As states have begun to legalize marijuana, its use has been more openly discussed. While the effects of other commonly used drugs, such as alcohol, have been studied extensively, the effects of marijuana – especially on developing babies during pregnancy – have been much less studied and less widely publicized. This relative silence from the scientific community has affected the public’s opinion on the safety of marijuana: 70 percent of U.S. women think there is “slight or no risk of harm” to the baby from using marijuana during pregnancy. Expectant mothers may use marijuana rather than prescription drugs during pregnancy to relieve pain because they feel “natural” or home remedies are a safer option than prescription drugs. However, just because something is “natural” doesn’t mean it is any safer or a better alternative to well-studied prescription drugs. This seems to be the case for marijuana. Given that marijuana is the most commonly used illicit drug during pregnancy, understanding its risks and impacts on the developing fetus is important.

Three large-scale longitudinal studies tracked how maternal cannabis use affected their child’s development, and they have had surprisingly consistent results. The Ottawa Prenatal Prospective Study surveyed 700 pregnant women who used marijuana in 1978 and has followed about 200 of those children into adulthood. The U.S.-based Maternal Health Practices and Child Development Study has studied 580 children of marijuana users from pregnancy through age 14. The Generation R study is tracking almost 8,000 children in the Netherlands.

Children of marijuana users were more impulsive and hyperactive, and exhibited behavioral issues, lower IQ scores, and memory problems when compared to children of non-users. These mental health problems persisted through their teenage years, where they were significantly more likely to have attention problems and depression. Marijuana-exposed children were also almost twice as likely to display delinquent behavior, such as drug use, by the age of 14 and were more than twice as likely to regularly use marijuana and tobacco as adults. The very consistent results between mice and human studies (summarized in the infographic from The Scientist below) highlights an increasing understanding of the impacts of marijuana use on development.


It’s important to note that some behavioral outcomes may not be completely related to fetal marijuana exposure. Children of marijuana users may have grown up in a different social environment with more lax views on drugs, contributing to their increased drug use.

As marijuana continues to be legalized, we should expect to see more studies on its health effects and safety.


Managing Correspondent: Chelsea Weidman Burke

Press Article: The Scientist

Original Journal Articles: The Ottawa Prenatal Prospective Study

The Maternal Health Practices and Child Development Study

The Generation R Study

Image Credit: Cleveland Public Library

50 thoughts on “How Marijuana Exposure Affects Developing Babies’ Brains

  1. I’m curious how many if these mother’s had underlying genetic-based anxiety or ADHD related conditions themselves. How much is genetic-based vs exposure related.

    1. All the bad effects of marijuana are also everything I went through as a child into my teenage years. So I’m really doubtful this has any truth and reality. My mother didn’t smoke weed when she was pregnant and I still had all these issues.

    2. My husband had and I had different issues growing up from above. His mom and my mom definitely didn’t smoke weed. So it really doesn’t make a difference. I have many friends that told me their parents smoked weed during pregnancy and they are successful, smart individuals. More research needs to be done.
      I think using cannabis is better than taking a ton of prescription drugs sold to you by pharmaceutical companies that are owned by the wealthiest and scary powerful families! It’s all a conspiracy!

    3. Exactly, Im not bragging by any means but I smoked with my son and he’s always outshining the other students quiet and attentive. My sister smoked throughout her pregnancy with my nephew and he’s a chess champion and well behaved his school wanted to skip a grade but he didnt want to leave his friends. These studies are HIGHLY questionable when the side effects on a national website list the same as cocaine, and thats absurd.

  2. My Grandson has been diagnosed with ADHD. BUT I have watched him he seems to be autistic. Dr diagnosed in in like 10 minutes I have been studying his behavior for years.

  3. My daughter at the age of 10 was diagnosed by a doctor not a nurse with petit mal seizures. We knew there was something wrong since the age of 4 years but the mother who is a registered nurse insisted she had adhd. I thought my daughters behavior was a result of the mothers Marijuana use all through her pregnancy wich I never supported and was against. She said her doctor told her it would be easier on the child to continue useing while pregnant. My doctor told me he does not believe any doctor would say such a thing. I do not believe their are any benefits to useing Marijuana for the child and can’t say for sure it caused her problems but it definitely did not help.

  4. I adopted a girl from a cannabis mother. The list above of finding is her. She also has very low empathy . Highly manipulative. Balance issues .she flinches and jitters all time. Struggles with eating and low weight. Poor immunes system. Poor coping skill.

    1. Probably because she’s adopted. I grew up in the system. Don’t blame pot. It’s been a blessing in my life after I was forced to take meth in the system

    2. My mother didn’t use marijuana when she was pregnant with me and I had all these same issues growing up. But I was also in an abused household. These problems sound completely normal for a child that is going through something. I wouldn’t be so quick to blame it on the mother and your bad parenting skills. I had a lot of terrible homes through the adoption agency and terrible parents with no patience. They think they want to travel child now they want a perfect little baby just like everyone else.

