Pesticides and risk of diabetes in pregnancy

Exposure to agricultural pesticides in the first-trimester increases a woman's risk of developing diabetes during pregnancy. Previous studies have examined the relationship between pesticides and diabetes but none have focused on pregnancy-related or gestational diabetes. Researchers from the National Institute of Environmental Health Sciences, Research Triangle Park, USA, assessed the risk of developing gestational diabetes following pesticide exposures among wives of farmers. Of 11,273 women who became pregnant within 25 years after entering the study, 506 (5 percent) reported having gestational diabetes. It was found that overall, 57 percent of women reported having mixed or applied pesticides at some time in their life, and the proportion was similar for those with and without gestational diabetes mellitus. However, women who mixed or applied pesticides or repaired pesticide-related equipment during the first trimester of pregnancy had a more than two-fold increased risk of developing gestational diabetes. In contrast, there was no increased gestational diabetes risk among women with residential exposures to pesticides or indirect exposures during the first trimester. Similarly, women who had mixed or applied pesticides at any time before enrolment in the study did not face an increased risk of gestational diabetes compared with those who did not. Although, much is known about common risk factors for pregnancy-related diabetes, the understanding of whether and how environmental exposures may affect risk is still limited. Understanding any potential effect of environmental exposures on glucose (sugar) tolerance during pregnancy may have substantial public health importance beyond the direct effects on gestational diabetes.