The main psychoactive component of cannabis, tetrahydrocannabinol (THC), is excreted into breastmilk in small quantities. The duration of detection of THC in milk has ranged from 6 days to greater than 6 weeks in various studies. Concern has been expressed regarding the possible effects of cannabis on neurotransmitters, nervous system development and endocannabinoid-related functions.[1,2] A 1-year study found that daily or near daily use might retard the breastfed infant’s motor development, but not growth or intellectual development. This and another study found that occasional maternal cannabis use during breastfeeding did not have any discernable effects on breastfed infants, but the studies were inadequate to rule out all long-term harm. Although cannabis can affect serum prolactin variably, it appears not to adversely affect the duration of lactation. However, maternal perception that their use of cannabis is harmful to their infants are likely to discontinue breastfeeding earlier than mothers who do not believe it is harmful. Other factors to consider are the possibility of positive urine tests in breastfed infants, which might have legal implications, and the possibility of other harmful contaminants in street drugs. When it comes to life for a new mom, there are a ton of questions both during pregnancy and after. How much does what you put in your body affect your baby? What’s considered safe? What isn’t? And are there natural alternatives that are better for you and your child than prescription medications that may […]
NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.
Drugs and Lactation Database (LactMed) [Internet].
Last Revision: June 20, 2022 .
Estimated reading time: 9 minutes
Drug Levels and Effects
Summary of Use during Lactation
The main psychoactive component of cannabis, tetrahydrocannabinol (THC), is excreted into breastmilk in small quantities. The duration of detection of THC in milk has ranged from 6 days to greater than 6 weeks in various studies. Concern has been expressed regarding the possible effects of cannabis on neurotransmitters, nervous system development and endocannabinoid-related functions.[1,2] A 1-year study found that daily or near daily use might retard the breastfed infant’s motor development, but not growth or intellectual development. This and another study found that occasional maternal cannabis use during breastfeeding did not have any discernable effects on breastfed infants, but the studies were inadequate to rule out all long-term harm. Although cannabis can affect serum prolactin variably, it appears not to adversely affect the duration of lactation. However, maternal perception that their use of cannabis is harmful to their infants are likely to discontinue breastfeeding earlier than mothers who do not believe it is harmful. Other factors to consider are the possibility of positive urine tests in breastfed infants, which might have legal implications, and the possibility of other harmful contaminants in street drugs.
Because of insufficient long-term data on the outcome of infants exposed to cannabis via breastmilk, health professionals’ opinions on the acceptability of breastfeeding by cannabis-using mothers varies. In general, professional guidelines recommend that cannabis use should be avoided by nursing mothers, and nursing mothers should be informed of possible adverse effects on infant development from exposure to cannabis compounds in breastmilk. In addition to possible adverse effects from cannabinoids in breastmilk, paternal cannabis use may also increase the risk of sudden infant death syndrome in breastfed infants. Cannabis should not be smoked by anyone in the vicinity of infants because the infants may be exposed by inhaling the smoke.[6-9]
The main active psychoactive component of cannabis is delta-9-tetrahydrocannabinol (THC), although it also contains other active compounds. THC is very fat soluble and persistent in the body fat of users and slowly released over days to weeks, depending on the extent of use.
Maternal Levels. Two women who smoked marijuana daily while nursing had their randomly collected milk analyzed. One mother who reported smoking marijuana once daily had a milk tetrahydrocannabinol concentration of 105 mcg/L; other metabolites were absent. The second mother who reported smoking marijuana 7 to 8 times daily had a milk concentration of 340 mcg/L; the metabolite 11-hydroxy-THC was found in a concentration of 4 mcg/L and 9-carboxy-THC was absent. A milk sample that was collected 1 hour after smoking marijuana contained 60.3 mcg/L of THC, 1.1 mcg/L of 11-hydroxy-THC and 1.6 mcg/L of 9-carboxy-THC. One source used data in this case to estimate that the infant receives about 0.8% of the maternal weight-adjusted dosage. However, a poorly characterized assay was used that might not be accurate and the portion of milk (i.e., foremilk versus hindmilk) that was collected by the mothers was not stated. This is important because of the high fat solubility of THC.
