Do Pesticides Impact Fertility, Masculinity and Miscarriages?
An Overview of Scientific Literature
In 1962, Rachel Carson’s best-seller Silent Spring warned the world that pesticides, which were (deceptively) marketed to farmers after World War II, act like toxic nerve agents and wreak havoc on our bodies, our planet and its animals (particularly bird/fish). In the U.S., entire cities (like Detroit from the air!) and groups (like children in Texas) were “sprayed” with pesticides. By 1980’s nearly all persons tested had pesticide compounds in their blood. Although Carson’s book led to the banning of DDT, and books like Toxic Legacy: How the Weedkiller Glyphosate Is Destroying Our Health and the Environment by research scientist Stephanie Seneff have shared more recent compelling evidence against pesticides, humans are using pesticides more than ever before, currently at a rate of one pound per year for each living person on the planet. Between 1990 and 2020, average pesticide usage worldwide increased by 50%1. This article reviews trusted scientific evidence from countries across the world about reproductive and neurological harms associated with pesticides.
Nerve Agents Sprayed onto Our Farms?
Synthetic petroleum-based pesticides are designed to eradicate weeds, insects and fungi that reduce crop yields in non-organic farming. Genetically-modified crops either integrate the pesticide chemistry into the cash crop seeds or ensure when they are sprayed they can resist the pesticide (glyphosate for example) and not wither or die. There are two major types of chemistries currently used as pesticides:
Organochlorine pesticides such as DDT (Dichlorodiphenyltrichloroethane), Atrazine (of Triazine class), and 2,4-D2 (2,4-dichlorophenoxyacetic acid, a component of the notorious chemical weapon called “Agent Orange”) are chemically stable and strongly lipophilic (fat loving) so their residues (not degraded or excreted from the body) tend to “bioaccumulate” in lipid-rich tissues in the body such as in the brain and our nervous system (the fatty myelin sheet covering neurons). These compounds have also received the most attention because of their persistence in the environment, because of their ability to concentrate up the food web, and their continuous detection in the food supply and drinking water. They also seem to accumulate in organisms and then can cause endocrine (hormonal) disruption at environmentally realistic exposure levels (read on to find out more about endocrine disruptors).
Organophosphorus (OP) pesticides such as glyphosate, malathion, diazinon, chlorpyrifos use phosphorous chemistry (instead of chlorine) and are used heavily as insecticides, herbicides, nerve gases (for chemical warfare, e.g., Sarin and Soman), which is also utilized in low cost flame-retardants in our textiles, furniture and electronics. Many "organophosphates" are potent nerve agents, functioning by inhibiting the action of acetylcholinesterase (AChE) in nerve cells3. The AChE enzyme helps break down acetylcholine (ACh), the important neurotransmitter with many critical roles in our nervous system such as activation of motor neurons and muscles, balancing both our sympathetic and parasympathetic nervous systems (Discussed in my other Substack articles Learn the 4 F's, 4 P's and 4 B's of Balancing Your Body and Brain Health and These 3 S's will Show Your State of Health) and regulating (in the brain) our attention, memory and motivation. So pesticides, fire retardants and certain venoms (produced by plants and animals), which result in accumulation of acetylcholine cause continuous stimulation of the muscles, glands, and central nervous system, and may lead to fatal convulsions, muscular paralysis, bronchial constriction, death by asphyxiation as well as brain disorders such as memory loss, foggy brain, Alzheimer's disease, depression, irritability, confusion and sleep disorders4.
In bees and certain other animals and insects, exposure to organophosphorus insecticides and chlorinated hydrocarbons are associated with aggressiveness, stupefaction, paralysis, and abnormal activities. The most common symptom of bee poisoning is the appearance of excessive numbers of dead bees in front of the hives. Another common symptom is lack of foraging bees. Regurgitation of the honey stomach contents is often caused by poisoning with organophosphorus insecticides. Bees may perform abnormal communication dances on the horizontal landing board at the hive entrance while under the influence of insecticide poisoning. Disorganized behavior patterns may lead to lack of recognition of affected field bees by guard bees. Exposure to organophosphates often disrupts bees’ ability to find pollen and return to the hive, leaving the colony vulnerable to developing colony collapse disorder. Foragers returning to the hive with a load of contaminated pollen or nectar can cause extreme agitation and death of other bees. Bees that interacted with organophosphates have had mortality rates up to 100%.
