Effects of prenatal and infant daily exposure to pyrethroid pesticides on the language development of 2-year-old toddlers: A prospective cohort study in rural Yunnan, China.

BACKGROUND: Prenatal and infant daily exposures to pyrethroid pesticides (PYRs), used in the elimination of harmful organisms in the family environment and agricultural activities, may have an impact on children's language development. OBJECTIVES: To determine the impacts of prenatal and infant PYRs exposure on 2-year-old toddlers' language development. METHODS: From January 2016 to December 2018, women in the third trimester of pregnancy, in Yunnan rural area, China, were recruited, and the development of their newborns was observed from birth till the age of two. We examined three PYRs metabolites: 3-phenoxybenzoic acid (3PBA), 4-fluoro-3-phenoxybenzoic acid (4F3PBA), and cis-2,2dibromovinyl-2,2-dimethylcyclopropane-1-carboxylic acid (DBCA) in urine samples collected from women in the third trimester of pregnancy and their infants of 6-8 months after birth, and assessed language development of 2-year-old toddlers by the Bayley Scales of Infant and Toddler Development-Third Edition (BSID-III). Generalized linear models were used to analyze the impacts of exposure to PYRs on 2-year-old toddlers' language development. RESULTS: The median concentrations of 3PBA, 4F3PBA and DBCA creatinine-adjusted were 0.21, 0.19, and 0.15 µg/g in pregnancy, and 0.25, 0.72, and