Can THC from marijuana remain in breast milk long after consumption? What effect might it have on your baby? Read on to find out what the deal is with cannabis and breast milk.
What you need to know about cannabis and breast milk
- THC was present in 63% of breast milk samples, even six days after consumption.
- Marijuana may concentrate in breast milk more than in blood.
- Some studies suggest neurodevelopmental deficits in infants exposed to THC.
- Health professionals advise against marijuana use during pregnancy and breastfeeding.
How high?
Since the legalization of cannabis in Canada and many parts of the USA, consumption by women in their twenties has steadily risen. In fact, marijuana is quickly becoming the most popular recreational drug among pregnant women and breastfeeding mothers with up to 5% of breast feeding women saying they used it in the last year.1 Health organisations have so far, collected little data about safety of maternal majiuana use for foetuses and new babies.This has led to a concerning situation where in 2015, up to 70% of women questioned, wrongly believed that cannabis was harmless during pregnancy and nursing.2
Doctors are increasingly discovering that THC and cannabinols can affect how a child’s brain develops and can cause birth defects.3, 6, 7 With as many as 70% of women who use the drug assuming their weekend weed is safer than smoking cigarettes, it’s matter of urgency to find out whether THC passes in to breast milk.
Paediatrics Researchers based at UCSD medical School, La Jolla, US aimed to clear up some of the confusion surrounding marijuana safety for newborns. They put together a study to find out how long THC hangs around in a nursing mother’s body and how high the concentrations are.
The group reported in the medical journal Paediatrics, that the active ingredient in cannabis, tetrahydrocannabinol (THC), was found in 63% of the breast milk samples up to six days after the mothers’ last marijuana use. They found cannabidiol in 9% of the samples. So, it takes more than a week for the THC to work its way out of a mother’s milk supply. Sounds like if you are a regular cannabis user, breast is not best.1
THC Transmission
Breastmilk has numerous health benefits for the baby and it is strongly recommended for mothers to exclusively breastfeed their infants for the first six months of life. This means nursiung mothers need to be aware of how what they eat, drink or inhale can affect their baby.
The psychoactive ingredients in cannabis (THC, cannabinol and cannabidiol) are fat soluble. That means that it will easily slip into fat stores in your body and collect there. Milk is a suspension of fats, sugars and proteins in water. So when your body manufactures breast milk, if you have THC stored in your fat deposits, chances are it’ll end up in the milk.
More recent research shows that psychoactive compounds including THC are 7.5 times more concentrated in breast milk than they are in blood.4
Marijuana in breastmilk found up to six days after last use
In the study published in the journal Pediatrics, researchers examined 54 samples from 50 breastfeeding mothers who had provided their samples to the Mommy’s Milk breast milk research repository.
The researchers performed an analysis using liquid chromatography-mass spectrometry electrospray ionization, which revealed various concentrations of the different types of cannabinoid tetrahydrocannabinol (THC), cannabinol, and cannabidiol.
The researchers detected tetrahydrocannabinol (THC) 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.
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.
The findings in this study are consistent with other research that has demonstrated a high concentration of cannabinoids, especially THC, in breast milk. They specifically found these concentrations six days after the last marijuana use.
The study aligns with previous findings on marijuana in breast milk
A previous study found that the more marijuana a mother smoked, the higher concentrations of marijuana they found in the milk sample. Marijuana is also more concentrated in breast milk than in the blood.
Another study found that the infant’s stool had a higher concentration of marijuana than the mother’s milk following ingestion, demonstrating that the infant sucked, absorbed, and digested the marijuana.
A study tracking the levels of THC in breastmilk reported not only that THC was present in breastmilk, but also estimated that the infant ingested 2.5% of the amount that was initially ingested by the mother.5
In terms of effects on infants, neurodevelopmental deficits in infants who were exposed to marijuana have been documented, however, this is not consistent among studies.
More studies are needed to determine the effect of marijuana on babies exposed to breastmilk
Based on the presence of a detectable, measurable amount of marijuana found in these studies, coupled with the previous studies documenting psychomotor deficits and neurodevelopment effects in babies exposed to marijuana through breastmilk, researchers recommend that more studies are urgently needed investigating the effect of marijuana on nursing babies.
Meanwhile, based on existing evidence regarding the amounts and how long marijuana stays in breast milk, health professionals strongly advise against the use of marijuana by pregnant women and nursing mothers.
References:
- 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.
- Ko JY, Farr SL, Tong VT, Creanga AA, Callaghan WM. Prevalence and patterns of marijuana use among pregnant and nonpregnant women of reproductive age. American journal of obstetrics and gynecology. 2015;213(2):201.e1. doi:10.1016/j.ajog.2015.03.021
- Lo JO, Hedges JC, Girardi G. Impact of cannabinoids on pregnancy, reproductive health and offspring outcomes. American journal of obstetrics and gynecology. 2022;227(4):571. doi:10.1016/j.ajog.2022.05.056
- Moss MJ, Bushlin I, Kazmierczak S, et al. Cannabis use and measurement of cannabinoids in plasma and breast milk of breastfeeding mothers. Pediatr Res. 2021;90(4):861-868. doi:10.1038/s41390-020-01332-2
- Baker T, Datta P, Rewers-Felkins K, Thompson H, Kallem RR, Hale TW. Transfer of Inhaled Cannabis Into Human Breast Milk. Obstet Gynecol. 2018 May;131(5):783-788. doi: 10.1097/AOG.0000000000002575. PMID: 29630019.
- Grzeskowiak LE, Grieger JA, Andraweera P, et al. The deleterious effects of cannabis during pregnancy on neonatal outcomes. Med J Aust. 2020;212(11):519-524. doi:10.5694/mja2.50624
- Hayer S, Mendelbaum AD, Watch L, et al. Cannabis and Pregnancy: A review. Obstetrical & gynecological survey. 2023;78(7):411. doi:10.1097/OGX.0000000000001159