Few studies have investigated maternal exposures during pregnancy to pesticides currently in use. Castorina et al. measured metabolites of current-use pesticides and other precursor compounds in urine samples collected twice during pregnancy from 538 California women enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort. Precursors of these metabolites included fungicides; carbamate, organochlorine, organophosphorus (OP), and pyrethroid insecticides; and triazine and chloroacetanilide herbicides. The authors also measured ethylenethiourea, a metabolite of the ethylene-bisdithiocarbamate fungicides. To understand the impact of the women