Is it bad to smoke marijuana while you breastfeed? Experts weigh in

Ah, marijuana. Whether you love it or hate it, state governments across America are slowly legalizing it. And within the past couple of years, it has clearly become liked by many—including moms. But while this drug is widely used, there seems to be a growing concern about the safety of smoking weed while breastfeeding within the motherhood community. So, is it safe to use while a mother breastfeeds her baby?

According to an international board-certified lactation consultant, Andrea Syms-Brown, substantial studies on the relationship between breastfeeding and THC and CBD were only published recently. “Believe it or not, there have only been a few experimental studies that were done in the ’70s and ’90s—and then nothing until [years later],” she explains. While there isn’t much data to show if and how often breastfeeding mothers are smoking weed, a 2016 meta-analysis of 24 studies claimed that women who used cannabis during their pregnancy found that their babies had lower birth weights compared to other breastfeeding women who didn’t use the drug. It’s important to address that this information is only accurate when one decides to smoke at a high frequency.

Plus, a 2018 study that was published in the journal Pediatrics reported that out of the 54 samples of breast milk that were provided by 50 breastfeeding women, who either smoked pot or ate an edible, 63% of the samples contained low levels of marijuana, even up to six days after reported use.

But can having marijuana chemicals in one’s breast milk affect the development and growth of their baby when they choose to breastfeed? Well, according to Syms-Brown, “The risk of THC in breast milk could include increased sedation, reduced muscular tonus, and decreased motor development of children at one year of age.” This means that if a mom chooses to smoke while breastfeeding, they might not see any potential development problems with their baby until they’re one year old. It has been proven that cannabis enters via the bloodstream and can affect the prefrontal cortex, which doesn’t fully develop until someone is 25 years old and is part of the brain that deals with complex cognitive behavior and one’s personality. So, what does this mean for new moms and their newborns?

It’s also worth noting that THC levels in mother’s milk are highest one hour after inhalation, so if you do decide to smoke before breastfeeding, make sure to wait a few hours.

When it comes to ingestibles, there are no clear answers. Generally, studies done on the effects of maternal marijuana use on breastfed babies are few and far between.

“One of the challenges involved is that mothers who smoke cannabis may also ingest other substances like alcohol, tobacco, and controlled or illicit drugs. It, therefore, becomes very difficult to discern any effects associated specifically to marijuana use,” Syms-Browns says. Additionally, having to rely on reports from mothers about their use of marijuana and its subsequent effects is further complicated by a few factors.

“First, use of marijuana usually precedes pregnancy and breastfeeding so isolating effects that are prenatal from postpartum is impossible,” she explains. “Second, many states require punitive measures against mothers who use illegal drugs, making it difficult to collect data from doctors who are placed in an adversarial position with their patients who are unwilling to be truthful. Thirdly, level of usage (heavy vs. casual) and the age of the baby must be taken into consideration when helping mothers understand how marijuana use affects their offspring.” In other words, it’s difficult to make a clear determination of when the observed results originated from in their babies (i.e. was it during pregnancy? during breastfeeding?), which also makes it difficult to perform large studies.

As more states consider changing their laws around marijuana use, we’ll have more research on this topic to determine exactly how it affects babies during breastfeeding and beyond. Until then, examine these studies with a grain of salt. At the end of the day, moms know what’s best for their babies, and while it’s important for researchers to provide more concrete evidence behind this information, for now, do what’s best for you and your child.