Washington State University-led research has found the intoxicating cannabinoid THC shows up in the breast milk of mothers using cannabis.
With so many US states making marijuana and/or medical cannabis legal, it’s becoming increasingly important to know about potential issues – such as the impact on breastfeeding.
“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,” said Courtney Meehan, who led a study on the issue.
Ms. Meehan and her colleagues discovered not only did tetrahydrocannabinol (THC) show up in the breast milk cannabis users produced, but there was no consistent time when THC concentration levels peaked and then started declining. While the levels detected were low, it’s a concern given the lack of knowledge of any impacts.
The study involved 20 breastfeeding mothers who used cannabis and had infants younger than six months. The milk was collected after least 12 hours since last cannabis use and then at regular intervals. The milk always had detectable THC in participants who used cannabis multiple times during the study, and the majority showed a continual increase in concentrations across the day.
The reason why cannabinoids appear and accumulate in breast milk is they dissolve in lipids, a component of breast milk. Patients using cannabis oil are often advised to accompany it with “good fats” to increase cannabinoid bioavailability.
While nursing mothers are provided guidance in relation to alcohol use, there’s no advice on cannabis. The research team is working to address gaps in knowledge with further research on cannabis use in breastfeeding mothers, composition of the milk they produce and its effects on infant development.
“This is an area that needs substantial, rigorous research for moms to know what’s best,” said study co-author Shelley McGuire.
The study has been published in the journal Breastfeeding Medicine
Generally speaking, THC can be detected in blood for days to weeks since last use depending on the individual, even though the effects have long worn off. It’s one of the reasons why medical cannabis patients using THC need to be particularly careful with driving in jurisdictions that have zero-THC driving laws, such as much of Australia – with the exception of Tasmania if it has been legally prescribed and the driver is not impaired.
