• Posted August 20, 2025

Pesticide Linked To Impaired Brain Development Among Kids

Exposure to a common pesticide during pregnancy can impair children’s brain development and motor function for years to come, a new study says.

The widely used pesticide chlorpyrifos (CPF) is linked to altered brain function and poorer fine motor control among children exposed to it while in the womb, researchers report in JAMA Neurology.

“The disturbances in brain tissue and metabolism that we observed with prenatal exposure to this one pesticide were remarkably widespread throughout the brain,” lead researcher Dr. Bradley Peterson said in a news release. He’s chief of child and adolescent psychiatry at the University of Southern California’s Keck School of Medicine.

For the study, researchers conducted behavioral assessments and MRI scans of 270 kids in upper Manhattan whose mothers had been exposed to CPF during pregnancy when their apartments were fumigated.

These assessments occurred between 1998 and mid-2005. The U.S. Environmental Protection Agency banned CPF for residential use in 2001, but it’s still used as an agricultural pesticide for non-organic fruits, vegetables and grains such as apples, strawberries, asparagus, tart cherries, citrus and peaches, researchers noted.

CPF is an organophosphate pesticide, in the same chemical family as nerve gas, researchers note. The chemical can cross the placenta to the fetus, and easily traverse the fetal blood-brain barrier.

CPF has been used to control cockroaches, fleas and termites, and has been an active ingredient in some flea and tick collars for pets, according to the Agency for Toxic Substances and Disease Registry.

The MRI scans revealed that the children had specific changes in their brain’s cortex, white matter, network pathways and nerve insulation, all of which could impair development, motor control and brain function.

Further, progressively higher exposure to CPF was significantly associated with increasingly greater alterations in brain structure and function, as well as poorer motor function, researchers said.

“More CPF exposure led to more thickening of the cerebral cortex — the area of the brain that directs functions like thinking, memory and movement,” Peterson said. “We don't know the consequences of these brain effects, but we found that CPF exposure most impairs motor functioning.”

The data strongly suggest that CPF exposure affects the way that neurons develop, Peterson said.

“That happens early in pregnancy, when neurons develop in the cortex and differentiate into cortical gray matter — densely packed nerve cells which process information — and underlying white matter — which is mostly nerve fibers that connect neurons,” Peterson said.

“All these abnormalities can contribute to poor motor function in these kids,” he continued. “The contributing mechanisms seem to be the inflammation and oxidative stress that CPF and other pesticides produce.”

Results also showed that children exposed to CPF had dramatically reduced blood flow to the brain.

“To me, this is the most profound finding because it's so powerful and very rare to see something like this,” Peterson said. “Blood flow is an important indicator of underlying metabolism — the energy used by brain tissue. In my opinion, it’s maybe the most important finding of the paper, because it says that globally there’s a problem with brain metabolism in direct proportion to how much CPF exposure they had.”

Toxic exposure to CPF continues to be a risk during pregnancy, either through the food supply or from outdoor air and dust near farmland, researchers said.

“Current widespread exposures, at levels comparable to those experienced in this sample, continue to place farm workers, pregnant women and unborn children in harm’s way,” senior researcher Virginia Rauh said in a news release. She’s a professor of population and family health at Columbia University Mailman School of Public Health in New York City.

“It is vitally important that we continue to monitor the levels of exposure in potentially vulnerable populations, especially in pregnant women in agricultural communities, as their infants continue to be at risk,” Rauh added.

Peterson said pregnant women also should be wary of potential exposure through produce.

“It’s in our food supply,” he said. “And other chemicals used in the home act in similar ways and almost certainly increase inflammation and oxidative stress. This is why it is important to do these studies about the chemicals in our environment to protect children’s health.”

More information

The U.S. Environmental Protection Agency has more about chlorpyrifos.

SOURCES: Columbia University, news release, Aug. 18, 2025; Children’s Hospital Los Angeles, news release, Aug. 18, 2025; JAMA Neurology, Aug. 18, 2025