Tuesday, August 28, 2018

Minuscule Amounts of THC Found in Breast Milk - Is it Harmful?

The headlines are reading, "THC Found in Breast Milk!" but like previous studies, a new study in the journal Pediatrics found THC in breast milk only at the nanogram level (on average, 9.5 ng/mL). Since an adult dose of cannabis is 10 mg, and babies take in about 750 mL daily, this level is about 1,000 times less. The most THC found was 323 ng/mL, 30 times less than an adult dose.   

An oral absorption level of 6% was used to calculate plasma concentration in infants by the authors, who confirmed that blood levels in infants would be 0.040 ng/mL, or ~1000 times less than an adult dose. Still, they worried about accumulation in infants exposed daily. Using cannabis less often, and using methods other than inhaling, reduced levels in milk. 

"The question is, does it matter? ... Is it possible that even low levels in breast milk may have an effect on a child's neurodevelopment? And we don't know the answer to that," study author Christina Chambers of UCSD told CNN

The authors hope to follow up with neurobehavioral testing on the infants to help determine whether these levels of THC in breast milk are safe. (Too bad that NIDA refused to fund a follow-up study on Melanie Dreher's Jamaican study on marijuana-using mothers and their children.) 

The study was funded by NIH and The Gerber Foundation. Gerber makes infant formulas "inspired by breast milk." The US recently attempted to derail an international resolution supporting breast feeding at the behest of infant formula manufacturers.

The Pediatrics article is accompanied by a literature survey on the topic from the American Academy of Pediatrics Committee on Substance Use and Prevention and an editorial titled, "Counsel against marijuana use in pregnancy, breastfeeding."

"Women should definitely be counseled that it’s not a good idea to use marijuana while pregnant,” Dr. Seth Ammerman, a clinical professor of pediatrics at Stanford who worked on the report told the LA Times. In addition, he said, “if you’re breastfeeding, we would encourage you to cut back or quit.” However, if a new mother is not able or willing to do so, she should continue nursing. “The benefits of breastfeeding would outweigh the potential exposure to the infant,” he said.

Endocannabinoids (naturally occurring molecules) are found in breast milk, and recent studies indicate that "a balanced level of endocannabinoids is important for pregnancy and that the breast milk in animals and humans has endocannabinoids for the growth and development of the new born." Also, activation of CB(1) receptors appears to be critical for milk sucking by newborn mice, apparently activating oral-motor musculature.

Meanwhile, a new CDC report found that national rates of opioid use disorder are increasing among reproductive-aged and pregnant women, and those rates at delivery more than quadrupled during 1999–2014. And a pediatrics professor wrote an article in the New York Times titled,"Study Causes Splash, but Here’s Why You Should Stay Calm on Alcohol’s Risks" and failed to mention any harms to children from alcohol-using mothers.

Also see: NORML's factsheet on cannabis and pregnancy/breastfeeding

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