Smoking Marijuana While Pregnant- Why The Jamacian Study Doesn't Matter

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Once upon a time I did a post on why women shouldn't smoke marijuana while pregnant.  You should read it.

I am staunchly opposed to the recreational use of drugs (and yes I consider marijuana a drug) while pregnant.  In fact, I tend to agree with Dr Bradley, that there is no drug proven to be safe for the unborn baby.  

If you don't need a drug and the benefit doesn't outweigh the risk, then I am of the mind that those things should be avoided....just in case.  Babies, and their health, are not to be trifled with.   

Oddly though, the same women who are staunchly opposed to drugs in labor, find the use of the "natural plant" to be just fine while pregnant.  

Discussion concerning marijuana smoking while pregnant is heated and emotional (especially I noticed, by people named anonymous).  But one thing that is brought up often to SUPPORT the use of marijuana while pregnant is something referred to as "The Jamaican Study."

The Jamaican study, which you can read here, is said to prove that not only do babies whose mothers smoke marijuana while pregnant do just fine, they are actually SUPERIOR to non-exposed infants. 

I want to take a few minutes to point out some of the reasons why the "Jamaican study" is not a sufficient reason to embrace recreational use of marijuana while pregnant. 
One of the first problems with this study is the size of the sample used- only 24 babies were exposed to marijuana prenatally and only 20 were in the unexposed group.  A grand total of 44 babies.   

This is a TINY sample size.  Personally, even when I find studies that I WANT to agree with, I dismiss them when the sample size is that small.  

Is this really a big enough group to make broad statements about what is safe or not in pregnancy?  

Babies in the study were scored using something called the Brazelton Neonatal Behavioral Assessment Scale at one day of life and again at one month.  The researchers admit that findings have been conflicting from other researchers on this same subject.  This is NOT a study that has been replicated over and over again, quite the contrary.  The ability to reproduce results is something often used to "prove" the validity of a study.  In this case, it has not been done.
" Despite the prevalence of marijuana use among women of childbearing age, reports on the behavioral teratogenic effects of prenatal marijuana exposure have been conflicting and inconclusive. Fried and Makin, for example, found that moderate levels of marijuana use in their middle-class Ottawa sample (7.0 joints per week) were associated with poorer habituation to light, higher levels of irritability, and increased tremors and startles as assessed by the Brazelton Neonatal Behavioral Assessment Scale (NBAS) between the third and sixth days of life."
Another problem with the Jamaican study is that the results really cannot be applied to women in America. Why? Because:

"The sample was drawn from the vast category of "rural poor," which constitute the majority of the population of this region of Jamaica. "
They were looking at a group of women who matched each other closely in income level- but they and their lifestyle, do NOT translate well to the average American woman.  These are women who differ in many ways - income, access to nutrition, lifestyle culture, etc, from women in America.  The results of this study can't necessarily be considered important to a very different population here or in other wealthier nations.  Any study that closely examines a specific group may or may not translate well to surrounding or different populations.

One thing that is often problematic in studies looking at marijuana use in pregnancy is separating out the use of this substance from the use of other substances.  What is really causing changes in test results?  Is it marijuana or is it another substance?  I had assumed that this study in particular was often cited by those supporting marijuana use in pregnancy because it did this. 
 "The use of alcohol and tobacco was minimal in both groups and did not exceed 3 beers or 15 tobacco cigarettes per week for any of the women in the study"
Alcohol and cigarette use in the study wasn't excessive- but it WAS NOT completely eliminated either.  Those are both known to impact fetal development.  

Another reason why the results of this study are flawed is that the heaviest users of marijuana actually had the highest education level.  Could it be that the education of the mother has an impact on the babies ability to test well? 
"First, as a group, the heavy users had the highest level of education. All the heavy users had had some schooling beyond the primary school level and three had had some post secondary training."
 Not only did the heaviest users have higher education levels, they also had more control over resources in their home.  This suggests that possibly they were able to have more control over what they ate- and some believe that maternal diet can impact the health of the baby.  
" The heavy-marijuana-users did not have more income and status than the other women, but they did have more control over how they acquired and spent their resources."
 Now- to the results.  
 "The heavily exposed neonates were more socially responsive and were more autonomically stable at 30 days than their matched counterparts. The quality of their alertness was higher; their motor and autonomic systems were more robust; they were less irritable; they were less likely to demonstrate any imbalance of tone; they needed less examiner facilitation to become organized; they had better self-regulation; and were judged to be more rewarding for caregivers than the neonates of nonusing mothers at 1 month of age."
 At one month the children of heavy using mothers did better on the given test.  This much is true.  Why doesn't it matter?  Why isn't this enough evidence to say "Go smoke a joint for a smarter baby!!!!"  The quote below illustrates this well:
" Furthermore, unlike the United States, in which heavy marijuana use often is associated with maternal incompetence and a suboptimal caregiving environment, the data from this study indicate that in Jamaica, the heavy-marijuana-using mother's education, independence, and greater access to resources converge in a constellation of maternal competence and a supportive context for neonatal development."

