Prenatal exposure to halogenated, aryl, and alkyl organophosphate esters and child neurodevelopment at two years of age

Neurotoxicity of organophosphate esters (OPEs) has been reported in toxicological studies, but epidemiological findings are limited. We aimed to assess the associations between prenatal OPE exposures and children's neurodevelopment at 2 years old. We measured urinary concentrations of OPEs collected in the first and third trimester from 184 pregnant women in Wuhan, China. Childhood neurodevelopment was assessed using the Chinese revision of Bayley Scale of Infant Development. A two-fold increase in the average of bis (1,3-dichloro-2propyl) phosphate (BDCIPP) was associated with 3.50 decrease in Psychomotor Development Index (PDI) score (95%CI:-5.86,-1.14) and 5.75 decrease in Mental Development Index (MDI) score (95%CI:-8.94,-2.55). Average of the molar concentrations of chlorinated-alkyl OPEs (sigma Cl-OPEs) during pregnancy was inversely associated with PDI i beta =-3.24 (95%CI:-5.95,-0.53)] and MDI scores i beta =-5.86 (95%CI:-9.52,-2.20)]. Prenatal concentrations of BDCIPP and sigma Cl-OPEs were inversely associated with neurodevelopment scores in boys, but not in girls. Our study provides evidence that elevated prenatal exposure to chlorinated-alkyl OPEs especially BDCIPP might be inversely associated with childhood neurodevelopment, and the effect seems to be sex-specific.