Organophosphate pesticides can be absorbed by all routes, including inhalation, ingestion, and dermal (skin) absorption. Their toxicity is not limited to the acute phase, however, and chronic (long-term) effects such as foggy brain have long been noted. Neurotransmitters such as acetylcholine (which is affected by organophosphate pesticides) are profoundly important in the brain's development, so many organophosphates have neurotoxic effects on developing organisms, even from low levels of exposure. Fetuses and young children, whose brain development depends on a strict sequence of biological events, may be most at risk.
In most of the studies conducted in North America, glyphosate and atrazine are the two commonly found pesticides in water bodies. Other pesticides found in less concentration are malathion, chlorpyrifos, diazinon, lindane, dieldrin and dichlorodiphenylethane (DDE).
Infertility and Birth Defects in Women
The estrogenic effects of endocrine disrupting chemicals found in pesticides have been well characterized in a number of assay systems, leading to the conclusion that many pesticides adversely affect reproductive outcomes, either by causing birth defects, increasing pregnancy complications, or by affecting fertility. Many pesticides are known to cross the human placenta, and these compounds can be found in the tissues of mothers and newborns. In a cohort of 325 women undergoing infertility treatment with assisted reproductive technology, intake of high–pesticide residue fruits and vegetables was associated with a lower probability of live birth, while low–pesticide residue fruit and vegetable intake was not associated with this outcome.
A 2023 study of 100 pregnant women living in rural and farming areas of Egypt exposed to organophosphorus (OP) pesticides showed that the gestational age at delivery, and birth weight, were significantly reduced in 60% of these women impacted by the pesticides’ reduction of the acetylcholinesterase (AChE) enzyme, which was also significantly associated with increased previous abortions (20% vs. 5% in control), congenital malformations (15% vs. 2.5% in control) and neonatal respiratory distress (26.7% vs 10.0% in control).
In Argentina, maternal residential proximity to rural fruit croplands with intense pesticide applications was associated with pregnancy complications and alterations in their newborn parameters compared to the urban populations.
In southeast Iran, a study confirmed severe oxidative stress caused by Organophosphorus Pesticides (OPPs) and Organochlorine Pesticides (OCPs) in the families of farmworkers.
In Ecuador, Cholinesterase inhibitor pesticides, especially organophosphates were linked to increased depression and anxiety, particularly among women.
Different animal models of exposure to glyphosate or glyphosate-based herbicides have shown that the effects on the female reproductive tract may be related to the potential and/or mechanisms of actions of an endocrine-disrupting compound. Studies have also demonstrated that the exposure to glyphosate-based herbicides alters the development and differentiation of ovarian follicles and uterus, affecting fertility when animals are exposed before puberty. In addition, exposure to glyphosate-based herbicides during gestation could alter the development of the offspring.
Miscarriages, Recurrent Miscarriages and Transgenerational Effects
Researchers who studied the risk of abortion/miscarriages, could not find consistent correlations with risk factors such as infections, hormonal imbalances, parity, menstrual disorders, nutritional deficiencies, psychological trauma, stress life events alcohol and caffeine intake of the mother yet they found a positive association with exposure to pesticides and smoking. There are also indications that exposure to pesticides may contribute to adverse reproductive outcomes as stated in the previous section. For example, a statistically significant association (p = 0.01) was observed between blood γ-HCH (Hexachlorocyclohexane) levels (fund in Lindane, a broad-spectrum chlorinated pesticide) and women with recurrent miscarriages. In Northern India, a study suggests that high blood levels of γ-HCH may be associated with risk of recurrent pregnancy loss.
This is of concern because exposure to these chemicals prenatally or during adult life can negatively impact the reproductive health of future generations. So the endocrine-disrupting chemicals that humans are exposed to on a daily basis will have transgenerational effects on male and female reproduction in the future.
Male Reproductive Health Problems
As we discussed in the last section, pesticides can cause transgenerational harm. For example, research confirms that a woman’s exposure to DDT increases her son's risk of testicular cancer up to 30 years later! Also, epidemiological research and animal models are increasingly linking several male reproductive health problems prevalent in Western countries, including hypospadias (abnormal opening of urethra in penis) and cryptorchidism (urogenital tract malformations), abnormalities of spermatogenesis (declining sperm counts and sperm quality), alterations to puberty, development of prostatic hyperplasia (abnormal enlargement), and gynecomastia (man breasts or inappropriate male breast growth) with exposure to estrogenic chemicals and endocrine disruptors such as those found in pesticides, plastics and additives. Such an array of reproductive abnormalities are most likely to arise from exposure to complex mixtures of chemicals rather than just pesticides.
