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  • Writer's pictureRebecca Genuis

Organophosphate pesticides in pregnancy

Organophosphate (OP) pesticides were developed in the early 1900s as human nerve gas agents, and then went on to be developed into insecticides. Their use is widespread, with some of the most common OPs being chlorpyrifos, malathion and dichlorvos. Because of this, much research has been conducted looking at if and how these chemicals may have an impact on human health. Unfortunately, many studies have suggested that this risk is very real.

Most recently, a great review paper was published in PLoS one, a highly reputable medical journal. It examines the evidence around how these pesticides are affecting specifically children's neurodevelopment and makes recommendations for what can be done going forward.

In reviewing existing research, it found compelling evidence that these chemicals may be having an effect on brain development of the fetus in the mother's womb:.

Directly from the paper

"Outcomes associated with OP pesticide exposure to the fetus include abnormal primitive reflexes in newborns; mental and motor delays among preschoolers; and decreases in working and visual memory, processing speed, verbal comprehension, perceptual reasoning, and IQ among elementary school–age children. Prenatal exposures also elevated risks for symptoms or diagnoses of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD)."

In addition to detailing the potential harms of these chemicals, the authors go on to make some practical and much needed recommendations for reforms that could lead to the protection and maintenance of human health. PLoS one is an open access journal, so the article is available for free to anyone who wishes to read it (

Here, I will highlight one recommendation that I think is of particular importance

"[We] encourage schools of nursing and medicine to incorporate curricula on environmental hazards that include pesticides and medical boards to include environmental health in their examinations."

For me, it has been a source of some frustration that I spent so much of my time and resources attending medical school, and graduated only to realize there was an area of medicine and human health I still knew very little about. I believe it is so important that institutions that educate health care professionals begin to explore and teach material concerning how a person's physical environment can have a profound influence on their health.

This information is not only crucial in caring for the health of our patients, it is also so very hopeful. It means that we are not destined to become whatever is encoded in our genes, but that we can have a profound and meaningful influence on our health by the choices we make.

In a couples' reproductive years, it also means that they choices they make can, and indeed will, have a lasting impact on the health of their children. Preconception care is one way to examine the choices you are currently making and to seek to optimize them before conceiving a child. If you would like help with this process, feel free to contact the office to see how we can help.


Hertz-Picciotto, Irva, et al. “Organophosphate Exposures during Pregnancy and Child Neurodevelopment: Recommendations for Essential Policy Reforms.” PLOS Medicine, vol. 15, no. 10, 2018, doi:10.1371/journal.pmed.1002671.


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