Can I use cannabis while breastfeeding?

The verdict

No, and this page is not going to hedge it. Every authority that has looked at this advises stopping cannabis while breastfeeding. What none of them says is that using cannabis means you must stop breastfeeding, and both halves of that need stating plainly.

The Canadian Paediatric Society is the most direct: there is no known safe amount of cannabis use during breastfeeding, the safest approach is to not use cannabis during breastfeeding, and this includes all modes of use, smoking, vaping and ingesting.

The American College of Obstetricians and Gynecologists, in its 2025 clinical consensus on cannabis use during pregnancy and lactation, states that clinicians should advise cessation of cannabis use during pregnancy and lactation, that there are no medical indications for cannabis use during pregnancy and the postpartum period, and, in the same recommendation, that continued cannabis use is not a contraindication to breastfeeding and breastfeeding should not be discouraged.

What the evidence shows about THC in milk

LactMed, the National Library of Medicine's lactation database, is the source to read on this and it does not soften anything.

THC, the main psychoactive component of cannabis, is excreted into breast milk. Because it is fat-soluble it is stored in body fat and released slowly, which is why it lingers far longer than most people expect. LactMed records that the duration of detection of THC in milk has ranged from six days to greater than six weeks in various studies.

That figure is the single most important one on this page. It means that abstaining for a day, or expressing and discarding for a few hours, does not clear THC from milk. There is no reliable pump-and-dump interval for cannabis, and anyone offering one is guessing.

On effects, LactMed reports that a one-year study found daily or near daily use might retard the breastfed infant's motor development, but not growth or intellectual development, and that occasional maternal cannabis use during breastfeeding did not have any discernible effects on breastfed infants. It also notes a registry study suggesting that postnatal use of cannabis may increase the risk of autism spectrum disorder, with male infants affected to a greater extent than female infants. ACOG notes that THC is lipid-soluble, crosses the placenta and can transfer into breast milk.

The honest summary: the signal is strongest for frequent, heavy use, the evidence base is limited by study quality and size, and the direction of every finding points the same way. That is why the advice is to stop rather than to moderate.

The risks that are not about milk at all

Two of the most serious risks have nothing to do with what is in your milk.

Smoke exposure. LactMed states that cannabis should not be smoked by anyone in the vicinity of infants because the infants may be exposed by inhaling the smoke. It also records that paternal cannabis use may increase the risk of sudden infant death syndrome in breastfed infants. The Canadian Paediatric Society lists second-hand cannabis smoke alongside cigarette smoke as increasing SIDS risk after birth.

Impaired care. Cannabis affects judgement, reaction time and alertness. Every safer sleep authority lists drugs that make you sleepy or less aware among the circumstances in which sharing a sleep surface with a baby is dangerous. The Lullaby Trust says co-sleeping is very dangerous if you or anyone in the bed has taken any drugs or medication that make you feel sleepy. Unicef UK's figures place the risk of SIDS while co-sleeping after alcohol or drugs at around one in 203, compared with a background risk of around one in 3,710.

If you use cannabis, arrange for a sober adult to be responsible for your baby, and do not share a bed or a sofa with them. That instruction does more to protect your baby than any decision about milk.

CBD, edibles and dispensary products

The Canadian Paediatric Society's advice covers all modes of use, including ingesting. Edibles avoid the smoke exposure but deliver THC to milk in the same way, and the dose in unregulated products is unpredictable.

Products sold as CBD are not automatically THC-free, are not consistently regulated for content, and have not been studied in lactation. Nothing here supports treating them as a safe alternative.

If you are using and feeding

Two things are true at once, and neither cancels the other.

The first is that stopping is the recommendation, and support exists to help. Tell a clinician you trust, and ask about local substance use support that works with parents rather than against them.

The second is that fear of being told to stop feeding, or of a child protection referral, should not push you into weaning or into hiding use. ACOG says explicitly that continued cannabis use is not a contraindication to breastfeeding and that lactation should be encouraged regardless of cannabis use, and that biologic testing should not be used as a screening assessment. The Academy of Breastfeeding Medicine's protocol on substance use takes the same approach: assess, support, and do not use breastfeeding as a lever.

Reducing frequency reduces exposure even if you cannot stop. Never smoke near your baby or in your home. Never share a sleep surface. Never be the only adult responsible for a baby while impaired.

Where guidance differs

Less than you might expect, given how differently cannabis is regulated across these countries.

The US, through ACOG, advises cessation during lactation while insisting that use is not a contraindication to breastfeeding and that breastfeeding should not be discouraged.

Canada, through the Canadian Paediatric Society, states there is no known safe amount and that the safest approach is not to use, covering smoking, vaping and ingesting.

Internationally, LactMed states that professional guidelines recommend cannabis use should be avoided by nursing mothers, and that nursing mothers should be informed of possible adverse effects on infant development.

The UK has no separate national breastfeeding guidance on cannabis, and clinicians here generally work from LactMed and the Academy of Breastfeeding Medicine protocol. The Breastfeeding Network's Drugs in Breastmilk service will answer individual questions.

Nobody publishes a safe amount, a safe frequency or a safe waiting time. That absence is the finding, not a gap someone will fill later.