Will cannabis show up in breast milk?

This is a very good question. Many compounds can become concentrated in breast milk. Endogenous endocannabinoids (molecules made by our own bodies) are found in high levels in breast milk. This is thought to increase feeding in suckling newborns. THC and other cannabinoids can be found in breast milk and can be passed onto the breast feeding baby. Whether or not this causes harm to the baby is debatable. Melanie Dreher, PhD did some of the best work on this subject, studying a large number of pregnant women and babies in Jamaica, and her findings are reassuring. Her study was published in Pediatrics……
Pediatrics, February 1994, Volume 93, Number 2, pp. 254-260. American Academy of Pediatrics
Prenatal Marijuana Exposure and Neonatal Outcomes in Jamaica:
An Ethnographic Study
Melanie C. Dreher, PhD; Kevin Nugent, PhD; and Rebekah Hudgins, MA
Setting. Rural Jamaica in heavy-marijuana-using population.
Objective. To identify neurobehavioral effects of prenatal marijuana exposure on
neonates in rural Jamaica.
Design. Ethnographic field studies and standardized neurobehavior assessments
during the neonatal period.
Participants. Twenty-four Jamaican neonates exposed to marijuana prenatally
and 20 nonexposed neonates.
Measurements and main results. Exposed and nonexposed neonates were
compared at 3 days and 1 month old, using the Brazelton Neonatal Assessment
Scale, including supplementary items to capture possible subtle effects. There
were no significant differences between exposed and nonexposed neonates on day
3. At 1 month, the exposed neonates showed better physiological stability and
required less examiner facilitation to reach organized states. The neonates of
heavy-marijuana-using mothers had better scores on autonomic stability, quality
of alertness, irritability, and self-regulation and were judged to be more
rewarding for caregivers.
Conclusions. The absence of any differences between the exposed on nonexposed
groups in the early neonatal period suggest that the better scores of exposed
neonates at 1 month are traceable to the cultural positioning and social and
economic characteristics of mothers using marijuana that select for the use of
marijuana but also promote neonatal development. Pediatrics 1994;93:254-
260; prenatal marijuana exposure, neonatal outcomes, Jamaica, Brazelton scale
supplementary items.
Considerable controversy surrounds this subject and one should use their best judgement in deciding how to best care for their children.


This is a common question and my opinion is quite clear. The "Jamaica" study done over 22 years ago and the quality and potency of the cannabis was never mentioned and most likely much different from those today. It was also done in a different patient population that the more varied one that uses cannabis today.

As I have stated we have touched on this subject previously regarding cannabis use during pregnancy as well. For breast feeding while using cannabis there are "studies" and opinions from both side that you can find as to whether it effects the infant in any way.

Marijuana is secreted in milk with a reported milk/plasma ratio of 8:1. In one study of 27 women who used cannabis daily during breastfeeding, no differences in growth, mental and motor development were noted in this study population. Most studies suggest a significant absorption in infants following exposure via breast milk. Since the measure is usually of THC, the CBD content was not mentioned, but can assume there is CBD present.

While an analysis of breast milk samples in chronic heavy users revealed an eight-fold increase in accumulation in breast milk compared to plasma, the dose obtained is still insufficient to produce clinical effects in the infant. It may be, however, sufficient to alter long-term neurobehavioral functioning. Infants exposed to marijuana through breastmilk will test positive in urine screens for long periods of time (2-3 weeks)

This also touches on the fact that if your baby for some reason has their urine tested and it is in fact positive for cannabis, the pediatrician will most likely report this to police/child protection etc.

The main point being that some of the cannabis will be in your breast milk and will be fed to you child. Since you do not know the end result that this will have one your child, do you want to take that chance?

Perry Solomon, MD

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