Drinking chlorinated tap water puts pregnant women at a higher risk for miscarrying or bearing children with birth defects, according to a new study by two environmental organizations. The Washington, D.C.-based Environmental Working Group and U.S. Public Interest Research Group studied water quality data from thousands of water utilities before publishing their findings yesterday. Chlorine is used to disinfect polluted drinking water, but when added to some organic matter it can form compounds called trihalomethanes that are linked to cancer, miscarriages, and birth defects. The Chlorine Chemistry Council disputed the findings of the new study and reiterated the importance of chlorine in disinfecting water. But EWG’s Bill Walker disagreed: “Wouldn’t it be smarter to simply prevent the pollution of the water in the first place?”