According to a review article in the Journal of Toxicology, the use of cannabis during breastfeeding may cause a delay in children’s motor development.
The authors of the this article found evidence that THC, the main psychoactive chemical in cannabis, could be secreted in human breast milk.
“In one feeding, the infant would ingest 0.8% of the weight-adjusted maternal intake of one joint,” as the researchers explain.
Unfortunately, there has been little research concerning the effects of cannabis use during breastfeeding.
The researchers reviewed two studies which examined the effects of cannabis use during lactation and noted that, “in the first study, no significant differences were found in terms of weaning, growth, and mental or motor development with regard to age.”
On the other hand, “the second study found that cannabis exposure via the mother’s milk during the first month postpartum appeared to be associated with a decrease in infant motor development at one year of age.”
Although there needs to be more research conducted in this area before any definite conclusions can be drawn, because of the potential risks the authors of this review article strongly advise breastfeeding women to abstain from the use of cannabis.
Aurélia Garry, Virginie Rigourd, Ammar Amirouche, Valérie Fauroux, Sylvie Aubry, & Raphaël Serreau. (2009). Cannabis and Breastfeeding. Journal of Toxicology, Vol 2009. Full text: http://www.hindawi.com/journals/jt/2009/596149.html