Can I use CBD or cannabis while breastfeeding?

The verdict

You are advised not to, by every authority that has published on it. The UK Advisory Committee on Novel Foods and Processes advises avoiding CBD products while breastfeeding, and the Breastfeeding Network passes that on. ACOG recommends avoiding cannabis during breastfeeding. LactMed says professional guidelines generally recommend that cannabis use should be avoided by nursing mothers.

ACOG then adds a sentence that matters enormously and is almost always dropped when this advice is repeated: the benefits of breastfeeding are likely to be much more important than the potential harms of cannabis exposure through breast milk, so you should not stop breastfeeding even if you cannot stop using. Avoiding the drug and avoiding breastfeeding are not the same instruction.

What is known about transfer

LactMed sets out the pharmacology and the honest gaps in it. THC, the main psychoactive component of cannabis, is excreted into breastmilk in small quantities. The striking feature is not the amount but the duration: the window over which THC has been detected in milk has ranged from days to more than a month in different studies, and computer modelling puts its clearance from milk at several days.

That persistence is what makes cannabis different from most substances covered in this series. Alcohol leaves milk as it leaves your blood, so waiting works. THC is fat-soluble and stored in fatty tissue, and milk is fat-rich, so timing a feed around a dose does not achieve much. The Breastfeeding Network makes the same point about both THC and CBD staying in the body for a long time, which means more can transfer with repeated use.

What the outcome studies show

LactMed is careful here and so is this page. A one-year study found that daily or near-daily use might retard a breastfed infant's motor development, though not growth or intellectual development. That study and others found no discernible effects from occasional use, but LactMed says explicitly that they were inadequate to rule out long-term harm and were conducted when cannabis was far less potent than it is now. A large registry study in Australia and New Zealand suggested postnatal use might increase the risk of autism spectrum disorder, but did not report the breastfeeding status of the mothers.

The fair summary is that the evidence is thin, dated, and pointing in a direction that argues for caution rather than proving harm. ACOG says the same thing from the clinical side: researchers do not know much, and it is not clear how much transfers.

The supply and milk composition question

LactMed records that cannabis can affect prolactin variably and might decrease milk supply and the duration of lactation. One preliminary study found reduced secretory IgA, one of the immune components of milk, in cannabis users. Two studies found decreases in milk fat content, though they disagreed about protein and carbohydrate. LactMed notes the clinical relevance of these compositional changes is questionable, which is a fair caveat, but the supply signal is worth knowing about.

CBD is not a loophole

CBD is marketed as the non-intoxicating part of the plant and is sold legally in the UK as a food supplement in oils, capsules, gummies and drinks. That legal status does not carry a lactation clearance. The Advisory Committee on Novel Foods and Processes advises avoiding CBD products while breastfeeding, and the Breastfeeding Network passes that advice on directly.

LactMed's record is equally thin: cannabidiol has not been studied in nursing women taking the licensed pharmaceutical product, though it has been detected in the milk of mothers using cannabis products, and because no published information exists an alternate drug may be preferred, especially while nursing a newborn or preterm infant. There is a second issue with the retail products specifically. Government resources highlight that CBD products may also contain THC, and the Breastfeeding Network flags this, so a product bought for its CBD content may deliver something else as well.

If you have already had some

The Breastfeeding Network answers this directly for accidental CBD consumption. As a one-off, the risk is relatively low, especially if you are feeding a child over a year old. Some risk cannot be ruled out if your milk is the main or sole source of milk for your baby, or if your baby is newborn or premature. Its advice is to contact its Drugs in Breastmilk team rather than to act unilaterally, and nothing in that guidance instructs you to stop feeding.

Smoke, vape and storage

ACOG raises two risks that have nothing to do with milk. Secondhand smoke and vape aerosol from cannabis products may be just as harmful as secondhand tobacco smoke, particularly for babies and young children, so if you do smoke or vape, do it away from your baby. And edible products must be locked away, because a child who finds them can easily take a large dose and become seriously unwell.

There is a third consideration that applies to any intoxicating substance in a household with a baby: impairment affects your ability to respond, and it changes the safety of sharing a sleep surface. The same reasoning that underlies UK advice against bed-sharing after alcohol or sedating medicines applies here.

Getting help to stop

ACOG states that about one in three users develops cannabis use disorder and about one in ten becomes addicted, that withdrawal symptoms include irritability, trouble sleeping, cravings and restlessness, and that anyone with a substance use problem should receive medical care and counselling rather than judgement. It points to national substance use support services. Raising it with a health visitor or GP is not the same as inviting intervention, and the alternative, quietly stopping breastfeeding to hide it, is the outcome every one of these bodies is trying to prevent.

Who to ask

If you want an answer about your own situation rather than a general one, the UK has a service for exactly this. The Drugs in Breastmilk service, run by the charity The Breastfeeding Network and staffed by pharmacists, answers questions about specific medicines and specific babies. NHS prescribers use the Specialist Pharmacy Service and its UK Drugs in Lactation Advisory Service, so your GP or pharmacist can escalate a question you cannot resolve at the counter. In the United States the equivalent public reference is LactMed, the drugs and lactation database published by the National Institute of Child Health and Human Development, alongside the MotherToBaby counselling service. In Australia, healthdirect points to a pharmacist advice line and the Australian Breastfeeding Association helpline. In Ireland the HSE tells you to ask your GP, pharmacist, lactation nurse or midwife before taking any medicine, herbal remedy or supplement.

The Drugs in Breastmilk service answers questions about substances as well as medicines, and it is a better first call than an internet forum.