evidence: Twenty women in Oregon who admitted to using a cannabis product while breastfeeding their infants provided milk samples for analysis. The mothers reported using cannabis almost daily. Fifteen women provided milk samples at their infant’s 2-week and 2-month checkup and 5 provided a sample at only one of the visits for a total of 35 milk samples. All but one milk sample contained at least one cannabinoid. None of the mothers reported using a cannabidiol (CBD) product, but 13 had detectable CBD in breastmilk. Median (IQR) concentrations in milk were as follows: THC 27.5 (0.8 to 190.5) mcg/L; 11-OH-THC 1.4 (0.7 to 5.2) mcg/L; THC-COOH 1.9 (0.5-16.6) mcg/L; CBD 1.2 (0.5 to 17) mcg/L. Three patients using edible products had similar cannabinoid levels as those who smoked cannabis. Fourteen mothers reported an increase in use of cannabis between the 2-week and 2-month visit. Median breast milk THC concentrations were 16.7 mcg/L at visit 1 and 54.5 mcg/L at visit 2. The authors estimated that overall the breastfed infants received an average THC dose of 4.12 mcg/kg daily (range 0.52 to 123 mcg/kg daily) in milk.[19] [...] Cannabis use and measurement of cannabinoids in plasma and breast milk of breastfeeding mothers. [...] Human milk cannabinoid concentrations and associations with maternal factors: The Lactation and Cannabis (LAC) study.