Bisphenol A and Human Reproductive Health

BPA Exposure Affects Mouse Gastruloids Axial Elongation by Perturbing the Wnt/β-Catenin Pathway

Mammalian embryos are very vulnerable to environmental toxicants (ETs) exposure. Bisphenol A (BPA), one of the most diffused ETs, exerts endocrine-disrupting effects through estro-gen-mimicking and hormone-like properties, with detrimental health effects, including on reproduction. However, its impact during the peri-implantation stages is still unclear. This study, using gastruloids as a 3D stem cell-based in vitro model of embryonic development, showed that BPA exposure arrests their axial elongation when present during the Wnt/β-catenin pathway activation period by β-catenin protein reduction. Gastruloid reshaping might have been impeded by the downregulation of Snail, Slug and Twist, known to suppress E-cadherin expression and to activate the N-cadherin gene, and by the low expression of the N-cadherin protein. Also, the lack of gastruloids elongation might be related to altered exit of BPA-exposed cells from the pluripotency condition and their following differentiation. In conclusion, here we show that the inhibition of gastruloids' axial elongation by BPA might be the result of the concomitant Wnt/β-catenin perturbation, reduced N-cadherin expression and Oct4, T/Bra and Cdx2 altered patter expression, which all together concur in the impaired development of mouse gastruloids.

The Correlation of Urine Bisphenol A with Semen Parameters in Men Referred to Infertility Centers: A Cross-Sectional Study

BACKGROUND

Bisphenol A (BPA) is known as an endocrine disruptor that has harmful effects on general health. It is commonly used in various industrial products. In this study we tried to evaluate the amount of BPA in urine samples of the men referred to an infertility center.

MATERIALS AND METHODS

The cross-sectional study population consisted of male partners of infertile couples, who were referred to infertility clinic in Mazandaran, a northern state of Iran. Questionnaires included demographic characteristics, medical history, lifestyle factors, physical examinations. A semen sample and a spot urine sample were taken from each participant. In the initial study group of 240 men, 3 groups were excluded, and 122 men remained for the analysis. Highperformance liquid chromatography (HPLC) was applied to measure the amount of BPA in the urine samples.

RESULTS

BPA was not detected in about half of the samples (53.3%). Multiple linear regression analysis showed that no significant relationship existed between the urine concentrations of BPA, semen parameters and male reproductive hormones. However, in a comparison with semen parameters in people with detectable urine BPA versus nondetectable ones, an inverse association was noticed with sperm concentration. In other parameters, differences were not significant. Smoking had no effects on sperm parameters, but body mass index (BMI) ≥25 reduced the percentage of normal sperm parameters.

CONCLUSION

In most participants, urinary BPA was not detected. Probably in this study low environmental exposure to BPA is the cause of lower urine BPA concentrations compared to other industrially developed countries. Therefore, no overall relationship was observed between BPA level and male infertility.

Combined Toxic Effects of BPA and Its Two Analogues BPAP and BPC in a 3D HepG2 Cell Model

Bisphenol A (BPA) is one of the most commonly used substances in the manufacture of various everyday products. Growing concerns about its hazardous properties, including endocrine disruption and genotoxicity, have led to its gradual replacement by presumably safer analogues in manufacturing plastics. The widespread use of BPA and, more recently, its analogues has increased their residues in the environment. However, our knowledge of their toxicological profiles is limited and their combined effects are unknown. In the present study, we investigated the toxic effects caused by single bisphenols and by the combined exposure of BPA and its two analogues, BPAP and BPC, after short (24-h) and prolonged (96-h) exposure in HepG2 spheroids. The results showed that BPA did not reduce cell viability in HepG2 spheroids after 24-h exposure. In contrast, BPAP and BPC affected cell viability in HepG2 spheroids. Both binary mixtures (BPA/BPAP and BPA/BPC) decreased cell viability in a dose-dependent manner, but the significant difference was only observed for the combination of BPA/BPC (both at 40 µM). After 96-h exposure, none of the BPs studied affected cell viability in HepG2 spheroids. Only the combination of BPA/BPAP decreased cell viability in a dose-dependent manner that was significant for the combination of 4 µM BPA and 4 µM BPAP. None of the BPs and their binary mixtures studied affected the surface area and growth of spheroids as measured by planimetry. In addition, all BPs and their binary mixtures studied triggered oxidative stress, as measured by the production of reactive oxygen species and malondialdehyde, at both exposure times. Overall, the results suggest that it is important to study the effects of BPs as single compounds. It is even more important to study the effects of combined exposures, as the combined effects may differ from those induced by single compounds.

Adverse (geno)toxic effects of bisphenol A and its analogues in hepatic 3D cell model

Bisphenol A (BPA) is one of the most widely used and versatile chemical compounds in polymer additives and epoxy resins for manufacturing a range of products for human applications. It is known as endocrine disruptor, however, there is growing evidence that it is genotoxic. Because of its adverse effects, the European Union has restricted its use to protect human health and the environment. As a result, the industry has begun developing BPA analogues, but there are not yet sufficient toxicity data to claim that they are safe. We investigated the adverse toxic effects of BPA and its analogues (BPS, BPAP, BPAF, BPFL, and BPC) with emphasis on their cytotoxic and genotoxic activities after short (24-h) and prolonged (96-h) exposure in in vitro hepatic three-dimensional cell model developed from HepG2 cells. The results showed that BPFL and BPC (formed by an additional ring system) were the most cytotoxic analogues that affected cell viability, spheroid surface area and morphology, cell proliferation, and apoptotic cell death. BPA, BPAP, and BPAF induced DNA double-strand break formation (γH2AX assay), whereas BPAF and BPC increased the percentage of p-H3-positive cells, indicating their aneugenic activity. All BPs induced DNA single-strand break formation (comet assay), with BPAP (≥0.1 μM) being the most effective and BPA and BPC the least effective (≥1 μM) under conditions applied. The results indicate that not all of the analogues studied are safer alternatives to BPA and thus more in-depth research is urgently needed to adequately evaluate the risks of BPA analogues and assess their safety for humans.

Association of urinary bisphenol A concentrations with in vitro fertilisation outcomes: a systematic review and meta-analysis protocol

INTRODUCTION

Bisphenol A (BPA) is a common environmental endocrine disruptor. BPA has been reported to be associated with female infertility, which may not only affect natural pregnancy and natural fertility but also affect the outcomes of in vitro fertilisation (IVF). BPA exposure may help to partly explain the unsatisfactory IVF outcomes, but the relationship between the concentrations of BPA in urine and IVF outcomes remains controversial. Therefore, we will perform a meta-analysis to identify and review the relationship between urinary BPA concentrations and IVF outcomes.