This is big.  If you read the study in full, you will find that the heavy marijuana users had the most social support.  They had fewer little children at home, they had more adults to help them and so - yes - their babies did seem to respond better in the tests.  But even the researchers thought that this improved testing could have a lot to do with the different situations the heavy using mothers were in, as opposed to the nonusers and NOT necessarily the use of marijuana.  

So- a quick recap on all the things that make the "Jamaican study" a joke.  

1.  The sample size was laughably small.

2.  The study has not been replicated.

3.  The study did not eliminate other substances known to impact fetal development such as alcohol or tobacco.

4.  The mothers who used the most marijuana while pregnant had the highest education level.

5.  The mothers with the most usage also had a more supportive home environment than the non-using mothers.

6.  The researchers themselves noted that this could have had an impact on their study results.  
But- if that is not enough to convince you that marijuana is not a good thing for your baby- how about this-  this study ONLY looked at the babies at one month of age.  What happens to them LATER in life?  Does marijuana use in the mother impact later development?  

It is known that many drugs can impact the baby but not SHOW until much later in life.  

These studies both showed that marijuana smoking was correlated with a negative impact on children when they were the age of ten. 

And here is another showing that cannabis impacts the baby negatively.

End results- the Jamaican study doesn't prove that smoking marijuana while pregnant is good for you baby.  If anything it shows that the environment surrounding a baby being supportive can be helpful in that infants development.  It doesn't show these babies are better off when they are adults or older children.  It doesn't really show much of anything about marijuana being good for the newborn.  

I wish that women would carefully consider the impact of what they smoke on their children.  We can't assume that something is "good" for our babies because our friends babies seem fine or because one study shows that it is a good thing.  

It is time we stopped making excuses for ourselves just because we don't want to give up part of our old lifestyle when we are pregnant.  Choose your baby first. 


So what about medical marijuana use during pregnancy as opposed to recreational use? Marijuana is an excellent way to treat nausea and low appetite, two conditions that can negatively impact the fetus. Marijuana does not have to be smoked to receive the medical benefits. You can vaporize or ingest to eliminate exposure to smoke. How do you feel about it when it is having a positive impact on a woman's physical or mental health?

I would also like to point out that many women still paint their nails, dye their hair, clean with harsh chemicals, and a use a slew of other things that expose their babies to teratogens that we know can cause defects and other problems but no one is making them out to be irresponsible and selfish. Beacause these things are socially acceptable, the possible negative effects are mostly ignored by the general public.
Unknown said…
I could care less on who smokes it. I don't and won't smoke it, but it has been proven that weed has more toxins in it than cigarettes. Both are not healthy but they compare one joint to 1 1/2 packs of cigarettes. Yes it may help people in the cancer area and other places but you wont find me smoking any more.

As long as you dye your hair in a well ventilated area you should be fine. We probably get more toxins in the air outside than we do in our own home.
When it comes to toxins, it doesn't matter so much anymore - they're in everything. You really can't avoid them in our world today - and chances are, exposure happened before WE were even born; perhaps before our PARENTS were. I'm sure there is some cumulative effect when you consider the age of modern conveniences and packaging of foods in the 1950s, for instance.

This quote from the study, which I read awhile ago, kind of confounded me: "they had better self-regulation; and were judged to be more rewarding for caregivers than the neonates of nonusing mothers at 1 month of age." What the heck is that supposed to mean? Rewarding in the sense that they're so laid back, they don't fuss? Does generational marijuana use start to mess with people after awhile? Who knows.

