Aug. 20, 2010 -- Exposure in the womb to pesticides known as organophosphates may increase the chance that children, especially boys, will develop attention problems by age 5, a study shows. The research is published in Environmental Health Perspectives. Researchers followed more than 300 children who took part in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study. It was designed to look at how exposure to organophosphate pesticides affects reproductive health. The researchers measured levels of the breakdown products from these pesticides in the mother's urine twice during pregnancy. Children were followed up at 3.5 years and at five years to see if they showed any symptoms of attention deficit hyperactivity disorder (ADHD). ADHD is marked by inattention, impulsivity, and hyperactivity. Children with ADHD don't do as well in school or in social situations as their peers without ADHD.

Pesticides and ADHD Risk Moms who had higher concentrations of metabolites or breakdown products of these pesticides in their urine during pregnancy were more likely to have children who showed signs of attention problems by age 5, the study showed. The risk was more pronounced in boys than girls. The children in this study lived in agricultural Salinas Valley, Calif. They had greater than average exposure to the organophosphate pesticides studied. "It is worth looking at this more carefully and conducting more research on this topic since low-level exposure to pesticides and pesticide residues in food is quite common," says study researcher Amy Marks, MPH, who was a research analyst at the University of California at Berkeley's School of Public Health when the new study was conducted. Other classes of pesticide compounds should be looked at as well, Marks says in an email. "Given the impact and prevalence of attention disorders in children (and adults), finding potential opportunities for prevention is important."