Persistent Effects of Maternal Prenatal Exposure to Phthalates on Child IQ at Age 7 Years

Background Prior research reports inverse associations between maternal prenatal urinary phthalate metabolite concentrations and mental and motor development in inner-city preschoolers. No study evaluated whether these associations persist into school age. Methods In a follow up study of n=328 inner-city mothers and their children, we measured metabolites of di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBzP), di-isobutyl phthalate (DiBP), di-2-ethylhexyl phthalate and diethyl phthalate in maternal prenatal urine. At child age 7 years, we administered the Wechsler Intelligence Scale for Children, 4th edition (WISC-IV), which measures four areas of cognitive function associated with overall intelligence quotient (IQ). Results Child full-scale IQ was inversely associated with prenatal urinary metabolite concentrations of DnBP and DiBP: b=-2.69 (95% confidence interval [CI] -4.33 to -1.05) and b= -2.69 (95% CI -4.22 to -1.16), respectively, for each log unit increase. Among children whose mothers had t...