METHODS AND ANALYSIS

A comprehensive literature search will be performed in PubMed, Web of Science and the Cochrane central register of controlled trials for relevant articles using MeSH terms and related entry terms (up to 20 April 2022). The language will be restricted to English. Articles will be screened for inclusion in or exclusion from the study independently by two reviewers after removing the duplicates. The titles and abstracts followed by full-text screening will also be conducted independently by two reviewers. In addition, the references of the included literature will also be traced to supplement our search results and to obtain all relevant literature. The Newcastle-Ottawa Scale will be used to assess the methodological quality of the included studies using a star rating system ranging from 0 to 9 stars. Heterogeneity in estimates from different articles will be quantified, and publication bias will be investigated using funnel plots. Finally, a sensitivity analysis will also be conducted to estimate whether our results could have been markedly affected by a single included study.

ETHICS AND DISSEMINATION

Ethical approval is not required for this protocol, as participants are not included. Findings will be disseminated through peer-reviewed publications and conference presentations.

Starch-Based Hydrogel Nanoparticles Loaded with Polyphenolic Compounds of Moringa Oleifera Leaf Extract Have Hepatoprotective Activity in Bisphenol A-Induced Animal Models

Bisphenol A (BPA) is an xenoestrogenic chemical used extensively in the fabrication of baby bottles, reusable plastic water bottles and polycarbonate plastic containers. The current study aims to investigate the hepatoprotective activity of Moringa oleifera Lam leaf extract (MOLE) and hydrogel NPs made of starch-MOLE-Bovine Serum Albumin (BSA) against Bisphenol A-induced liver toxicity in male rats. Fabrication and characterization of hydrogel NPs formed of starch-MOLE-BSA were investigated using FTIR, TEM, zeta potential, UV-visible spectroscopy and fluorescence spectrophotometer. The potential efficacy of hydrogel NPs was studied. Compared to the results of control, the level of liver function, oxidative stress markers and lipid profile status were remodulated in the groups treated with MOLE and hydrogel NPs (Encap. MOLE). Meanwhile, the administration of MOLE and Encap MOLE significantly increased antioxidant activity and decreased the level of apoptotic pathways. Heme oxygenase (HO)-1 and growth arrest -DNA damage-inducible gene 45b (Gadd45b) were also regulated in the groups treated with MOLE and Encap. MOLE compared to the group which received BPA alone. In the present study, MOLE and hydrogel NPs led to remarkable alterations in histological changes during BPA administration. Overall, MOLE has a potential antioxidant activity which can be used in the treatment of liver disorders.

Determination of bisphenols and parabens in cow urine distillate from India: implication of human exposure and risk assessment

The exposures of a wide range of endocrine-disrupting chemicals to cows have been linked to diseases and are a major concern. In Indian scripts, cow urine is believed to be a treatment for many diseases. Nonetheless, exposure of bisphenols and parabens to cow urine distillates is unknown. Hence, in this study, we determined the concentration of bisphenols and parabens in commercially available cow urine distillate collected from India. The mean concentration of total bisphenols and parabens ranges from the limit of quantification (LOQ) to 149.3 ng/mL and 1479.88 ng/mL, respectively. Predominant bisphenol-F and bisphenol-A were accounted for 88.6% and 6% of total bisphenol concentration, respectively, in marketed cow urine distillate, whereas methyl and propyl parabens were dominant and accounted for 33% and 65%, respectively. The estimated mean daily intake (EDI) of bisphenol for males and females were 45.94 ng/kg-bw/day and 54.29 ng/kg-bw/day, respectively, while for parabens EDI was 455.35ng/kg-bw/day and 538.14 ng/kg-bw/day for males and females, respectively. Hazard quotient, to evaluate the potential risk of exposure, showed no risk in the studied samples. Even though the EDI results from the Monte-Carlo risk assessment analysis did not exceed the acceptable daily intake, their estrogenic actions cannot be ignored in general populations. The estrogenic activities contributed by parabens and bisphenol A measured by estradiol equivalency quotient (EEQ) ranged from 0.00033-42 pg/mL and 2.3 pg/mL, respectively. Our results revealed higher concentrations of bisphenols and parabens in cow urine distillates; hence, special attention should be given to the quality and safety of cow urine distillates. Moreover, strict guidelines should be enforced for the quality of cow urine distillates.

Environmental endocrine disruptor concentrations in urine samples from Mexican Indigenous women

The Indigenous communities in Mexico show significant degrees of vulnerability to pollution due to the lack of knowledge of health risks, traditions, low levels of support, and restricted access to healthcare. As a result, exposure to environmental endocrine disruptors increases in these populations through plastic components or indoor air pollution. Therefore, the aim of the study was to evaluate the exposure to phthalate metabolites, 1-hydroxypyrene, and bisphenol A through biomonitoring data from indigenous Mexican women. A total of 45 women from the Tocoy community in San Luis Potosí, Mexico, were included. Urine samples were analyzed for Bisphenol A and 4 phthalate metabolites by ultra-performance liquid chromatography couples to tandem mass spectrometry; additionally, the 1-hydroxypyrene concentrations were evaluated by high-performance liquid chromatography coupled to a fluorescence detector. Among the main pollution sources were the use of plastic containers and burning garbage (98-100%). Indigenous women presented an exposure of 100% to mono-2-ethyl phthalate, mono-n-butyl phthalate, and 1-hydroxypyrene, with a median (25th-75th percentiles) of 17,478 (11,362-37,355), 113.8 (61.7-203.5), and 1.2 (0.9-1.7) µg/g creatinine, respectively. The major findings show urinary mono-2-ethyl phthalate concentrations higher than those measured from other studies. Therefore, these results show an impressive exposure to di(2-ethylhexyl) phthalate in Indigenous women. The current study reflects the absence of regulatory policies in marginalized populations. It highlights the need to design strategies that mitigate exposure and the importance of biological monitoring to evaluate and prevent health risk associated with exposure to environmental endocrine disruptors.