  5. I’m a preschool Director/Teacher. I’ve seen first hand the effects that marijuana has on a childs ability to think.
    They just can’t grasp what they are being taught. It’s so sad. Their little brains just don’t work properly.
    If you’re a pregnant mom don’t smoke marijuana, or take cannabis. Choose your baby first.

      1. No they don’t. Speak for yourself. Thats quite a blanket statement, bulking “everyone” in together like that. I think that you’re defining disorders as “any medical conditions known to man” lols, and you’re wrong because a disorder is one specific category of a medical condition. You should know this stuff.

  6. I am a pretty avid pot smoker. I have had 2 kids now and I am 25. I did not start smoking until I was 18. It has actually helped me through my ADHD and depression and anxiety. I was pre-diagnosed with these disorders before I ever touched pot. My daughter is smart, she learns quick, can do different brain teasers and puzzles in record time. She is now 5. I have a boy who has recently turned 3 months. There is not a single thing wrong with him. He’s smart, since he was just over 1 month old he could hold his head up and himself up, he started rolling over at 2 months and tried pushing himself. He is healthy and happy. There is not enough research done yet to say that the effects of marijuana are going to cause problems. I mean nothing in life is entirely healthy but I’m pretty sure marijuana has killed less people than peanuts. So until I am given better research results I am a complete advocate for marijuana.

    1. I agree, I also have 2 children, one whom was just born and is only 7 days old and is VERY alert, she’s already trying to lift her head, she responds to noises by turning in the direction she heard the noise and I’ve never seen her jitter or jump in her sleep or anything they’re saying happens when they’re exposed to marijuana. Also I have a 22 month old who also was exposed to marijuana and my baby is already saying her ABC’s, she’s potty trained, and she loves for me to read to her, she’s very outgoing and just advanced overall for a one—almost two year old!

    2. Thanks for sharing I appreciate it I’m 35 weeks & can’t really stop because it is my medicine for my depression & anxiety

    3. >My daughter is smart, she learns quick, can do different brain teasers and puzzles in record time. She is now 5. I have a boy who has recently turned 3 months. There is not a single thing wrong with him. He’s smart…

      Sad they are “just smart”. They would have been brilliant with higher IQ’s if you didn’t smoke put during your pregnancy. Ever consider that?

      1. So Ken, please explain to me how being smart is not enough? And how do you know that if she didn’t smoke marijuana that her kids would be deemed “brilliant”? Hell, my mom never smoked with me and I can tell you that I am smart, but no where near brilliant.
        Here are some “smart” words that my mother did teach me, “if you have nothing nice to say don’t say anything at all.” You could’ve addressed your stance on the issue without bringing someone else down.

    4. Kudos to you for sharing, i totally agree. None of the studies so far inclide enough info about the patient;how they were raised or conditions previously diagnosed in family history

    5. Same. My 2 year old son is almost too smart actually, and this just isn’t his mother talking. I’m encircled with internationally known Montesorri administrators and school social workers, who have shared how impressed they are with how quick, coordinated, how they can see him problem solving when faced with a task. He was holding his head up in the hospital shortly after birth! Myself and his father are both educated and athletic so I’m sure his genetics haven’t hurt, I think my use of cannabis during pregnancy, to help with joint pain accelerated/enhanced his brain. He sings the ABCs, some letters are repeated-he’ll be two end of March, and counts while he’s on stairs “8, 9, 10” repeated. Hit hit every milestone early. . . I call Bullshit on this article.

      1. How much marijuana would you recommend a pregnant mother to take while carrying. 2 or 3 fatties a day?

    6. I agree with you. I smoked pot while I was pregnant to quell my anxiety and depression (prediagnosed & medicated before both pregnancies, stopped taking meds while pregnant). I only smoked my second pregnancy because I was so sick (I only gained 27 lbs) and all the research I found beforehand was nothing but positive, other than the people who just disagree with “drug use” or smoking while pregnant altogether. One of the things that’s stood out to me was the artistic ability that was assumed to have been raised in moms who smoke. The only reason that stands out to me now is because my son is 14 and has been making music since he was 8 & playing piano (Fur Elise from memory!) by 10. He creates YouTube intros for friends and all kinds of stuff. Highly intelligent, gets As & Bs, very socially active & healthy. My now 9 year old daughter is too very artistic. She likes to build things and engineer…. the 3D LEGO’s architectures are her preferred Christmas and birthday gifts. However, she was born with a heart murmur and hypo active thyroidism. The murmur went away naturally but she will have to take synthroid her whole life bc she basically doesn’t have a thyroid. My mother in law has the same issue, so I’m not sure where that would fall. She’s also an A-B student and has won 1 & 2nd place in her school district for art (mixed media & pastels) in the last 2 years. I say nothing is good in excess, but in moderation everything can be manageable. Just talk with your doctor and be honest. Also, if you’re aware of studies going on and you’re pregnant & smoke pot, help expand research if you’re comfortable with it. I wish I would have so the scary stories wouldn’t be the only stories out there.

    7. Thank you the first mother with real life experiences. My mother did not use marijuana when she was pregnant with me and I actually had all of these problems listed above. Trouble concentrating trouble thinking. However as an adult, I do use marijuana which helps me with my depression and my ADHD. There’s no conclusive evidence that marijuana affects your fetus.

