Maternal serum concentrations of bisphenol A and propyl paraben in early pregnancy are associated with male infant genital development

The Effect of Various Environmental Pollutants on the Reproductive Health in Children: A Brief Review of the Literature

PURPOSE OF REVIEW

Environmental pollutants in air, water, soil, and food are a significant concern due to their potential adverse effects on fetuses, newborns, babies, and children. These chemicals, which pass to fetuses and babies through trans-placental transfer, breast milk, infant formula, dermal transfer, and non-nutritive ingestion, can cause health problems during childhood. This review aims to discuss how exposure to various environmental pollutants in early life stages can disrupt reproductive health in children.

RECENT FINDINGS

Environmental pollutants can affect Leydig cell proliferation and differentiation, decreasing testosterone production throughout life. This may result in cryptorchidism, hypospadias, impaired semen parameters, and reduced fertility. Although many studies on female reproductive health cannot be interpreted to support causal relationships, exposure to pollutants during critical windows may subsequently induce female reproductive diseases, including early or delayed puberty, polycystic ovary syndrome, endometriosis, and cancers. There is growing evidence that fetal and early-life exposure to environmental pollutants could affect reproductive health in childhood. Although diet is thought to be the primary route by which humans are exposed to various pollutants, there are no adopted nutritional interventions to reduce the harmful effects of pollutants on children's health. Therefore, understanding the impact of environmental contaminants on various health outcomes may inform the design of future human nutritional studies.

Endocrine disruption and male reproductive disorders: unanswered questions

Maternal exposure to endocrine-disrupting chemicals (EDCs) in human pregnancy is widely considered as an important cause of adverse changes in male reproductive health due to impaired foetal androgen production/action. However, the epidemiological evidence supporting this view is equivocal, except for certain phthalates, notably diethyl hexyl phthalate (DEHP). Maternal phthalate exposure levels associated with adverse reproductive changes in epidemiological studies are several thousand-fold lower than those needed to suppress foetal androgen production in rats, and direct studies using human foetal testis tissue show no effect of high phthalate exposure on androgen production. This conundrum is unexplained and raises fundamental questions. Human DEHP exposure is predominantly via food with highest exposure associated with consumption of a Western style (unhealthy) diet. This diet is also associated with increased exposure to the most common EDCs, whether persistent (chlorinated or fluorinated chemicals) or non-persistent (phthalates, bisphenols) compounds, which are found at highest levels in fatty and processed foods. Consequently, epidemiological studies associating EDC exposure and male reproductive health disorders are confounded by potential dietary effects, and vice versa. A Western diet/lifestyle in young adulthood is also associated with low sperm counts. Disentangling EDC and dietary effects in epidemiological studies is challenging. In pregnancy, a Western diet, EDC exposure, and maternal living in proximity to industrial sites are all associated with impaired foetal growth/development due to placental dysfunction, which predisposes to congenital male reproductive disorders (cryptorchidism, hypospadias). While the latter are considered to reflect impaired foetal androgen production, effects resulting from foetal growth impairment (FGI) are likely indirect. As FGI has numerous life-long health consequences, and is affected by maternal lifestyle, research into the origins of male reproductive disorders should take more account of this. Additionally, potential effects on foetal growth/foetal testis from the increasing use of medications in pregnancy deserves more research attention.

The Association between Maternal Endocrine-Disrupting Chemical Exposure during Pregnancy and the Incidence of Male Urogenital Defects: A Systematic Review and Meta-Analysis

The increasing incidence of hypospadias and cryptorchidism, coupled with the widespread presence of endocrine-disrupting chemicals (EDCs), has raised concerns about the potential impact of these environmental factors on male urogenital development. This systematic review and meta-analysis aims to evaluate the association between maternal exposure to various EDCs and the risk of hypospadias and cryptorchidism. We conducted a comprehensive search of PubMed, Scopus, Web of Science, and Cochrane databases from inception until May 2024. We included case-control and cohort studies that examined the association between maternal EDC exposure and hypospadias or cryptorchidism, reporting adjusted odds ratios (aOR) or crude odds ratios (cOR). Data were extracted and pooled using a random effects model, and heterogeneity was assessed using the Q test and I-square statistics. The risk of bias was evaluated using the Newcastle-Ottawa Scale (NOS). A total of 48 studies were included in the systematic review, with 46 studies included in the meta-analysis. The pooled analysis revealed a significant association between maternal EDC exposure and an increased risk of hypospadias (aOR = 1.26, 95% CI: 1.18-1.35, p < 0.0001) and cryptorchidism (aOR = 1.37, 95% CI: 1.19-1.57, p < 0.001). Subgroup analyses showed that exposure to pesticides, phthalates, alkyl phenolic compounds (ALKs), and heavy metals significantly increased the risk of hypospadias. In contrast, polychlorinated biphenyls (PCBs) did not show a significant association. Significant associations were found with pesticide and PCB exposure for cryptorchidism, but not with phthalate, ALK, or heavy metal exposure. Maternal exposure to certain EDCs is associated with an increased risk of hypospadias and cryptorchidism in male children. These findings underscore the importance of addressing environmental and occupational exposures during pregnancy to mitigate potential risks. Further research is needed to elucidate the mechanisms by which EDCs affect urogenital development and to develop effective interventions to reduce exposure among vulnerable populations.

