Urinary bisphenol A concentrations and association with in vitro fertilization outcomes among women from a fertility clinic.
Are urinary BPA concentrations associated with in vitro fertilization (IVF) outcomes among women attending an academic fertility center?
Urinary BPA concentrations were not associated with adverse reproductive and pregnancy outcomes among women from a fertility clinic.
Bisphenol A (BPA), an endocrine disruptor, is detected in the urine of most Americans. Although animal studies have demonstrated that BPA reduces female fertility through effects on the ovarian follicle and uterus, data from human populations are scarce and equivocal.
This prospective cohort study between 2004 and 2012 at the Massachusetts General Hospital Fertility Center included 256 women (n = 375 IVF cycles) who provided up to two urine samples prior to oocyte retrieval (total N = 673).
Study participants were women enrolled in the Environment and Reproductive Health (EARTH) Study. Intermediate and clinical end-points of IVF treatments were abstracted from electronic medical records. We used generalized linear mixed models with random intercepts to evaluate the association between urinary BPA concentrations and IVF outcomes adjusted by age, race, body mass index, smoking status and infertility diagnosis.
The specific gravity-adjusted geometric mean of BPA was 1.87 µg/l, which is comparable to that for female participants in the National Health and Nutrition Examination Survey, 2011-2012. Urinary BPA concentrations were not associated with endometrial wall thickness, peak estradiol levels, proportion of high quality embryos or fertilization rates. Furthermore, there were no associations between urinary BPA concentrations and implantation, clinical pregnancy or live birth rates per initiated cycle or per embryo transfer. Although we did not find any associations between urinary BPA concentrations and IVF outcomes, the relation between BPA and endometrial wall thickness was modified by age. Younger women (<37 years old) had thicker endometrial thickness across increasing quartiles of urinary BPA concentrations, while older women (≥37 years old) had thinner endometrial thickness across increasing quartiles of urinary BPA concentrations.
Limitations to this study include a possible misclassification of BPA exposure and difficulties in extrapolating the findings to the general population.
Data on the relation between urinary BPA concentrations and reproductive outcomes remain scarce and additional research is needed to clarify its role in human reproduction.
This work was supported by NIH grants R01ES022955, R01ES009718 and R01ES000002 from the National Institute of Environmental Health Sciences (NIEHS) and grant T32DK00770316 from the National Institute of Child Health and Human Development (NICHD). None of the authors has any conflicts of interest to declare. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
Mínguez-Alarcón L
,Gaskins AJ
,Chiu YH
,Williams PL
,Ehrlich S
,Chavarro JE
,Petrozza JC
,Ford JB
,Calafat AM
,Hauser R
,EARTH Study Team
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Urinary concentrations of bisphenol A, parabens and phthalate metabolite mixtures in relation to reproductive success among women undergoing in vitro fertilization.
We have previously investigated whether urinary concentrations of bisphenol A (BPA), parabens, and phthalate metabolites were individually associated with reproductive outcomes among women undergoing in vitro fertilization (IVF) treatment. However, humans are typically exposed to many man-made chemicals simultaneously. Thus, investigating one chemical at a time may not represent the effect of mixtures.
To investigate whether urinary concentrations of BPA, parabens, and phthalate metabolite mixtures are associated with reproductive outcomes among women undergoing IVF.
This prospective cohort study included 420 women contributing 648 IVF cycles who provided up to two urine samples per cycle prior to oocyte retrieval (N = 1145) between 2006 and 2017 at the Massachusetts General Hospital Fertility Center, and had available urine biomarker data. Urinary concentrations of BPA, parabens, and phthalate metabolites were quantified using isotope-dilution tandem mass spectrometry. Intermediate and clinical end-points of IVF treatments were abstracted from electronic medical records. Principal component analysis (PCA) and Bayesian kernel machine regression (BKMR) were used to identify main patterns of BPA, parabens, and phthalate metabolites concentrations. We used generalized linear mixed models to evaluate the association between PCA-derived factor scores, in quartiles, and IVF outcomes, using random intercepts to account for multiple IVF cycles and adjusting for known confounders. Because of temporal trends in exposure, we conducted a sensitivity analysis restricted to women who underwent IVF cycles in the earlier years of study (2006-2012).
Urinary concentrations of BPA, parabens, and most phthalate metabolites were significantly lower during the second half of the study period (2013-2017) than during the first half (2006-2012). None of the three factors derived from the PCA [di(2-ethylhexyl) phthalate (DEHP), non-DEHP, and paraben] was associated with IVF outcomes in the main analyses. Similarly, BKRM analyses did not identify any associations of individual urinary concentrations of BPA, paraben and phthalate metabolites with IVF outcomes while accounting for correlation between exposures. However, in sensitivity analyses restricted to women who underwent IVF cycles from 2006 to 2012, where concentrations of most phthalates and phenols were higher, there were decreases in implantation, clinical pregnancy, and live birth across quartiles of the DEHP factor. Specifically, women in the highest quartile of the DEHP factor had, on average, lower probabilities of implantation (-22% p, trend = 0.08), clinical pregnancy (-24% p, trend = 0.14), and live birth (-38% p, trend = 0.06) compared to women in the lowest quartile. Among this group of women, BKMR results did not identify any single contributor driving the decreased probabilities of live birth within the DEHP factor.
We confirmed that women undergoing IVF are concurrently exposed to multiple endocrine disrupting chemicals (EDCs). While we found no overall significant associations, we observed diminished pregnancy success with specific clusters of chemicals among women who underwent IVF cycles in earlier years of study, when urinary concentrations of these EDCs were higher.
Mínguez-Alarcón L
,Messerlian C
,Bellavia A
,Gaskins AJ
,Chiu YH
,Ford JB
,Azevedo AR
,Petrozza JC
,Calafat AM
,Hauser R
,Williams PL
,Earth Study Team
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Dietary folate intake and modification of the association of urinary bisphenol A concentrations with in vitro fertilization outcomes among women from a fertility clinic.
Experimental data in rodents suggest that the effects of bisphenol A (BPA) on oocyte development may be modified by dietary methyl donors. Whether the same interaction exists in humans is unknown. We evaluated whether intake of methyl donors modified the associations between urinary BPA concentrations and treatment outcomes among 178 women who underwent 248 IVF cycles at a fertility center in Boston between 2007 and 2012. Participants completed a validated food frequency questionnaire and provided up to two urine samples per treatment cycle. High urinary BPA concentrations were associated with a 66% lower probability of implantation (p=0.007) among women who consumed <400μg/day of food folate, but not among women consuming ≥400μg/day (21% higher probability of implantation, p=0.18) (p,interaction=0.04). A similar pattern was observed for probability of clinical pregnancy (p,interaction=0.07) and live birth (p,interaction=0.16). These results are consistent with previous animal data but further evaluation in other human populations is needed.
Mínguez-Alarcón L
,Gaskins AJ
,Chiu YH
,Souter I
,Williams PL
,Calafat AM
,Hauser R
,Chavarro JE
,EARTH Study team
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