Group B Streptococcus (GBS) Screening and Prophylaxis Overview

Summary

Routine Screening

• Recommended for all pregnant individuals between 36+0 to 37+6 weeks of gestation.

Collection Method

• Swabbing involves the lower vagina and rectum without the use of a speculum.

Laboratory Analysis

• Standard: GBS culture.
• For those with severe penicillin allergies: Add clindamycin susceptibility testing.
• In urgent situations: Consider a rapid nucleic acid amplification test (NAAT).

Indications for Prophylaxis

• Positive GBS screening result.
• GBS bacteriuria identified at any point during the pregnancy.
• A history of delivering a newborn with early-onset GBS infection.
• Women in labor or with ruptured membranes but with unknown GBS culture status.
• Intrapartum fever ≥100.4°F (≥38°C).
• Delivery before 37+0 weeks of gestation.
• Rupture of membranes ≥18 hours.

Prophylaxis Not Required When

• Pre-labor cesarean delivery is performed without membrane rupture.
• No GBS risk factors are present.

Antibiotic Regimens

• Without Penicillin Allergy: IV penicillin G or IV ampicillin.
• With Penicillin Allergy:
  • Non-severe reactions: IV cefazolin.
  • Severe reactions: IV clindamycin or IV vancomycin if resistant.