A new study has raised serious concerns about a pesticide that has been widely used around the world for decades.
Researchers found that children exposed to chlorpyrifos before birth showed lasting changes in brain development and had more difficulty with movement-related tasks years later.
The research was published in JAMA Neurology and is being described as one of the strongest pieces of evidence yet linking prenatal pesticide exposure to long-term brain changes in children and teenagers.
Chlorpyrifos is an insecticide used to kill bugs that damage crops. For many years it was also commonly sprayed inside homes and buildings. Scientists have long questioned whether the chemical is safe for developing babies because it belongs to a group of pesticides known to affect the nervous system.
In 2001, the U.S. Environmental Protection Agency stopped allowing chlorpyrifos to be used indoors in homes because of concerns about children’s health. However, the pesticide has continued to be used in agriculture on crops such as fruits, vegetables, and grains.
Because of this ongoing agricultural use, many people may still encounter chlorpyrifos through food, dust, air, or nearby farm spraying. Pregnant women living near agricultural areas may face especially high exposure.
The new study involved researchers from Columbia University, Children’s Hospital Los Angeles, and the Keck School of Medicine of USC.
Scientists tracked 270 children and adolescents who were enrolled in a long-running health study called the Columbia Center for Children’s Environmental Health birth cohort.
All of the participants were born to African-American and Latino mothers and had detectable levels of chlorpyrifos in their umbilical cord blood at birth. This showed that exposure had occurred before birth while the babies were still developing in the womb.
When the children reached ages between 6 and 14 years old, researchers evaluated them using behavioral testing and advanced brain scans.
The scientists discovered that higher prenatal exposure to chlorpyrifos was linked to widespread changes in brain structure, brain function, and brain metabolism.
Children with higher exposure levels also performed worse on tests involving motor speed and motor programming. These abilities are important for movement coordination, planning physical actions, and carrying out tasks smoothly.
One important feature of the study was that the effects followed a dose-response pattern. In general, children with greater exposure levels showed more severe brain changes and poorer performance.
This kind of pattern often strengthens scientific evidence because it suggests the effects become larger as exposure increases.
The researchers said the brain disturbances appeared surprisingly widespread rather than limited to one small region. The findings suggest that chlorpyrifos may interfere with multiple biological systems involved in healthy brain development.
The human brain develops rapidly during pregnancy and early childhood. During this time, nerve cells form connections that support memory, learning, emotions, movement, language, and attention. Scientists say this period is especially vulnerable because toxic chemicals may interfere with delicate developmental processes.
Researchers have previously linked pesticide exposure to attention problems, developmental delays, reduced IQ, learning difficulties, and behavioral changes. However, the new study is particularly important because it directly examined brain imaging changes alongside behavioral outcomes.
Senior author Dr. Virginia Rauh from Columbia University warned that current exposure levels may still be putting some pregnant women and children at risk, especially in farming communities.
She emphasized the importance of monitoring exposure among vulnerable populations, including farm workers and families living near agricultural areas.
Dr. Bradley Peterson from the Keck School of Medicine of USC said the broad disturbances observed in brain tissue and metabolism were especially concerning. He also warned that other organophosphate pesticides may produce similar effects.
Scientists say the findings highlight the importance of protecting pregnant women and young children from potentially harmful chemicals whenever possible.
Experts often recommend washing produce carefully, reducing exposure to pesticide spraying, improving environmental protections, and strengthening public health policies aimed at protecting children’s development.
The study also reflects a larger scientific concern about how environmental toxins may affect children’s long-term health. Researchers increasingly believe that even low levels of exposure during pregnancy may sometimes influence development in ways that are not immediately visible at birth.
At the same time, the researchers acknowledged limitations in the study. Because the research was observational, it cannot fully prove that chlorpyrifos directly caused all the brain changes. Other environmental, social, nutritional, or health-related factors may also contribute.
In addition, the participants came from a specific population group, so the results may not apply equally to all communities around the world.
Still, many experts believe the findings are highly significant because the study followed children for many years and used advanced brain imaging techniques. The clear relationship between higher exposure and greater effects also strengthens confidence in the results.
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Source: Columbia University Mailman School of Public Health.