Enhanced photo-fenton and photoelectrochemical activities in nitrogen doped brownmillerite KBiFe2O5

Visible-light-driven photo-fenton-like catalytic activity and photoelectrochemical (PEC) performance of nitrogen-doped brownmillerite KBiFe₂O₅ (KBFO) are investigated. The effective optical bandgap of KBFO reduces from 1.67 to 1.60 eV post N-doping, enabling both enhancement of visible light absorption and photoactivity. The photo-fenton activity of KBFO and N-doped KBFO samples were analysed by degrading effluents like Methylene Blue (MB), Bisphenol-A (BPA) and antibiotics such as Norfloxacin (NOX) and Doxycycline (DOX). 20 mmol of Nitrogen-doped KBFO (20N-KBFO) exhibits enhanced catalytic activity while degrading MB. 20N-KBFO sample is further tested for degradation of Bisphenol-A and antibiotics in the presence of H₂O₂ and chelating agent L-cysteine. Under optimum conditions, MB, BPA, and NOX, and DOX are degraded by 99.5% (0.042 min^-1), 83% (0.016 min^-1), 72% (0.011 min^-1) and 95% (0.026 min^-1) of its initial concentration respectively. Photocurrent density of 20N-KBFO improves to 8.83 mA/cm² from 4.31 mA/cm² for pure KBFO. Photocatalytic and photoelectrochemical (PEC) properties of N-doped KBFO make it a promising candidate for energy and environmental applications.

Comparison of daily bisphenol A intake based on dietary and urinary levels in breastfeeding women

Bisphenol A (BPA) is an artificial chemical, and one of the significant external routes of daily BPA exposure is diet. Dietary BPA exposure can be calculated by urinary BPA concentration and dietary recall data. This cross-sectional study investigates exclusively breastfeeding women's BPA exposure by urinary total BPA concentration and nutritional records, including the 24 h Dietary Recall (HDR) and Food Frequency Questionnaire (FFQ). In this study, we included exclusively breastfeeding, healthy women volunteers (n = 80; 18-40 years), collected spot-morning urine samples and conducted a comprehensive face-to-face survey. Moreover, the women's urine BPA concentration was adjusted according to their urine creatinine concentrations. We assessed dietary BPA intake with the 24HDR and FFQ. Estimated daily BPA exposure according to urinary output volume and urinary creatinine concentration median values were 0.0507 and 0.06 μg/kg bw/day, respectively. Moreover, dietary BPA daily intake was found to be 0.17 and 0.95 μg/kg bw/day according to 24HDR data and FFQ data. The milk and dairy product group's and soft drinks group's contributions to the daily intake of BPA were 55.9 % and 25.92 %, respectively. The hazard ratio for BPA exposure was within limits according to references, including US EPA, Health Canada, and EFSA. This study indicates that BPA exposure, based on both total urinary BPA concentration and dietary recall data, was within the recommended daily intake level (4 μg/kg bw/day). However, further studies are required to understand the influence of seasonal, multicentre, and socioeconomic differences on BPA exposure.

Counteracting Environmental Chemicals with Coenzyme Q10: An Educational Primer for Use with "Antioxidant CoQ10 Restores Fertility by Rescuing Bisphenol A-Induced Oxidative DNA Damage in the Caenorhabditis elegans Germline"

Environmental toxicants are chemicals that negatively affect human health. Although there are numerous ways to limit exposure, the ubiquitous nature of certain environmental toxicants makes it impossible to avoid them entirely. Consequently, scientists are continuously working toward developing strategies for combating their harmful effects. Using the nematode Caenorhabditis elegans, a model with many genetic and physiological similarities to humans, researchers in the Colaiácovo laboratory have identified several molecular mechanisms by which the toxic agent bisphenol A (BPA) interferes with reproduction. Here, we address their recent discovery that a widely available compound, Coenzyme Q10 (CoQ10), can rescue BPA-induced damage. This work is significant in that it poses a low-cost method for improving reproductive success in humans. The goal of this primer is to assist educators and students with navigating the paper entitled "Antioxidant CoQ10 Restores Fertility by Rescuing Bisphenol A-Induced Oxidative DNA Damage in the Caenorhabditis elegans Germline." It is ideally suited for integration into an upper-level undergraduate course such as Genetics, Cell and Molecular Biology, Developmental Biology, or Toxicology. The primer provides background information on the history of BPA, the utility of the C. elegans germ line as a model for studying reproductive toxicity, and research methods including assessment of programmed cell death, fluorescent microscopy applications, and assays to quantify gene expression. Questions for deeper exploration in-class or online are provided.Related article in GENETICS: Hornos Carneiro MF, Shin N, Karthikraj R, Barbosa F Jr, Kannan K, Colaiácovo MP. Antioxidant CoQ10 restores fertility by rescuing bisphenol A-induced oxidative DNA damage in the Caenorhabditis elegans Germline. Genetics 214:381-395.

Effects of bisphenol S and bisphenol F on human spermatozoa: An in vitro study

Bisphenol A (BPA), the main chemical monomer of epoxy resins and polycarbonate plastics, has generated concerns about its endocrine disruptor properties, along with the reported possible links with several human health disorders. Accordingly, some restrictions on its use have been recommended. Bisphenol S (BPS) and bisphenol F (BPF) are the main replacements to BPA, with which they share homologies in chemical structure. However, to date, little is known about their possible adverse effects for human reproduction. As the in vitro exposure of human spermatozoa to BPA induces oxidative/pro-apoptotic effects, the aim of the present study was to verify whether BPS and BPF could represent safer compounds for human sperm functions. The exposure of motile sperm suspensions to scalar concentrations of BPS or BPF for 4 h did not significantly reduce sperm motility (as assessed by computer-aided semen analysis) and viability. At flow cytometry, no changes in mitochondrial membrane potential, or mitochondrial generation of reactive oxygen species were detected by using the JC-1 and MitoSOX red probes, respectively. Interestingly, it nor even the combination of both BPS and BPF at the highest concentrations impaired sperm mitochondrial functions. In conclusion, BPS and BPF seem to be safer alternatives to BPA for sperm biology, as they do not affect mitochondrial functions, sperm motility and viability. These findings could help regulatory agencies to identify more secure chemicals to replace BPA in industrial production of plastics.

Clinical use and implications of sexual devices and sexually explicit media

Given that sexual pleasure is a core component of sexual health, devices that are designed to enhance and diversify sexual pleasure are particularly useful in clinical practice. Despite their growing popularity and widespread use in various biopsychosocial circumstances, many taboos still seem to exist, as indicated by the paucity of scientific literature on the prevalence, application and effectiveness of sexual devices for therapeutic use. However, sex toys and sexual devices are commonly used and have a variety of indications to expand individual and partnered sexuality and to treat sexual difficulties. Different devices are associated with specific advantages and potential risks, opportunities, barriers and ethical challenges when used in a clinical context. Increased knowledge about the aim and functional possibilities of sexual devices might help health-care professionals overcome potential embarrassment, preconceptions and other barriers, learn which patients might benefit from which products, consider their use in treatment programmes, educate about correct use and safety issues, and facilitate open communication about sexual pleasure with their patients.

