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Welcome to PSR's Environmental Health Policy Institute, where we ask questions -- then we ask the experts to answer them. Join us as physicians, health professionals, and environmental health experts share their ideas, inspiration, and analysis about toxic chemicals and environmental health policy.


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"Don't Methylate My DNA or Perturb My Thyroid": An OB/GYN gets tough on pesticides

Posted on February 24, 2011

By Joanne L. Perron, MD FACOG

This essay is in response to: How does our food production system drive our exposure to toxic chemicals?

Spreckels, California
Spreckels, California

Biblical locusts, medieval plague, and unrelenting malarial mosquitoes: humans have always lived in a pestiferous world. Ever ingenious, humans have devised myriad solutions over the centuries to eradicate insects and vermin. Chemical pesticide usage began in the 19th century with sulfur and arsenical compounds and progressed to the large-scale development of warfare chemicals during WWII, many of which are still used today as pesticides. Consequently, over the last 60 years, pesticides have become a ubiquitous chemical product of modern agriculture which often remains in our food or can contaminate our air, fresh water, and oceans. Furthermore, with pesticides used in our homes, schools, and recreation areas, there is a bouillabaisse of possible exposure routes. Not surprisingly, regardless of occupation, United States population studies have documented urinary metabolites of pesticides in the majority of samples analyzed. Pesticides, even banned ones, have also been detected in other body fluids, sadly including amniotic fluid. Now, that is a profound loss of sanctity and a crying shame.    

As an OB/GYN who trained at Los Angeles County/USC Women’s Hospital during its heyday of 18,000 deliveries per year, I saw countless women with fibroids and ovarian masses the size of term pregnancies and an overwhelming number of third-world-like adverse birth outcomes, maternal and fetal. In those ancient times of the late 80s-early 90s, the prevailing wisdom was that these women, who often lacked preventive care, were the unfortunate carriers of bad genes. When people ask me how I first became interested in environmental causes of disease, I recall that I privately thought, never risking professional scorn as a resident, there had to be another component that conventional medical teachings ignored which contributed to the adverse reproductive disorders I was learning about. 

Of course then, my cursory knowledge was only of acute pesticides exposures since many of my patients were migrant farm workers. I surmised that there were mutagenic or genotoxic mechanisms from pesticides responsible for their health problems, but other than the nature vs. nurture debate, had never heard of epigenetic mechanisms in my medical training. So fast forward to 2001 when I started training in integrative medicine with Andrew Weil at the University of Arizona, Tucson. This is when I first heard the term xenoestrogens. I started wondering if chemicals in the water and food supply could be related to the reproductive disorders I was increasingly seeing in a middle class population. I say increasingly, because even women who came to see me for their annual “well woman” exam seemed to have an inordinate number of complaints such as abnormal bleeding, pelvic pain, endometriosis, fibroids, fibrocystic breasts, ovarian cysts, or PMS. And most of these women did not work in agriculture. 

I also started wondering if all of the cases of non-familial pre-menopausal breast cancer were due to some environmental causes. And then in 2004, at age 45, having breast fed my sons, never smoked, eaten healthy, and exercised regularly, I too got the diagnosis of breast cancer. And I was the kid who actually liked eating eggplant and other “weird” vegetables. With no family history of breast cancer, I started serious study of the potential environmental causes of breast cancer and while I am aware of the multitude of other environmental contaminants, pesticides were something, as a beginner, I could wrap my mind around.  

A close friend from childhood, Kristie, who lived 4 houses away, died at 38 from breast cancer.  She had no family history of breast cancer. Additionally, both of her sisters had unexplained infertility (their mom was a “fertile Myrtle”). With every high school reunion, I heard of former classmates who had passed away from different types of cancer. We grew up in the west San Fernando Valley, which had mostly ranches and agriculture until the post WWII building boom. In the late 1950s to early 1970s, many of the schools and residences abutted orange groves, onion fields, and corn fields. Not only do I recall frequent spraying of nearby fields, but also the sweet smell of regular misting from the mosquito trucks during the summer months. 

Did early pesticide exposure cause my individual case of breast cancer? My scientific training informs me that I will never know for sure. However, a large body of data is beginning to point the finger at early life, including in-utero, pesticide exposure as a crucial factor in many adverse health outcomes, some occurring many years after initial exposure, that clinicians see on a daily basis, including birth defects, reproductive disorders (male and female), cancers, metabolic disease, neurodevelopmental disorders, and neurological diseases.

To this day, when I talk about epigenetics to same-age colleagues in the trenches, some are disbelieving because they didn’t learn about it in medical school and the journals that they read don’t mention epigenetics, oxidative stress, or even endocrine disruption with linkage to adverse health outcomes. The sentinel 2009 Endocrine Society Scientific Statement should be mandatory reading for every health care professional before assuming practice or getting recertified. Most importantly, it states that there is evidence that endocrine disrupting chemicals (EDCs) can have effects on human reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism and obesity, and cardiovascular endocrinology. I admit it took my brain a bit of time to rewire and integrate an understanding of the mechanisms underlying epigenetic factors of disease and to appreciate that disruption of the intricate orchestrated endocrine signaling is more complicated than the lock and key theory of hormone function that I learned many moons ago.

