Scientists report disturbing reproductive health trends around the world, and research shows that pesticides are at least partly to blame.
The American Congress of Obstetricians and Gynecologists points to a growing body of scientific evidence linking chemicals to many reproductive health harms. Research is particularly strong linking pesticide exposure to reduced sperm count and quality, early puberty in girls, birth defects, miscarriage and stillbirth.
One group of chemicals — endocrine disruptors — are particularly prone to interfere with reproductive health, even when exposure levels are extremely low.
Timing of exposure is key
An infant in the womb is particularly vulnerable to endocrine-disrupting chemicals, as hormones are busy regulating the differentiation of cells and development of organs.
Infants exposed to the wrong chemical just when the reproductive organs are forming can experience harm that plays out over the course of a lifetime. Scientists from the Endocrine Society explain why the timing of exposure is so important:
In those cases in which disruption is directed toward programming of a function, e.g., reproductive health, this may interfere with early life organization, followed by a latent period, after which the function becomes activated and the dysfunction can become obvious.
Exposure to chemicals when an infant’s reproductive system is developing can thus derail the process, though the impacts may not be seen until years later when problems arise during puberty or when trying to conceive.
Pesticides: Clear evidence of harm
Scientists now understand that exposure to pesticides can cause a wide range of reproductive harms. Here are just a few of the many studies linking pesticide exposure to reproductive and developmental harms:
- In 2015, scientists at Harvard found that men who ate food with more pesticide residue had lower sperm count and fewer normal sperm.
- Exposure to the herbicide atrazine has been linked to menstrual disorders, low-birth weight babies and birth defects.
- A 2013 study linked legacy pesticides, including the organochlorine insecticide lindane, to increased risk of endometriosis in women.
Pesticides determined by the state of California to cause reproductive and developmental harm (e.g., birth defects, infertility, sterility and impairment of normal growth and development) are included on the “Prop 65” list of chemicals maintained by state agencies under the Safe Drinking Water and Toxic Enforcement Act.
Under the national Toxic Release Inventory program, U.S. EPA maintains a list of chemicals produced in the U.S. that are “toxic to humans or damaging to the environment,” including those that cause reproductive or developmental harms. More than half of the 750 chemicals on the current TRI list are pesticides.*
For those interested in diving deeper, the Collaborative on Health and the Environment maintains a database of scientific evidence linking chemicals to human health harms, including reproductive damage among both men and women, as well as miscarriage rates, premature birth, and more. Our partners at Beyond Pesticides also maintain a list of recent studies examining pesticide impacts on reproductive health.
* Note that the absence of a pesticide on the Prop 65 or TRI list does not necessarily mean it is not a reproductive or developmental toxicant. It may simply mean that it has not yet been evaluated.