design-group-b-strep-protocol

Design Group B Strep Protocol

Screen for GBS at 35–37 weeks and execute the intrapartum antibiotic prevention protocol.

Why This Is Best Practice

Adopted by: ACOG, CDC, AAP — universal GBS screening and intrapartum antibiotic prophylaxis (IAP) is the standard of care in the US, UK, Canada, and Australia. Impact: IAP reduced early-onset neonatal GBS disease by 80% from 1990 to 2020 (CDC surveillance data). Without IAP, GBS-positive mothers have a 1 in 200 chance of neonatal sepsis; with IAP, risk falls to <1 in 4,000 (ACOG 2020). Why best: GBS colonization is transient and harmless to the mother but causes severe sepsis, meningitis, and death in neonates. Screening + IAP is the most effective intervention.

Steps

1. Screening (weeks 35–37):
   • Vaginal-rectal swab (one swab, self-collected or provider-collected)
   • Culture takes 24–48 hours; document result in chart for labor
   • Screen even if GBS-negative in prior pregnancy — colonization status changes
2. Automatic IAP (regardless of culture result):
   • GBS bacteriuria (any amount) in current pregnancy → treat bacteriuria + IAP in labor
   • Prior infant with invasive GBS disease → IAP in labor regardless of culture
3. Culture-positive → IAP in labor:
   • Preferred: Penicillin G 5 million units IV loading dose, then 2.5–3 million units IV q4h until delivery
   • Penicillin allergy (low risk): ampicillin 2g IV then 1g IV q4h
   • Penicillin allergy (high risk/anaphylaxis): culture-based — clindamycin if susceptible; vancomycin if resistant
4. Timing: IAP must begin ≥4 hours before delivery to be fully protective — communicate GBS status clearly when going to labor and delivery.
5. Culture unknown at delivery (no result/unscreened):
   • Give IAP if: <37 weeks gestation, ROM ≥18 hours, or intrapartum fever ≥38°C
6. Planned cesarean (no labor, intact membranes): IAP not required even if GBS-positive — exposure risk is membrane/birth canal.

Rules

• GBS-positive status on chart must be communicated to labor and delivery team — it is a care-critical flag.
• Do not treat GBS colonization with oral antibiotics in pregnancy (except bacteriuria) — it will recur and may affect IAP choice.
• If water breaks and labor hasn't started, go to hospital — IAP window depends on time to delivery.

Examples

GBS positive at 36 weeks: Document result, give patient card to carry, tell patient to notify L&D of GBS+ status on arrival; receive Pen G on admission, before any other interventions. Unknown GBS status, water broke at 39 weeks: Go directly to hospital; receive IAP because ROM ≥18 hours threshold may be crossed.

Common Mistakes

• Not asking GBS result at L&D intake — if documented in chart, team must confirm and administer IAP.
• Confusing "GBS treated" (bacteriuria treatment) with "cleared" for IAP — bacteriuria treatment does not remove need for IAP in labor.
• Arriving at hospital without communicating GBS status — carry a written record; verbal communication in active labor is unreliable.

Health Disclaimer: GBS management requires coordination between prenatal care provider and labor and delivery team. Patients should understand their GBS status before 37 weeks and communicate it on arrival to hospital.