Using GLP-1 Therapy While Breastfeeding: What You Should Know

Deciding whether to continue or begin GLP-1 therapy while breastfeeding involves balancing maternal health goals with infant safety. Although research is limited, recent studies provide helpful insights — but many questions remain. Below is what we currently understand, along with key considerations and precautionary steps.

What the Research Shows So Far

One recent study measured levels of a GLP-1 analog (similar to semaglutide) in breast milk from eight nursing mothers after weekly injections. The drug was not detected above the limit of quantification in any of the milk samples.

Using a conservative assumption, researchers estimated that an infant’s exposure would be at most ~1.26 % of the maternal dose — far below the often-cited 10 % safety threshold for many medications in breast milk.

These findings support the idea that transfer into breast milk is low.

Still, the study authors caution that long-term effects on infants — especially over extended use or during critical developmental windows — have not been established.

MotherToBaby also states that there is insufficient evidence to conclude whether GLP-1 therapy is safe during lactation.

Key Considerations & Risks

Because the evidence is still emerging, using GLP-1 therapy while breastfeeding should be approached with care. Some of the primary concerns include:

• Unknown long-term infant effects: Even low-level exposure over months or years might have subtle impacts not captured in short-term studies.
• Impact on milk supply: Appetite suppression and rapid weight loss might reduce caloric intake, which could indirectly affect milk production.
• Early postpartum vulnerability: Infants in their early months (especially preterm or medically fragile) are more sensitive to exposures.
• Variability in GLP-1 formulations: Oral or other modified forms may use absorption enhancers whose safety in breast milk is less studied.

When GLP-1 Therapy Might Be Considered During Breastfeeding

In selected situations, with close monitoring, some clinicians might consider continuing or initiating therapy. The decision is highly individual and depends on:

1. Maternal health needs — e.g. if diabetes control or weight-related risks are strong.
2. Infant health and age — older, healthy infants may tolerate exposure better than neonates.
3. Milk supply stability — ideally waiting until supply is well established before starting a GLP-1.
4. Frequent monitoring — for infant growth, developmental markers, and any signs of adverse effects.

Practical Strategies to Reduce Risk

If a provider and mother decide to proceed, these precautions may help minimize risk:

• Use the lowest effective dose and increase only if needed.
• Monitor infant growth, feeding, stool patterns, and overall well-being closely.
• Ensure adequate caloric and protein intake for the mother to support lactation.
• Consider timing medication administration relative to feeding (though drug half-lives may make that less impactful).
• Coordinate care with a lactation consultant and pediatrician.

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