Paternal mixtures of urinary concentrations of phthalate metabolites, bisphenol A and parabens in relation to pregnancy outcomes among couples attending a fertility center

Abstract

Background: Few epidemiologic studies have evaluated the impact of paternal environmental exposures, particularly as mixtures, on couples' pregnancy outcomes.

Objective: We investigated whether mixtures of paternal urinary bisphenol A (BPA), paraben, and phthalates were associated with pregnancy outcomes among couples attending a fertility center.

Methods: We included 210 couples undergoing 300 in vitro fertilization (IVF) between 2004 and 2017 in this prospective analysis. We quantified paternal urinary biomarker concentrations in one sample per cycle using isotope-dilution tandem mass spectrometry. We used principal component analysis (PCA) to identify correlations of biomarker concentrations and multivariable Cox proportional hazards models for discrete survival time to estimate the hazard ratios (HRs) and 95% CIs for the associations between PCA-derived factor scores and probability of failing to achieve a live birth. Interactions were also included in the models to examine strength of associations over three vulnerable periods [embryo transfer to implantation, implantation to clinical pregnancy, and clinical pregnancy to live birth]. Models were adjusted for paternal and maternal ages and body mass indexes, urinary dilution (specific gravity) and year of collection, infertility diagnosis, and other PCA factor scores. Sensitivity analyses with further adjustment for maternal PCA factor scores were performed.

Results: We identified three factors, representing di-2-ethylhexyl phthalate (DEHP) metabolites, BPA and non-DEHP metabolites, and parabens, accounting for 56%, 15% and 10%, respectively, of the total variance explained. An interquartile range (25th and 75th percentiles) increase in the DEHP-related factor score was associated with elevated probability of failing prior to live birth (HR = 1.41, 95% CI: 1.08, 1.81) and the association was stronger between implantation and clinical pregnancy as well as between clinical pregnancy and live birth compared to before implantation. The overall HRs of failure for the BPA/non-DEHP-related and paraben-related factor scores were HR = 1.24 (95% CI: 0.97, 1.59) and HR = 0.99 (95% CI: 0.80, 1.24). We found similar HRs when additionally adjusting for maternal PCA factor scores.

Conclusion: Paternal mixtures of urinary concentrations of DEHP metabolites were related to higher infertility treatment failure.

Keywords: Bisphenol A; Parabens; Paternal chemical mixtures; Phthalates; Pregnancy outcomes; Survival analysis.

Figure 1.. Adjusted^a hazard ratios (95% CI) for cycle failure by PCA-derived factor scores from paternal urinary phenols and phthalate metabolite concentrations among 210 couples contributing 300 fresh IVF cycles in the EARTH Study.

^aModels were adjusted for parental age and body mass index, year of urine collection, urine dilution, infertility diagnosis, and scores of the other two factors.