Prenatal exposure to phthalates and infant development at 6 months: prospective Mothers and Children's Environmental Health (MOCEH) study.

Background: There are increasing concerns over adverse effects of prenatal phthalate exposure on the neurodevelopment of infants.

Objectives: Our goal was to explore the association between prenatal di(2-ethylhexyl) phthalate and dibutyl phthalate exposure and the Mental and Psychomotor Developmental Indices (MDI and PDI, respectively) of the Bayley Scales of Infant Development at 6 months, as part of the Mothers and Children's Environmental Health Study.

Methods: Between 2006 and 2009, 460 mother-infant pairs from Seoul, Cheonan, and Ulsan, Korea, participated. Prenatal mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-n-butyl phthalate (MBP) were measured in one urine sample acquired from each mother during the third trimester of pregnancy. Associations with log-transformed creatinine-corrected phthalate concentrations were estimated using linear regression models adjusted for potential confounders.

Results: MDI was inversely associated with the natural log concentrations (micrograms per gram creatinine) of MEHHP [β = -0.97; confidence interval (CI), -1.85 to -0.08] and MEOHP (β = -0.95; CI, -1.87 to -0.03), and PDI was inversely associated with MEHHP (β = -1.20; CI, -2.33 to -0.08). In males, MDI was inversely associated with MEHHP (β = -1.46; CI, -2.70 to -0.22), MEOHP (β = -1.57; CI, -2.87 to -0.28), and MBP (β = -0.93; CI, -1.82 to -0.05); PDI was inversely associated with MEHHP (β = -2.36; CI, -3.94 to -0.79), MEOHP (β = -2.05; CI, -3.71 to -0.39), and MBP (β = -1.25; CI, -2.40 to -0.11). No significant linear associations were observed for females.

Conclusions: The results suggest that prenatal exposure to phthalates may be inversely associated with the MDI and PDI of infants, particularly males, at 6 months.