Early Pregnancy Targeted Exposome: Biological Response and Maternal BMI

Physiological and metabolic adaptations during pregnancy may increase susceptibility to harmful environmental chemicals. High maternal BMI that perturbs the metabolic, inflammatory, and hormonal milieus could modulate toxicant effects on pregnancy outcomes. First-trimester targeted urinary exposomes of 119 women (BMI ≥ 25 = 55; BMI < 25 = 64) from the Michigan Mother–Infant Pair cohort were profiled to assess how BMI influences urinary exposomes and related biological responses. A validated approach measured 96 chemicals and biomarkers of oxidative stress and glucocorticoids. Women in both groups reported similar lifestyles and consumer product use. Women with high BMI had lower urinary concentrations of several chemicals than women with low BMI. Phytoestrogens, polycyclic aromatic hydrocarbons, and insect repellants showed a higher magnitude of positive associations with other markers of exposure, oxidative and glucocorticoid stress in the high-BMI group, while UV filters, flame retardants, and phthalates showed a higher magnitude of positive associations with oxidative stress markers in the low-BMI group. The patterns of associations of exposure markers with stress markers and pregnancy outcomes (gestational age and birthweight) differed by maternal BMI. This highlights the importance of incorporating maternal BMI into the evaluation of exposure burden and its effects, as a factor that may actively shape biological responses.