I have always been shocked that they can't really come up with conclusive data to suggest that it might be harmful. Because to do so, at least in the American population, would probably be unethical. No one is going to openly admit to using regularly, and I'm not sure people would really be willing to subject their child to it, either. When you look at what it does to a full-grown adult, what can it do to an unborn baby? Mom's system probably filters out some of that, but I bet not all. Have we ever seen doppler or ultrasound data *while* a mother is smoking it? That might be way more conclusive than just observing the baby... and if mother is using heavily while pregnant, then she's probably using heavily while breastfeeding - perhaps those effects are more from that. I don't know.

I agree - this does not make a very convincing study to me. And I think just about anything can be used to justify use as "medicinal" in the general population; I think it'd have to be pretty freakin' bad morning sickness before I'd use this stuff, considering we don't know if the benefits outweigh the risks.
Tracy said…
While I like the article, I was disappointed in the links at the end as they all suffer from some of the things you complain about in the Jamaican study and thus should be held to equal scrutiny.

The Goldshcmidt study used a transformed variable which makes it unbelievably difficult to understand their results when they talked about controlling for other variables. A transformed variable isn't the same as the initial variable and can have very different outcomes. While they claimed to have done logistical regression (which is much more appropriate, they don't report the results, or at least not coherently). Finally, their model which found a link between marijuana use and inattentive symptoms showed a very very small relationship - notably gender had a greater effect than marijuana use.

The Gray, Eiden, et al. article on meconium suffers from the small sample size that you criticized the Jamaican study for. While they started with a larger N, they only had 20 infants with any cannabis in the meconium (and oddly one woman whose infant had cannabis in the meconium though she denied using and all her tests came back negative during pregnancy). That's the N you need to consider for power and it's small and thus must question the applicability.

Finally, the Grey et al. article on depression has the opposite of the small sample problem: the analyses are based on huge samples meaning that small correlations and differences become statistically significant but this doesn't make them practically significant. And for most of the analyses, other variables like prenatal alcohol and tobacco exposure, leading to huge confounds.

In my opinion, if you're going to discount the study that has findings you don't like for these reasons, you also have to discount the studies that do support your view for the same reasons :) Personally it seems that the research is rather non-committal on the fact simply because good research hasn't been done yet!
Jennie said…
I'll be brave here and post under my own name. :-) I have read your other post on this subject; I've been reading your blog for awhile, but this may be the first time I've commented.
I do use while pregnant.
I vaporize small amounts, on a daily basis.
It helps with the morning sickness, it helps keep my asthma in check and it eases the joint pains. All of that combined means I eat better, I'm not puffing up amphetamines from my inhaler and I stay more active.
I have an engineering degree, and I work 45-50 hours a week. That leaves me very limited time to eat/exercise/relax/love-the-other-children/be-intimate-with-hubby in the evenings. I really feel like using helps me balance everything and not run myself ragged.
For me, it's always felt like med use as opposed to a rec use, and the weighing balance and benefits always leaves me on the side of continuing the practice. Especially with the dearth of solid information showing definite downsides to baby.
When I travel for work to job sites, I notice the difference of not using. Not in a withdrawal sort of way, but more in a cumulative effects of those symptoms. I can't breathe as well, and I don't eat as well and I can't move as well, so my sleep is less restful, my blood sugar is less controlled and I'm worn out.
I do pay attention to studies that come out, but there aren't many of them, and they tend to be of such poor quality that I can't use them to evaluate the practice. All I have to go on is how I feel, and how my pregnancies go and how my children develop. I've not seen any warning signs from any of those sources while using, and I feel less healthy when I stop.
I'm not saying every mamma needs to toke up, but hopefully if there's another mamma out there reading this, she won't feel so alone in her choice.
As another commenter mentioned, pregnant women all over choose to paint nails, eat at McDonalds, use harsh chemicals and even induce at 39 weeks so their Dr can have Christmas off. (my cousin, last week, ended up c-secting, ugh!)
While I would never do any of those things, I respect their right to make choices about their own bodies, and prefer that others give me that same respect.
Anecdotal as it is, there's my input to this discussion. Thanks for bringing it up again, I did like your take on this study.
Mama Birth said…
Thank you all for your comments-
Very good point Tracy- and I stand corrected.
I appreciate your perspective Jennie.

I wish women were more supported, nurtured, and cared for in their pregnancies, so that things could be more comfortable through nutrition and nurturing.

My feeling on the Jamaican study was that the one group's babies did better because of the supportive group which the Rastafarian mamas were a part of.

