Does smoking weed while breastfeeding harm my baby?

Reviewed by Nicole Lee, MPH, RN, CEN, TCRN, CLC — Written by Neve Spicer — Updated on August 23rd, 2021

Marijuana is experiencing a newfound acceptance in areas that have historically criminalized its use. While still used as a recreational drug, it is also being utilized by doctors to treat medical and mental health issues.

If you are a breastfeeding mother who is currently using or would like to use this medicinal plant, you probably have questions as to the effects of marijuana on your breastmilk and your baby.

Real talk: your breastmilk, and therefore your baby, can be impacted by anything you put in your body, especially when it comes to drugs, herbal or otherwise. Oftentimes, foreign substances can lead to adverse outcomes in a baby’s development.

Before you ingest cannabis in any form, it is vital to educate yourself on the repercussions that it can have on your little one’s health.

In this article:

Marijuana

Also known as cannabis, weed, hash, dope, and probably a hundred other names, marijuana works primarily on our central nervous systems. It can be used to treat a myriad of illnesses, including multiple sclerosis, glaucoma, depression, and anxiety.¹ ²

Method of ingestion

Two common ways to self-administer cannabis are smoking and ingesting.

Smoking — This method leads to quicker effects. Unfortunately, it carries the risk of second-hand smoke, which is often considered as dangerous to bystanders as cigarette smoke. Also, as with cigarettes, the smoking of pot will generate irritants and byproducts (such as carbon dioxide) that can negatively impact your personal health.³

Furthermore, studies have shown that contact highs are real and, since it’s hard to contain smoke completely, you should always be aware of who is being exposed when smoking a joint.⁴

Ingesting — Eating the herb by baking it into food (edibles) eliminates the second-hand smoke issue completely, and does not produce the toxic byproducts of smoking. However, this method has its own drawbacks; it takes longer to feel the effects of the drug, and because of this delay, proper dosing is more difficult, with some people ending up using too much after assuming the edible is not working. Accidently sedating yourself is, of course, not what you want to do when looking after your child, so this is not necessarily ‘safer’ than smoking.⁵

Active ingredients

So, what exactly is it that gives marijuana its recreational and medical edge? It’s certainly a complicated plant, but scientists tend to single out two components for special attention.

THC (delta 9-tetrahydrocannabinol, for those who wish to embrace their inner nerd), is the mind-altering component of marijuana. It stimulates the release of dopamine, leading to that happy-hippy effect we often associate with pot smokers. It can also impact motor skills, impede your memory, and even cause hallucinations. On the up side, THC can reduce nausea, and also help with insomnia, pain, and anxiety.⁶ ⁷

CBD, or cannabidiol, can actually counteract the psychoactive effects of THC and does not induce a high. Believed to aid in the treatment of depression, anxiety, pain, seizures, and even IBS, some medical marijuana plants are being bred to contain higher amounts of CBD than of THC.⁸

Marijuana side effects on your body

The available science points to cannabis as having beneficial properties, but it’s important to remember that marijuana does not just come in and fix what’s wrong, while leaving nothing behind. It’s still a drug, and all drugs can have side effects, some of which are especially pertinent for mothers taking care of babies.

Mind

Smoking weed may make you feel:

Disconnected from reality⁹

Body

Marijuana can have less than desirable physical effects, too, such as:

Dry eyes

Upset stomach¹⁰

Marijuana and breastmilk

Even if you experience minimal to no side effects from smoking pot, it’s vital to keep in mind that it is impacting your body. And since your body is currently tasked with doubling as a milk bar, you need to consider how marijuana can ‘change up’ the menu.

THC body storage

THC enters the body and gravitates towards fatty areas, and areas with strong blood supplies, where it can remain for weeks or even months. Many scientists believe that this creates an environment where breastmilk contamination is not only likely but inevitable.¹¹

While more research is needed, there have been tests that demonstrate the ability of THC to infiltrate breast milk.

