Racial and ethnic variations in phthalate metabolite concentration changes across full-term pregnancies

Higher concentrations of certain phthalate metabolites are associated with adverse reproductive and pregnancy outcomes, as well as poor infant/child health outcomes. in non-pregnant populations, phthalate metabolite concentrations vary by race/ethnicity. few studies have documented racial/ethnic differences between phthalate metabolite concentrations at multiple time points across the full-course of pregnancy. the objective of the study was to characterize the change in phthalate metabolite concentrations by race/ethnicity across multiple pregnancy time points. women were participants in a prospectively collected pregnancy cohort who delivered at term (≥37 weeks) and had available urinary phthalate metabolite concentrations for ≥3 time points across full-term pregnancies (n=350 women). we assessed urinary concentrations of eight phthalate metabolites that were log-transformed and specific gravity-adjusted. we evaluated the potential racial/ethnic differences in phthalate metabolite concentrations at baseline (median 10 weeks gestation) using anova and across pregnancy using linear mixed models to calculate the percent change and 95% confidence intervals adjusted for sociodemographic and lifestyle factors. almost 30% of the population were non-hispanic black or hispanic. with the exception of mono-(3-carboxypropyl) (mcpp) and di-ethylhexyl phthalate (dehp) metabolites, baseline levels of phthalate metabolites were significantly higher in non-whites (p<0.05). when evaluating patterns by race/ethnicity, mono-ethyl phthalate (mep) and mcpp had significant percent changes across pregnancy. mep was higher in hispanics at baseline and decreased in mid-pregnancy but increased in late pregnancy for non-hispanic blacks. mcpp was substantially higher in non-hispanic blacks at baseline but decreased later in pregnancy. across pregnancy, non-hispanic black and hispanic women had higher concentrations of certain phthalate metabolites. these differences may have implications for racial/ethnic differences in adverse pregnancy and child health outcomes.