Agricultural Pesticides Do Appear To Cause Birth Defects, But Only When Exposed To Extreme Amounts

in #science4 years ago (edited)

Today lets return to a topic which I have discussed in the past, pesticides. Furthermore let us revolve our discussion around a recent article published in Nature Communications titled "Agricultural pesticide use and adverse birth outcomes in the San Joaquin Valley of California." In this article researchers were looking at the effect that pesticide exposure had on potential negative outcomes during a fetus' development.

I am going to TRY make this a shorter blog post where we just directly dive in and discuss the data with a minimal background section. Yes that means you are in luck, you don't have to read a whole PhD dissertation ha ha!... only half of one ;)


Ubiquitous in modern farming, pesticides appear to be a necessity in-order to produce the massive amounts of food needed to feed the growing world population (and we would need even more if so much of the world wasn't living in abject poverty and near starvation conditions... a situation that a remarkable new economic paradigm such as the one found here with STEEM may some day be able to make a significant dent in fixing!) As a result it's important that we focus at least some of our science researching time toward understanding the potential negative effects these compounds may have on our bodies (or the bodies of our children).

You will find a good number of bold claims on the internet about how pesticides are purely fire and brimstone, and are a root cause of all that is negative with regards to human health. However, despite the all of the negative discussion by the general public, I don't think that the scientific literature supports those claims (yet, if ever). [2] Nevertheless, there ARE clearly potential issues surrounding these compounds which extend beyond just human health, and into aspects of health pertaining to the animals that live on our planet with us, as well as insects we do not wish to target (eg. bees). [3], [4], [5]. There is clearly a lot to be studied.

Regardless of all of that, today's article addresses one such potential issue associated with pesticide exposure, birth defects. The authors of the article do this by exploring the data pertaining to more than 500,000 births in the San Joaquin Valley area of California which took place during the years of 1997-2011. The reason this particular area was chosen for study was due to the high concentration of farms and general high population density of residential areas surrounding them (basically there were a lot of people that would have been exposed to a lot of pesticides from those farms).

This Is NOT The First Study To Look At This Relationship

The authors discuss a variety of research available in the literature in which authors have described a relationship between birth defects (low birth weight, fetal developmental problems) and pesticide exposure (but could not illustrate a causal relationship). [6], [7] These prior studies also had additional discussed limitations, including an inability to depict the amounts of pesticides that people were exposed to. It is also interesting to note that while the aforementioned studies presented claims of a relationship, other studies found entirely the opposite, showing no link between pesticides and birth defects at all. [8]

So How About Todays Article?

Here the authors were trying to address some of the limitations in the previous studies. They were looking at a large sample size of births and also correlated those births with access to pesticide data from the mothers geographic area (aka the amounts and types of pesticides that the surrounding farms were spraying). As I mentioned previously this study focused on the San Joaquin Valley, California. California in general, despite its high population also has a very high density of farms. (This may surprise you) it also accounts for a staggering 30% of pesticides used in the US. Thus study of the San Joaquin Valley is ideal for trying to get a better understanding of the relationship between pesticide exposure and birth defects.

What Did The Authors Find?

A better look at the area they were examining and the relative levels of pesticide exposure

So taking a look at the figure to the left we can see the San Joanquin Valley and the areas where a lot of pesticides were used. (very dark colors in (a) ). You can also make a note that a lot of the area here was not exposed to any pesticides.

They report that they targeted a specific area with a high concentration of pesticide exposure and a total of over 130,000 births (so lots of data!) Additionally, the people in the study were organized by level of exposure. Those in the 75th percentile (top 1/4) of exposure, were exposed to the potential of 250 kg of pesticides (per 2.6 km2 area), while the 95th percentile were exposed to 4000 kg (per 2.6 km2 area) and the 99th percentile a whopping 11,000 kg (per 2.6 km2 area)!

Interesting Findings

  • Little effect on birth weight was observed for those in the low exposure group. The low exposure group was all people who were less than the 95th percentile of exposure. So that is a yearly exposure of less than 4000 kg of pesticides (per 2.6 km2 area).
  • For those in the high exposure (95th percentile and above) the authors report a statistically significant reduction in birth weight by an average of 13 grams.
  • Being in the high exposure group increases the likleihood of premature birth by 8%
  • Those who were in the top one percent of pesticide exposure had a greater chance of premature birth (11% increase) and a greater decrease in birth weight (up to 30 g smaller than normal).

Some Conclusions

  • Due to its size and the amount of data available for pesticide exposure, this study has a greater statistical power to draw conclusions from then previously published work.
  • They saw an average of an increase of 5-9% of adverse birth related effects for those with the very highest exposure levels to pesticides.
  • They draw a comparison with air pollution where relatively low levels of exposure lead to 5-10% increases in negative birth related effects. [9] Even stress during pregnancy they report results in a 6% increase in negative effects to births. [10
  • The negative effects the authors observed come from the most extreme amounts of pesticide exposure. As such they recommend that actions be taken to limit the concentrated use observed in certain areas. This would essentially eliminate the adverse effects reported in this study.