During one such study, regular marijuana users had their breast milk tested twenty minutes after taking the cannabis, and then at one, two, and four-hour points. While the highest THC levels occurred at the one hour mark, it was detected in the breast milk during each test-time. In turn, it was estimated that exclusively breastfed babies were ingesting 2.5% of the dose their mothers had.¹²

Marijuana and prolactin

There is evidence that shows that smoking marijuana can impact prolactin levels. One study showed that regular marijuana smokers had a lower baseline level of prolactin than their non-smoking counterparts.¹³

Since prolactin is a vital part of maintaining good milk generation, you don’t want to disrupt its healthy production. Doing so could lead to supply problems which, if you’re planning to exclusively breastfeed, can lead to a frustrating experience for both you and your child.

Marijuana’s impact on your baby

While scientists universally agree that there is a research gap between a baby’s direct exposure to the drug through breast milk and the health hazards, there are existing studies that suggest the risk is simply not worth the toke.

Testing positive

Since the science shows that your breastmilk can be contaminated with cannabinoids, it goes without saying that your baby will have a considerable chance of ingesting this drug.

If she is exposed via breast milk, it is possible that her urine and stool will show a positive result for marijuana exposure for up to two to three weeks.¹⁴

Cognitive development

Unfortunately, very few studies are available on the brain development of marijuana-exposed infants, and even fewer have had meaningful follow-up studies with the children’s ongoing health.

Scientists have, however, conducted animal research on this issue. One such study involved exposing mice to THC. Grouped by age, the younger mice who were exposed to the cannabinoid demonstrated difficulty in learning tasks and experienced memory impairment.¹⁵

While no one can say with absolute certainty that this result would be mirrored in humans, it is enough to give the scientific community pause when asked their feelings about breastfeeding and marijuana use.

Motor development

In 1990, a study was conducted comparing babies exposed to marijuana with those who had no contact with the drug. It was noted that, by one year old, those exposed to marijuana via breastmilk had fallen behind on their motor skill milestones. While the scientists who ran the study noted that additional research was necessary before they could draw any hard conclusions, it is certainly a red flag.¹⁶

Legality

Laws regarding marijuana are a tangled web, with no two places seeming to agree. In America, for example, marijuana is legal (to varying degrees) in 49 states, but remains federally illegal.¹⁷

The stakes become far higher for a mother smoking marijuana. The stigma attached is still prevalent, and both the medical and scientific communities tend to take a better-safe-than-sorry approach, which is understandable considering what research, even in its infancy, is showing.

Local child-service agencies may become involved if they hear of a baby who has tested positive for marijuana. In these cases, you might not be protected by your local laws and, worse still, may be subject to child endangerment charges or even abuse allegations.¹⁸

What about CBD oil?

Since many people are utilizing medical marijuana to treat serious health issues, it is natural to consider alternatives to smoking while breastfeeding. Considering CBD is one of the reasons medicinal marijuana is as effective as it is, many mothers wonder if substituting their smoking with CBD oil is a viable option.

Unfortunately, there is even less research about the effects of CBD oil than there is on smoking marijuana while breastfeeding. It binds with fat, much like THC, but in such a way that measuring its amounts in breast milk has shown to be very difficult. While sometimes administered to young children to combat seizures, there are no studies clearly demonstrating whether CBD oil exposure is safer or not than THC exposure in breastfeeding babies.¹⁹

Expert note:
Whenever you are unsure about the safety of a medication or substance while breastfeeding, a great resource is talking to a lactation consultant: experts on all things breast milk! Your local hospital, breastfeeding support group, or a local organization like a La Leche League chapter are all great ways to connect with one.

Wrapping it up

There’s no denying that marijuana impacts the human body and that many of its effects on adults can be positive. Unfortunately, there is evidence that suggests the opposite is true for babies exposed to the drug.

It is clear there needs to be more research conducted on the matter but, until then, we recommend following the advice of leading scientific experts and doctors. It is difficult to advise taking a chance on something that could impact your child’s motor skills and brain development, what to speak of putting you on the radar of child services.

Reviewed by Nicole Lee, MPH, RN, CEN, TCRN, CLC — Written by Neve Spicer — Updated on August 23rd, 2021

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