Cannabis use while Breastfeeding
Medically reviewed by Drugs.com. Last updated on Jul 27, 2021.
Cannabis Levels and Effects while Breastfeeding
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 <2 mcg/L; the other two had 5.8 and 15.8 mcg/L of THC in their milk at baseline. The average THC concentration in breastmilk was 53.5 mcg/L (median 27.6 mcg/L; range 8.4 to 186.1 mcg/L), and the average peak THC concentration was 94 mcg/L (range 12.2 to 420.3 mcg/L) 1 hour after inhalation. The metabolites were not measurable (<0.097 mcg/L). The estimated daily THC intake for the infant was 8 mcg/kg, which corresponded to 2.5% (range 0.4 to 8.7%) of the weight-adjusted maternal dosage.
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 (<1 mcg/L) THC and the sample with the highest cannabidiol concentration contained no detectable THC. Of the 34 milk samples from mothers who reported using cannabis, the half-life of THC in milk was estimated to average about 27 hours. Using the median value, the median infant THC dosage would be 1.4 mcg/kg daily.
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).
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.[20-22] The effects of long-term use is unclear, with some studies finding no effect on serum prolactin.[23-25] However, hyperprolactinemia has been reported in some chronic cannabis users,[26-28] 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.
Schuel H, Burkman LJ, Lippes J, et al. N-acylethanolamines in human reproductive fluids. Chem Phys Lipids. 2002;121:211–27. [PubMed: 12505702]
Fernández-Ruiz J, Gómez M, Hernández M, et al. Cannabinoids and gene expression during brain development. Neurotox Res. 2004;6:389–401. [PubMed: 15545023]
Astley SJ, Little RE. Maternal marijuana use during lactation and infant development at one year. Neurotoxicol Teratol. 1990;12:161–8. [PubMed: 2333069]
Tennes K, Avitable N, Blackard C, et al. Marijuana: Prenatal and postnatal exposure in the human. NIDA Res Monogr. 1985;59:48–60. [PubMed: 3929132]
Coy KC, Haight SC, Anstey E, et al. Postpartum marijuana use, perceptions of safety, and breastfeeding initiation and duration: An analysis of PRAMS data from seven states, 2017. J Hum Lact. 2021:890334421993466. [PMC free article: PMC8361861] [PubMed: 33586506]
Reece-Stremtan S, Marinelli KA. ABM clinical protocol #21: Guidelines for breastfeeding and substance use or substance use disorder, revised 2015. Breastfeed Med. 2015;10:135–41. [PMC free article: PMC4378642] [PubMed: 25836677]
Committee Opinion No. 722: Marijuana Use During Pregnancy and Lactation. Obstet Gynecol. 2017;130:e205–e9. [PubMed: 28937574]
Ryan SA, Ammerman SD, O'Connor ME. Marijuana use during pregnancy and breastfeeding: Implications for neonatal and childhood outcomes. Pediatrics. 2018;142:e20181889. [PubMed: 30150209]
Metz TD, Borgelt LM. Marijuana use in pregnancy and while breastfeeding. Obstet Gynecol. 2018;132:1198–210. [PMC free article: PMC6370295] [PubMed: 30234728]
Perez-Reyes M, Wall ME. Presence of delta 9-tetrahydrocannabinol in human milk. N Engl J Med 1982;307:819-20. Letter. PMID: 6287261. [PubMed: 6287261]
Bennett PN, ed. Drugs and human lactation, 2nd ed. Amsterdam. Elsevier. 1996:348-9.