A woman who admitted to smoking cannabis (amount not stated) donated milk for analysis at an unknown time after the previous use. THC was present in a concentration of 86 mcg/L and 11-hydroxy-THC was present in a concentration of 5 mcg/L; 11-nor-carboxy-9-tetrahydrocannabinol was not detected.
Eight exclusively nursing women who were 3 to 5 months postpartum and reported previous or current cannabis smoking were studied. After 24 hours of abstinence, each smoked a 100 mg of a standardized cannabis containing 23.18% THC. The product was smoked over 10 to 20 minutes from a glass pipe until it was fully consumed. Milk was pumped before smoking and at 20 minutes, 1, 2 and 4 hours after inhalation. THC and its metabolites, 11-OH-delta-9-tetrahydrocannabinol and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol were measured in the milk samples. Six of the women had baseline THC concentrations of
Fifty women who reported using cannabis in the prior 14 days donated milk samples for analysis of THC and its major metabolites. Four women donated two samples each for a total of 54 samples. THC was detectable in 63% of the samples. The median concentration of THC was 9.47 mcg/L (range 1 to 323 mcg/L). Only 5 samples had measurable concentrations of 11-OH-THC (range 1.3 to 12.8 mcg/L) and 5 samples had measurable concentrations of cannabidiol (range 1.3 to 8.6 mcg/L). Samples collected 140 hours (about 6 days) or longer after reported use contained no detectable (
Twenty women in Oregon who admitted to using a cannabis product while breastfeeding their infants provided milk samples for analysis. The mothers reported using cannabis almost daily. Fifteen women provided milk samples at their infant’s 2-week and 2-month checkup and 5 provided a sample at only one of the visits for a total of 35 milk samples. All but one milk sample contained at least one cannabinoid. None of the mothers reported using a cannabidiol (CBD) product, but 13 had detectable CBD in breastmilk. Median (IQR) concentrations in milk were as follows: THC 27.5 (0.8 to 190.5) mcg/L; 11-OH-THC 1.4 (0.7 to 5.2) mcg/L; THC-COOH 1.9 (0.5-16.6) mcg/L; CBD 1.2 (0.5 to 17) mcg/L. Three patients using edible products had similar cannabinoid levels as those who smoked cannabis. Fourteen mothers reported an increase in use of cannabis between the 2-week and 2-month visit. Median breast milk THC concentrations were 16.7 mcg/L at visit 1 and 54.5 mcg/L at visit 2. The authors estimated that overall the breastfed infants received an average THC dose of 4.12 mcg/kg daily (range 0.52 to 123 mcg/kg daily) in milk.
Seven women who used cannabis during pregnancy more than twice weekly, primarily by smoking, and were documented to be abstinent postpartum donated blood and milk levels 2 to 5 times weekly for 6 to 7 weeks. Maximum milk THC levels ranged from 2.8 to 26.1 mcg/L and the elimination half-life from milk averaged 17 days (range 12.2 to 21 days).
Ninety lactating persons who reported using cannabis within the prior 48 hours donated 104 milk samples to a milk biorepository. THC, 11-hydroxy-THC, 11-COOH-THC, cannabidiol, and cannabinol were measured in the samples. The median concentration of THC was 22.7 mcg/L (range 0.1, 1620.0). The two main metabolites of THC, 11-OH-THC and 11-COOH-THC, were detected in 22 (21.2%) and 84 (80.8%) of samples, respectively. Cannabidiol was measurable in 44 (42.3%) of samples and cannabinol was measurable in 43 (41.3%)of samples. The number of hours since last use, route of use and number of puffs taken were significant predictors of the log of THC concentrations.
Infant Levels. The urine of 2 breastfed infants whose mothers smoked marijuana found none of the 9-carboxy-THC metabolite. One mother reported smoking marijuana once daily and the other reported smoking marijuana 7 to 8 times daily. Analysis of the feces of the latter mother’s infant revealed a higher proportion of metabolites than THC, indicating that THC was probably absorbed from the milk, metabolized by the infant, and excreted in feces.