Potential Complications In This Study

  • They can not account for individual adaptations to pesticide use (they list people choosing to stay inside at certain times, like during spraying, to limit exposure).
  • They can not study the direct effects of exposure, as that is unethical. (can't go around spraying people with pesticides directly and looking for negative effects, this is a limiting factor for all studies related to these compounds)
  • They do not have data related to individual compounds, as pesticides are very often sprayed in cocktails of several at once. So no conclusions can be made here related to specific compounds.
  • Birth records don't necessarily accurately account for all potential negative outcomes, things may have been missed and not included in the study.
  • Due to the size of the areas they used for quantifying pesticides (2.6 km2), the highest amounts could actually be underestimates of exposure for some people.


Pesticides appear to cause birth defects (low birth weight, pre mature birth etc.) but only in the most extreme exposure cases. The authors recommend public policy changes to limit the likleyhood of these very high levels of exposure, and indicate that this could eliminate the possibility of issues related to birth.

So to answer the question posed in the thumbnail image...Yes there is a relationship, but it doesn't appear to be as strong as many might believe.


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It is important to thoroughly clean your fresh produce, especially if it is not organic. Thanks for sharing, I am new to Steemit and just posted my introduction post. Please read it and let me know what you think when you have a chance! Thanks

Yes, washing is important but remember Glyphosphates wont be washed off. Great to see you on steemit. Upvoted!

I think I find the assessment here accurate. Glyphosate likely needs a modern broad scale risk assessment done on it. Likely that will find that exposure levels need to be lower than are currently allowed (as old research indicated that it was entirely safe, likely not correct but likely still a concentration dependence that skews to the high side).

At this point, the vehement opposition to glyphosate is still NOT supported by the scientific literature. There are plenty of studies reporting some issues, but these for the most part are not an endorsement against the use of glyphosate, but rather increasing the regulation of use. Setting more strict exposure limits for people. That sort of thing. Heck I have even written a post discussing a study describing a link between glyphosate and fatty liver disease in a mouse model. I also discuss some of the limitations and criticisms of this work (it's not a great study).

I've also written posts discussing work showing issues with carbamide pesticides. However as with glyphosate this work really doesn't illustrate that these are necessarily an issue given low exposure levels (it's a common theme with a lot of this research).

You're fear-mongering IMO.

This isn't really about pesticide exposure on that level. This is about people who are being exposed to extreme amounts from living near farms.

I think it depends on the persons immune system, some people can just take external poisons like pesticides in small quantities better than others. I know people who worked for years with Nemagon used in banana plantations up to the 80's and sure enough many of these guys suffered skin lesions which are practically incurable, others became sterile, others impotent and others got absolutely no incidence from it, all of them having had the same exposure.

Upvoted - I know it hard but what were the approx proportions of this as in comparing numbers of effected to non effected?

No, that would be nearly impossible, many of these men are already dead, no way of knowing if the exposure killed them or they had natural deaths, others emigrated etc.

Interesting, these guys would have had a massive exposure. Many times higher then anyone in this study. Thank you for sharing.

Educating the farmers is the only way ..this being said , Educating them and the amount of time and promotion needed is not a joke . New and better ways need to be designed to reach the farmers. And on a whole i thing organic farming is any day healthier as long as its done sustainably . Thank you for the informative post .

Education is indeed needed. However I don't think "organic" farming is an economically viable solution, at least not going forward. There are a lot of people on this planet that need access to food, and a lot of it.

Thanks for reading!

The big misinformation is that we need GMO or pesticides. It's proven with time yields decrease massively. Old school, biodynamic and organic is the way forward for higher yields and safe food.

Wrong, old school is insufficient to produce high enough yields from small enough spaces. Thee compounds are used out of necessity.

I disagree with your self voting rewards.

But you self voted your post? Why have you desrtoyed my post and these words? "The big misinformation is that we need GMO or pesticides. It's proven with time yields decrease massively. Old school, biodynamic and organic is the way forward for higher yields and safe food."
Disagreeing is fine but why the sabotage bordering on censorship?

By flagging my comment so aggressively you have greyed it out and made it invisible. I think Steemit invented that for obscenities, not for civilised difference of opinion of scientific data.

You removed your self vote, so I removed my flag.

I didn't destroy anything. I tried to only nullify your self vote. If you disagree with the reward on my post, use your power to adjust it.

