2017 | United States and Europe | Randomized placebo-controlled trial
Wymore EM et al. JAMA Pediatrics. 2021;175:632-634.
Methods: Twenty-five women with prenatal cannabis exposure enrolled in postpartum milk and plasma sampling; 12 had biological evidence of abstinence. Elimination modeling focused on seven women who abstained for more than five weeks.
Findings: THC remained detectable during follow-up. In the seven-person modeling subset, the estimated mean milk half-life was approximately 17 days, with projected elimination taking more than six weeks.
Limitations: The estimate comes from a very small subset with prior, usually repeated, exposure. It is not a universal timetable after occasional use. Detectability alone cannot quantify an infant’s developmental risk or establish a safe exposure threshold.