    8. Was your babies tested for THC? My daughter just had her baby and they tested the baby and she came up positive…now my daughter is going thru all this crap! Can they take the baby from her because of this?

      1. No they can’t take the baby! They can only do a home study and CPS just doesn’t want any smoking around the baby which is perfectly understandable. Don’t let them intimidate you.

    9. I am with you Mama O smoke for 28 weeks pregnant with my son who is now 9 years old and he is a straight A student and was advanced as a baby he was walking at 8 months old. There needs to be more research done I’ve seen healthy moms who don’t smoke weed have the most problematic children and illnesses in their children than mothers who smoked weed. It is all a crock of crap. These kids with seizures are being given Marijuana to control their seizures so who is to really say it has that negative of an impact on a child’s brain?! If it wasn’t for weed I would have never been able to hold down food and stopped being nauseous all day long with having Hypermesis Gravidarum this pregnancy. I just quit at 31 weeks and I’m due in 9 days. My baby is perfectly healthy and is almost 8lbs! I’m not hearing any of the negativity.

    10. Exactly. There is not enough research that’s been done, so why take the risk? It’s selfish on your part to make the choice knowing there isn’t enough research to prove it’s okay or not okay to smoke weed while you are pregnant. You’re just going based on your bias in thinking smoking weed is absolutely fine. Wouldn’t you just want to be cautious and not take that risk IF there are adverse affects on your baby. Just so irresponsible that you made that choice for your children who are powerless and incapable of making that decision for themselves.

  7. Why do I feel that these women are already a high risk group for these depression/anxiety issues – what was their use for cannabis? Was it to treat such problems or used recreationally? If it was used for mental issues, I’d say babies problems are hereditary rather than from exposure There really needs to be more studies done so people don’t take half information and run with it.

    1. Is called being dependant on weed and does not cure your anxiety but actually is the cause of it while you are off the herb. Your fooling yourself into believing weed is the cure for your problems

      1. Weed is not meant to be a cure. Is tylenol a cure for a fever or does it help the symptoms? Most people smoke weed to help them get through situations or problems they are having…not to cure them.

  8. We have many studies but marijuana users will never believe them. We could have a thousand studies that say marijuana is harmful and one study saying it helps and that the they will run with.

    1. Please list one of those thousands of studies because based on my hundreds of hours of Google research I can find nothing that is conclusive. It all says it may affect your fetus. As of now there is not enough data. And there’s not enough negative data as well. A lot of information online is just opinionated BS. But I want to see the scientific studies with conclusive data of factual information. It doesn’t exist. They’re studying rats not humans. My friend is a heavy marijuana user and her child is on honor roll in a Tech High School. So I see no proof that it affected him negatively at all. He’s an athlete and he’s brilliant.

  9. People with ADHD are more attracted to drug use. And considering the fact that ADHD is herditary, we can safely assume that the reason kids of Marijuana users have ADHD and similar “disorders” is purely hereditary.
    Meaning the main argument of this article lacks the understading of the diffrence between corolation and causality.

    (I apologize for mispells im not that used to typing in english. but this article was so painful I just had to reply)

  10. Hi there,
    Just came across this article and I must agree that it makes sense, all that you wrote in it about the dopamine reception specially.
    Marijuana use creates a havoc on the natural dopa receptors and it has been proven, especially when consumed frequently.
    I am glad that you are spreading this type of awareness. Our digital world and technologies can help us substitute Marijuana anytime, it’s over to people to realize it. There are many other natural remedies

  11. Ok personal experiences are not the same as a peer reviewed study. I hope everyone understands this. Not hating on how you feel but these are longitudinal studies. If you dont agree, either do your own research or accept that that may be the case. Marijuana may be good for some things but marijuana does indeed affect a developing brain, it does it to preteens who use it everyday so of course it would affect a brain that’s forming in the womb.

  12. Let’s all take the time to understand that Studies are done for a reason, mostly to gain a better understanding of the affects that substances may have on the body while being used. This does not mean that everyone will experience these affects. It is to educate on the risk involved, and possibility of these affects. It is then up to us as consumers, to determine if we are willing to take that chance. In this case, are we willing to take the chance of exposing the unborn fetus to this substance, after learning there may be a POSSIBILITY of a negative outcome for this child and their future? It all comes down to how much you’re willing to gamble, and how much risk your willing to take.

  13. My 3 month old grandson is precious but he is experiencing direct affects of his mother’s smoking in the same apartment where he sleeps. She puts a towel under the door but that does nothing for the vapors permeating the entire apartment. it’s in the carpet, in the walls, in everything that can hold a smell-fabric, clothing, etc. he can;t keep still most times but not as in baby motions– he is jerking and startled by magnitude of rapid motions. This calms down a great deal while he is at my house. It is abuse. plain and simple.

    1. Does he sleep alot my 3 month old grand daughter is in a home where they smoke I find she sleeps alot when I keep her she wakes more often to eat

  14. It is a great blog post.I am always read your blog helpful

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