Marchei E, Escuder D, Pallas CR, et al. Simultaneous analysis of frequently used licit and illicit psychoactive drugs in breast milk by liquid chromatography tandem mass spectrometry. J Pharm Biomed Anal. 2011;55:309–16. [PubMed: 21330091]
Baker T, Datta P, Rewers-Felkins K, et al. Transfer of inhaled cannabis into human breast milk. Obstet Gynecol. 2018;131:783–8. [PubMed: 29630019]
Bertrand KA, Hanan NJ, Honerkamp-Smith G, et al. Marijuana use by breastfeeding mothers and cannabinoid concentrations in breast milk. Pediatrics. 2018;142:e20181076. [PMC free article: PMC6317767] [PubMed: 30150212]
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 [PubMed: 33469174]
Wymore EM, Palmer C, Wang GS, et al. Persistence of Δ-9-tetrahydrocannabinol in human breast milk. JAMA Pediatr. 2021 [PMC free article: PMC7941249] [PubMed: 33683306]
Klonoff-Cohen H, Lam-Kruglick P. Maternal and paternal recreational drug use and sudden infant death syndrome. Arch Pediatr Adolesc Med. 2001;155:765–70. [PubMed: 11434841]
Ilett KF, Hackett LP, Gower S, et al. Estimated dose exposure of the neonate to buprenorphine and its metabolite norbuprenorphine via breastmilk during maternal buprenorphine substitution treatment. Breastfeed Med. 2012;7:269–74. [PubMed: 22011128]
Bertrand K, Borchelt J, Honerkamp-Smith G, et al. Infant adverse reactions, postnatal growth and neurodevelopmental outcomes in infants and toddlers breastfed by mothers who use marijuana. Birth Defects Res 2020;112:876. Abstract. doi:10.1002/bdr2.1760. [CrossRef]
Mendelson JH, Mello NK, Ellingboe J. Acute effects of marihuana smoking on prolactin levels on human females. J Pharmacol Exp Ther. 1985;232:220–2. [PubMed: 3965692]
Mendelson JH, Mello NK, Ellingboe J, et al. Marihuana smoking suppresses luteinizing hormone in women. J Pharmacol Exp Ther. 1986;237:862–6. [PubMed: 3012072]
Murphy LL, Muñoz RM, Adrian BA, et al. Function of cannabinoid receptors in the neuroendocrine regulation of hormone secretion. Neurobiol Dis. 1998;5 6 Pt B:432–46. [PubMed: 9974176]
Block RI, Farinpour R, Schlechte JA. Effects of chronic marijuana use on testosterone, luteinizing hormone, follicle stimulating hormone, prolactin and cortisol in men and women. Drug Alcohol Depend. 1991;28:121–8. [PubMed: 1935564]
Brown TT, Dobs AS. Endocrine effects of marijuana. J Clin Pharmacol. 2002;42:90S–6S. [PubMed: 12412841]
Ranganathan M, Braley G, Pittman B, et al. The effects of cannabinoids on serum cortisol and prolactin in humans. Psychopharmacology (Berl). 2009;203:737–44. [PMC free article: PMC2863108] [PubMed: 19083209]
Olusi SO. Hyperprolactinaemia in patients with suspected cannabis-induced gynaecomastia. Lancet. 1980;1:255. [PubMed: 6101701]
Harmon J, Aliapoulios MA. Gynecomastia in marihuana users. N Engl J Med 1972;287:936. Letter. PMID: 5075561. [PubMed: 5075561]
Rizvi AA. Hyperprolactinemia and galactorrhea associated with marijuana use. Endocrinologist. 2006;16:308–10. [CrossRef]
Crume TL, Juhl AL, Brooks-Russell A, et al. Cannabis use during the perinatal period in a state with legalized recreational and medical marijuana: The association between maternal characteristics, breastfeeding patterns, and neonatal outcomes. J Pediatr. 2018;197:90–6. [PubMed: 29605394]
Ko JY, Tong VT, Bombard JM, et al. Marijuana use during and after pregnancy and association of prenatal use on birth outcomes: A population-based study. Drug Alcohol Depend. 2018;187:72–8. [PMC free article: PMC7479809] [PubMed: 29627409]
CAS Registry Number
Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.
More about cannabis
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.