Honestly- I don't know if you could ever "prove" beyond a shadow of a doubt that marijuana was good or bad for the growing fetus-

With pregnancy, there are so very many influences and variables, unless something is very obviously damaging, it is really hard to say one way or the other.

I am of the mind that it is better safe than sorry, but in all honesty, I am less cautious with some things that others avoid- like donuts- so- whatever that is worth.
Maria said…
I appreciate your analysis, but I am curious if you circumcise or support the genital cutting of children, namely boys. Because the Uganda studies about HIV suffer even more fallacies than you point out here about the Jamaican studies, yet those are commonly touted as reasons to violate human rights. And unlike marijuana, circumcision actually has negative effects on the man a boy will become. Jus sayin.

I can never understand people who support natural birth, and abhor marijuana use in pregnancy, but somehow find a way to justify strapping babies down and cut their genitals, stealing a very important part of their sexuality from them. Doesn't jive.
george said…
I read this article after watching the study on jamaican women ... I know many people who are everyday users like myself I also work as a engineer and I function at peak all day long stoned or not... I have friends who smoked during their whole pregnancy and the babies are perfect little bundles and I have a friend who smoked cigarettes an d drank during pregnancy and her babie was premature and far under weight ... Your knowledge means nothing . Until you smoke marijuana and actually find substantial evidence that it DOES cause harm to humans and our babies wich u cant .. Then rant and rave about it but until now ive seen first hand in canada that there is no harm.... What.can.u say toyhat
Anonymous said…
In every single paragraph you've written in response to the jamanican report there is more than one sentence that begins with " I believe" " my thoughts" , which inturn tells everyone its your OPINION on marijuana use not your research. Get some back up on your OPINIONS, I've looked being a marijuana user and pregnant, and you will find ten-fold to one there is no harm that can be proven by marijuana use during pregnancy no more than eating fast food everyday.
Anonymous said…
Over and over you state how there is no proof that marijuana is good for unborn and nursing babies and that their wellbeing is more likely related to their surroundings. You don't have a single reference that shows marijuana HARMS unborn or nursing babies. People like me and Jennie use marijuana to ease morning sickness. It can be debilitating and harmful for an unborn child if the mother cannot get nutrients into her system. The alternative drug has a major side effect: it may cause miscarriage. Marijuana on the other hand has no such side effect. Are you reallly suggesting that women take a pill that could kill their unborn baby instead of vaporizing or eating marijuana? That may sound harsh, but that is the reality of what you suggest. And people post anonymously because it ot illegal. When I had my first, he tested positive in the hospital for the presence of canabinoids. The hospital sent CPS to my home. I had to suffer through the worry that the state would take my newborn baby away when there was nothing wrong with him. However, once the CPS agent arrived, she explained that not only does CPS not care to pursue cases of parental marijuana, but they can't due to the fact that it is almost imppossible to show harm to a child from parental marijuana use, except in cases of severe neglect which is often the result of severe post-partum depression regardless of marjuana use or the combination of the use of marijuana and more harmful drugs like heroin, pharmaceuticals, or cocaine in it's various forms. We are at a turning point in this country. Studies are showing that marijuana absolutely does have medical benefits with fewer and less severe side effects than pharmaceutical drugs. It can therefore not be classified as Schedule 1 for much longer. Intense public pressure, societal pressure, and international pressure will soon win the war against marijuana. So once it is as legal as benadryl, will you still keep the same opinion of it?
Anonymous said…
I know a mother who smoked marijuana throughout her pregnancy. Her baby was born addicted to marijuana (and yes this was the only substance she used) it's not like women quit using after the birth. Children should never be exposed to drugs.
Anonymous said…
I am a board certified internal medicine physician and a mom and I want to weigh in on this question. I'm not an OB but I have enough medical knowledge to make a better call than most people with strong personal opinion. I practice in California, a state that allows medicinal marijuana use.

Essentially, marijuana is a Class C medication and the same rules apply to it that apply to all the other Class C pregnancy medications. That is, we don't know that it causes any risks to the child but we are not 100% sure yet. Marijuana is worth taking if you believe that the benefits to the mother outweigh a small undetermined risk to the fetus.

As with everything else, moderation is the key. It is best to use it in minimal amount. Thus, a couple times a month is extremely unlikely to cause any harm, while daily use has more potential for concern. Technically speaking, there is no evidence to believe that marijuana (especially in vaporized or orally ingested form) is no more harmful than Ambien or Codeine which are commonly prescribed by OBs during pregnancy.

