First and second trimester concentrations of environmental phenols in association with gestational weight gain in the ECHO Cohort.

Inconsistent evidence links pregnancy concentrations of environmental phenols to altered gestational weight gain. We analyzed maternal urinary concentrations of 10 phenols in first trimester and 12 phenols in second trimester in the Environmental influences on Child Health Outcomes (ECHO) cohort study sites (n=3,960). Phenols ≥85% above the limit of detection (LOD) were modeled continuously; phenols with 55% - 85% of samples > LOD were modeled as three categories; and phenols with <55% of samples > LOD were modeled as detected/non-detected. We used generalized estimating equations models to evaluate associations between each phenol and gestational weight gain (difference between pre-pregnancy and delivery weight). Bayesian Kernel Machine Regression assessed associations of the second trimester phenol mixture with gestational weight gain. We also evaluated effect modification by pre-pregnancy body mass index (BMI). First trimester concentrations of many phenols, including bisphenol A (BPA), bisphenol S (BPS), benzophenone-3 (BP3), ∑bisphenols (∑BPA, BPS, bisphenol F), and ∑parabens (ethyl, methyl, propyl, butyl paraben) were associated with greater total gestational weight gain. For example, each doubling in ∑bisphenols and ∑parabens were associated with 0.28 (95% confidence interval (CI): 0.18, 0.39) kg and 0.45 (95%CI: 0.07, 0.83) kg greater gestational weight gain, respectively. In contrast, associations between second trimester concentrations of phenols and total gestational weight gain were generally null both for individual phenols and the phenol mixture. Associations were not consistently modified by pre-pregnancy BMI. Early pregnancy exposure to environmental phenols is associated with greater gestational weight gain. Further investigation into potential windows for endocrine disruption is warranted.