Greetings All,

On March 25th, I shared a new study on this forum, "Persistence of Δ-9-Tetrahydrocannabinol in Human Breast Milk".  

Nikki Lee responded, "My point is that the research showing that THC in breastmilk is harmful to the infant has not yet been found" and ended her response with these important points: "The research showing that the impact of delivery practices (i.e. cesarean section), formula feeding, and use of antibiotics on the infant gut microbiome (and future health) is growing.  Shouldn't the public be made aware of the dangers of routine cesarean section (31% in the US today), formula use, and routine antibiotics?"

As a devotee of public health in general, and as a registered nurse and IBCLC who has spent much of my long career in public health, I agree that public health education is critical in countless areas, including on the topics Ms. Lee mentioned.  There was nothing in my original post to the contrary.   Periodically I have shared new studies on human milk and infant feeding here, on the blog section of the MoreThanReflexes website, and in professional social media forums, along with other topics related to infant feeding.  

In response to my March 25th post, Ms. Lee also states, "When one examines the impact of smoking tobacco in pregnancy on babies, that impact is similar to the impact of smoking cannabis in pregnancy on the babies. So is it the substance or the smoking that is the problem?  Research tells that smoking reduces placental blood flow."

In regard to THC in human milk via inhalation of cannabis, Dr. Thomas Hale of the InfantRisk Center shares this insightful commentary:  

"First, you must know that doing research with Cannabis products is virtually impossible in the USA today.  The effect of all the governmental legal restrictions virtually stops all research.  We were most fortunate to find a wonderfully supportive group of lactation consultants and cannabis using moms in Colorado, who helped us find breastfeeding mothers who were using this product while breastfeeding.  Nine of these moms followed our directions, and provided milk samples.  This is one of the first really accurate assessments of THC transfer into human milk.  What it suggests to us is that THC does transfer into human milk, and it is apparently a function of the daily use in mothers.  We think that in occasional users, the level of transfer is minimal (about 2.5% or lower).  We also surmise that in heavy users it could be 3 times this dose.  This is probably a function of the filling of the adipose sites with chronic daily use.  Once these fat sites are FULL of THC, less is transferred out to fat tissues following smoking...thus leaving more in the plasma compartment to transfer into milk.   We strongly urge cannabis-using moms to avoid using these products while breastfeeding, as we simply do not know what happens neurobehaviourally to these exposed infants.   Again, thanks to those wonderful support groups that helped Dr. Baker and I do this beginning study.  TWH"

Please see the following abstract of the above-mentioned 2018 study by Hale and his colleagues:    

Title: Transfer of Inhaled Cannabis into Human Breast Milk.

Authors: Baker T, Datta P, Rewers-Felkins K, Thompson H, Kallem RR, Hale TW.

In:  Obstetrics & Gynecology 2018 May;131(5):783-788.

Abstract:  "To evaluate the transfer of delta-9-tetrahydrocannabinol and its metabolites into human breast milk after maternal inhalation of 0.1 g cannabis containing 23.18% delta-9-tetrahydrocannabinol. In this pilot pharmacokinetic study, breast milk samples were collected from mothers who regularly consumed cannabis, were 2-5 months postpartum, and exclusively breastfeeding their infants. Women were anonymously recruited for the study. After discontinuing cannabis for at least 24 hours, they were directed to obtain a baseline breast milk sample, then smoke a preweighed, analyzed, standardized strain of cannabis from one preselected dispensary, and collect breast milk samples at specific time points: 20 minutes and 1, 2, and 4 hours. Quantification of delta-9-tetrahydrocannabinol and its metabolites in these collected breast milk samples was performed by high-performance liquid chromatography tandem mass spectrometry. A total of eight women were enrolled. Most were occasional cannabis smokers and one a chronic user. Delta-9-tetrahydrocannabinol was detected at low concentrations at all the time points beyond time zero. No metabolites were detected at any time point. Delta-9-tetrahydrocannabinol was transferred into mother's milk such that exclusively breastfeeding infants ingested an estimated mean of 2.5% of the maternal dose (the calculated relative infant dose=2.5%, range 0.4-8.7%). The estimated daily infant dose was 8 micrograms per kilogram per day. This study documents inhaled delta-9-tetrahydrocannabinol transfer into the mother's breast milk. Low concentrations of delta-9-tetrahydrocannabinol were detected. The long-term neurobehavioral effect of exposure to delta-9-tetrahydrocannabinol on the developing brain is unclear. Mothers should be cautious using cannabis during pregnancy and breastfeeding."   https://www.infantrisk.com/blog/transfer-inhaled-cannabis-human-breast-milk

Open access:   https://journals.lww.com/greenjournal/Fulltext/2018/05000/Transfer_of_Inhaled_Cannabis_Into_Human_Breast.5.aspx


The InfantRisk Center also discusses the relationship of high potency cannabis use and first-episode psychosis in a 2015 study published in The Lancet:  

Title:  Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study.

In:  The Lancet 2015 Mar;2(3):233-8. doi: 10.1016/S2215-0366(14)00117-5. Epub 2015 Feb 25.

Authors:  Di Forti M, Marconi A Carra E, Fraietta S, Trotta A, Bonomo M, Bianconi F, Gardner-Sood P, O'Connor J, Russo M, Stilo SA, Marques TR, Mondelli V, Dazzan P, Pariante C, David AS, Gaughran F, Atakan Z, Iyegbe C, Powell J, Morgan C, Lynskey M, Murray RM.

