Cannabis (also known as marijuana, weed, or pot) and related substances, including CBD oil, are known to pass into human milk. This section will review the use of these substances and current recommendations surrounding their use during lactation.

For more detailed information and references on specific medications, please refer to LactMed, e-lactancia, Infant Risk, or Mother to Baby.

Cannabis use during lactation is not ideal. THC (tetrahydrocannabinol), the active component in marijuana, is known to pass into human milk. Small amounts of occasional cannabis use (not daily) are less likely to cause harm to the infant as compared to heavy daily use (1). Because we don’t have high quality long-term studies on the safety of THC exposure by breastfed or human milk fed infants, professional organizations such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists suggest avoiding marijuana during lactation. However, they do not suggest that cannabis users avoid lactation. It is important to not expose infants to secondhand smoke due to increased risk of SIDS (sudden infant death syndrome) (2, 3).

CBD is a non-psychoactive component of marijuana and is often taken on its own for chronic pain and anxiety. Very little information is available on CBD oil during lactation. Cannabidiol as a metabolite has been found in the milk of lactating individuals after marijuana use. It appears to remain detectable for 3-4 hours in human milk after marijuana ingestion (4). CBD oil is fat-soluble and accumulates in human milk. No studies have evaluated CBD levels in human milk among lactating people taking CBD oil by itself. Patients and providers should engage in shared decision-making regarding CBD oil and review the risks and benefits of this medication so the parent can make an informed decision.