Moms Who Smoke Pot Might Have THC In Their Breast Milk, Study Says — But Don't Worry Yet

People have written a lot about the effects of marijuana on pregnancy, babies, and kids in the past. The stigma against using cannabis has only really recently started to dissipate, making its use and the effects of it more easy to study. Most recently, researchers found that moms who smoke marijuana may have THC in their breast milk, but it's not time to panic about babies getting anything more than "milk drunk" off their mother's breast milk just yet.

Researchers reportedly took samples of breast milk from eight anonymous test subjects who regularly used cannabis, then tested the milk for delta-9-tetrahydrocannabinol (THC) and its metabolites, Healthline reported. The study found that babies who breastfed exclusively ingested an estimated 2.5 percent of the dose that their mothers smoked, and that THC levels were at their highest one hour after the study subjects smoked cannabis. For comparison, the breast milk was tested 20 minutes after ingestion, then at one, two, and finally four hours post-ingestion.

Babies who were exclusively breastfed in the study ingested an estimated daily infant dose of 8 micrograms of THC per kilogram of a "preweighed, analyzed, standardized strain of cannabis" that their mothers smoked every day, according to the study, which was published in the medical journal Obstetrics and Gynecology. The levels of THC in the milk are pretty low, but a very small amount could potentially transfer to infants.

OK, so let's break this down a little bit. First of all, eight women were enrolled in this study. Eight. That's an incredibly small sample size to extrapolate any data from. According to the notes for the study, most of the subjects were occasional cannabis smokers, and just one was "a chronic user." I'm a little skeptical of these results partly because I didn't get a good sense of how regular marijuana use can impact breast milk or an infant when just one person in this study is considered a regular smoker.

And even the study's authors say the levels of THC they found in breast milk were not very high. Senior study author Thomas Hale, director of the Infant Risk Center at Texas Tech University School of Medicine in Amarillo, said, according to HealthDay:

This study is just a start to see if marijuana transferred into breast milk. Levels in milk were quite low.

In addition, although the researchers in this study were able to measure the THC in breast milk, they were not able to collect blood samples from the infants — aged 3 to 5 months old — to see if they actually had "measurable" THC levels in their bodies, Healthline noted. So the researchers had to determine an "estimated mean" of THC ingestion in the babies. Though that is legitimate, it does not sound as exact as the measurement of a definite amount of transferred THC would be.

Now, I'm not saying all pregnant or breastfeeding moms should just go ahead and smoke marijuana every day. The American College of Obstetricians and Gynecologists (ACOG) still discourages the use of marijuana during pregnancy, and in that organization's opinion, "There are insufficient data to evaluate the effects of marijuana use on infants during lactation and breastfeeding, and in the absence of such data, marijuana use is discouraged."

But as more pregnant women appear to be using pot, according to CNN, it's important that the effects of its use and its impact on babies — as well as on practices like breastfeeding — are studied further. And one study with a very small sample size just isn't enough.

Even Hale, the study's co-author, and Teresa Baker, co-director of the Infant Risk Center at Texas Tech, told HealthDay further research is needed because there are a lot of unanswered questions. For instance, this study only looked at mothers who smoked marijuana, and it didn't evaluate parents who ingested or vaporized marijuana. And we don't know whether heavy users would have different levels of THC in their breast milk than occasional smokers.

Plus, this unanswered question persists: what did exposure to cannabis products actually do to the babies in the study? The study itself concluded, "The long-term neurobehavioral effect of exposure to delta-9-tetrahydrocannabinol on the developing brain is unclear."

Generally, doctors don't recommend smoking marijuana during pregnancy or while nursing, and Hale said cannabis-smoking mothers shouldn't smoke while nursing just as tobacco-smoking mothers shouldn't. Even in places like Colorado, where the women in the study obtained cannabis from the same medical marijuana dispensary and where its use is legal, if an infant's blood test shows any level of THC, doctors are obligated to inform child protective services under state law, Healthline reported. "It’s still a reportable offense," Baker said.

The bottom line is, further study is needed to determine whether THC transfers to babies through their mother's breast milk in larger, controlled studies.