There is inconsistent evidence regarding the effects of prenatal phthalate exposure on children's neuropsychological development. We evaluate the association between prenatal phthalate exposure and the cognitive, psychomotor and behavioral development of 367 children at repeated ages in a prospective birth cohort study. We measured phthalate metabolites (sum of four DEHP metabolites - Sigma 4DEHP, MBzP, MEP, MiBP and MnBP) in urine samples collected during the 1st and 3rd trimesters of pregnancy in women participating in the INMA-Sabadell birth cohort study. We assessed cognitive and psychomotor development of their children at 1 and 4 years, and social competence, ADHD symptoms and other behavioral problems at 4 and 7 years. No associations were observed between prenatal phthalate exposure and cognitive and psychomotor scores at the age of 1 year and at the age of 4 years, except for an association between MBzP and lower psychomotor scores (β=-1.49 [95% confidence interval (CI)=-2.78, -0.21]). Sigma 4DEHP concentrations were associated with increased social competence scores at 4 years and with reduced ADHD symptoms at age 4 and 7 years. Increasing MEP concentrations were associated with a reduced risk of inattention symptoms at 4 years. No associations were observed for MBzP, MiBP or MnBP in relation to behavioral problems. This study, with multiple phthalate exposure measurements and measures of neuropsychological domains at different ages, suggest that prenatal phthalate exposure does not adversely affect children's cognitive, psychomotor or behavioral development.
