Living near areas of pesticides use may boost foetal death due to birth defects

The study, which involved almost 700 women in 10 California counties, showed an increased risk of death among developing babies, ranging from 40% to 120% among those whose mothers lived near farms where certain pesticides were sprayed. Researchers have stressed however, that their findings suggest a hazard, but do not necessarily prove it.

Scientists compared the cases of 73 women whose pregnancies ended because of birth defects with 611 control subjects whose pregnancies ended in normal live births. “Our study showed a consistent pattern with respect to timing of exposure,” said Dr. Erin M. Bell, an epidemiologist with the National Cancer Institute. “The largest risks for foetal death due to birth defects were from pesticide exposure during the third week to the eighth week of pregnancy. The risks appeared to be strongest among pregnant women who lived in the same square mile where pesticides were used.”

Five pesticide classes were examined in the study: phosphates, pyrethroids, halogenated hydrocarbons, carbamates and endocrine disruptors. Researchers tapped information about dates, locations and amounts of chemicals applied by air or ground equipment, which was facilitated by a California law requiring that all restricted pesticide use be reported. They compared the data with detailed information about where pregnant women lived and the outcome of their pregnancies. “This is the first study, to our knowledge, of pesticides and pregnancy in which exposures were in close proximity to the subjects and the verification of pesticide use was objective, not relying on people’s memories of what they might have been exposed to,” said Dr. Irva Hertz-Picciotto, Professor of Epidemiology at UNC.

The researchers cautioned that further study is needed since they lacked certain information. “Our exposure classification method did not guarantee that a mother was in fact exposed because wind and weather conditions, hour of application and the location of the mother at the times of application were all factors that would determine actual exposure,” Bell said.