How legalizing cannabis changes our view of it

After years of debate, the U.S. House passed a bill to legalize marijuana at the federal level in 2020. It looks as if prospects for the federal decriminalization of marijuana may be just around the corner. For many Americans, this is a welcome change as medical marijuana has many benefits with few side effects. This may send the message that cannabis is safe to use while breastfeeding. However, evidence has shown that marijuana use can be harmful to nursing babies.

How does weed affect breastmilk?

Marijuana has more than 400 chemicals, including cannabidiol (CBD) and tetrahydrocannabinal (THC), the plant’s main pychoactive component. When a breastfeeding mother uses cannabis, some of the chemicals get into her milk supply. According to a study conducted in 2018, more than 6 in 10 women who used weed had detectable levels of THC in their breastmilk samples up to six days after their last use. Another study found that it could stay in a woman’s system for as long as six weeks.

This is likely due to the fact that breastmilk is highly fatty, and both THC and CBD bind heavily to fats. While alcohol is dispensed from breastmilk at the same rate it leaves the blood, the chemicals found in marijuana tend to build up in breastmilk. In fact, the same report found that a mother could have eight times as much THC in her milk as in her blood.

How do THC and CBD affect newborns?

Very little human research has been conducted in recent years, so it’s hard to say with 100% certainty how THC and CBD affect newborns. A study of suckling mice exposed to cannabis extract showed decreased weight gain. A study of rats exposed to THC in utero found that exposure leads to lasting neurodevelopmental impairment. What these mean for human babies is hard to say.

However, THC does inhibit the production of prolactin, the hormone that controls milk production. Further, some studies have shown that babies exposed to THC may not nurse as long or as vigorously.

What does the CDC say about using marijuana while breastfeeding?

While data is currently limited on the effects of marijuana use while breastfeeding, the CDC provides the following guidance:

Data on the effects of marijuana and CBD exposure to the infant through breastfeeding are limited and conflicting. To limit potential risk to the infant, breastfeeding mothers should be advised not to use marijuana or marijuana-containing products in any form, including those containing CBD, while breastfeeding.

Talk to your doctor about using marijuana while breastfeeding

If you’ve been using marijuana medicinally, it’s a good idea to talk to your doctor about how to proceed while you’re breastfeeding. They will be able to advise you on possible alternatives or best use scenarios.