Antibiotic Treatment for Streptococcal Respiratory Infection in Pregnancy
Penicillin or amoxicillin are the first-line antibiotics for treating streptococcal respiratory infections in pregnant women, with ampicillin as an acceptable alternative. 1, 2
Primary Treatment Recommendations
For patients without penicillin allergy:
- Penicillin G or amoxicillin should be prescribed as first-line therapy due to their narrow spectrum of activity, established safety profile in pregnancy, and excellent activity against streptococcal organisms 1, 3, 4
- Ampicillin is an acceptable alternative with equivalent efficacy 5, 4
- These beta-lactam antibiotics have decades of clinical experience documenting their safety for the fetus and are the most favored agents for use in pregnancy 6, 7
For Penicillin-Allergic Patients
Assess the type of allergic reaction first:
If non-anaphylactic allergy (no history of anaphylaxis, angioedema, respiratory distress, or urticaria):
- First-generation cephalosporins (e.g., cefazolin) are recommended 5, 1
- Cefazolin dosing: 2g IV initial dose, then 1g IV every 8 hours 8
If high-risk anaphylactic allergy (history of anaphylaxis, angioedema, respiratory distress, or urticaria to penicillin):
- Clindamycin if the bacterial isolate is susceptible to it 1
- Erythromycin if the isolate is susceptible 1
- Azithromycin is also a safe macrolide option for respiratory streptococcal infections in pregnancy 8, 4
Important Safety Considerations
Antibiotics to absolutely avoid during pregnancy:
- Tetracyclines (contraindicated after 5th week of pregnancy due to tooth discoloration and bone effects) 5, 3, 6
- Fluoroquinolones (contraindicated due to potential cartilage damage) 5, 3, 7
- Aminoglycosides (avoid due to nephrotoxicity and ototoxicity unless life-threatening infection) 3, 6
- Trimethoprim-sulfamethoxazole (avoid due to fetal risks) 5, 3
Dosing Adjustments in Pregnancy
Physiologic changes in pregnancy require consideration:
- Increased glomerular filtration rate, total body volume, and cardiac output may lead to lower serum antibiotic concentrations 7, 9
- Standard or slightly increased doses of beta-lactams are generally appropriate, as these antibiotics are safe with wide therapeutic windows 9
Clinical Pitfalls to Avoid
- Do not delay treatment in pregnant women with confirmed streptococcal respiratory infection, as untreated infections pose significant maternal and fetal risks 3, 7
- Do not use prophylactic antibiotics for colonization outside the intrapartum period, as this is ineffective and may cause adverse consequences 5
- Amoxicillin is pregnancy category B with no evidence of fetal harm in animal studies at doses up to 6 times the human dose, though adequate human studies are limited 2