Research is scant, but knowing that THC passes from mother to child, doctors warn it's best to err on the side of caution.
Q: Is it safe to consume marijuana while breastfeeding?
A: Uh, we don't exactly know. Perhaps not. For now, it's probably best to take that as a “no.”
Little research has been done investigating the possible health effects on newborns of mothers who use cannabis while they nurse.
Even the Centers for Disease Control (CDC), the top national health institute in the United States, concedes that “data are insufficient to say yes or no” on the question of whether it's safe for mothers who consume marijuana to breastfeed.
Here's what we do know.
Tetrahydrocannabinol (THC), the chief psychoactive compound in marijuana, enters the bloodstream, is stored in body fat, and accumulates in breast milk. When a mother is nursing, a small portion of that THC is passed onto the suckling infant. In a May 2018 study reported in the Obstetrics & Gynecology journal published by Wolters Kluwer, eight mothers of infants 2 to 5 months old smoked weed before nursing. An analysis showed that through breast milk the infants ending up ingesting about 2.5 percent of the THC in their mother's dose.
Experts say that it doesn't matter how marijuana is consumed — smoked, vaped, eaten in edibles or extracts, even applied topically — the mother-to-infant transmittal of THC will still take place.
What's potentially problematic is how that THC interacts with the infant's budding endocannabinoid system (ECS). Endocannabinoid receptors are found throughout the body and play an important role in every aspect of development.
Dr. Lauren M. Jansson, the director of pediatrics at the Center for Addiction and Pregnancy at the Johns Hopkins University School of Medicine in Baltimore, believes that exposing infants to THC can modify the endocannabinoid system in ways that might impair both motor skills and cognitive development. Co-writing in the Journal of the American Medical Association, Jansson noted that although “cannabis does have known medical utility for some conditions,” she believes that the risks of exposure to marijuana during pregnancy or breastfeeding are “underappreciated.”
She's observed these effects firsthand, she said, in the infants and children she sees in her clinical practice.
“It's difficult to relay in words,” Dr. Jansson said. “What I'm seeing is a kind of neuro-irregularity, infants who have difficulty paying attention or controlling their movements. They may have tremors or they're easily overstimulated. What's more, sometimes you won't see the impact of exposure to marijuana during pregnancy or nursing for years later. It might show up as developmental and behavioral issues in adolescence.”
Dr. Carly Snyder, a New York City psychiatrist who specializes in women's health during pregnancy and after childbirth, acknowledges that some women might find that marijuana helps them manage the stress of new motherhood.
But, she said, “As both a physician and a mom, I think there are still too many unknowns about the impact of marijuana on an infant. When it comes to infant development I strongly believe we need to err on the side of caution.”
For women who are struggling with depression or anxiety after giving birth, there are other treatment options that don't carry the potential risks of marijuana use, Snyder said. She urges women to speak to a psychiatrist or psychologist with a focus on postpartum mental health.
“These are not issues that should be taken lightly,” Dr. Snyder said, adding that there are also alternatives to breast milk if a woman feels she doesn't want to give up marijuana use. “And never mind the argument, made by some, that cannabinoids occur naturally in human breast milk. We naturally make melatonin, too, but we still tell women not to take melatonin supplements when they're pregnant. More isn't necessarily better, even with substances that we produce on our own.”
For Jansson, the bottom line is that “women should be advised to stop all marijuana use when they're trying to conceive, during pregnancy and while they're nursing. If you're having a difficult time quitting, you'll want to seek help.”
Both the American College of Obstetricians and Gynecologists in a 2017 statement and the Society of Obstetricians and Gynaecologists of Canada in its 2018 campaign take a similar stance: Until more is known about the health impact of marijuana on your baby, it's best to lay off the weed, baby.