marijuana in breast milk

In a recent study in San Diego, USA, researchers examined marijuana in breast milk of nursing mothers to measure the amount of cannabinoids in breast milk after marijuana use.

There has been a surge in the number of individuals engaging in the use of medicinal and recreational marijuana probably due to an increase in availability and accessibility following the legalisation of the marijuana in many states in the USA and soon in Canada. Unlike in the past, marijuana is rapidly becoming the most recreational drug of abuse among pregnant women and breastfeeding mothers.

Breast milk has numerous health benefits to the baby and the mother and it is strongly recommended for mothers to breastfeed their newborn and infants with only breast milk in the first six months of life. Therefore, it is imperative to know of any possible potential health risks of using marijuana and breast milk.

Marijuana, otherwise known as cannabis, contains psychoactive components such as cannabinoids. Cannabinoids (tetrahydrocannabinol, cannabinol, and cannabidiol) are known to have some effects on the brain. They also attach to fat molecules, which are abundant in breast milk. Because of this, it is crucial to know if marijuana affects breast milk and the possible exposure to nursing babies.

Marijuana in breast milk found up to six days after last use

In a study published in the journal Pediatrics, researchers examined 54 breast milk samples from 50 breastfeeding mothers who had provided their samples to a research repository called Mommy’s Milk. The researchers performed an analysis using liquid chromatography-mass spectrometry electrospray ionization to revealed various concentrations of the different types of cannabinoid tetrahydrocannabinol (THC), cannabinol, and cannabidiol. The researchers detected tetrahydrocannabinol in 63% of the samples up to six days after the mothers’ last marijuana use. They found cannabidiol in 9% of the samples. They did not detect any cannabinol.

The limitations of this study were in the collection and sampling which were done under various conditions. Some samples were not collected under direct observation and the researchers depended on online questionnaires and interviews to determine the mothers’ exposure to marijuana. However, this study does use a relatively large number of samples and, participants were professionally guided on how and when to collect the samples. Again, the findings in this study are consistent with other previous studies which had demonstrated a high concentration of cannabinoids, especially THC, in breast milk. They specifically found these concentrations six days after the last marijuana use.

Study aligns with previous findings on marijuana in breast milk

A previous study found that the number of times a mother smoked marijuana is proportional to the concentration of marijuana found in the breast milk. This means that the more marijuana the mother smoked, the higher concentrations of marijuana they found in the breast milk sample. Also, marijuana is more concentrated in breast milk than in the blood. Another study found that the infant’s stool had more concentration of marijuana than the mother’s breast milk following ingestion, demonstrating that the infant sucked, absorbed, and digested the marijuana. Another study also documented neurodevelopmental deficits in infants who were exposed to marijuana in breast milk, while a contrast study documented no neurodevelopmental issues in infants exposed to marijuana.

More studies needed to determine the effect of marijuana on babies exposed through breast milk

Based on the presence of a detectable measurable amount of marijuana found in this study, coupled with the previous studies documenting psychomotor deficits and neurodevelopment effect of babies exposed to marijuana through breast milk, the researchers recommend that more studies are urgently needed on the effect of marijuana on nursing babies exposed through breast milk.

Meanwhile, health professional strongly advise against the use of marijuana by pregnant women and nursing mothers.

Written by Ijeoma C. Izundu, MBBS


  1. Bertrand K, Hanan N, Honerkamp-Smith G, Best B, Chambers C. Marijuana Use by Breastfeeding Mothers and Cannabinoid Concentrations in Breast Milk. Pediatrics. 2018;142(3):e20181076.
  2. Marijuana found in breast milk up to six days after use [internet]. EurekAlert! 2018 {cited 2 October 2018].–mfi082318.php
Facebook Comments