The study looked at eight new mothers who were all at least occasional pot smokers with exclusively breastfed babies ages 2 to 5 months. Breast milk samples were collected from each mom after discontinuing pot smoking for 24 hours, then again 20 minutes, one hour, two hours, and four hours after smoking a “preweighed, analyzed, standardized strain of cannabis from one preselected dispensary” — 0.1 grams of cannabis, containing a 23.18 percent concentration of THC.
The amounts of THC that transferred into the mothers’ milk samples were “detected at low concentrations” each time a collection was made after the moms smoked, but was highest an hour after smoking. It was estimated that 2.5 percent of the maternal dose of THC was ingested by the babies.
“The levels are low in the milk, and even less would be absorbed by the infants,” study author Tom Hale, PhD, professor of pediatrics at the Texas Tech University School of Medicine, executive director of the school’s InfantRisk Center, told Healthline