I don't vote negatively. At the moment all with steempower are using it to get posts and comments noticed. I'm very concerned Steemit will turn into Wikipedia, which is controlled by majority opinion, squashing all independent minority thought, if we as a community are not careful. I realise this is your post and I was disagreeing - could be considered rude - but its a very important subject with millions of lives at risk. We also cant reply on a lot of data as its published by the manufacturers, or controlled by them. As a PHD holder I'ms sure you're aware of the commercial pressures on research causing massive bias. I wish you no personal offence.

No no, I don't think you are being rude at all. I'm well aware of bias in research as well as other prevalent issues (non-reproducible published is rampant). I am NOT trying to silence your opinion. I hope none of your comments are hidden, if so I will go back and adjust.

We also cant reply on a lot of data as its published by the manufacturers

Not a factual statement. You can rely on good data, however should look closely at data with disclosed biases, and even closer at data with later discovered undisclosed biases. Manufacturers are quite capable of publishing material that is well done, many of which will even publish material that exposes flaws with their products because science is what it is. Not all companies are unethical monsters ;)

The problem is definitely not really the pesticides themselves, but what we, humans, do with them. Over-usage is always the issue. I am wondering what become the numbers when restricted to areas where pesticides were used reasonably.

According to the authors of this article, moderating use would eliminate the effects they observed entirely.

So, in short, it is sufficient for humans to be less extreme... hmmm... we are far from there... :/

Solid read, it seems important to remember that even with a study and data this in-depth that we can't jump to unsupported conclusions or claims.

There can be many unobserved factors that are affecting outcomes. It seems best to say that babies/children and pesticides have no business mingling. But also many other things are dangerous as well and they should probably also be researched to understand the cumulative interactions as we develop through our lives.

It would be nice if there were less environmental risks and more information about why they exist.

It would be nice if there were less environmental risks and more information about why they exist.

It is this reason why these studies are useful. Hopefully we can slowly understand more and work to mitigate any risks.

Well, its good to know that moderate use of pesticides isn't too detrimental. Good post!

Yeah at least not through the eyes of birth defects.

Upvoted & RESTEEMED :]

Great read from you again my friend! If you look well, most of the world crops are using pesticides, if not it will be impossible to feed the world population. It's only a portion of them who are being affected by it, most certainly maybe they have been exposed to a high quantity or maybe about their immune system.

Indeed, good points. They are certainly a necessary evil at this point. More moderate use seems key.

Very informative, i have a bit knowledge about Pesticides, i have a plan to plant the pepper, next time we can discuss about this pesticides, hehe

Thanks a lot for sharing this. We are just about to write down research proposal in this field. Our goal is actually to save and restore Abongphen Highland Forest in NW Region of Cameroon which is one of the most important watershed areas in the region and it also belongs to biodiversity hotspots where hundreds of endemic species are found. Unfortunately, the mountain area with thousands of springs has been strongly degraded by agriculture using a combination of slush burning approach with a lot of chemicals (fertilizers, insecticides, fungicides). People use it directly in spring areas. The area is supplying drinking water directly for 100,000 people. Indirectly to million of them. We would like to know the effect of water pollution on people's health living in surrounding areas.
That is why we decided to save and restore the forest. If you are more interested you could find more information on our steemit profile or
We are also trying to use steemit as a great fundraising opportunity and besides author and curations rewards we have voting bot @treeplanter. So you can also plant trees with us.
Thanks a lot.
Nice day.

Sounds like a great endeavor. Good luck as you continue to fundraise.

Well, are the farmers aware of this? Has anyone tried to inform them on the side effects of overuse? Keeping people ignorant is a great way for companies to make more money, but shouldn't someone spread the word?
Great article!

Well the package usually does a good job describing the dangers of mis/over use.

It does @trumpman, but people usually don't read those labels. I mean that, if not presented with real evidence, farmers won't give a damn. We live in the same country, we both know how people work in agriculture.

I don't know the answers, good questions. Likely the farmers are not aware.

@justtryme90 does the pesticides taken in general or they were categorized based on their chemical classes or content. Since all pesticides doesn't have thesame chemical composition. Great article.

It was pesticides in general, not classified by their chemical content.

I used to drive through a huge plantation (I think it was chicory) to go to work, whenever I saw the crops being sprayed I wondered about the local residents and how detrimental it was to them. I never stopped to think about the pregnant women though. I am now asking myself if their exposure would count as extreme! I always enjoy reading your posts @justtryme90. I have actually been going through your older ones :)

It's a good question. You can see that a lot of the people in this area that was studied we're exposed to quite a bit of pesticides. Only 5% were classified under the highest category where effects we're observed.

Let's hope not.


and most farmers are ignorant of the sideffect or the company representatives who are exposed too much to this stuffs, May we help ourselfs while God does his own part, thanks great post

Thanks for giving it a read.

informative 😍

your most welcome friend keep giving us informative posts😍😍

Really interesting, thanks for posting!

good article

Well, this isn't so bad. It seems like it can be easily fixed, if proper action is taken. And as you say it's only in 95th+ percentile, and the effects are comparable to those of stress! So, overall it wasn't as bad as I imagined going into it, or as is often portrayed in sensationalist media. But it does merit much further research.

