Association of Phenols, Parabens, and Their Mixture with Maternal Blood Pressure Measurements in the PROTECT Cohort

Abstract

Background: Phenols and parabens are two classes of high production volume chemicals that are used widely in consumer and personal care products and have been associated with reproductive harm and pregnancy complications, such as preeclampsia and gestational diabetes. However, studies examining their influence on maternal blood pressure and gestational hypertension are limited.

Objectives: We investigated associations between individual phenols, parabens, and their mixture on maternal blood pressure measurements, including systolic and diastolic blood pressure (SBP and DBP) and hypertension during pregnancy (defined as stage 1 or 2 hypertension), among $N=\mathrm{1,433}$ Puerto Rico PROTECT study participants.

Methods: We examined these relationships cross-sectionally at two time points during pregnancy (16-20 and 24-28 wks gestation) and longitudinally using linear mixed models (LMMs). Finally, we used quantile g-computation to examine the mixture effect on continuous (SBP, DBP) and binary (hypertension during pregnancy) blood pressure outcomes.

Results: We observed a trend of higher odds of hypertension during pregnancy with exposure to multiple analytes and the overall mixture [including bisphenol A (BPA), bisphenol S (BPS), triclocarbon (TCC), triclosan (TCS), benzophenone-3 (BP-3), 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), methyl paraben (M-PB), propyl paraben (P-PB), butyl paraben (B-PB), and ethyl paraben (E-PB)], especially at 24-28 wk gestation, with an adjusted mixture $\text{odds ratio}\left(\text{OR}\right)=1.57$ (95% CI: 1.03, 2.38). Lower SBP and higher DBP were also associated with individual analytes, with results from LMMs most consistent for methyl paraben (M-PB) or propyl paraben (P-PB) and increased DBP across pregnancy [adjusted M-PB $\beta =0.78$ (95% CI: 0.17, 1.38) and adjusted P-PB $\beta =0.85$ (95% CI: 0.19, 1.51)] and for BPA, which was associated with decreased SBP (adjusted $\beta =-0.57$; 95% CI: $-1.09$, $-0.05$). Consistent with other literature, we also found evidence of effect modification by fetal sex, with a strong inverse association observed between the overall exposure mixture and SBP at visit 1 among participants carrying female fetuses only.

Conclusions: Our findings indicate that phenol and paraben exposure may collectively increase the risk of stage 1 or 2 hypertension during pregnancy, which has important implications for fetal and maternal health. https://doi.org/10.1289/EHP14008.

Figure 1.

Adjusted $\mathrm{\beta }$ coefficients [mmHg change in systolic blood pressure (SBP) or diastolic blood pressure (DBP) per interquartile range increase in log-transformed exposure], ORs (referent group: no hypertension), and 95% CIs for the association of each analyte and their mixture with BP measurements at visits 1 and 3. *$p<0.05$. Multivariable models adjusted for maternal age, prepregnancy BMI, and maternal education. $N$ complete cases: $\text{visit\hspace{0.17em}}1\left(\mathrm{V}1\right)=\mathrm{1,037}$; $\text{visit\hspace{0.17em}}3\left(\mathrm{V}3\right)=752$. Linear and logistic regression used for point estimates in single pollutant models. Quantile g-computation used for mixture analyses. Results correspond to data in Table S2. Note: 2,4-DCP, 2,4-dichlorophenol; 2,5-DCP, 2,5-dichlorophenol; BMI, body mass index; BP-3, benzophenone-3; BPA, bisphenol A; BPS, bisphenol S; CI, confidence interval; M-PB, methyl paraben; OR, odds ratio; P-PB, butyl paraben; TCC, triclocarbon; TCS, triclosan.