In a new study published in JAMA Pediatrics, researchers at Children’s Hospital Colorado (Children’s Colorado) have found that tetrahydrocannabinol (THC), the psychoactive component of marijuana, stays in breast milk for up to six weeks, further supporting the recommendations of the American Academy of Pediatrics, the American College of Obstetricians and Gynecologists and the Academy of Breastfeeding Medicine to abstain from marijuana use during pregnancy and while a mother is breastfeeding. This is the first study examining THC in breastmilk and plasma among women with known marijuana use in pregnancy since a 1982 study in the New England Journal of Medicine.