Detrimental Effects of Bisphenol Compounds on Physiology and Reproduction in Fish: A Literature Review

Bisphenol-A is one of the most studied endocrine-chemicals, which is widely used all over the world in plastic manufacture. Because of its extensive use, it has become one of the most abundant chemical environmental pollutants, especially in aquatic environments. BPA is known to affect fish reproduction via estrogen receptors but many studies advocate that BPA affects almost all aspects of fish physiology. The possible modes of action include genomic, as well as and non-genomic mechanisms, estrogen, androgen, and thyroid receptor-mediated effects. Due to the high detrimental effects of BPA, various analogs of BPA are being used as alternatives. Recent evidence suggests that the analogs of BPA have similar modes of action, with accompanying effects on fish physiology and reproduction. In this review, a detailed comparison of effects produced by BPA and analogs and their mode of action is discussed.

Road impact in a protected area with rich biodiversity: the case of the Sebitoli road in Kibale National Park, Uganda

While road network expansion is crucial for economic development, it can cause a notable disturbance of fauna, especially in protected area in terms of habitat fragmentation, risk of collision, and also indirect threat such as pollution. In this study, we monitored the 4.6-km long tarmac road crossing the Kibale National Park in Uganda, home to a rich variety of wild species including the endangered chimpanzees. We evaluated the effects of collisions and pollution, as well as the impact of the renovation process in terms of disturbance and the mitigation measures deployed. This survey reports the death of 24 wild animals killed by cars, including two chimpanzees. The atmospheric concentrations of O₃, NO₂, SO₂, and BTEX did not exceed recommended limits. More than 5000 plastic bottles were collected along the road within 4 months, and for the first time, the presence of BPA and BPS was detected in the hairs of wild chimpanzees. The road bisecting the Kibale National Park poses a high danger in terms of traffic and an underestimated risk related to plastic pollution. Measures (signpost, speed bumps) should be urgently deployed to decrease the risk posed by the renovated road for emblematic species such as chimpanzees, which are crucial for tourism and economy in Uganda.

Effects of Bisphenol A on expression of genes related to amino acid transporters, insulin- like growth factor, aquaporin and amino acid release by porcine trophectoderm cells

The peri-implantation period of pregnancy is critical for conceptus development, implantation, and signaling for establishment of pregnancy. This study evaluated the effects of bisphenol A (BPA) on proliferation, adhesion, and migration of porcine trophectoderm (pTr2) cells, expression of transporters of arginine and synthesis of amino acids. All concentrations of BPA decreased proliferation and adhesion of pTr2 cells after 96 h compared to the control group. Lower concentrations of BPA (1 × 10^-9, 1 × 10^-8, 10^-7M) increased (P < 0.05), but higher concentrations of BPA (1 × 10^-5, 1 × 10^-4 M) decreased migration of pTr2 cells. BPA increased expression of SLC7A1 mRNA at lower concentrations (1 × 10^-9 to 1 × 10^-6M) and SL7A6, another cationic acid transporter, at higher concentrations (1 × 10^-5, 1 × 10^-4 M). BPA also down-regulated the expression of IGF1 and IGF1 receptor at concentrations of 1 × 10^-7 to 1 × 10^-4 M compared to the control group. The expression of mRNAs for aquaporins (AQP) 3 and 4 were reduced at all concentrations of BPA, but at lower concentrations of BPA, (1 × 10^-9 to 1 × 10^-8M) expression of AQP9 mRNA increased and the expression of AQP11 was not affected by BPA (P > 0.05). There was an inhibitory effect of BPA on the release of synthesis of asparagine, threonine, taurine, tryptophan, and ornithine into the culture medium by pTr2 cells. Collectively, BPA adversely affected the expression of transporters for cationic amino acids like arginine, as well as AQPs, IGF1, and IGF1R associated with proliferation, migration, and adhesion of pTr2 cells. Those adverse effects would likely increase pregnancy losses during the peri-implantation period of pregnancy.

Zinc deficient diet increases the toxicity of bisphenol A in rat testis

Zinc (Zn) plays an important role in maintaining the process of spermatogenesis and reproductive health. Bisphenol A (BPA), an endocrine disrupting chemical is known to be a reproductive toxicant in different animal models. The present study was designed to study the effect of two of the utmost determinative factors (Zn deficient condition and influence of toxicant BPA) on germ cell growth and overall male reproductive health in the testis, epididymis, and sperm using (a) biochemical, (b) antioxidant, (c) cellular damage, (d) apoptosis, and (e) protein expression measurements. Rats were divided into Control (normal feed and water), BPA (100 mg/kg/d), zinc deficient diet (ZDD; fed with ZDD), and BPA + ZDD for 8 weeks. Body and organ weights, sperm motility and counts, and sperm head morphology were evaluated. The histology of testes, epididymides, and prostate was investigated. Testicular deoxyribonucleic acid (DNA) damage was evaluated by Halo and Comet assay, apoptosis of sperm and testes were quantified by TUNEL assay. Serum protein electrophoretic patterns and testicular protein expressions such as Nrf-2, catalase, PCNA, and Keap1 were analyzed by Western blot analysis. The results showed that BPA significantly increased the testicular, epididymal, and prostrate toxicity in dietary Zn deficient condition due to testicular hypozincemia, hypogonadism, increased cellular and DNA damage, apoptosis, as well as perturbations in protein expression.

Bisphenols and Male Reproductive Health: From Toxicological Models to Therapeutic Hypotheses

Bisphenols, and in particular bisphenol A (BPA), have been widely used for the production of plastic manufacts in the last 50 years. Currently, BPA is present in a variety of daily use polycarbonate plastics and epoxy resins, and dietary ingestion is considered the main route of human exposure. Accordingly, BPA is the chemical pollutant with the widest exposure in humans, involving nearly 90% of general population, according to recent studies. Concerns about BPA effects on human health date back to 1930s, when severe impact on male sexual development was suggested. Now, the acknowledged biological effects of BPA are various. In regard to human fertility, BPA has been shown to disrupt hormone signaling even at low concentrations. Results from human epidemiological studies have reported BPA interference with follicle stimulating hormone, inhibin B, estradiol, testosterone levels, and sexual function in male subjects. Moreover, recent studies have reported an association between BPA levels and reduced sperm concentration, motility, normal morphology, sperm DNA damage, and altered epigenetic pattern, resulting in trans-generational legacy of BPA effects. In this review, the recognized effects of BPA on male reproductive health are described, from the most recent issues on experimental models to epidemiological data. In addition, the very recent interest about the use of nutraceutical remedies to counteract BPA effects are discussed.