The thing with a lot of data is that it can be spun a lot of ways. It's important to take things into context, and also realize that many many things that we use every day have the potential to be very damaging to our health at the right concentrations. Placing the appropriate safeguards so those concentrations are not achievable is extremely important.

However discussion like that doesn't generate clicks.


Birth defects are just one indicator and a devastating indicator at that. How about apparently more subtle indicators like behavioural issues, autism, diabetes, cancer, iQ issues, obesity and many many other health defects. I really hope everyone reading this post takes just some time to watch part of this free series. It's called GMO revealed but deals with roundup, glycophosphates in general and other agricultural toxins. Highly recommended viewing... even if you catch just 30 mins. I'd love to know your thoughts. Here's the link::::

Please remove your large self vote or I will flag to remove rewards.

Secondly the evidence against pesticides is just not stacking up. The evidence against glyphosate is also entirely unconvincing to date. It's clearly not harmless but the fearmongering is overblown and seemingly unwarranted.

180 links to research papers on the dangers of Glyphoshate here:

I've read into it in the past. The data doesnt support the level of fearmongering that goes along with it. I don't go around recommend anyone use it, or take a bath in it. I'm no fan of Monsanto, their shady business practices, or generally their products.

So @justtryme90, you award yourself a large self vote on your post but ask me to remove the self upvote on my comment? What values of the Steemit community are you abiding by?

It's my post, I can do as I see fit within it. Don't like it? Dont read it or comment in it.

If you feel my post is too highly rewarded, feel free to adjust the payout. I suspect based upon your activity in this post, that you award you self a heck of a lot more rewards then I did with my vote on this post (my only one in the past week).

I don't care for large self votes on comments. My apologies if this offends you. This is MY post, so I withhold the right to adjust the payouts of the comments as I like.

100% incorrect. Have you checked out the video link I offered, or are you and whoever flagged this post just doing so without deeper investigation?

A well researched article but please look at the paper below and the link to 179 more papers. It seems to me there is possibly a great risk so we as a society should be cautious until we know the effects for sure. Rates of birth defects (major damage) with high exposure suggests a proportionally lower yet unacceptable damage with lower exposure too. Surely?

Abstract Title:
Exposure to pesticides as risk factor for non-Hodgkin's lymphoma and hairy cell leukemia: pooled analysis of two Swedish case-control studies.

Abstract Source:
Leuk Lymphoma. 2002 May;43(5):1043-9. PMID: 12148884

Abstract Author(s):
Lennart Hardell, Mikael Eriksson, Marie Nordstrom

Article Affiliation:
Department of Oncology, Orebro University Hospital, Sweden. [email protected]

Increased risk for non-Hodgkin's lymphoma (NHL) following exposure to certain pesticides has previously been reported. To further elucidate the importance of phenoxyacetic acids and other pesticides in the etiology of NHL a pooled analysis was performed on two case-control studies, one on NHL and another on hairy cell leukemia (HCL), a rare subtype of NHL. The studies were population based with cases identified from cancer registry and controls from population registry. Data assessment was ascertained by questionnaires supplemented over the telephone by specially trained interviewers. The pooled analysis of NHL and HCL was based on 515 cases and 1141 controls. Increased risks in univariate analysis were found for subjects exposed to herbicides (OR 1.75, CI 95% 1.26-2.42), insecticides (OR 1.43, CI 95% 1.08-1.87), fungicides (OR 3.11, CI 95% 1.56-6.27) and impregnating agents (OR 1.48, CI 95% 1.11-1.96). Among herbicides, significant associations were found for glyphosate (OR 3.04, CI 95% 1.08-8.52) and 4-chloro-2-methyl phenoxyacetic acid (MCPA) (OR 2.62, CI 95% 1.40-4.88). For several categories of pesticides the highest risk was found for exposure during the latest decades before diagnosis. However, in multivariate analyses the only significantly increased risk was for a heterogeneous category of other herbicides than above.

Article Published Date : May 01, 2002
Study Type : Human Study
Additional Links
Diseases : Hairy Leukoplakia : CK(10) : AC(2), Lymphoma : CK(253) : AC(83), Lymphoma: Non-Hodgkin : CK(363) : AC(79)
Problem Substances : Glyphosate : CK(502) : AC(160), Roundup (herbicide) : CK(502) : AC(160)
Adverse Pharmacological Actions : Carcinogen : CK(59) : AC(11)

179 more studies studies here showing glyphosphate damage.

So you've flagged the above comment @justtryme90 again? What happened to scientific debate?

The comment is clearly visible.

So what? It's not hidden. Get over it.