Is co‑amoxiclav (amoxicillin + clavulanic acid) safe for use while breastfeeding?

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Last updated: February 8, 2026View editorial policy

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Co-amoxiclav Safety During Breastfeeding

Co-amoxiclav (amoxicillin/clavulanic acid) is safe and compatible with breastfeeding, representing one of the highest safety designations for antibiotics during lactation. 1

Safety Classification and Evidence

  • The American Academy of Dermatology and European Respiratory Society classify co-amoxiclav as "compatible" with breastfeeding—the highest safety designation for antibiotics during lactation. 1

  • Co-amoxiclav is FDA Pregnancy Category B, and the drug label confirms that penicillins are excreted in human milk, though amounts are small and oral bioavailability in infants is generally low. 2, 1

  • Multiple international guidelines, including the European Respiratory Society/Thoracic Society of Australia and New Zealand (ERS/TSANZ), explicitly list co-amoxiclav as compatible with nursing. 1

Clinical Evidence Supporting Safety

  • A prospective controlled study of 67 breastfeeding women taking amoxicillin/clavulanic acid found that 22.3% of infants experienced minor adverse effects (primarily mild gastrointestinal symptoms), which were self-limiting and did not require interruption of breastfeeding. 3

  • All reported adverse effects in exposed infants were minor, self-limiting, and did not necessitate stopping breastfeeding—no serious adverse events occurred. 3

  • The FDA drug label states that ampicillin-class antibiotics are excreted in milk, but caution (not contraindication) is advised when administering to nursing women. 2

Infant Monitoring Considerations

  • All breastfed infants whose mothers take co-amoxiclav should be monitored for mild gastrointestinal effects such as diarrhea or altered intestinal flora, though serious adverse events are rare. 1

  • Antibiotics in breast milk may alter intestinal flora, potentially causing mild diarrhea or gastroenteritis in the infant, but these effects are typically transient. 1

  • Antibiotics in breast milk could potentially cause falsely negative cultures if the breastfed infant develops fever requiring evaluation—inform pediatricians of maternal antibiotic use. 1

Important Caveat: Pregnancy vs. Breastfeeding Context

  • Co-amoxiclav should not be used in women at risk of pre-term delivery due to a very low risk of necrotizing enterocolitis in the fetus. 1

  • This caveat applies specifically to the pregnancy/delivery context, NOT to postpartum breastfeeding in term infants—co-amoxiclav remains fully compatible and safe for breastfeeding mothers after term delivery. 1

  • A 2001 study reported increased necrotizing enterocolitis risk with prophylactic amoxicillin-clavulanic acid before delivery in preterm prelabor rupture of membranes, but this has not been confirmed in subsequent studies and does not apply to breastfeeding after term delivery. 4

Dosing and Practical Recommendations

  • Standard dosing for co-amoxiclav during breastfeeding follows usual adult dosing regimens without modification. 1

  • Breastfeeding should not be interrupted when co-amoxiclav is prescribed—the benefits of continued breastfeeding outweigh the minimal risks of antibiotic exposure through breast milk. 1

  • Co-amoxiclav is recommended as a first-line safe and effective antibiotic choice for breastfeeding mothers requiring antibiotic therapy. 1

Common Pitfalls to Avoid

  • Do not confuse the pregnancy-related concern about necrotizing enterocolitis (which applies to pre-term delivery situations) with breastfeeding safety—these are separate clinical contexts. 1, 4

  • Do not unnecessarily discontinue breastfeeding when prescribing co-amoxiclav, as short courses of this antibiotic are commonly used with no evidence of harmful effects in breastfeeding women. 1

  • Do not fail to counsel mothers that minor gastrointestinal symptoms in the infant (if they occur) are self-limiting and do not require stopping the antibiotic or breastfeeding. 3

References

Guideline

Safety of Antibiotics During Breastfeeding

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Research

[Amoxicillin-clavulanic acid in late pregnancy].

Gynecologie, obstetrique, fertilite & senologie, 2022

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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