Identification of profiles and determinants of maternal pregnancy urinary biomarkers of phthalates and replacements in the Illinois Kids Development Study

Variability and Longitudinal Trajectories of Phthalate and Replacement Biomarkers across Pregnancy in the Human Placenta and Phthalates Study

“…Two recent pregnancy studies measured biomarkers of both DiNCH and DEHTP, while an additional study measured only DiNCH. These studies noted detection frequencies that were similar to what we observed in the HPP study population. ,, Across studies, LODs were generally similar though slightly higher in our laboratory analyses. For DiNCH metabolites, detection in previous studies ranged from 50 to 66% for MCOCH and 58 to 77% for MHiNCH, compared to 43 and 75% in our study, respectively.…”

“…For DiNCH metabolites, detection in previous studies ranged from 50 to 66% for MCOCH and 58 to 77% for MHiNCH, compared to 43 and 75% in our study, respectively. Both DEHTP metabolites, MEHHTP and MECPTP, were detected in 100% of samples in both studies, similar to our detection frequency. , Furthermore, biomarker concentrations in our population were generally similar to those from reproductive-aged women in a similar time period in NHANES, suggesting that exposures in our population are similar to those within the general U.S. population.…”

“…Yet, many studies examining phthalate exposure in pregnancy collect measurements from a single-spot urine sample during gestation. Some studies measure phthalate metabolites in spot urine samples from multiple trimesters, − but few have greater than 3 measures during pregnancy. , …”

“…The latter approach, which has been applied to other environmental chemicals 13 Instrumental-reading concentrations below the limit of detection (LOD) were retained and concentrations reported as 0 (i.e., absence of analytical signal) were imputed using LOD/√2. 16 Molar sums were created by summing the molar concentrations (nmol/mL) of metabolites from the same parent compound: 12,14 MEHP, MEHHP, MEOHP, and MECPP for the sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP); MCNP and MCOP for the sum of diisononyl phthalate metabolites (∑DiNP); MBP and MHBP for the sum of di-n-butyl phthalate metabolites (∑DnBP); MiBP and MHiBP for the sum of di-iso-butyl phthalate metabolites (∑DiBP); MHiNCH and MCOCH for sum of 1,2-cyclohexane dicarboxylic acid, diisononyl ester (∑DiNCH); and MEHHTP and MECPTP for the sum of di(2-ethylhexyl) terephthalate metabolites (∑DEHTP). Molar concentrations (nmol/mL) were converted to nanograms per milliliter by multiplying the sum by the molecular weights of MECPP, MCOP, MBP, MiBP, MHiNCH, and MECPTP, respectively.…”

“…Some studies measure phthalate metabolites in spot urine samples from multiple trimesters, 8−10 but few have greater than 3 measures during pregnancy. 11,12 The paucity of data on repeated measures of phthalate exposure biomarkers during gestation means that knowledge of the variability and temporal patterning of concentrations and exposure concentration profiles over this highly sensitive period is limited. To fill this gap, the Human Placenta and Phthalates (HPP) study collected urine samples at up to 8 time points across pregnancy.…”