Risk rises for babies conceived in spring, summer, when chemical concentrations peak
TUESDAY, March 31 (HealthDay News) -- Pesticides may increase the risk of birth defects, say researchers who found that the highest rates of birth defects in U.S. babies occur among those conceived in the spring and summer, the same time that there are increased levels of pesticides in surface water.
Researchers analyzed all 30.1 million births in the United States between 1996 and 2002. They found a strong association between higher rates of birth defects among women whose last menstrual period was in April, May, June or July and elevated levels of nitrates, atrazine and other pesticides in surface water during those same months.
The data showed a statistically significant correlation between the last menstrual period and higher rates of birth defects for half of 22 categories of birth defects, including spina bifida, cleft lip, clubfoot and Down's syndrome.
"Elevated concentrations of pesticides and other agrochemicals in surface water during April through July coincided with significantly higher risk of birth defects in live births conceived by women whose last menstrual period began in the same months," study first author Dr. Paul Winchester, professor of clinical pediatrics at the Indiana University School of Medicine, said in a school news release. "While our study didn't prove a cause and effect link, the fact that birth defects and pesticides in surface water peak during the same four months makes us suspect that the two are related," he said.
It's long been believed that these chemicals pose a threat to developing embryos, but this is the first study to make the connection between birth defects and elevated levels of pesticides at the time of conception, the authors said. The study is in the April issue of the journal Acta Paediatrica.
"Birth defects, which affect about three out of 100 newborns
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