Is co-amoxiclav (amoxicillin/clavulanic acid) safe during pregnancy?

Co-amoxiclav Safety in Pregnancy

Co-amoxiclav (amoxicillin/clavulanic acid) is safe to use during pregnancy and is classified as FDA Pregnancy Category B, with extensive guideline support and no evidence of teratogenic effects. 1, 2

Evidence Supporting Safety

• The FDA drug label explicitly states that reproduction studies in pregnant rats and mice at doses up to 1,200 mg/kg/day revealed no evidence of harm to the fetus due to amoxicillin/clavulanic acid. 2

• Multiple major guidelines classify amoxicillin (the primary component) as "compatible" for use during pregnancy, including recommendations from the American College of Obstetricians and Gynecologists and CDC. 1, 3

• The CDC specifically recommends amoxicillin 500 mg every 8 hours for various infections during pregnancy, including anthrax post-exposure prophylaxis and as an alternative for Chlamydia trachomatis infection. 1, 3

• The American College of Obstetricians and Gynecologists recommends amoxicillin 500 mg IV/PO every 8 hours for uncomplicated urinary tract infections in pregnancy. 3

Critical Advantage Over Other Antibiotics

• Unlike tetracyclines and fluoroquinolones, which are absolutely contraindicated in pregnancy, amoxicillin/clavulanic acid has no known teratogenic effects. 1, 3

• Tetracyclines cause dental staining of fetal primary teeth, depressed fetal bone growth, and rare hepatic necrosis in pregnant women—making co-amoxiclav a far safer choice. 1

• Fluoroquinolones should be avoided entirely during pregnancy. 3

Important Caveat for Preterm Delivery Risk

• Co-amoxiclav should be used with caution in women at risk of preterm delivery due to a very low risk of necrotizing enterocolitis in neonates. 4, 3, 2

• The FDA drug label specifically notes that in a single study of women with premature rupture of fetal membranes, prophylactic treatment with amoxicillin/clavulanic acid may be associated with increased risk of necrotizing enterocolitis in neonates. 2

• This caveat applies specifically to the pregnancy/delivery context in at-risk women, not to routine use in uncomplicated pregnancies. 4

Clinical Decision Algorithm

For routine infections in pregnancy:

• Co-amoxiclav is safe and appropriate as first-line therapy 1, 3, 2

For women at risk of preterm delivery or with premature rupture of membranes:

• Consider amoxicillin alone (without clavulanic acid) as a safer alternative 4, 3
• If co-amoxiclav is specifically indicated, weigh the infection risk against the very low risk of neonatal necrotizing enterocolitis 2

For women with penicillin allergy:

• Avoid co-amoxiclav entirely and use alternative antibiotics such as cephalosporins (if no cross-reactivity) or erythromycin 5

Breastfeeding Compatibility

• Co-amoxiclav is classified as "compatible" with breastfeeding, representing the highest safety designation for antibiotics during lactation. 4

• Penicillins are present in breast milk at low concentrations, and breastfed infants should be monitored for mild gastrointestinal effects, though serious adverse events are rare. 4, 1

Common Pitfall to Avoid

• Do not confuse the safety profile of co-amoxiclav with contraindicated antibiotics—tetracyclines and fluoroquinolones are absolutely contraindicated in pregnancy, while co-amoxiclav is safe. 1, 3

• The FDA drug label states "this drug should be used during pregnancy only if clearly needed," which is standard cautionary language for Category B drugs, not an indication of danger—animal studies show no harm, and clinical use is well-established. 2