Short-Term Effects of Maternal Cannabis Use on Human Milk Macronutrient Composition: The Lactation and Cannabis (LAC)...

Cannabis use has increased among reproductive-aged women, including those who are breastfeeding. However, aside from the appearance of cannabinoids in milk, almost nothing is known about how cannabis use might affect human milk composition. This study explored the short-term effects of maternal cannabis use on milk macronutrient content.

Breastfeeding women who used cannabis (cases, n = 20) were matched by body mass index and time postpartum with breastfeeding women who did not use cannabis (controls, n = 19). After abstaining from cannabis use for ≥12 hours, cases collected a baseline milk sample, used cannabis as desired, and collected additional samples 30-≤40 minutes, 1-<2 hours, 2-<4 hours, 4-<6 hours, and 8-<12 hours after use. Controls collected milk at matched time points. Delta-9-tetrahydrocannabinol (Δ⁹-THC) and lipid concentrations were quantified in all samples, and fatty acids, lactose, and protein concentrations were quantified in baseline, 1-2 hours, and 8-12 hours samples.

There were no differences between controls and cases in the concentration of any macronutrient at baseline. After cannabis use, concentrations of lipids and 10 of the 39 identified fatty acids were lower in milk from cases compared to controls. Milk lactose levels increased over time in controls but not in cases. Protein levels were not different between groups at any timepoint. In milk produced by cases, Δ⁹-THC levels were positively correlated with lipids and negatively correlated with lactose.

Cannabis use may transiently influence lipid, fatty acid, and lactose concentrations, highlighting the need for further research to understand the physiology of these alterations.