Research has also confirmed that certain pesticides such as Vinclozolin (a fungicide) are known antiandrogenics and can affect reproduction in male rats by altering sperm function.
Gender Identification and Transgenderism
Transgender or gender dysphoria is defined in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), as distress resulting from the incongruence between one’s experienced gender and one’s assigned gender, along with a persistent and strong desire to be of another gender, and accompanied by clinically significant distress. Transsexualism involves prenatal neuroanatomical changes, has a psychiatric association, and is found to be more prevalent in conjunction with schizophrenia and autism spectrum disorders. Endocrine disruptors like those found in plastics, synthetic perfumes, and pesticides, may be the cause of high fetal testosterone exposure leading to increased risk of autism spectrum disorders as well as gender dysphoria.
Atrazine, for example, is shown to induce complete feminization and chemical castration in male African frogs. The 2010 study by Hayes et. al examined sex ratios, testosterone levels, sexual dimorphism, reproductive behaviors, and fertility in 40 100% genetically male frogs exposed to 2.5 ppb (parts per billion) atrazine throughout the larval period and for up to 3 years after metamorphosis. The study showed that 10% of the atrazine-exposed animals were chromosomal males which turned into females (lacked visible nuptial pads on the forearms and had protruding cloacal labia and ovaries typical of females) and produced viable eggs. Atrazine exposure also resulted in a significant reduction in the relative number of testicular tubules in about 45% of the tested animals. Also, among the atrazine-treated males which did not feminize, only two out-competed control (untreated natural) males in mating with females and achieving amplexus (an external mating and egg fertilization mechanism in amphibians). In addition, Atrazine-treated males (even those with relatively high sperm content) had significantly lower fertility rates (proportion of eggs fertilized) vs. control.
The results of the frog study are also consistent with other studies that examined long-term behavioral effects of atrazine in fish. Salmon exposed to atrazine (≥6 ppb) showed a dose-dependent decrease in androgens. and a significant decline in sperm production (milt), and exposed males lost the ability to respond to the attractant female pheromone.
Atrazine exposure5 is highly correlated (P < 0.009) with demasculinization of rodents and with low sperm count, poor semen quality, and impaired fertility in male humans. Unfortunately, Atrazine has been widely applied to eliminate broadleaved weeds and perennial grasses in U.S. corn fields since the early 1960s. Globally, it is popularly used on corn as well as pineapples, sugarcane and many other crops. Atrazine has been banned for use in the European Union because of its established pathology.
Other Diseases and Disorders
Because of the lipophilic (fat-loving) nature of synthetic (petroleum-based) pesticides, exposure to them affects primarily the nervous system, liver, bone marrow and the brain. Pesticide exposure has been associated by EPA to cancers of liver, prostate, kidney and blood (leukemia) and to neurological disorders in the brain such as Parkinson’s disease.
A recent study published in Nature associates long-term exposure to 53 pesticides with Parkinson’s disease as a result of toxicity to dopaminergic neurons and mitochondrial dysfunction. About one fourth of epidemiologically implicated pesticides tested in vitro resulted in substantial dopaminergic neuron cell death.
Due to their endocrine disrupting nature, many pesticides disrupt not only our reproductive system but also our thyroid and adrenal functions, leading to adverse outcomes such as unexplained obesity (weight gain), sweating, feeling too hot or too cold, mood instability, fatigue and excessive inflammation (as a result of adrenal fatigue), and unhealthy hair, skin and nails. Pesticides could also impact our gut microbiome and lead to food sensitivities, brain fog, digestive problems and allergies and auto-immune disorders.
Pesticides also adversely impact reproductive health and immune status of farm animals (sheep, cows, etc.). In Uganda, 25% of monitored wild (forest) chimpanzees which raided nearby pesticide-sprayed corn farms (with glyphosate, chlorpyrifos, 2,4-D amine and others) exhibited abnormalities including reduced nostrils, cleft lip, limb deformities, reproductive problems and hypopigmentation.
The Economics of Pesticides and Genetically-Engineered Seeds?
There is a lot of evidence that weeds and insects develop resistance over time to pesticides. Genetically-engineered (GE) seeds came onto the US agricultural scene in the late 1990s when corporate scientists engineered seeds for plants that could withstand the spraying of the herbicide glyphosate, allowing farmers to spray over growing corn while killing weeds. For about three years (1996-1999) GE seeds achieved what they promised which is increasing yield while decreasing the amount of pesticides applied. But soon that changed and glyphosate-tolerant soybeans and corns needed more weedkillers than their non-GE neighbors because weeds evolved resistance and immunity to the chemicals. For example, weeds such as horseweed in the U.S., poinsettia in Brazil and goosegrass in Malaysia have become resistant to the Glyphosate.
