Children exposed to chlorpyrifos-an insecticide, while in their mother's womb, show significant reduction in mental and motor development by three years of age and also have a higher risk for behavior problems. This observation was made in a peer-reviewed study conducted by Academy of Pediatrics.

Chlorpyrifos, which was banned for residential use in 2001, is still widely applied to agricultural crops in the U.S. and abroad, including many fruits and vegetables.

The study assessed development of approximately 250 inner-city children from New York City who were born between 1998 and 2002. By age three, the children with the highest levels of chlorpyrifos at birth (upper 20th percentile) had significantly worse mental development and poorer motor skills than children with lower exposure levels. The more highly exposed children were also more likely by age three to exhibit early indications of behavior and attention problems. The study was co-authored by researchers from the Columbia Center for Children's Environmental Health at Columbia University's Mailman School of Public Health, and from the Centers for Disease Control and Prevention.

"These findings indicate that prenatal exposure to the insecticide chlorpyrifos not only increases the likelihood of developmental delay, but may have long-term consequences for social adjustment and academic achievement" said lead author and investigator on the study, Virginia Rauh, ScD. "Relatively speaking, the insecticide effects reported here are comparable to what has been seen with exposures to other neurotoxicants such as lead and tobacco smoke."

The study is part of a broader multi-year research project started in 1998, which examines the health effects of exposure of pregnant women and babies to indoor and outdoor air pollutants, pesticides, and allergens. Prior research findings have shown that prenatal chlorpyrifos exposure can reduce birth weight and length. The research has also shown that the residential ban on chlorpyrifos use by the U.S. Environmental Protection Agency has been effective at reducing blood levels of the insecticide.

"Our findings have important public health significance," said Robin Whyatt, DrPH, senior author on the study. "Prior to the ban, chlorpyrifos was one of the most widely used insecticides for residential pest control across the United States. Despite a recent regulatory ban on residential use of chlorpyrifos in the U.S., agricultural applications continue in the U.S. and abroad."

Frederica Perera, DrPH, director of the Columbia Center for Children's Environmental Health noted that, "By identifying environmental exposures that adversely effect fetal development and also affect children's ability to learn, the research provides new opportunities for prevention. However, protection of children's health and development would be best served by thorough testing of chemicals before they are marketed."

The investigators controlled for other exposures that might have contributed to developmental problems such as socioeconomic factors and exposure to tobacco smoke, lead, and other environmental contaminants.