I recently wrote about pot in pregnancy, and immediately people asked. What about breastfeeding? It turned out I had written about this in Medium last year. Here are the relevant paragraphs:
First, the active ingredient in marijuana, delta-9-tetrahydrocannabinol or THC, does pass into breast milk. The concentration is lower than in the mother, although unlike in the case of alcohol it seems like it may be higher than the concentration in maternal blood. Also unlike alcohol, it takes a long time to leave the bloodstream — counted in days, rather than hours. What’s more, data on infants has shown (through poop analysis) that infants do metabolize some THC when their mothers do. We know that THC has an effect on adult brains — indeed, this is why people like it — and it has been argued that long-term use may lead to cognitive impairments.
This all means it is possible that infants could be affected, although that is not the same as saying they are. Current research shows mixed results: At least one study argued that exposure to marijuana early in life lowers later motor development, but the sample is small at less than 150 infants studied, and it’s hard to separate early lactation use from pregnancy use. And other studies haven’t found this same effect. But the bottom line is there is almost no evidence either way — all together, existing studies do not cover more than a few hundred people.
Where does this leave us, other than desperately hoping for more data? Certainly the most cautious approach would be to avoid marijuana while breastfeeding. On the other hand, it would be a mistake to panic if you had some edibles a few times while nursing. Ultimately, there’s not enough data to say for certain one way or the other. For the time being, mothers will have to weigh their decision to use marijuana on personal factors.
Also one million people wrote to ask about CBD in pregnancy and breastfeeding after the last pot post and the answer is that we do not have any studies about this yet. I’m sorry! I’m sure these are coming given that CBD is now on offer everywhere I go, in everything.