Universal Screening for Group B Streptococcus, Not Group A Streptococcus
No, prenatal patients do not need routine Group A Streptococcus (GAS) swabs—you are likely confusing this with Group B Streptococcus (GBS), which requires universal screening at 36-37 weeks' gestation. 1, 2
Critical Distinction Between GAS and GBS
Group B Streptococcus (GBS) - Universal Screening Required
- All pregnant women should undergo universal screening for GBS colonization between 36 0/7 and 37 6/7 weeks' gestation with both vaginal and rectal specimens. 1, 2
- The CDC and ACOG recommend this screening to prevent early-onset neonatal disease, which occurs in 1-2% of exposed newborns without prophylaxis. 2
- Women with positive GBS cultures receive intrapartum antibiotic prophylaxis (penicillin G 5 million units IV initially, then 2.5 million units IV every 4 hours until delivery). 1
- Women with GBS bacteriuria at any concentration during pregnancy receive intrapartum prophylaxis without need for additional screening. 1
Group A Streptococcus (GAS) - No Routine Screening
- There is no recommendation for routine prenatal GAS screening in asymptomatic pregnant women. 3
- GAS screening is only indicated during outbreak investigations or when healthcare-associated infection is suspected. 3
- Pregnancy-related GAS infections are rare (0.8 cases per 1000 live births) and typically occur postpartum, not prenatally. 4
When GAS Testing Is Appropriate in Pregnancy
Symptomatic Infection
- Pregnant women with signs of GAS infection (fever, pharyngitis, skin lesions, genital tract infection) should be tested and treated at the time of diagnosis. 3
- Documentation of GAS infection should be clearly noted in maternity records. 3
Outbreak Investigation
- GAS isolates from peripartum patients should be saved for six months to facilitate outbreak investigation if needed. 3
- Screening of healthcare workers and environmental sources occurs only during outbreak investigations, not routinely. 3
Common Pitfalls to Avoid
- Do not confuse GAS with GBS—the screening protocols are completely different, and only GBS requires universal prenatal screening. 1, 2
- Do not order routine GAS swabs on asymptomatic pregnant women—this is not evidence-based and wastes resources. 3
- Do not delay treatment if a pregnant woman has documented GAS infection earlier in pregnancy—treat at the time and document clearly. 3
- Maternal deaths from GAS genital tract sepsis increased from 1 per year (2000-2002) to 4 per year (2006-2008) in the UK, emphasizing the importance of recognizing symptomatic infection. 3
Risk Factors for Postpartum GAS Infection
- Vaginal delivery (cesarean delivery is protective with perioperative antibiotics). 4
- Multiparity (primiparous women have lower risk, likely due to less exposure to children who carry GAS). 4
- Recent respiratory tract infection or family members with sore throats. 3
- The infection typically manifests postpartum with fever and abdominal tenderness, not during routine prenatal care. 4