Concern is mounting that a family of chemicals, called phthalates, may pose human health risks based on numerous animal studies and a limited number of observational studies in humans. There have been no studies to investigate the relationship between phthalates and neurodevelopment. The Mount Sinai Children's Environmental Health Center undertook an investigation of maternal prenatal phthalate exposure on pregnancy outcome and child neurodevelopment in an inner-city multiethnic cohort between 1998 and 2002.
The majority of participants were Black or Latina women aged 25 years or younger who were unmarried at the time of enrollment and had a relatively low educational attainment. Severely preterm births were excluded by design; therefore, most delivered term babies (92.9%) of normal birthweight (97.8%). The Brazelton Neonatal Behavioral Assessment Scale was administered before hospital discharge (n = 311). All babies were evaluated by 5 days of age, the majority by day 2. Maternal third trimester urine samples were analyzed by the Centers for Disease Control and Prevention (CDC) for ten phthalate metabolites. Metabolites were summed into three groups: di(2-ethylhexyl) (DEHP) metabolites, monoester metabolites of high (>250 dalton) (high-MWP) and low (<250 dalton) (low-MWP) molecular weight. Groups were chosen to represent similar molecular structure, biological activity, and sources of exposure.
In multivariate adjusted generalized linear models, third trimester log-DEHP was associated with poorer neonatal orientation (beta = −0.20, 95%CI −0.40, −0.01), and log high-MWP was associated with poorer regulation of state (beta = −0.21, 95%CI −0.39, −0.04). There was a significant interaction among infant gender, log low-MWP, and the infant motor domain, such that increasing log low-MWP was associated with better motor performance among boys, but worse motor performance among girls (interaction P-value = 0.04). Infant gender, log high-MWP and orientation interacted such that increasing log high-MWP was associated with significantly worse orientation among girls (beta = −0.45, P = 0.01), with no effect among boys (interaction P-value 0.02).
These data suggest that third trimester maternal phthalate metabolite urinary concentrations may be predictive of measures of neonatal behavior as measured shortly after delivery, and may indicate the importance of phthalates in human neurodevelopment. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.