Cannabis use during lactation may alter the composition of human breast milk

Background

Cannabis is often used by women to manage symptoms of morning sickness during pregnancy, and postpartum stress and anxiety. While exclusive breastfeeding has been recommended for the first 6 months of an infant’s life, the presence of cannabinoids in the milk of cannabis users complicates this recommendation. The objective of this study was to investigate the effect of maternal cannabis use on changes in the levels of macronutrients and bioactive factors in breast milk.

Methods

Milk was collected from women who were 6–8 weeks postpartum and were either using cannabis post-delivery, had used cannabis during pregnancy, or were non-users. Levels of cannabinoids, macronutrients, lactose, and SIgA were assessed in the milk of all subjects.

Results

THC was detected in the milk of women who reported cannabis use during lactation (n = 13, median: 22 ng/mL). Carboxy-THC, 11-hydroxy-THC, CBD, and CBN were also detected in the milk of women who used cannabis postpartum. Relative to non-users (n = 17), lactose levels were higher and SIgA levels were significantly lower in the milk of subjects who used cannabis during lactation (n = 14).

Conclusions

The presence of cannabinoids, along with altered lactose and SIgA levels in the milk of cannabis users, may have implications for infant health.

Impact

• Metabolites of cannabis are found in breast milk and can accumulate in higher concentrations with ongoing consumption, which is concerning for potential exposure among infants born to mothers who consume cannabis.
• This work reports that lactose levels are increased and SIgA levels are decreased in the breast milk of cannabis users, relative to the milk of non-users.
• Change in levels of lactose and SIgA in the milk of cannabis users may have significant implications on infant health, which must be investigated in the future to better inform mothers.