Effects in Breastfed Infants
Twenty-seven mothers reported smoking marijuana during breastfeeding. Twelve of them smoked once a month or less, 9 smoked weekly, and 6 smoked daily. Six of their infants were compared at 1 year of age to the infants of mothers who did not smoke marijuana during pregnancy or breastfeeding. No differences were found in growth, or on mental and motor development.
Sixty-eight infants whose mothers reported smoking marijuana during breastfeeding were compared to 68 matched control infants whose mothers did not smoke marijuana. The duration of breastfeeding varied, but the majority of infants were breastfed for 3 months and received less than 16 fluid ounces of formula daily. Motor development of the marijuana-exposed infants was slightly reduced in a dose-dependent (i.e., number of reported joints per week) manner at 1 year of age, especially among those who reported smoking marijuana on more than 15 days/month during the first month of lactation. No effect was found on mental development.
A small, case-control study found that paternal marijuana smoking postpartum increased the risk of sudden infant death syndrome. In this study, too few nursing mothers smoked marijuana to form any conclusion.
A study of women taking buprenorphine for opiate substitution during pregnancy and lactation found that 4 of the women were also using cannabis as evidenced by positive urine screens for THC between 29 and 56 days postpartum. One was also taking unprescribed benzodiazepines. One infant was exclusively breastfed and the other 3 were mostly breastfeeding with partial supplementation. Infants had no apparent drug-related adverse effects and showed satisfactory developmental progress.
Fifty women who reported using cannabis in the prior 14 days donated milk samples for analysis of THC and its major metabolites. THC was detectable in 66% of the samples and below the limit of quantification in 32% of samples. Preliminary evidence found no differences in infant adverse reactions, postnatal growth, or neurodevelopmental outcomes were found between the groups with quantifiable and nonquantifiable THC in breastmilk.
Effects on Lactation and Breastmilk
Acute one-time marijuana smoking suppresses serum concentrations of luteinizing hormone and prolactin in nonpregnant, nonlactating women.[21-23] The effects of long-term use is unclear, with some studies finding no effect on serum prolactin.[24-26] However, hyperprolactinemia has been reported in some chronic cannabis users,[27-29] and galactorrhea and hyperprolactinemia were reported in a woman who smoked marijuana for over 1 year. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.
Of 258 mothers who reported smoking marijuana during pregnancy, 27 who had smoked marijuana during breastfeeding were followed-up at 1 year. No difference was found in the age of weaning between these mothers and 35 who reported not smoking marijuana during pregnancy or breastfeeding.
The US state of Colorado legalized medical cannabis in 2001 and recreational cannabis in 2012. A cross-sectional survey conducted in Colorado in 2014 and 2015 found that both prenatal and postnatal cannabis use were associated with a shorter duration of breastfeeding. Among women who reported using cannabis during pregnancy, 64% breastfed for 9 or more weeks compared with 78% of women who did not use cannabis during pregnancy. Among women who reported postpartum cannabis use, 58% breastfed for 9 or more weeks compared with 79% of women who did not use cannabis postpartum. Both differences were statistically significant.
A study using a database of 4969 postpartum women found that those who reported using marijuana were more likely to smoke cigarettes, experience postpartum depressive symptoms, and breastfeed for less than 8 weeks. Tobacco smoking is known to decrease the duration of breastfeeding, so the effect of marijuana is not clear. Most of the women who smoked marijuana postpartum also used it during pregnancy.
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CBD & Breastfeeding
When it comes to life for a new mom, there are a ton of questions both during pregnancy and after. How much does what you put in your body affect your baby? What’s considered safe? What isn’t? And are there natural alternatives that are better for you and your child than prescription medications that may have potentially dangerous side effects?
We get asked questions like these a lot, and one thing most new moms want to know is whether or not it’s safe to take CBD while breastfeeding. Like the answer to every question regarding CBD, the answer starts with understanding more about the human body and its endocannabinoid system.
Understanding the Endocannabinoid System
The Endocannabinoid System (ES) plays a critical role in your body’s functioning and well-being. The Endocannabinoid System maintains a number of integral functions, including mental health and wellness, mood, appetite, nutrient transport, energy storage, immune function and the regulation of stress and pain perception.
When CBD enters the human body, it binds to CB receptors within the Endocannabinoid System. This can help to boost the endocannabinoids your body is already producing, and may help to improve the functions the ES is part of. You can learn more about the Endocannabinoid System here and see how CBD works in the body.
