with GBS Disease: Women who had a prior infant with early-onset GBS disease.

3.GBS Bacteriuria During Current Pregnancy: Indicates heavy colonization, regardless of the colony count.

4.Unknown GBS Status with Risk Factors:

  • Preterm labor (<37 weeks).
  • Prolonged rupture of membranes (≥18 hours).
  • Intrapartum fever (≥100.4°F or 38.0°C).

Exemptions from Prophylaxis:

1.Women with a planned cesarean delivery who have intact membranes and no labor.

2.GBS-negative screening results during the current pregnancy.

Antibiotic Regimen:

1.First-line Agent: Penicillin G

2.Alternative: Ampicillin

3.Penicillin Allergy:

Low-risk allergy: Cefazolin 

High-risk allergy (anaphylaxis): Clindamycin, if GBS is susceptible. Vancomycin, if resistance to clindamycin.

Timing of Antibiotics: Antibiotics should be started as soon as possible after the onset of labor or rupture of membranes.

Duration of Antibiotics: The recommended duration of antibiotic therapy is typically four hours.

GBS bacteriuria during pregnancy: Sterile urine must be documented after treatment, and periodic screening cultures should be obtained throughout the pregnancy to identify recurrent bacteriuria. Women with documented GBS bacteriuria should not be screened for GBS rectal/vaginal colonization later in pregnancy but should be considered persistently GBS colonized and receive intrapartum chemoprophylaxis at the time of delivery. 

Effectiveness:

  • Intrapartum prophylaxis significantly reduces early-onset GBS disease in neonates (within the first 7 days of life).
  • Does not prevent late-onset GBS infection (after 7 days of life).

Neonatal Risk Factors Without Prophylaxis:

1.Prematurity.

2.Prolonged rupture of membranes.

3.Maternal fever.

4.Heavy maternal GBS colonization.

SUPERpoints for Medical Practice:

1.Universal GBS screening at 35-37 weeks of gestation.

2.Early identification of at-risk women during labor.

3.Prompt administration of antibiotics to reduce neonatal morbidity and mortality.

By following these guidelines, intrapartum GBS prophylaxis effectively minimizes the risk of severe neonatal infections.

SUPERpoint: Intrapartum GBS prophylaxis involves administering antibiotics, primarily Penicillin G, during labor to prevent early-onset neonatal GBS infections in at-risk pregnancies.

SUPERformula: Patient presents for labor and delivery + history of GBS bacteriuria during pregnancy or unknown GBS status with risk factors = Intrapartum GBS Prophylaxis