This is just a brief summation of the science and concerns that scientists have about pesticides and other EDCs, but what about the local anecdotes that I frequently observe or hear about? From two different sources, I have learned that Stanford hospital receives most of its cases of congenital cardiac defects and childhood cancers from the Salinas valley. Also, that the Monterey/Salinas cancer clinicians are seeing more cases of premenopausal breast cancer from the Salinas area. Monterey County, the salad bowl of the US and the biggest producer of strawberries, is my home. It is an area of exquisite natural beauty, but has some of California’s most polluted streams and rivers from agricultural run-off. I shudder to think of the quality of our drinking water. To add to our woes and potentially contaminate our ground water even more, a great big experiment may soon occur on those who live in proximity to strawberry fields with the December 2010 approval by the California Department of Pesticide Regulation for the use of Über-toxic methyl iodide to fumigate those fields. 

Neither does the Pacific Ocean escape the toxic effects of pesticides; the Salinas and Pajaro river watersheds drain those same pesticide laden fields and empty into the Monterey Bay National Marine Sanctuary (MBNMS). Perusal of the MBNMS maps on this site clearly illustrates the color red to indicate “impaired” rivers. Meanwhile, the fishermen wonder where all the salmon have gone and I wonder about the local tide pools that once teemed with loads of hermit crabs, urchins, and starfish for John Steinbeck and my little boys to learn about. 

I try not to turn into an Eeyore when I discuss these issues with those I am trying to educate.  I often think about the messaging we use in this line of work and how we could better persuade those who are comfortable with the status quo or those who lack knowledge and understanding of the connections between the pervasive use of dangerous chemicals and the health of future generations. At one time I preached about a future scenario similar to the book and movie “Children of Men,” but that didn’t win me any converts. Now, I jokingly tell colleagues that I want to design tee shirts that say “Bugger off, don’t methylate my DNA or perturb my thyroid!” or “Halogens are not for children and other living things.” Mostly, I just breathe deep and acknowledge that I am a foot soldier to take this information to clinicians, policy makers, and patients, but as with many issues in public health this may be a long and arduous march.


Aurora Moore said ..

My husband grew up in Salinas and when his mom was pregnant with him in 1975 she a house with a well that was in the middle of all the artichoke fields. We have 11 fertilizrd.embryos waiting for us in petri dishes...IVF with ICSI at the cost of over 20K due to my husband's severe male factor infertility that is due to testicular abnormalities otherwise unexplained. It's so very sad.

March 30, 2015
Phil M said ..

Well written and compelling. Thank you for informing us with both hard-hitting facts and heartfelt stories.

May 17, 2013
tequilla said ..

"don't methylate my DNA"...I like this a lot!

March 21, 2013
pam bayer said ..

my 21yr old is having a masechtomy friday, a organic vegan since 13, runner, no history in my family, live in agricultural district upstate ny. concern about her future any suggestions. what about tamoxifen. how to check the water? i am sure this is endrocine disruptors and birth control which she did use. help, no doctors in my area that i can find who are open to discussions. rochester ny

August 16, 2011
Patty said ..

Good job, Jo! Very informative and persuasive writing! I agree with all the other comments! Keep moving forward with the fight! The tide will change! Very proud of you and what you have accomplished!

March 9, 2011
Kathleen said ..

SThis was a great article. I would also like one of your shirts.

March 7, 2011
Jane said ..

Thank you so much for doing this work and being a foot soldier.

March 4, 2011
Neil Shapiro said ..

What a wonderful piece of work. Rational and analytic, but at the same time both personal and powerful. Keep telling people things that they need to know.

March 3, 2011
Sandy Kahn said ..

Taking the difficult cards you have been dealt and turing them into an important contribution to the well being of all of us is as healing as it gets. Thank you Jo. I miss you and your wisdom at CW but am very grateful to see all you are accomplishing with your heart and mind.

March 3, 2011
Lynn Bushnell said ..

Thank you for your hard work and dedication. What can the average citizen do to stop this? I want one of your shirts.

March 2, 2011
Mary Dean Mundo said ..

Thank God for you,Joanne. Scary stuff out there. I can't wait to send this article to my friends and family.

March 2, 2011
Kirstie said ..

Damn! I'm moving.

March 1, 2011
B.Ettinger said ..

Well done!

March 1, 2011
Hideko Graves said ..

This is a great article; thank you for making it easy to understand. I am sending this to a young friend who's currently a resident at UCI with two young boys.

March 1, 2011
Esther Konigsberg said ..

Wonderful disturbing article told with your amazing wit. Thank-you for fighting the good fight!

February 28, 2011
Mary S said ..

Thanks, Jo, for enlightening us, and for working so hard to protect us.

February 28, 2011
Annemarie said ..

Great job,'s a necessary fight, and one that future generations will (also) thank you for!

February 28, 2011
Brian said ..

Jo, this is absolutely superb writing from the heart. Each of us reading these words not only becomes so much more aware of the dangers to our health but also are inspired by you to help do something about it. Kudos!

February 28, 2011
graham fowler said ..

Thank you, Joanne! You are making a difference.

February 28, 2011
Kathy said ..

More power to you, sister! You are not alone.

February 27, 2011
P.Harris-Swenson said ..

Thanks for telling your story. Too bad profit out sells the public's health. Too bad everyone doesn't remember when farmers like my father raised vegetables without man made chemicals. Organic must be subsidized not these agri-farmers who support toxic chemical companies... or is it the other way around.

February 26, 2011
Julia Baumann said ..

Thank you. Keep up the good fight.

February 25, 2011
molly arthur said ..

Dear Joanne, You are my heroine, we will learn to speak about this extraordinary, pervasive situation.

February 25, 2011

Comments closed.