The Difference Between THC and CBD
By now, you probably know that THC and CBD are two of the most beneficial compounds found in hemp oil. CBD is a compound widely known for its beneficial properties that produces no psychoactive effects whatsoever. THC may also be useful in helping to treat various ailments, and it’s the compound responsible for creating the “high” associated with cannabis.
There’s been limited research done on the effects of CBD and THC on a developing fetus, but we discuss how to choose if taking CBD during pregnancy is right for you at length.
Taking CBD While Breastfeeding
When it comes to THC, research points to staying away from it while breastfeeding. However, there really hasn’t been enough research done to determine whether or not it’s safe to take CBD while breastfeeding. The truth is that many women who choose to take CBD during their time as a new mom have reported that they also enjoy powerful and natural relief from common postpartum symptoms.
Like any decision that involves your health or the health of your new baby, we strongly recommend talking with your doctor about whether CBD is the right option for you.
To learn more about the research out there and the arguments being made on taking CBD while breastfeeding, let’s dive into the ways CBD may be beneficial and the concerns about taking it.
A Natural Fighter of Anxiety and Depression
For the surprisingly high percentage of new moms struggling with postpartum depression and anxiety, CBD may be especially helpful. Studies suggest between 11% to 15% of women struggle with these challenges, though the true number could be much higher.
Women with postpartum depression often find it more difficult to bond with their babies or provide them with adequate care, potentially impacting a child’s psychological development and leading to problems down the road. Often, when women bring these symptoms to a doctor’s attention, the prescribed “solution” is an antidepressant, like Lexapro or Zyban. Once these drugs finally take effect weeks after the first dose, they can come with a host of side effects like insomnia, weight gain and dizziness. While newer antidepressants have thankfully been formulated so they won’t interfere with breastfeeding, these drugs simply aren’t guaranteed to work. For new mothers without the financial means to obtain these antidepressants, PPD can feel like an impossible challenge.
The most controversial aspect of taking CBD while breastfeeding is simply the lack of research. Most of the studies done on cannabis involve a targeted look at THC. And while this research does point to negative effects of THC on developing fetuses and newborns (like low birth weight), what this indicates is that women shouldn’t smoke marijuana or take THC-rich products while pregnant or breastfeeding. It doesn’t indicate anything negative about CBD.
However, there is one thing we do know for sure – breast milk already naturally contains cannabinoids.
Cannabinoids in Breast Milk
Yep, that’s correct – breast milk is already chock-full of cannabinoids crucial for a baby’s development. This is one of the most important and significant findings surrounding CBD and cannabinoids at large.
Endocannabinoids are incredibly important because they play various vital roles in a baby’s development. They help stimulate the process of suckling and promote appetite, teaching newborns the vital process of eating and getting essential nutrients. It has been widely observed that babies who drink breast milk are more calm after feeding. While we do know that cannabinoids are present in breast milk, scientists aren’t yet sure which cannabinoids are present. One of the challenges in determining which cannabinoids are in breast milk is that CBD binds closely with fat, making it near impossible to measure its amount.
In the future, researchers believe they’ll be able to figure out which cannabinoids are in breast milk – and in what amounts – through a process called “saponification,” which separates those compounds from the milk. All of these advancements are important in determining how CBD might affect a newborn and making progress in the larger picture of CBD as a potentially awesome natural alternative to prescription medications.
Is Taking CBD Worth the Possible Risk?
That’s ultimately a choice between you and your doctor. There simply isn’t enough information currently about the ways CBD could impact your breast milk or your baby for us to definitively state that it’s a completely safe option.
However, after consulting with their doctors and analyzing the benefits of CBD over certain prescription medications, many mothers make the decision that CBD is right for them. And we do know that CBD is regularly prescribed for children struggling with seizures as a safe, non-intoxicating and natural solution.
If I Choose to Take CBD, How Much Should I Take?
As always, we recommend starting small and taking CBD at a consistent time of day. If you’re new to CBD, we recommend starting with 25-50 mg a day and increasing the amount as needed. To learn more, check out this complete guide of how much CBD you should take.