What is the recommended ceftriaxone prophylaxis dosing for a cesarean delivery?

Ceftriaxone is NOT the first-line antibiotic for cesarean section prophylaxis

Cefazolin, not ceftriaxone, is the guideline-endorsed first-line prophylactic antibiotic for cesarean delivery, with a recommended dose of 2 grams IV within 60 minutes before skin incision (3 grams if weight ≥120 kg). 1

Why Cefazolin is Preferred Over Ceftriaxone

The most recent 2026 ACOG/CDC/WHO guidelines explicitly recommend cefazolin as the first-line agent for cesarean prophylaxis 1. Cefazolin provides:

• Optimal tissue penetration at the surgical site
• Proven reduction in surgical site infections (SSI) and endometritis
• Cost-effectiveness compared to broader-spectrum agents
• Safety for the neonate
• Appropriate antimicrobial stewardship (narrower spectrum than ceftriaxone)

When Ceftriaxone May Be Considered

While ceftriaxone is not the standard prophylactic agent, historical studies show it can be effective 2, 3, 4, 5. However, using ceftriaxone instead of cefazolin represents unnecessarily broad-spectrum coverage and is not aligned with current antimicrobial stewardship principles.

If ceftriaxone were to be used (not recommended), the dosing from older studies was:

• 1 gram IV given 15-60 minutes before skin incision 3, 4, 5
• Single dose was as effective as multiple doses 2, 4

The Correct Prophylaxis Protocol

Standard patients:

• Cefazolin 2 g IV within 60 minutes before incision 1
• Increase to 3 g if weight ≥120 kg 1

High-risk scenarios (unscheduled cesarean with labor/ruptured membranes):

• Add azithromycin 500 mg IV to cefazolin 1
• Particularly beneficial in obese patients (BMI ≥40) 1

Severe penicillin allergy (anaphylaxis, angioedema):

• Clindamycin 900 mg IV + gentamicin 5 mg/kg IV 1

Critical Timing Considerations

Administration before skin incision (not after cord clamping) significantly reduces maternal infectious morbidity without increasing neonatal complications 1, 3. The 2013 systematic review definitively showed preoperative administration reduced endometritis (RR 0.59) compared to post-cord clamping administration 1.

Common Pitfall to Avoid

Do not substitute ceftriaxone for cefazolin based on availability or familiarity. Ceftriaxone has broader gram-negative coverage than necessary for cesarean prophylaxis, promoting unnecessary antibiotic resistance. The 2026 guidelines are clear that cefazolin remains the evidence-based standard 1, 6.