From the abstract:  "This study suggests that daily use of HIGH potency cannabis may be associated with higher rates of psychosis.  Daily users of high potency cannabis were 5 times more likely to encounter psychosis. "  Dr. Hale's note:  "Cannabis has a high attraction for lipid-rich adipose (fatty) tissue. Once [adipose tissue is] filled with daily use of high levels of THC, plasma levels probably rise significantly, leading to super-high levels of THC in the brain leading to psychosis." - Dr. Thomas Hale     https://www.infantrisk.com/blog/high-potency-cannabis-linked-higher-risk-psychosis

Open access:  https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(14)00117-5/fulltext



A brief and not exhaustive PubMed search for THC in human milk and cannabis use during lactation yielded this review paper:

Title:  Is Breast Best? Examining the effects of alcohol and cannabis use during lactation.

In:  Journal of Neonatal-Perinatal Medicine 2018;11(4):345-356. doi: 10.3233/NPM-17125.

Authors:  R A Brown, H Dakkak, J A Seabrook.

Abstract:  "Maternal drug use during lactation may have adverse effects on the health of their children. Two common drugs used during this period are alcohol and cannabis. A literature search was conducted using PubMed, CINAHL, Nursing and Allied Health, and Google Scholar with the following search terms: marijuana, cannabis, THC, alcohol, ethanol, breastfeeding, lactation, and breastmilk. The search strategy was restricted to papers since the year 2000, and limited to English language journals. Reference lists were also used to capture any articles that were missed from the database searches. In total, 19 articles were found related to alcohol and breastfeeding (n = 17 original research papers; n = 2 systematic reviews), and 4 articles were specific to cannabis (n = 2 original papers; n = 2 systematic reviews). The most common outcomes associated with alcohol consumption and breastfeeding included changes in sleep patterns, reduced milk production and flow, lower milk intake, and impaired immune function. Maternal outcomes related to cannabis consumption included panic attacks, delayed response time, increased heart rate, reduced short-term memory, dizziness, and impaired motor performance; infant outcomes associated with maternal cannabis use and breastfeeding were reduced muscular tonus, poor sucking, and growth delay and restriction. Mothers should be advised to refrain from substance use during the lactation period for the health and safety of their children."

Abstract only:  https://content.iospress.com/articles/journal-of-neonatal-perinatal-medicine/npm17125


As Ms. Lee noted, LactMed reports paternal smoking of cannabis with an increased risk of sudden infant death syndrome.  Per this LactMed entry, "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."  

This LactMed entry on cannabis also discusses a study with "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."

The cannabis entry in LactMed ends with this content:  

"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."

https://www.ncbi.nlm.nih.gov/books/NBK501587/#:~:text=The%20main%20active%20psychoactive%20component,on%20the%20extent%20of%20use.


In sharing the new THC study in my March 25th post, I did not express any personal or professional beliefs for or against the use of recreational or medicinal cannabis.  Although I am not obligated to explain my personal stance on cannabis in this forum, I will nevertheless share my personal belief that illicit substances of abuse should be decriminalized, as alcohol has been in the U.S., with ample federal funds dedicated to treatment for anyone in need.  Here in the U.S., we have been a long way from that extent of care.   

CBD oil, derived from the marijuana plant, has helped a number of patients suffering from seizure disorders, and has helped many more patients seeking relief from pain, including my late mother during her terminal illness, prior to receiving morphine at home through her hospice program.  Cancer patients and others who experience a prolonged loss of appetite can be prescribed a derivative of marijuana in pill form to help improve appetite, which was given to my late father during his terminal illness.  In my opinion, these are notable advances in health care.   As a young nurse many years ago, I was fascinated to learn that the decades-old drug, Digoxin (digitalis), was derived from the beautiful but poisonous foxglove plant.  According to the U.S. Forest Service, "A full 40 percent of the drugs behind the pharmacist’s counter in the Western world are derived from plants that people have used for centuries, including the top 20 best-selling prescription drugs in the United States today."  https://www.fs.fed.us/wildflowers/ethnobotany/medicinal/index.shtml#:~:text=A%20full%2040%20percent%20of,in%20the%20United%20States%20today.

I celebrate the freedom of speech that we still have here in the U.S., as protected by the 1st Amendment in the U.S. Constitution.  In respectfully sharing new studies here and on the More Than Reflexes website, I typically take the time to list all authors of a study, as opposed to listing only the first author's name followed by "et al.", in order to recognize and honor the work of all involved.  

I look forward to continuing to read and discuss new and old studies shared by members on this forum, including much-needed further studies on THC in human milk and cannabis use during lactation.  I enjoy and look forward to further collegial discussions on the topics at hand.  I also hope to continue sharing new studies on lactation and infant feeding topics as these studies emerge.  

With kind regards,

Debbie

Debra Swank, RN BSN IBCLC
Program Director
More Than Reflexes Education
Elkins, West Virginia USA
http://www.MoreThanReflexes.org

             ***********************************************

Archives: http://community.lsoft.com/archives/LACTNET.html
To reach list owners: [log in to unmask]
Mail all list management commands to: [log in to unmask]
COMMANDS:
1. To temporarily stop your subscription write in the body of an email: set lactnet nomail
2. To start it again: set lactnet mail
3. To unsubscribe: unsubscribe lactnet
4. To get a comprehensive list of rules and directions: get lactnet welcome