An Evaluation of the Relationship among Urine, Air, and Hand Measures of Exposure to Bisphenol A (BPA) in US Manufacturing Workers

Background

Exposure to bisphenol A (BPA) can be assessed using external and internal exposure measures. We examined the relationship between two measures of external BPA exposure (air and hand-wipe samples) and one of internal exposure (total BPA in urine) for a group of US manufacturing workers.

Methods

During 2013-2014, we recruited 78 workers from six US companies that made BPA or made products with BPA. We quantified BPA in seven urine samples, two full-shift air samples and in pre- and end-shift hand-wipe samples collected from workers over 2 consecutive days. We examined correlations between creatinine-corrected urinary concentrations of total BPA (total BPACR) and BPA levels in air and hand wipes using Pearson's correlation coefficient. We also applied mixed-effects regression models to examine the relationship between total BPACR with BPA in air (urine~air model) and with BPA in end-shift hand wipes (urine~hand model), separately and together (urine~air+hand model), after adjusting for covariates.

Results

End-shift total BPACR strongly correlated with BPA in air (rp = 0.79, P < 0.0001) and nearly as strongly with BPA in end-shift hand wipes (rp = 0.75, P < 0.0001). In mixed-effect models, BPA air concentration and end-shift hand-wipe BPA level were significantly and positively associated with end-shift total BPACR (P < 0.0001 each). We found a significant effect of the Day 1 BPA air concentration on Day 2 total BPACR (P = 0.0104). When BPA air concentration and end-shift hand-wipe BPA level were in the same model, the air concentration (P < 0.0001) was more significant than the hand-wipe level (P = 0.0106).

Conclusion

BPA levels in air and end-shift hand wipes strongly correlated with total BPACR, suggesting that both inhalation and dermal contract were likely exposure routes; however, inhalation, on average, appeared to be a more dominant exposure route than dermal contact for these manufacturing workers.

Male exposure to bisphenol A (BPA) and semen quality in the Home Observation of Periconceptional Exposures (HOPE) cohort

BACKGROUND

Exposure to bis-phenol A (BPA) has been associated with reduced semen quality. The objective of this study was to examine associations between BPA measured in serial daily first-morning urine samples and semen quality parameters among men trying to conceive.

METHODS

This prospective, preconception cohort included 161 men ages 18-40 without known subfertility. Men collected daily, first morning urine during their female partner's fertile window. Semen samples were collected through intercourse after the fertile window.

RESULTS

Samples from 161 men were analyzed. Higher geometric mean (GM) BPA exposures (ng/mL) were found among men with abnormal sperm tail morphology (GM = 3.12, 95% CI = 2.43, 4.01) compared to men with normal morphologic findings (GM = 2.39, 95% CI = 2.17, 2.74). There was no association with sperm count.

CONCLUSION

Higher exposure to BPA was associated with abnormal sperm tail morphology in this prospective, pre-conception cohort.

Application of the Draft NIOSH Occupational Exposure Banding Process to Bisphenol A: A case study

Bisphenol A is a commercially important chemical used to make polycarbonate plastic, epoxy resins, and other specialty products. Despite an extensive body of in vitro, animal and human observational studies on the effects of exposure to bisphenol A, no authoritative bodies in the U.S. have adopted or recommended occupational exposure limits for bisphenol A. In 2017, the National Institute for Occupational Safety and Health published a Draft process for assigning health-protective occupational exposure bands, i.e., an airborne concentration range, to chemicals lacking an occupational exposure limit. Occupational exposure banding is a systematic process that uses both quantitative and qualitative toxicity information on selected health effect endpoints to assign an occupational exposure band for a chemical. The Draft process proposes three methodological tiers of increasing complexity for assigning an occupational exposure band. We applied Tier 1 (based on the Globally Harmonized System of Classification and Labelling) and Tier 2 (based on authoritative sources/reviews) to assign an occupational exposure band to bisphenol A. Under both Tier 1 and 2, the occupational exposure band for bisphenol A was "E" (<0.01 mg/m³), an assignment based on eye damage. "E" is the lowest exposure concentration range, reserved for chemicals with high potential toxicity. If eye damage was excluded in assigning an air concentration exposure range, then bisphenol A would band as "D" (>0.01 to 0.1 mg/m³) under Tier 1 (based on reproductive toxicity and respiratory/skin sensitization) and under Tier 2 (based on specific target organ toxicity-repeated exposure). In summary, Tiers 1 and 2 gave the same occupational exposure band for bisphenol A when eye damage was included ("E") or excluded ("D") as an endpoint.

Aqueous extract of Eruca Sativa protects human spermatozoa from mitochondrial failure due to bisphenol A exposure

Medicinal plants are suggested to counteract health disorders from chemical pollutants. Here we explored the possible ameliorative effect of Eruca sativa aqueous extract (ESAE) on in vitro acute functional disturbance induced by Bisphenol A (BPA), a disruptor model in human spermatozoa. Phytochemical screening, high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) analysis and 2,2'-azino-bis [3-ethylbenzthiazoline-6-sulphonic acid]/α,α-diphenyl-β-picrylhydrazyl (ABTS/DPPH) tests disclosed antioxidant properties of ESAE, ascribed to polyphenols and flavonoids. The toxicological impact of BPA on sperm viability and motility was detected for concentration greater than 10 μM but co-incubation with ESAE recovered sperm function at low concentration (15.62 μg/ml). BPA reduced mitochondrial membrane potential (ΔΨm), with no impact on plasma membrane potential (ΔΨp). At low doses, ESAE recovered ΔΨm but higher doses were associated with impairment of both ΔΨm and ΔΨp. ESAE protects towards in vitro BPA-mediated toxicity and its possible use as complementary treatment for male reproductive disorders is critically discussed.

