Background

Emerging evidence suggests that increased exposure to environmental toxins during pregnancy is associated with an increased risk of hypertensive disorders of pregnancy (HDP). Exposure to toxins is ubiquitous, and a better understanding of its effects on pregnancy health outcomes is needed. We evaluated the environmental determinants of preterm HDP in a prospective cohort of Black women in Philadelphia.

Methods

In a subset of 68 participants enrolled in a prospective cohort of Black pregnant women, we measured plasma environmental chemicals collected between 16- and 24-weeks’ gestation via untargeted metabolomics. Cases of preterm HDP included women with gestational hypertension or preeclampsia who delivered before 37 weeks’ gestation, while controls included those who delivered at term (≥ 37 weeks’ gestation) without medical or obstetric comorbidities. Cases and controls (n=19 cases and 49 controls) were frequency matched by pre-pregnancy obesity (body mass index ≥30kg/m2), parity, insurance, education, and fetal sex. The association between log₂-transformed individual’s chemicals (n=32), dichotomized around the median (low/high), and HDP risk was assessed using logistic regression, while Weighted Quantile Sum regression (constrained in the positive direction) assessed the mixture effect, adjusted for the covariates.

Results

Higher exposure to 2-(phenyl methylene) octanal and carbofuran during pregnancy was associated with over 3-fold increase in the odds of HDP (OR: 3.28; 95%CI: 1.04- 10.27, and OR: 3.63, 95%CI: 1.06, 12.39, respectively). However, several environmental toxicants were significantly associated with a decreased risk of HDP. The mixture of chemicals was not significantly associated with the risk of HDP.

Conclusion

Our findings indicate a possible association between higher exposure to some environmental toxicants during pregnancy and increased risk of HDP in Black women. Larger prospective analyses are needed to strengthen this association.