What is the management of babies born to Group B Streptococcus (GBS) positive mothers?

Management of Babies Born to GBS Positive Mothers

Babies born to GBS positive mothers should be managed according to a risk-based algorithm that considers maternal intrapartum antibiotic prophylaxis status, gestational age, clinical status of the infant, and presence of maternal chorioamnionitis. 1

Maternal Intrapartum Antibiotic Prophylaxis

Before discussing neonatal management, it's important to understand maternal prophylaxis which directly impacts neonatal risk:

• Intravenous penicillin G (5 million units initial dose, then 2.5-3.0 million units every 4 hours until delivery) is the preferred agent for GBS-positive women without penicillin allergy 1
• Ampicillin (2g IV initial dose, then 1g IV every 4 hours until delivery) is an acceptable alternative 1
• For penicillin-allergic women not at high risk for anaphylaxis, cefazolin (2g IV initial dose, then 1g IV every 8 hours until delivery) is recommended 1
• For penicillin-allergic women at high risk for anaphylaxis, clindamycin (900mg IV every 8 hours) is recommended if the GBS isolate is susceptible; otherwise, vancomycin (1g IV every 12 hours) should be used 1
• Erythromycin is no longer an acceptable alternative for intrapartum GBS prophylaxis 1

Neonatal Management Algorithm

1. Infants with Signs of Sepsis

• Any newborn with signs of sepsis requires a full diagnostic evaluation and immediate antibiotic therapy regardless of maternal GBS status or antibiotic prophylaxis 1
• Full evaluation includes:
  • Blood culture
  • Complete blood count (CBC) with white blood cell differential and platelet count
  • Chest radiograph if respiratory symptoms are present
  • Lumbar puncture if the infant is stable enough and sepsis is suspected 1
• Empiric therapy should include antibiotics active against GBS (intravenous ampicillin) and other potential pathogens like E. coli 1

2. Well-appearing Infants Born to Mothers with Suspected Chorioamnionitis

• These infants require a limited evaluation and antibiotic therapy pending culture results 1
• Limited evaluation includes:
  • Blood culture
  • CBC with white blood cell differential and platelet count 1
• Chest radiograph and lumbar puncture are not routinely needed 1
• Consultation with obstetric providers to confirm suspected chorioamnionitis is important 1

3. Well-appearing Infants Born to GBS-positive Mothers Who Received Adequate IAP

• Adequate IAP is defined as ≥4 hours of penicillin, ampicillin, or cefazolin before delivery 1
• These infants can be managed with routine clinical care if born at ≥37 weeks gestation and if duration of membrane rupture was <18 hours 1
• No routine laboratory testing or empiric antibiotics are needed for these infants 1
• Observation in the hospital for at least 48 hours is recommended 1

4. Well-appearing Infants Born to GBS-positive Mothers with Inadequate IAP

• Inadequate IAP includes:
  • <4 hours of prophylaxis before delivery
  • Agents other than penicillin, ampicillin, or cefazolin
  • No prophylaxis despite indications 1
• For infants ≥37 weeks gestation with membrane rupture <18 hours:
  • Hospital observation for ≥48 hours is recommended 1
  • Limited evaluation with CBC and blood culture may be considered 1
• For infants <37 weeks gestation or with membrane rupture ≥18 hours:
  • Limited evaluation with blood culture and CBC
  • Hospital observation for ≥48 hours
  • Some clinicians may initiate empiric antibiotics pending culture results, particularly for very premature infants 1

Important Clinical Considerations

• Routine use of prophylactic antibiotics for all newborns born to mothers who received intrapartum prophylaxis is not recommended 1
• The duration of intrapartum antibiotics (≥4 hours) is more important than the number of doses for determining adequacy of prophylaxis 1
• Preterm infants have twice the risk of early-onset GBS disease compared to term infants, even with appropriate IAP 2
• Recent evidence suggests that even 2 hours of IAP may provide significant protection, though 4 hours remains the standard recommendation 3

Pitfalls and Caveats

• Do not delay medically necessary obstetric procedures to achieve 4 hours of GBS prophylaxis 1
• Oral antibiotics should not be used to treat GBS colonization during pregnancy as this is ineffective in preventing neonatal disease 1
• Even with ideal implementation of prevention strategies, some cases of early-onset GBS disease will still occur 1
• Late-onset GBS disease (after 7 days of life) is not prevented by intrapartum antibiotic prophylaxis 2
• False negative GBS screening results can occur, so clinicians should remain vigilant for signs of sepsis even in infants born to mothers who tested negative 2

By following this evidence-based algorithm, clinicians can significantly reduce the risk of early-onset GBS disease while avoiding unnecessary antibiotic exposure in low-risk newborns.