Marijuana can stay in breast milk for up to six days, researchers find

Breastfeeding mothers who smoke marijuana may be sharing their high with their baby.

In a study published in Pediatrics, the researchers found THC, the primary psychoactive component of marijuana, in 63 percent of the breast milk samples for up to six days after the mother’s last reported use.

“Pediatricians are often put into a challenging situation when a breastfeeding mother asks about the safety of marijuana use,” said Christina Chambers, principal investigator of the study, professor in the department of pediatrics at UC San Diego School of Medicine.

“We don’t have strong, published data to support advising against use of marijuana while breastfeeding, and if women feel they have to choose, we run the risk of them deciding to stop breastfeeding — something we know is hugely beneficial for both mom and baby.”

Cannabinoids — marijuana’s active compounds, such as THC — like to bind to fat molecules, which are abundant in breast milk.

“We found that the amount of THC that the infant could potentially ingest from breast milk was relatively low, but we still don’t know enough about the drug to say whether or not there is a concern for the infant at any dose, or if there is a safe dosing level,” said Chambers.

“The ingredients in marijuana products that are available today are thought to be much more potent than products available 20 or 30 years ago.”

Chambers said further research will be conducted to learn the effects of longterm use on the infant.

The World Health Organisation (WHO) recommends exclusive breastfeeding for up to six months.