The legality of cannabis depends on where you live, but it is consumed by millions of people around the globe for a variety of reasons from pain management, to relaxation, and recreational use, but a new study suggests that breastfeeding mothers may be unwittingly feeding traces of the drug to their offspring.

With 17% of Americans estimated to have smoked marijuana in 2023, not including those who take it in an editable form, the new study looked to find out if traces of cannabis could be found in the milk produced by women. They looked at samples from 20 breastfeeding participants who frequently used cannabis (but no other illicit drugs) and found that cannabinoids were indeed passed into the milk. While alcohol has a consistent time for peaking and declining in our systems, the same did not seem to be true of THC, a psychoactive compound that was detected, making it harder to determine how long it could last in the milk. (further info on the research gathered from Science Daily.)

Breastfeeding and THC

THC (delta-9-tetrahydrocannabinol), is the main psychoactive element of the cannabis plant and is what produces the “high” effect. The notion that passing on this substance to our offspring certainly gives cause for concern, because not enough is known about it’s effects on developing babies. On the plus side, researchers observed that the infants only received an average of 0.07mg of THC per day. To put that into perspective, one low-dose edible contains 2mg of THC.

“Breastfeeding parents need to be aware that if they use cannabis, their infants are likely consuming cannabinoids via the milk they produce, and we do not know whether this has any effect on the developing infant,” commented WSU biological anthropologist Courtney Meehan, a who led the project and is also the study’s corresponding author.

Compounds from cannabis are able to accumulate in milk because they are lipophilic, and dissolve into the milk’s lipids. Many women use cannabis because of the benefits that they feel it provides for their wellbeing, but the knowledge that cannabinoids are passed into breastmilk will be valuable as mothers determine whether or not to use cannabis while nursing children.