10 Things Every Nurse Needs to Know About Marijuana Use and Breastfeeding
A wave of marijuana legislation has rolled over the country during the past several years. As of now, 29 states and the District of Columbia have legitimized the use of medical marijuana; eight of these states also permit the recreational use of marijuana. Medical or recreational, legal or not, marijuana is the “illicit” drug used most commonly during pregnancy and lactation.
We can help our patients make decisions about breastfeeding and marijuana use by being informed and educated ourselves.
1. Cannabinoids (like THC) pass into breast milk. THC (delta-9-tetrahydrocannabinol) is one of the most physiologically active of over 400 chemical components of marijuana. Cannabinoids’ physiologic effects occur via the endocannabinoid system, which spans the brain and the central and peripheral nervous systems. The endocannabinoid system helps to regulate appetite, pain, mood, and memory by affecting neurotransmitter patterns.
Cannabinoids are fat-soluble and enter into breast milk via passive diffusion. THC is stored in the brain and may have both acute and cumulative neurological effects.
2. Professional organizations recommend that breastfeeding women stop using marijuana.
The Academy of Breastfeeding Medicine, the College of Family Physicians of Canada, and the American College of Obstetricians and Gynecologists all recommend that women stop using marijuana while breastfeeding. Screening pregnant women for the use of tobacco, alcohol, and other drugs during pregnancy is a standard of prenatal care and may help identify the women most likely to use marijuana while breastfeeding. Women who report cannabis use, or who test positive for THC, should be offered appropriate counseling and rehabilitation services without repercussions.
3. Research about the safety of marijuana use while breastfeeding is limited in quality and quantity. Research about the safety and efficacy of marijuana use is scant, period. Conditions further limit the study of maternal marijuana use and the breastfeeding infant.
- The studies of infants of women who have used marijuana while breastfeeding attempt to assess the effects of non-medical-grade marijuana. “Street” marijuana may be contaminated with other drugs or chemicals, confounding study results.
- Most of the studies either document or presume the use of C. sativa, which is not the only species of available marijuana. Even within a cannabis species, there are many varieties, and cannabis hybrids are common, each with different chemical constituents, properties, and levels of THC—which means there may not be universal effects, adverse or otherwise.
- In utero exposure confounds research results. At least some of the infants in the studies were exposed to marijuana both while in utero and during breastfeeding, rendering it impossible to conclude that the marijuana in breast milk is the causative factor of any ill effect on psycho-motor development.
- Studies of the psycho-motor development of children exposed to marijuana in breast milk have not been done beyond the age of one.
4. There is no available evidence about secondhand exposure of infants to marijuana smoke. We are aware of the risks to infants of exposure to secondhand tobacco smoke, which include respiratory conditions and SIDS. We could extrapolate that marijuana smoke exposure would have similar effects. We do not know what benefit, if any, there is to stopping breastfeeding if the infant will have secondhand exposure to THC and marijuana smoke.
5. Marijuana may reduce milk supply by inhibiting prolactin production. Prolactin is a hormone responsible for breast milk production. Regular and frequent suckling of the infant at the breast (or, less efficiently, breast pumping) stimulates appropriate prolactin production and release. This positive feedback mechanism helps to assure an adequate breast milk supply.
A drop in prolactin levels occurs when there is less frequent nipple stimulation, and there is down regulation of milk production. Prolactin levels may also drop in response to certain medications, such as the estrogens in many contraceptive products. Research suggests that prolactin levels may also drop in response to maternal marijuana use.
Women who are not making enough milk—for whatever reason—are likely to supplement or replace breastfeeding with formula. Formula feeding deprives mother and child of the beneficial effects of breastfeeding.
6. Most women who use marijuana during pregnancy will continue to use it while breastfeeding.
Studies have examined recreational marijuana use rates in pregnant and breastfeeding women and document a relationship between the two. However, screening for drug use during pregnancy may be an indicator of drug use while breastfeeding and would guide our counseling and treatment efforts during both pregnancy and lactation.
7. Women should be counseled regarding the potential adverse effects of marijuana use on infants while breastfeeding.
Women need to know that:
- Breastfeeding women should stop using marijuana.
- There is some, but limited, evidence about the safety of breastfeeding while using medical marijuana.