Americans are very overzealous when it comes to health care and pregnancy in particular. It is for the same reason that we run a myriad of unneccesary tests and in general practice defensive medicine in this country. For example, there is also no evidence of harm if you have a small glass of wine here and there after your first trimester, and no physician in Europe would advise against it but here in the US the formal recommendation is not even a sip of wine for the whole nine month.

In conclusion, I agree with the blog author that there is limited evidence to state that marijuana use during pregnancy is beneficial. However, I think there is just as little evidence that its use is harmful. I do not approve of the recreational use but if it is used to relieve the symptoms of nausea, insomnia, poor appetite, joint pain or anxiety than it is mother's individual decision and not something that she should be judged for. I would advise to use the very minimum amount needed.

It is sad that it is still something that is considered illegal, and the fact that a woman who smokes cigarettes throughout her whole pregnancy is not in danger of CPS being called on her but someone who has an occasional join is is bizarre, biased and unfair. Fortunately, we all know that it will probably not stay like this for much longer given that 56% of Americans support decriminalization of marijuana. There are more important things for police and CPS to focus on, and making marijuana a crime is simply a waste of tax payers money.
Valerie said…
I used marijuana for my migraines and insomnia before I was pregnant with my first child. I stopped smoking after I found out I was pregnant. I did not have morning sickness, I had all day sickness. I was continually being sent home from work because I vomiting so much. My midwife didn't want to prescribe me anything for it because she was afraid it could harm the fetus. After 5 months pregnant, 10 pounds of weight loss, and still having a flat stomach I finally gave in and smoked just enough for me to eat. I informed my midwife that I had started smoking and I was able to eat again and she said that was good. I stopped smoking once I had her and breastfed, no more nausea and vomiting, no reason to smoke and pass that too her through the breastmilk. I had the same problem with my second pregnancy and didn't wait 5 months that time. Both of my girls are healthy, happy, and very bright.
I don't think there is enough research to support or disprove any effects marijuana could have on an unborn baby in our society. I believe the government needs to give researchers the ability to do better studies.
Anonymous said…
Jennie ...u r brave for that but I'm glad u posted I feel the same way and am here looking for the effects and can't find anything that outweighs the good in smoking . I can have an appetite mainly only from smoking bc the nausea is so strong so I'd think it'd b better to smoke so I can eat healthy .
Kim Perez said…
This comment has been removed by the author.
Kim Perez said…
I read the Jamacain report when I was pregnant. It seemed valid, at the time, and so I didn't stop smoking weed. As an infant my son was perfect. Problems manifested when he was 4 years old. He is now 6 and his problems have gotten progressively more intense. He has what multiple doctors call the worst case of ADHD that they have ever seen. His emotional development is stunted. It is a full time job working with him, the doctors, the special ed staff at his school and his therapist to get him on track. If I could turn back the clock, I would have quit smoking weed while pregnant.
Unknown said…
The long term consequences may well be far more damaging than the short term relief. Marijuana crosses the placental barrier and has subtle effects on the new born baby, however, it is the longer lasting and more delayed effects on cognitive processing that are most alarming. The prenatal exposure to cannabis contributes to a vulnerability of neurocognitive functioning that has been observed as early as 3 years of age and most strikingly continuing into young adulthood.
Unknown said…
I couldn't agree with you more! Personally I vape cbd e-juice, but I would not while pregnant!
Unknown said…
This comment has been removed by the author.
Unknown said…
How did they know it was addicted?? I call bs
Unknown said…
I'm not a woman, but I wouldn't smoke ANYHING if I was pregnant no matter what any study says. Everyone knows that inhaling any kind of smoke is bad for you, and if it's bad for you it's bad for your baby. And even if you're just eating it, who knows how the psychoactive compounds are affecting your baby's brain. Just don't to it.

FZ @ HerbTools
Unknown said…
Sorry to tell you that cannabis is not a drug. Cannabis is food, a fruit from a plant that grows all over the world, high is fiber and omegas.... its also building material, was used after the nuclear bombs were dropped in japan and other nuclear sites to cleanse the soil, is a bio diesel as well as the worlds oldest and safest known medication. It has also been recognized in the state of tennesee vs thorne peters, and ruled by a judge, that it was not to be called a drug by the prosecution after mr peters had objected to the prosecutions use of the word drug in reference with marijuana. This comment might get deleted but i just wanted you to know the facts.