Urinary Bisphenol A Levels and Male Fertility

Bisphenol A (BPA) is a high-production volume industrial chemical found in many consumer products. BPA is a suspected potent endocrine disruptor, with endocrine-disrupting properties demonstrated in animal studies. Few human studies have examined bisphenol A exposure in relation to male fertility and, results are divergent. The aim of the study is to examine the associations between urinary BPA concentration and male fertility. Bisphenol A urinary concentrations were measured using gas chromatography coupled with tandem mass spectrometry in 315 men under 45 years of age with normal sperm concentration (⩾15 mln/ml) recruited from a male reproductive health clinic. Participants were interviewed and provided a semen sample. BPA was detected in 98.10% of urine samples, with a median concentration of 1.87 µg/l (1.63 µg/ g creatinine). A multiple linear regression analysis identified a positive association between the urinary concentrations of bisphenol A 25th–50th percentile and total sperm sex chromosome disomy (p = .004). Also when modeled as continuous variable urinary BPA concentration increased total sperm sex chromosome disomy (p = .01). Urinary concentration of BPA also increase the percentage of immature sperm (HDS) (p = .018) and decrease motility (p = .03). The study provides evidence that exposure to BPA is associated with poorer semen quality. Future studies are needed to confirm these findings.

Food Additives and Child Health

Increasing scientific evidence suggests potential adverse effects on children's health from synthetic chemicals used as food additives, both those deliberately added to food during processing (direct) and those used in materials that may contaminate food as part of packaging or manufacturing (indirect). Concern regarding food additives has increased in the past 2 decades in part because of studies that increasingly document endocrine disruption and other adverse health effects. In some cases, exposure to these chemicals is disproportionate among minority and low-income populations. This report focuses on those food additives with the strongest scientific evidence for concern. Further research is needed to study effects of exposure over various points in the life course, and toxicity testing must be advanced to be able to better identify health concerns prior to widespread population exposure. The accompanying policy statement describes approaches policy makers and pediatricians can take to prevent the disease and disability that are increasingly being identified in relation to chemicals used as food additives, among other uses.

Association of Bisphenol A Exposure with Breastfeeding and Perceived Insufficient Milk Supply in Mexican Women

Introduction Estrogen inhibits lactation and bisphenol A (BPA) is a high production environmental estrogen. We hypothesize an inhibitory effect of BPA on lactation and aim to analyze the association between third trimester pregnancy urinary BPA and breastfeeding rates 1 month postpartum. Methods Odds ratios (OR) and 95 % confidence intervals (95 % CI) of breastfeeding and perceived insufficient milk supply (PIM) in relation to maternal peripartum urinary BPA concentrations were calculated in 216 mothers. Results 97.2 % of mothers in the lowest BPA tertile were breastfeeding at 1 month postpartum, compared to 89.9 % in highest (p = 0.01). Adjusted ORs (95 % CI) for not breastfeeding at 1 month were 1.9 (0.3, 10.7) and 4.3 (0.8, 21.6) for second and third BPA tertiles, respectively, compared to the lowest (p = 0.06, trend). 4.2 % reported PIM in the lowest BPA tertile, compared to 8.7 % in the highest (p = 0.03). Adjusted ORs (95 % CI) for PIM were 1.8 (0.4, 7.7) and 2.2 (0.5, 9.5), for the second and third BPA tertiles, respectively, compared to the lowest (p = 0.29, trend). Discussion These results suggest an association between maternal BPA exposure and decreased breastfeeding.

Environmental Contaminants Affecting Fertility and Somatic Health

This review article summarizes the epidemiological findings published between 2011 and 2016 concerning bisphenol A (BPA), phthalates, dioxins, pesticides, air pollution, fracking chemicals, triclosan, and parabens and fertility parameters in men (i.e., semen volume, sperm concentration, sperm motility, and sperm morphology) as well as fertility parameters in women (i.e., cyclicity, fertility treatment outcomes), pregnancy outcomes (i.e., preterm birth, miscarriage), and reproductive disorders (i.e., polycystic ovary syndrome, endometriosis, and uterine fibroids). Overall, this review indicates that several environmental toxicants are significantly associated with reduced fertility parameters in men and women as well as several reproductive disorders in women. Although many studies reported that the selected exposures are associated with adverse fertility outcomes, several studies reported null associations. Thus, future studies are still needed to better elucidate the associations and potential mechanisms between these environmental chemicals and fertility outcomes in men and women.

Genome-wide alteration in DNA hydroxymethylation in the sperm from bisphenol A-exposed men

Environmental BPA exposure has been shown to impact human sperm concentration and motility, as well as rodent spermatogenesis. However, it is unclear whether BPA exposure is associated with alteration in DNA hydroxymethylation, a marker for epigenetic modification, in human sperm. A genome-wide DNA hydroxymethylation study was performed using sperm samples of men who were occupationally exposed to BPA. Compared with controls who had no occupational BPA exposure, the total levels of 5-hydroxymethylcytosine (5hmc) increased significantly (19.37% increase) in BPA-exposed men, with 72.69% of genome regions harboring 5hmc. A total of 9,610 differential 5hmc regions (DhMRs) were revealed in BPA-exposed men relative to controls, which were mainly located in intergenic and intron regions. These DhMRs were composed of 8,670 hyper-hMRs and 940 hypo-hMRs, affecting 2,008 genes and the repetitive elements. The hyper-hMRs affected genes were enriched in pathways associated with nervous system, development, cardiovascular diseases and signal transduction. Additionally, enrichment of 5hmc was observed in the promoters of eight maternally expressed imprinted genes in BPA-exposed sperm. Some of the BPA-affected genes, for example, MLH1, CHD2, SPATA12 and SPATA20 might participate in the response to DNA damage in germ cells caused by BPA. Our analysis showed that enrichment of 5hmc both in promoters and gene bodies is higher in the genes whose expression has been detected in human sperm than those whose expression is absent. Importantly, we observed that BPA exposure affected the 5hmc level in 11.4% of these genes expressed in sperm, and in 6.85% of the sperm genome. Finally, we also observed that BPA exposure tends to change the 5hmc enrichment in the genes which was previously reported to be distributed with the trimethylated Histone 3 (H3K27me3, H3K4me2 or H3K4me3) in sperm. Thus, these results suggest that BPA exposure likely interferes with gene expression via affecting DNA hydroxymethylation in a way partially dependent on trimethylation of H3 in human spermatogenesis. Our current study reveals a new mechanism by which BPA exposure reduces human sperm quality.

Urinary Bisphenol A (BPA) Concentrations among Workers in Industries that Manufacture and Use BPA in the USA

Background

Bisphenol A (BPA) toxicity and exposure risk to humans has been the subject of considerable scientific debate; however, published occupational exposure data for BPA are limited.

Methods

In 2013-2014, 77 workers at six US companies making BPA, BPA-based resins, or BPA-filled wax provided seven urine samples over two consecutive work days (151 worker-days, 525 samples). Participant information included industry, job, tasks, personal protective equipment used, hygiene behaviors, and canned food/beverage consumption. Total (free plus conjugated) BPA, quantified in urine by mass spectrometry, was detected in all samples.

