Do I need Group B Streptococcus (GBS) prophylaxis before a cesarean section (C-section)?

GBS Prophylaxis for Cesarean Deliveries

GBS prophylaxis is NOT recommended for planned cesarean deliveries performed before labor onset on women with intact amniotic membranes, regardless of GBS colonization status or gestational age. 1

Rationale and Evidence

The CDC guidelines clearly state that intrapartum antibiotic prophylaxis to prevent early-onset GBS disease is not recommended as a routine practice for cesarean deliveries performed before labor onset on women with intact amniotic membranes 1. This recommendation applies regardless of:

• The woman's GBS colonization status (positive, negative, or unknown)
• The gestational age of the pregnancy

The reasoning behind this recommendation is that the risk of GBS transmission during a planned cesarean delivery with intact membranes before labor onset is extremely low 1. In this specific circumstance, the potential risks to mother and infant from receiving intrapartum antibiotic prophylaxis may balance or outweigh the benefits.

Important Distinctions

It's important to understand when GBS prophylaxis IS needed for women undergoing cesarean delivery:

• If labor begins before the cesarean
• If membranes rupture before the cesarean
• If there are other indications for GBS prophylaxis (such as GBS bacteriuria during pregnancy or previous infant with invasive GBS disease)

Standard Perioperative Antibiotics

The CDC guidelines specifically note that:

• The use of perioperative prophylactic antibiotics to prevent infectious complications of cesarean delivery should not be altered or affected by GBS status 1
• Standard surgical prophylaxis for cesarean section should still be administered according to usual protocols

Screening Recommendations

Despite not needing GBS prophylaxis for planned cesarean deliveries with intact membranes:

• Women expected to undergo planned cesarean deliveries should still undergo routine vaginal and rectal screening for GBS at 35-37 weeks' gestation 1
• This is because labor or rupture of membranes may occur before the planned cesarean delivery, and in those circumstances, GBS-colonized women should receive intrapartum antibiotic prophylaxis

Special Situations

For cesarean deliveries in women with:

• Preterm labor: Follow the algorithm for threatened preterm delivery 1
• Ruptured membranes: GBS prophylaxis is indicated if the woman is GBS positive or has unknown status with risk factors
• Suspected chorioamnionitis: Broad-spectrum antibiotic therapy that includes an agent active against GBS should replace GBS-specific prophylaxis 1

Summary of Indications for GBS Prophylaxis

GBS prophylaxis IS indicated for:

• Previous infant with invasive GBS disease
• GBS bacteriuria during current pregnancy
• Positive GBS screening culture in current pregnancy (unless cesarean before labor with intact membranes)
• Unknown GBS status with risk factors (delivery <37 weeks, membrane rupture ≥18 hours, temperature ≥100.4°F)

GBS prophylaxis is NOT indicated for:

• Cesarean delivery before labor onset with intact membranes
• Negative GBS screening culture in current pregnancy
• GBS colonization in a previous pregnancy (without other current indications)

By following these evidence-based guidelines, unnecessary antibiotic exposure can be avoided while still protecting infants from early-onset GBS disease.