TUESDAY, Aug. 28, 2018 (HealthDay News) -- Most breast milk samples have measurable Δ-9-tetrahydrocannabinol (Δ9-THC) up to about six days after maternal use, according to a study published online Aug. 27 in Pediatrics.
Kerri A. Bertrand, M.P.H., from the University of California in San Diego, and colleagues quantified cannabinoids in human milk after maternal marijuana use. Fifty breastfeeding women who reported marijuana use provided 54 breast milk samples between 2014 and 2017.
The researchers found that up to about six days after last reported use, Δ9-THC was detectable in 63 percent of the 54 samples; the median concentration was 9.47 ng/mL. Detectable levels of 11-hydroxy-Δ-9-tetrahydrocannabinol or cannabidiol were seen in five samples. No measurable Δ9-THC was seen in the sample with the highest concentration of cannabidiol. A significant predictor of log Δ9-THC concentrations was the number of hours since last use (−0.03). Other significant predictors of log Δ9-THC concentrations were the number of daily uses and time from sample collection to analysis (0.51 and 0.08, respectively), after adjustment for time since last use.
"Δ9-THC was measurable in a majority of breast milk samples up to approximately six days after maternal marijuana use," the authors write.