Results

The geometric mean (GM) creatinine-adjusted total BPA (total BPACR) concentration was 88.0 µg g-1 (range 0.78-18900 µg g-1), ~70 times higher than in US adults in 2013-2014 (1.27 µg g-1). GM total BPACR increased during Day 1 (26.6-127 µg g-1), decreased by pre-shift Day 2 (84.4 µg g-1) then increased during Day 2 to 178 µg g-1. By industry, baseline and post-baseline total BPACR was highest in BPA-filled wax manufacturing/reclaim (GM = 111 µg g-1) and lowest in phenolic resin manufacturing (GM = 6.56 µg g-1). By job, total BPACR was highest at baseline in maintenance workers (GM = 157 µg g-1) and post-baseline in those working with molten BPA-filled wax (GM = 441 µg g-1). Workers in the job of flaking a BPA-based resin had the lowest concentrations at baseline (GM = 4.81 µg g-1) and post-baseline (GM = 23.2 µg g-1). In multiple regression models, at baseline, industry significantly predicted increased total BPACR (P = 0.0248); post-baseline, handling BPA containers (P = 0.0035), taking ≥3 process/bulk samples with BPA (P = 0.0002) and wearing a Tyvek® coverall (P = 0.0042) significantly predicted increased total BPACR (after adjusting for total BPACR at baseline, time point, and body mass index).

Conclusion

Several work-related factors, including industry, job, and certain tasks performed, were associated with increased urinary total BPACR concentrations in this group of manufacturing workers. The potential for BPA-related health effects among these workers is unknown.

Prenatal bisphenol a exposure leads to reproductive hazards on male offspring via the Akt/mTOR and mitochondrial apoptosis pathways

BACKGROUND

Bisphenol A (BPA) exposure is ubiquitous, and in laboratory animals and humans, exposure has been associated with male spermatogenesis dysfunction. However, it is largely unknown if this association has a fetal origin.

OBJECTIVE

The aim of this research is to explore the mechanism whereby prenatal BPA exposure exerts its reproductive toxicities on spermatogenesis in male offspring.

METHODS

We fed pregnant SD rats BPA at doses ranging from 1 to 100 mg/kg body weight during gestation days 14-21. The male offspring were euthanized at postnatal day 21, and the levels of sex hormones and reactive oxygen species (ROS), expressions of proteins and genes in the Akt/mTOR, and mitochondrial apoptosis pathways were detected. Several closely linked autophagy indexes were also measured incidentally. Additionally, semen quality of adult offspring was tested at the end of the study.

RESULTS

The results revealed that prenatal BPA exposure can cause endocrine disruption and oxidative stress in male offspring, leading to inhibition of spermatogenesis by suppressing the Akt/mTOR pathway and activating the mitochondrial apoptosis pathway.

CONCLUSIONS

These preliminary results indicate noteworthy and far-reaching effects of BPA on the reproductive system of male offspring. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1007-1023, 2017.

Bisphenol A in Edible Part of Seafood

Bisphenol A (BPA) is a man-made compound, mainly used as a monomer to produce polycarbonate (PC), epoxy resins, non-polymer additives to other plastics, which have many food related applications, such as food storage containers, tableware and internal coating of cans, as well as non-food applications such as electronic equipment, construction materials and medical devices. BPA exposure can occur when the residual monomer migrates into packaged food and beverages. Moreover, due to the ubiquitous presence of this compound, the general population can be exposed to environmental sources such as water, air and soil. Many studies have investigated the potential health hazards associated with BPA, which can elicit toxic and cancerogenic effects on humans. According to the European Food Safety Authority opinion, diet is considered to be the main source of exposure, especially canned food; moreover, among non-canned food, meat and fish products have the highest levels of BPA contamination. This review focuses on BPA contamination in seafood, analysing worldwide literature (from January 2010 to October 2015) on BPA contamination of edible parts. The authors try to identify differences between canned and non-canned seafood in literature, and gaps in the state of art. The data evaluated underline that all concentrations for both canned and non-canned seafood were below the specific migration limit set by the European Community Directive for BPA in food. Moreover, the canned seafood is more contaminated than the non-canned one.

Parental urinary biomarkers of preconception exposure to bisphenol A and phthalates in relation to birth outcomes

BACKGROUND

Bisphenol A (BPA) and phthalates are ubiquitous non-persistent endocrine disrupting chemicals whose relation with infant birth size is not clearly understood.

METHODS

We examined associations between maternal and paternal preconception urinary concentrations of total BPA and 14 phthalate metabolites and birth size for 233 infants. Multiple linear regression models were used to estimate parental quartiles of BPA and phthalates in relation to birth weight, length, head circumference, and ponderal index with separate models run for each parent adjusting for age, smoking, body mass index, education, alcohol, parity, and creatinine. Models also included an interaction term for each chemical and infant sex and were further adjusted to include the other partner's chemical concentrations.

RESULTS

In maternal models adjusted for partner's exposure and covariates, reductions in birth weight (range: 178-215 g; p < 0.05) were observed for the 2nd quartile of maternal monomethyl phthalate, mono-[(2-carboxymethyl) hexyl] phthalate and mono-n-octyl phthalate when compared with the 1st quartiles. The 3rd quartile of monoethylhexyl phthalate (mEHP) was also associated with a 200.16 g (95 % CI: -386.90, -13.42) reduction. Similar reductions in birth weight were observed for the 2(nd) quartile of paternal mEHP (β = -191.93 g; 95 % CI: -381.61, -2.25). Additionally, select maternal urinary metabolites were associated with decreased head circumference, birth length and gestational age. However, paternal concentrations were generally associated with increased birth length and gestational age.

CONCLUSIONS

We observed some suggestion that preconception maternal and paternal urinary concentration of BPA and specific phthalate metabolites may be associated with smaller birth size and increased gestational age, though the findings appeared to be parent and chemical specific.

Hormonal contraceptive use before and after conception in relation to preterm birth and small for gestational age: an observational cohort study

OBJECTIVE

To evaluate whether hormonal contraceptives, used before or in early pregnancy, confer increased risk of preterm birth or reduced fetal growth.

DESIGN

Population-based cohort study conducted by the Norwegian Institute of Public Health (Mother and Child Cohort Study, 1998-2008) with linkage to the Norwegian Prescription Registry and to the Medical Birth Registry of Norway.

SETTING

Norway.

POPULATION

Of the 48,615 pregnancies meeting study inclusion criteria, 44,734 pregnancies were included in the complete case analysis.

