Can a breastfeeding mother take azithromycin?

October 11, 2025 •

3 min read

According to the American Academy of Pediatrics, azithromycin is generally considered compatible with breastfeeding, offering reassurance to nursing mothers who require antibiotic treatment. Given this, many healthcare providers may prescribe it while a mother is lactating, but it is important to understand the specifics of how the medication affects both mother and infant.

Quick Summary

Azithromycin is considered largely safe for breastfeeding mothers, with only minimal amounts transferring to milk. While potential side effects in infants are rare, vigilance is key, especially during the early postpartum period, and medical advice is essential.

Key Points

Generally safe: Azithromycin is considered compatible with breastfeeding by major health organizations like the American Academy of Pediatrics.
Low infant exposure: Only a small amount of azithromycin transfers into breast milk, resulting in minimal infant exposure.
Monitor for side effects: Watch for mild gastrointestinal issues, oral thrush, or potential allergic reactions in your baby.
Caution in early weeks: A very low, unconfirmed risk of hypertrophic pyloric stenosis (IHPS) is associated with macrolide use in the first two weeks postpartum.
Consult your doctor: Always discuss medication use with your healthcare provider to ensure it is the most appropriate option for your specific situation.
Therapeutic benefits outweigh risks: The benefits of treating a mother's infection with azithromycin generally outweigh the low risk to the breastfed infant.

Understanding Azithromycin and Breastfeeding

Azithromycin is a macrolide antibiotic used to treat various bacterial infections. While effective, breastfeeding mothers often question its safety for their infants. Major health organizations like the American Academy of Pediatrics and the Drugs and Lactation Database (LactMed) generally consider azithromycin safe during lactation. This is mainly because only small amounts of the drug pass into breast milk, and the dosage infants receive through milk is usually much lower than therapeutic doses given directly to infants. Despite the low risk, it's important to monitor the infant for potential side effects, especially those affecting the gastrointestinal system.

How Azithromycin Transfers into Breast Milk

Azithromycin's transfer into breast milk is influenced by its characteristics, such as being a weak base that can accumulate in breast milk. Although concentrations in milk might be higher than in the mother's blood, the overall amount the infant ingests is low. Factors influencing this transfer include the mother's blood concentration, the drug's long half-life which can lead to accumulation, and its moderate lipid solubility.

Potential Side Effects in the Infant

While uncommon, infants may experience mild side effects, mainly related to changes in gut bacteria. These can include gastrointestinal issues like diarrhea or vomiting, oral candidiasis (thrush), a theoretical risk of allergic reaction, or irritability.

Understanding the Risk of Hypertrophic Pyloric Stenosis (IHPS)

A specific, very low and unconfirmed risk associated with maternal macrolide use is infantile hypertrophic pyloric stenosis (IHPS). This involves a thickening of the stomach muscle causing severe vomiting. This potential risk is mainly linked to macrolide use during the first two weeks of breastfeeding. Evidence is inconclusive, with some studies questioning the link. Mothers should watch for projectile vomiting, a key symptom of IHPS.

Comparison of Azithromycin with Other Antibiotics in Breastfeeding

When choosing an antibiotic for a breastfeeding mother, healthcare providers weigh several factors. Here's a comparison of azithromycin with other common antibiotics regarding lactation safety:


Feature	Azithromycin	Amoxicillin	Cephalexin
Drug Class	Macrolide	Penicillin	Cephalosporin
Safety in Breastfeeding	Generally considered safe, especially after the first 2 weeks postpartum.	Considered very safe and compatible.	Considered very safe and compatible with minimal milk passage.
Transfer to Breast Milk	Small amounts pass into breast milk, with some accumulation over time due to long half-life.	Very low transfer into breast milk.	Minimal passage into breast milk.
Primary Infant Side Effects	Low risk of GI issues, thrush, and theoretical risk of IHPS in early infancy.	Low risk of diarrhea and potential sensitization.	Generally well-tolerated with low risk of infant side effects.
Considerations	Caution advised during the first 13 days of nursing due to IHPS risk.	A first-line option for many infections due to high safety profile.	Good alternative if concern exists about macrolide use during early postpartum.

Key Monitoring Points While on Azithromycin

If prescribed azithromycin, carefully observe your infant for any changes:

Feeding: Note any decrease in feeding or increased fussiness during or after nursing.
Gastrointestinal: Watch for new or persistent diarrhea or vomiting.
Oral/Skin: Check for signs of thrush in the mouth or a resistant diaper rash.
Vomiting (early weeks): Be especially vigilant for projectile vomiting, a sign of IHPS, in the first two weeks and seek immediate medical care if seen.

When to Consult Your Doctor

Always consult your doctor or a lactation consultant before taking any medication while breastfeeding. This is especially important if your infant is a newborn (under 2 weeks) due to the unconfirmed IHPS risk, if your baby is premature or has health conditions, if you notice any adverse effects in your baby, or if you have concerns about your milk supply.

Conclusion

Azithromycin can be taken by breastfeeding mothers when necessary. It is considered compatible with lactation with a low risk to the infant, particularly after the first two weeks postpartum. The minimal amount of drug in breast milk and the benefits of treating the mother's infection typically outweigh the potential, usually mild, infant side effects. However, monitoring the infant for issues like GI problems or thrush is important. Decisions about using azithromycin should always be made in consultation with a healthcare provider who can consider individual circumstances.

For more detailed information, the Drugs and Lactation Database (LactMed) is a valuable resource: https://www.ncbi.nlm.nih.gov/books/NBK501200/.

Frequently Asked Questions

Only small amounts of azithromycin pass into breast milk. While its concentration in milk can be higher than in the mother's blood due to its chemical properties, the total dose the infant receives is very low and considered clinically insignificant compared to a therapeutic dose given directly to an infant.

Potential side effects are generally mild and uncommon, and include gastrointestinal disturbances like diarrhea or vomiting, and oral candidiasis (thrush). Parents should monitor the baby's feeding habits, stool, and oral health.

While generally safe, caution is advised during the first two weeks postpartum due to a very low and unconfirmed risk of hypertrophic pyloric stenosis (IHPS) associated with macrolides. After this period, the risk is not a concern.

If your baby exhibits symptoms like persistent vomiting, diarrhea, a rash, or signs of thrush, you should contact your healthcare provider immediately. They can help determine if the medication is the cause and advise on the next steps.

Yes, other antibiotics like amoxicillin or cephalexin are also considered very safe during breastfeeding and are often used as alternatives, especially during the early postpartum period. Your doctor will help you choose the best option based on your specific infection.

There is no clear evidence to suggest that azithromycin significantly affects a mother's milk supply. However, any changes in a baby's feeding pattern due to side effects could indirectly impact supply.

Azithromycin has a long half-life, and it can remain in the body and breast milk for an extended period, potentially several days, even after you have stopped taking the medication. The concentration gradually decreases over time.