When a breastfeeding mother gets a bacterial infection like mastitis or a sinus infection, a healthcare provider might prescribe an antibiotic. Amoxicillin, a type of penicillin, is a frequent choice [1.2.7]. Naturally, this leads to urgent questions about its safety and potential impact on lactation. The primary concern for many is whether taking this medication will reduce their milk production.
The Verdict on Amoxicillin and Milk Supply
According to the National Institutes of Health's Drugs and Lactation Database (LactMed®), there is no published information suggesting that amoxicillin has a negative effect on lactation or breast milk production [1.2.1, 1.3.2]. While some antibiotics might theoretically interfere with milk production hormones, amoxicillin is not listed among the drugs known to decrease supply [1.6.7]. The real threat to milk supply often comes from the maternal illness itself (like mastitis) or from not feeding or pumping frequently enough while feeling unwell [1.6.3]. It is crucial to treat infections promptly, as an untreated illness can pose a greater risk to both the mother's health and her ability to maintain a milk supply [1.2.5, 1.6.3].
How Much Amoxicillin Reaches the Infant?
Research shows that amoxicillin passes into breast milk in very low concentrations [1.3.2]. After a mother takes a 1-gram oral dose, the peak levels in her milk are minimal [1.2.1]. An exclusively breastfed infant is estimated to receive a maximum of about 0.1 mg/kg per day, which is only 0.25% to 0.5% of a typical therapeutic infant dose of amoxicillin [1.2.1, 1.3.2]. The U.S. Food and Drug Administration (FDA) considers drugs with a relative infant dose (RID) of less than 10% to be compatible with breastfeeding; amoxicillin's RID is calculated to be around 1% [1.3.1].
Potential Side Effects in Infants
While amoxicillin is generally well-tolerated, there are occasional, mild side effects reported in breastfed infants. These are not common but are important to be aware of [1.2.5].
- Gastrointestinal Issues: The most frequently mentioned side effects are disruptions to the baby's gastrointestinal flora, which may lead to diarrhea, changes in stool, or constipation [1.2.1, 1.2.2].
- Rash: A skin rash is another possible, though infrequent, reaction in infants exposed through breast milk [1.4.1, 1.4.3].
- Thrush or Irritability: Oral thrush (a fungal infection) and general irritability or restlessness have also been reported in some cases [1.2.2, 1.4.3].
These effects are typically mild and self-limiting [1.4.5]. It's also important to note that the combination drug amoxicillin-clavulanic acid (Augmentin) has a slightly higher rate of adverse effects in infants compared to amoxicillin alone [1.3.3, 1.4.6]. If you notice any of these symptoms in your baby, contact your pediatrician for advice [1.2.5].
Medication Safety Comparison While Breastfeeding
It's helpful to understand how amoxicillin compares to other substances and their potential effects on lactation.
| Medication/Substance | Effect on Milk Supply | General Breastfeeding Safety |
|---|---|---|
| Amoxicillin | No documented negative effect [1.2.1, 1.6.2] | Considered safe; low transfer to milk [1.3.2, 1.5.2] |
| Cephalexin (Keflex) | No documented negative effect | Considered safe [1.5.2, 1.5.5] |
| Pseudoephedrine (Sudafed) | Can decrease milk supply [1.5.4] | Likely safe for baby, but may cause irritability [1.5.4] |
| Bromocriptine (Parlodel) | Known to decrease milk supply | Not recommended for use in breastfeeding mothers [1.5.1] |
| Clindamycin | No documented negative effect | Use with caution; may cause GI issues in infant [1.4.4] |
Tips for Maintaining Milk Supply While on Antibiotics
If you need to take amoxicillin or another antibiotic, the focus should be on maintaining your health and your milk production routine. The illness itself is a more significant threat to your supply than the medication.
- Stay Hydrated and Rested: Drink plenty of fluids and get as much rest as possible to help your body fight the infection.
- Continue Nursing on Demand: Frequent and effective milk removal is the key driver of milk production. Nurse your baby often, ensuring a good latch.
- Pump if Necessary: If you are too ill to nurse or if your baby is not feeding well, pump regularly to protect your supply and prevent issues like clogged ducts [1.6.7]. Pumping in place of missed feeds is crucial [1.6.8].
- Monitor Your Baby: Keep an eye out for any unusual symptoms like rash or significant changes in diaper habits and consult a healthcare provider if you have concerns [1.4.3].
- Consider Probiotics: Some sources suggest that taking a probiotic may help protect your and your baby's GI system, though this should be discussed with a doctor [1.4.7].
Conclusion
The consensus among health authorities like the NHS and the NIH is that amoxicillin is safe to take while breastfeeding [1.2.5, 1.3.2]. Crucially, there is no scientific evidence to support the idea that does amoxicillin decrease milk supply. The amount of medication that passes into breast milk is very small and considered unlikely to cause harm to an infant, although mild, temporary side effects are possible. The benefits of treating a maternal infection and continuing to breastfeed far outweigh the minimal risks associated with amoxicillin use [1.4.5]. Always consult with your healthcare provider about any medications you need to take while nursing.
For more detailed information, you can review the Amoxicillin entry in the Drugs and Lactation Database (LactMed®).