METHODS

We characterised hormonal contraception by type (combination oral, progestin-only oral, vaginal ring, transdermal, and injectable) and specific progestin component. We used generalised estimating equations to estimate the odds of adverse outcome according to formulation used. Several sensitivity analyses were conducted.

MAIN OUTCOME MEASURES

Preterm birth, small for gestational age.

RESULTS

We observed a positive association between use of a combination oral contraceptive and preterm birth for all exposure periods (e.g. adjusted odds ratio 1.21, 95% confidence interval 1.04-1.41 for last use 12 to >4 months before conception); combination contraceptives containing the progestin norethisterone were consistently related to risk. Other types of hormonal contraception were generally not associated with preterm birth; none were related to small for gestational age. Observed associations were robust to sensitivity analyses.

CONCLUSION

Hormonally active agents may exert dose-, agent-, and timing-specific effects on growth and development. We found that the particular progestin component is important when assessing the potential for adverse effects among former users of hormonal contraceptives.

Bisphenol A Effects on Mammalian Oogenesis and Epigenetic Integrity of Oocytes: A Case Study Exploring Risks of Endocrine Disrupting Chemicals

Bisphenol A (BPA), originally developed as a synthetic oestrogen, is nowadays extensively used in the production of polymeric plastics. Under harsh conditions, these plastics may release BPA, which then can leach into the environment. Detectable concentrations of BPA have been measured in most analysed samples of human serum, plasma, or urine, as well as in follicular fluid, foetal serum, and amniotic fluid. Here we summarize the evidence about adverse BPA effects on the genetic and epigenetic integrity of mammalian oocytes. We conclude that increasing evidence supports the notion that low BPA concentrations adversely affect the epigenome of mammalian female germ cells, with functional consequences on gene expression, chromosome dynamics in meiosis, and oocyte development. Specific time windows, during which profound chromatin remodelling occurs and maternal imprints are established or protected, appear particularly vulnerable to epigenetic deregulation by BPA. Transgenerational effects have been also observed in the offspring of BPA-treated rodents, although the epigenetic mechanisms of inheritance still need to be clarified. The relevance of these findings for human health protection still needs to be fully assessed, but they warrant further investigation in both experimental models and humans.

Urinary bisphenol A and semen quality, the LIFE Study

Bisphenol A (BPA), a high-production volume industrial chemical found in several consumer products, has been negatively associated with sperm quality. This study aimed to estimate the association between BPA and 35 measures of semen quality among reproductive aged men recruited from 16 counties in Michigan and Texas, 2005-2009. Of 501 enrolled males, 418 (83.4%) provided a urine sample and at least one semen sample. Linear and logistic regression models assessed the association between urinary BPA levels and individual semen quality endpoints. Generalized estimating equations were used to account for repeated measures of semen quality and adjusted models accounted for 11 a priori covariates. Geometric mean total urinary BPA concentration among participants was 0.55ng/mL (95% CI 0.49-0.63). A negative relation between BPA and DNA fragmentation was the sole significant finding in adjusted linear regression (β=-0.0544, p=0.035) and suggestive of less sperm DNA damage.

Associations between urinary phenol and paraben concentrations and markers of oxidative stress and inflammation among pregnant women in Puerto Rico

Phenols and parabens are used in a multitude of consumer products resulting in ubiquitous human exposure. Animal and in vitro studies suggest that exposure to these compounds may be related to a number of adverse health outcomes, as well as potential mediators such as oxidative stress and inflammation. We examined urinary phenol (bisphenol A (BPA), triclosan (TCS), benzophenone-3 (BP-3), 2,4-dichlorophenol (24-DCP), 2,5-dichlorophenol (25-DCP)) and paraben (butyl paraben (B-PB), methyl paraben (M-PB), propyl paraben (P-PB)) concentrations measured three times during pregnancy in relation to markers of oxidative stress and inflammation among participants in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) project. Serum markers of inflammation (c-reactive protein (CRP), IL-1β, IL-6, IL-10, and tumor necrosis factor-α (TNF-α)) were measured twice during pregnancy (n=105 subjects, 187 measurements) and urinary markers of oxidative stress (8-hydroxydeoxyguanosine (OHdG) and isoprostane) were measured three times during pregnancy (n=54 subjects, 146 measurements). We used linear mixed models to assess relationships between natural log-transformed exposure and outcome biomarkers while accounting for within individual correlation across study visits. After adjustment for urinary specific gravity, study visit, maternal pre-pregnancy BMI, and maternal education, an interquartile range (IQR) increase in urinary BPA was associated with 21% higher OHdG (p=0.001) and 29% higher isoprostane (p=0.0002), indicating increased oxidative stress. The adjusted increase in isoprostane per IQR increase in marker of exposure was 17% for BP-3, 27% for B-PB, and 20% for P-PB (all p<0.05). An IQR increase in triclosan (TCS) was associated with 31% higher serum concentrations of IL-6 (p=0.007), a pro-inflammatory cytokine. In contrast, IQR increases in BP-3 and B-PB were significantly associated with 16% and 18% lower CRP, a measure of systemic inflammation. Our findings suggest that exposure to BPA, select parabens, and TCS during pregnancy may be related to oxidative stress and inflammation, potential mechanisms by which exposure to these compounds may influence birth outcomes and other adverse health effects, but additional research is needed.

Bisphenol A and the female reproductive tract: an overview of recent laboratory evidence and epidemiological studies

Bisphenol A (BPA) is a high production volume monomer used for making a wide variety of polycarbonate plastics and resins. A large body of evidence links BPA to endocrine disruption in laboratory animals, and a growing number of epidemiological studies support a link with health disorders in humans. The aim of this review is to summarize the recent experimental studies describing the effects and mechanisms of BPA on the female genital tract and to compare them to the current knowledge regarding the impact of BPA impact on female reproductive health. In particular, BPA has been correlated with alterations in hypothalamic-pituitary hormonal production, reduced oocyte quality due to perinatal and adulthood exposure, defective uterine receptivity and the pathogenesis of polycystic ovary syndrome. Researchers have reported conflicting results regarding the effect of BPA on premature puberty and endometriosis development. Experimental studies suggest that BPA's mechanism of action is related to life stage and that its effect on the female reproductive system may involve agonism with estrogen nuclear receptors as well as other mechanisms (steroid biosynthesis inhibition). Notwithstanding uncertainties and knowledge gaps, the available evidence should be seen as a sufficient grounds to take precautionary actions against excess exposure to BPA.