Prenatal Phenol and Phthalate Exposures and Birth Outcomes

TLDR

Phthalates and phenols are hormonally active chemicals suspected to disrupt fetal development. The study examined associations between prenatal phthalate and phenol metabolite levels and infant birth size. Urinary concentrations of 5 phenol and 10 phthalate metabolites were measured in 404 third‑trimester pregnant women, and infant birth size was recorded. Low‑molecular‑weight phthalate metabolites were higher than high‑molecular‑weight ones and positively associated with gestational age and head circumference, while 2,5‑dichlorophenol and benzophenone‑3 were linked to sex‑specific birth weight changes, but overall few exposures were associated with birth size, suggesting limited impact and possible confounding.

Abstract

Many phthalates and phenols are hormonally active and are suspected to alter the course of development.We investigated prenatal exposures to phthalate and phenol metabolites and their associations with body size measures of the infants at birth.We measured 5 phenol and 10 phthalate urinary metabolites in a multiethnic cohort of 404 women in New York City during their third trimester of pregnancy and recorded size of infants at birth.Median urinary concentrations were > 10 microg/L for 2 of 5 phenols and 6 of 10 phthalate monoester metabolites. Concentrations of low-molecular-weight phthalate monoesters (low-MWP) were approximately 5-fold greater than those of high-molecular-weight metabolites. Low-MWP metabolites had a positive association with gestational age [0.97 day gestational age per ln-biomarker; 95% confidence interval (CI), 0.07-1.9 days, multivariate adjusted] and with head circumference. Higher prenatal exposures to 2,5-dichlorophenol (2,5-DCP) predicted lower birth weight in boys (-210 g average birth weight difference between the third tertile and first tertile of 2,5-DCP; 95% CI, 71-348 g). Higher maternal benzophenone-3 (BP3) concentrations were associated with a similar decrease in birth weight among girls but with greater birth weight in boys.We observed a range of phthalate and phenol exposures during pregnancy in our population, but few were associated with birth size. The association of 2,5-DCP and BP3 with reduced or increased birth weight could be important in very early or small-size births. In addition, positive associations of urinary metabolites with some outcomes may be attributable partly to unresolved confounding with maternal anthropometric factors.