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Breastfeeding, Nutrition, and Early Life Health (Oral Session 2)

(OR02-02-25) Association of Maternal Cannabis Use With the Macronutrient Composition of Human Milk

Saturday, May 31, 2025
10:12 AM – 10:24 AM ET
Location: S230 E-H
Emerging Leaders in Nutrition Science Poster Competition
Objectives: Cannabis use is rising among reproductive-aged women, and cannabinoids have been detected in milk of breastfeeding women who use cannabis. Scant research exists on whether maternal cannabis use affects the nutrient composition of human milk. This study explores the acute effect of maternal cannabis use on total lipid, fatty acids, protein, and lactose content in human milk.

Methods: Breastfeeding women who used cannabis (cases, n = 20) were matched with breastfeeding women who did not use cannabis (controls, n = 19; one excluded for testing positive for cannabis) based on body mass index and time postpartum. After ≥12h abstention, cases collected a baseline sample via full breast expression, then used cannabis as desired. Additional samples were collected at 30-40 min, 1-2h, 2-3h, 4-5h, and 8-12h after initial cannabis use. Controls collected samples at the same times of the day as their matched cases. Delta-9-tetrahydrocannabinol (∆9- THC) and total lipid concentrations were measured in all samples (n = 229); fatty acids, lactose, and protein concentrations were quantified at baseline, 1-2h and 8-12h after initial use (n = 114).

Results: No differences in milk macronutrient concentrations were identified between cases and controls at baseline (t-test p > 0.05). Linear mixed effect models showed that, over the 12h after cannabis use, concentrations of lipid, protein, lactose, and fatty acids in milk from cases remained similar to those in milk from controls. However, ∆9-THC was positively correlated with total lipid content (ρ = 0.55; p < 0.001) and negatively correlated with lactose (ρ = -0.39; p = 0.024) in milk from women who used cannabis. No correlation was observed between THC and protein concentrations.

Conclusions: Concentration of THC in human milk is positively correlated with milk lipid content and negatively correlated with milk lactose content. There was no effect of cannabis use on macronutrients concentrations in human milk collected from cases during the 12h after use compared to controls. These findings highlight the need for further research on maternal cannabis use during breastfeeding and its impact on infant health.

Funding Sources: National Institutes of General Medical Sciences P20GM152304, Idaho Agricultural Research Station, State of Washington Initiative Measures 171 and 502, Washington State University Health Equity Research Center.