Chemicals in Marijuana Detectable in Breast Milk up to Six Days after Use

The active ingredient in marijuana may still be measurable in a mother’s breast milk up to six days after using the drug, a new study has found. 

According to the findings, published online in the journal Pediatrics, low levels of tetrahydrocannabinol, or THC, were still found six days following marijuana use, whether the drug was smoked, ingested, or consumed in another form. 

Researchers studied 54 breast milk samples between 2014 and 2017; THC was detectable in 63% of them (n = 34) six days later. THC is the mind-altering chemical present in marijuana. Traces of cannabidiol (CBD) were found in five of the samples. CBD is a non-psychoactive compound found in marijuana. A report from the World Health Organization (WHO) stated last year, “To date, there is no evidence of recreational use of CBD or any public health related problems associated with the use of pure CBD.” 

Despite the legalization of marijuana in some states, experts say there isn’t enough information to determine potential side effects for nursing mothers. 

“The fact that marijuana is legal in many states may give the impression the drug is harmless during pregnancy, especially with stories swirling on social media about using it for nausea with morning sickness,” said Dr. Sheryl A. Ryan, chair of the American Academy of Pediatrics’ (AAP) Committee on Substance Use and Prevention. “But in fact, this is still a big question. We do not have good safety data on prenatal exposure to marijuana. Based on the limited data that does exist, as pediatricians, we believe there is cause to be concerned about how the drug will impact the long-term development of children.” 

“There’s still a lot we don’t know about how marijuana affects a baby’s rapidly developing brain,” said Dr. Mary E. O’Connor, executive committee member of the AAP Section on Breastfeeding. “But, based on what we know now, we’re advising women who are pregnant or nursing that the safest choice for their child is to avoid marijuana.”