The Effect of Cannabis Consumption During Lactation on the Macronutrient Concentrations in Breast Milk.

Introduction: Human breast milk macronutrients play a vital role in the development of breastfed infants and are known to be influenced by several factors. There is limited information on the influence of cannabis use during lactation on these macronutrients. Given the rising use of cannabis among lactating women with its widespread legalization, this study aimed to examine the association of cannabis use during lactation on breast milk macronutrients. Materials and Methods: A cross-sectional study design was used and 637 breast milk samples with measured macronutrients were utilized. Of these, 165 samples that had detectable cannabis metabolites were defined as the study group, and 472 samples from mothers who did not report cannabis use and from mothers who reported cannabis use but did not have measurable metabolites of cannabis in their milk samples were defined as the control group. Multivariable linear regression models were used to assess the association of presence of cannabis metabolites with protein, carbohydrates, fat, and calories in breast milk. Results: Greater protein levels (95% confidence interval [CI]: 0.112-0.376; p < 0.001) and lower fat levels (95% CI: -0.217, -0.018; p = 0.020) were found in the milk exposed to cannabis compared with reported nonexposure. The presence of cannabis was associated with an increase of 0.244 mg/dL in protein and a reduction of 11% in fats in breast milk. The levels of energy and carbohydrates were not significantly different among the two groups. Conclusions: This study demonstrated a statistically significant association between the presence of metabolites of cannabis in breast milk and protein and fat concentrations in breath milk. Further studies are required toward building the body of evidence to determine safety of cannabis use during lactation.