If you're pregnant (or trying to become so), step away from the bug spray. Recently three separate studies have linked pesticide exposure during pregnancy to diminished IQ in the children born.
The April 21, 2011, issue of the peer-reviewed journal Environmental Health Perspectives (EHP) featured the results of investigations that were conducted independently at the University of California, Berkeley, School of Public Health; the Mailman School of Public Health at Columbia University; and Mount Sinai School of Medicine. The studies found that prenatal exposure to organophosphate (OP) pesticides--found in numerous insecticides and DCT -resulted in IQ deficits in school-age children.
Each of the studies enrolled pregnant women. The Berkeley and Mount Sinai investigators measured OP pesticide in the pregnant women's urine, while the Columbia investigators measured its levels in umbilical cord blood. Intelligence tests were administered to the children of these mothers between ages 6 and 9 years at Mount Sinai and at age 7 years at Berkeley and Columbia.
While these studies cannot be directly compared to each other because of their subtle differences, it is worth noting that all three found evidence that there are adverse effects related to prenatal OP exposure on the cognitive function of children. "It is well known that findings from individual epidemiologic studies may be influenced by chance and other sources of error. This is why researchers often recommend their results be interpreted with caution until they are supported by similar findings in other study populations," said EHP Editor-in-Chief Hugh A. Tilson in a prepared statement. "As a group, these papers add substantial weight to the evidence linking OP pesticides with adverse effects on cognitive development by simultaneously reporting consistent findings for three different groups of children."
For a listing of natural alternatives to pesticide, see this guide from the Sonoma Environmental Research Institute.