Other seeds were engineered (as compared to slowly and naturally evolved) to produce their own insecticide known as Bacillus thuringiensis (Bt), with the hopes of limiting insecticide spraying because the GE crops could now produce their own chemical defenses. For a while, adopters of insect-resistant engineered maize used less insecticide than nonadopters but there is evidence now that insects such as Corn rootworms have evolved resistance to one of the genes that has been deployed against them in Bt corn. This means a constant line of new products and profits for the corporations and higher costs for farmers.
Although yield in organic (non sprayed) farms can be up to 25% less than conventional (sprayed) farms (except in crops like rye, hay, alfalfa, safflower and oats that organic seem to do well), analysis of USDA survey data shows mean operating, and operating plus capital costs per acre for crop production were generally less for organic than for conventional farms. For example, total operating costs and operating plus capital costs per acre for organic corn were about $80 and $50 per acre lower, respectively, than for conventional corn. Conventional corn growers had significantly higher seed, fertilizer, and chemical costs than organic growers, but lower costs for labor, as organic systems substituted manure and field operations for fertilizers and chemicals. On the sales side, organic products often sell at 30%-100% higher prices in retail markets and stores, so as a result, organic farmers, while protecting their ecosystem and soil’s fertility, seem to have higher profit margins than conventional farmers of the same size.
So the higher yields achieved by using synthetic petroleum-based pesticides (whether sprayed or genetically integrated into engineered seeds) are both transient and costly because they lead in the long term to pesticide resistance as well as disastrous ecological, neurological and reproductive problems.
Soil and Water Health
Pesticide applications are often inefficient and associated with reduction in soil fertility and microbiome diversity. Some 30–50% of the applied pesticides may not reach their targets and end up on the soil surface. There are also concerns for the persistence of pesticides in both surface and ground waters (as documented in the book “Toxic Deception”6) and even in rainwater. There is a theory that soil particles, from agricultural areas, blown into the atmosphere by the wind, are the chief sources of vitamin B12 in rainwater. If that is true, soil particles contaminated with pesticides could also be carried to the atmosphere and collected in rainwater.
Studies have consistently reported long-term adverse effects of pesticides on the soil nitrogen cycle (fertility), and transient adverse effects on abundance, diversity or composition of soil microbial communities. In fact, pesticide residues were consistently negatively associated (harmful) with bacterial diversity but had stimulating effects on the diversity of fungi (perhaps linked to fungi’s capability to produce enzymes to biodegrade pesticides). Pesticides can affect the competition for ecological niches by giving advantages to less susceptible microbes and accelerate predator-prey and host-pathogen relationships when the prey/host was stressed by the pesticides. Besides these indirect effects and the direct toxic effects, one could also speculate that the dominance of a few pesticide-degrading bacterial groups leads to a subsequent decline in the overall bacterial diversity. Overall, pesticides seem to drastically disturb the natural microbial balance and health of the soil.
US uses about 2.5 kilogram per hectare) and application in many countries (such as Hong Kong, Israel, Oman, Ecuador, Japan, Netherlands and South Korea) exceeds 10 kilograms per hectare. Meanwhile, many African countries (except Ghana) and countries like Sweden, Romania, Finland, Norway, Russia, Iran, Pakistan and Iceland use relatively small amounts and other countries like Belgium, Tajikistan, Egypt, UK and France are drastically cutting their consumption (although still at high levels).
2,4-D was associated with decrease in thyroid gland function and kidney damage in animal studies and toxic effects on the gonads following exposure.
It has also been shown that the main active ingredient in cannabis, THC (tetrahydrocannabinol), is a competitive inhibitor of acetylcholinesterase.
On the contrary, certain antibiotics, diuretics, Botulinum toxin (Botox) and hypocalcemia (low serum calcium levels) inhibit the release of acetylcholine and act in an opposite way to Organophosphorus pesticides, which means
Although atrazine reportedly affects vertebrates through a number of mechanisms, a primary mechanism seems to be the induction, transcription and subsequent translation of aromatase leading to estrogen production, which in turn directs differentiation of the ovary from the undifferentiated gonad.
Toxic Deception: How the Chemical Industry Manipulates Science, Bends the Law and Endangers Your Health, by Dan Fagin and Marianne Lavelle