- We know that marijuana passes into breast milk but we don’t know how it affects a breastfeeding baby, immediately or long term.
- There are potential risks to using marijuana, just like there are for any other drug.
- The risks of marijuana use and of formula feeding may affect both a mother and her baby.
- There are alternatives to dealing with anxiety and depression that have been studied more rigorously during lactation and are potentially safer for the breastfeeding infant.
- Using marijuana may affect the ability to parent.
- Using marijuana may reduce a mother’s milk supply, affecting her ability to provide her child with optimal nutrition.
- There may be legal repercussions to using marijuana while breastfeeding, which may or may not involve custody issues.
- We will support her breastfeeding efforts whether or not she chooses to stop using marijuana.
- If she does continue to use marijuana while breastfeeding, she should observe her infant for signs of delayed motor development, lethargy, low tone, irritability, and poor sucking, which are considered possible effects of infant marijuana exposure.
- If she chooses to continue marijuana and stop breastfeeding, she needs education about formula feeding.
- If she chooses to continue using marijuana and stops breastfeeding, she needs to know the presumed risks of smoking marijuana in proximity to her baby, or use marijuana in another form to avoid secondhand smoke exposure to the infant.
8. Lactation support should not be withheld from women who choose to use marijuana while breastfeeding. Not breastfeeding has health risks. The benefits of breastfeeding for both mom and baby are well established, and there is a lack of information about long-term infant exposure to marijuana. From what we know about premature neonates, we can assume that the risks of maternal marijuana use are higher for breast milk–fed preemies. However, depriving preemies of human milk has significant and well-established health risks. Women who are appropriately counseled about the potential for adverse neonatal neurodevelopmental effects of breastfeeding while using marijuana should not be prohibited from breastfeeding.
9. Some breastfeeding women may be using marijuana for medical indications. There is no data on how often we might encounter breastfeeding women using marijuana for medical purposes. The most common indications for medical marijuana use are chronic pain, cancer, PTDS, HIV/AIDS, seizure disorders, and muscle spasms due to multiple sclerosis and other chronic conditions. We think of pregnant and breastfeeding women as being relatively healthy and have no indication for medical marijuana use. This would be true in an ideal world, but we all know that health conditions are not ideal for every pregnant and breastfeeding woman. Keep in mind that women may self-medicate with recreational (not medical grade) marijuana.
10. There are many areas that require further research. The ethical issues surrounding the research of drug use (prescription or otherwise) in pregnant and breastfeeding women are prohibitive, yet we need answers to the following questions and more:
- Does using marijuana impact parenting skills?
- If maternal marijuana use while breastfeeding increases the risk of SIDS, what is the cause of the increased risk? Would it be because the infant is exposed to cannabinoids? Or that the exposure to smoke (as a product of combustion) that might increase the risk of SIDS?
- Does maternal marijuana exposure by routes other than smoking result in the same levels of marijuana in the breastfed infant as does a mother’s smoking marijuana?
- Given the risks to mom and infant of not breastfeeding, we need a reliable risk–benefit analysis between breastfeeding and using marijuana versus discontinuing (or never initiating) breastfeeding and continuing to use marijuana.
- Are there deleterious long-term consequences for infants exposed to marijuana through breast milk?
Perhaps the legalization of marijuana will help facilitate more research. Perhaps women will feel more comfortable disclosing marijuana use if they are less afraid of legal repercussions. Knowing that women are using marijuana or any other drug during pregnancy or while breastfeeding provides us with the opportunity to intervene for the best interests of women and their families, even when we have incomplete information.
For more information, see Cannabis, from Springer Publishing’s medsmilk.com. (Registration is required. If you would like to talk to someone about getting personal, group, or institutional access to medsmilk.com, please contact us.)
American Academy of Pediatrics. Breastfeeding and the use of human milk. 2012. Available at: www.pediatrics.org/cgi/doi/10.1542/peds.2011-3552.
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Djulus J., Moretti M., and Koren G.: Marijuana use and breastfeeding. Can Fam Physician 2005; 51: pp. 349-350. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1472960/
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Perez-Reyes M., and Wall M.E.: Presence of delta-9-tetrahydrocannabinol in human milk. N Engl J Med 1982; 307: pp. 819-820.