HealthDay News — Low concentrations of delta-9-tetrahydrocannabinol are transferred from inhaled cannabis to breast milk of women who regularly consume cannabis, according to a study published online April 9 in Obstetrics & Gynecology.

Teresa Baker, MD, from Texas Tech University in Amarillo, and colleagues collected breast milk samples from 8 women who regularly consumed cannabis, were 2 to 5 months postpartum, and exclusively breastfeeding their infants. Samples were collected after discontinuing cannabis for 24 hours (baseline) and then at 20 minutes and 1, 2, and 4 hours following smoking of a standardized cannabis product. 

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The researchers found that delta-9-tetrahydrocannabinol was detected at low concentrations at all the time points beyond time 0, but no metabolites were detected at any time point. Given the transfer rates of delta-9-tetrahydrocannabinol, exclusively breastfeeding infants ingested an estimated mean of 2.5% of the maternal dose or 8µg/kg/day per infant.

“The long-term neurobehavioral effect of exposure to delta-9-tetrahydrocannabinol on the developing brain is unclear,” the authors write. “Mothers should be cautious using cannabis during pregnancy and breastfeeding.”

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