Sex-Specific and Trimester-Specific Associations of Prenatal Exposure to Bisphenols, Parabens, and Triclosan with Neonatal Birth Size and Gestational Age

Bisphenols, parabens, and triclosan (TCS) are common endocrine disrupters used in various consumer products. These chemicals have been shown to cross the placental barrier and affect intrauterine development of fetuses. In this study, we quantified serum levels of six bisphenols, five parabens, and TCS in 483 pregnant women from southern China. Quantile-based g-computation showed that combined exposure to bisphenols, parabens, and TCS was significantly (p < 0.05) and negatively associated with birth weight (β = -39.9, 95% CI: -73.8, -6.1), birth length (β = -0.19, 95% CI: -0.34, -0.04), head circumference (β = -0.13, 95% CI: -0.24, -0.02), and thoracic circumference (β = -0.16, 95% CI: -0.29, -0.04). An inverse correlation was also identified between mixture exposure and gestational age (β = -0.12, 95% CI: -0.24, -0.01). Bisphenol A (BPA), bisphenol Z (BPZ), bisphenol AP (BPAP), propylparaben (PrP), and TCS served as the dominant contributors to the overall effect. In subgroup analyses, male newborns were more susceptible to mixture exposure than females, whereas the exposure-outcome link was prominent among pregnant women in the first and second trimesters. More evidence is warranted to elucidate the impacts of exposure to mixtures on birth outcomes, as well as the underlying mechanisms.

The epidemiology of cryptorchidism and potential risk factors, including endocrine disrupting chemicals

Congenital cryptorchidism, also known as undescended testis, is the condition where one or both testes are not in place in the scrotum at birth and is one of the most common birth defects in boys. Temporal trends and geographic variation in the prevalence of cryptorchidism from 1% to 9% have been reported in prospective cohort studies. The testes develop in the abdominal cavity and descend to the scrotum in two phases, which should be completed by gestational week 35. Thus, the risk of cryptorchidism is higher in preterm boys. In many cases a spontaneous descent occurs during the first months of life during the surge of gonadotropins and testosterone. If not, the testis is usually brought down to the scrotum, typically by surgery, to increase future fertility chances and facilitate cancer surveillance. The increasing frequency of impaired semen quality and testicular cancer, with which cryptorchidism is associated, represents a concern for male reproductive health in general and a need to understand its risk factors. The risk of cryptorchidism is closely related to gestational factors (preterm birth, low birth weight and intrauterine growth restriction), and especially maternal smoking seems to be a risk factor. Evidence is accumulating that the increasing prevalence of cryptorchidism is also related to prenatal exposure to environmental chemicals, including endocrine disrupting compounds. This association has been corroborated in rodents and supported by ecological studies. Conducting human studies to assess the effect of endocrine disrupting chemicals and their interactions is, however, challenged by the widespread concomitant exposure of all humans to a wide range of chemicals, the combined effect of which and their interactions are highly complex.

The Conflict between Regulatory Agencies over the 20,000-Fold Lowering of the Tolerable Daily Intake (TDI) for Bisphenol A (BPA) by the European Food Safety Authority (EFSA)

BACKGROUND

The European Food Safety Authority (EFSA) recommended lowering their estimated tolerable daily intake (TDI) for bisphenol A (BPA) 20,000-fold to 0.2  ng / kg  body weight  ( BW ) / day . BPA is an extensively studied high production volume endocrine disrupting chemical (EDC) associated with a vast array of diseases. Prior risk assessments of BPA by EFSA as well as the US Food and Drug Administration (FDA) have relied on industry-funded studies conducted under good laboratory practice protocols (GLP) requiring guideline end points and detailed record keeping, while also claiming to examine (but rejecting) thousands of published findings by academic scientists. Guideline protocols initially formalized in the mid-twentieth century are still used by many regulatory agencies. EFSA used a 21st century approach in its reassessment of BPA and conducted a transparent, but time-limited, systematic review that included both guideline and academic research. The German Federal Institute for Risk Assessment (BfR) opposed EFSA's revision of the TDI for BPA.

OBJECTIVES

We identify the flaws in the assumptions that the German BfR, as well as the FDA, have used to justify maintaining the TDI for BPA at levels above what a vast amount of academic research shows to cause harm. We argue that regulatory agencies need to incorporate 21st century science into chemical hazard identifications using the CLARITY-BPA (Consortium Linking Academic and Regulatory Insights on BPA Toxicity) nonguideline academic studies in a collaborative government-academic program model.

DISCUSSION

We strongly endorse EFSA's revised TDI for BPA and support the European Commission's (EC) apparent acceptance of this updated BPA risk assessment. We discuss challenges to current chemical risk assessment assumptions about EDCs that need to be addressed by regulatory agencies to, in our opinion, become truly protective of public health. Addressing these challenges will hopefully result in BPA, and eventually other structurally similar bisphenols (called regrettable substitutions) for which there are known adverse effects, being eliminated from all food-related and many other uses in the EU and elsewhere. https://doi.org/10.1289/EHP13812.

The adverse role of endocrine disrupting chemicals in the reproductive system

Reproductive system diseases pose prominent threats to human physical and mental well-being. Besides being influenced by genetic material regulation and changes in lifestyle, the occurrence of these diseases is closely connected to exposure to harmful substances in the environment. Endocrine disrupting chemicals (EDCs), characterized by hormone-like effects, have a wide range of influences on the reproductive system. EDCs are ubiquitous in the natural environment and are present in a wide range of industrial and everyday products. Currently, thousands of chemicals have been reported to exhibit endocrine effects, and this number is likely to increase as the testing for potential EDCs has not been consistently required, and obtaining data has been limited, partly due to the long latency of many diseases. The ability to avoid exposure to EDCs, especially those of artificially synthesized origin, is increasingly challenging. While EDCs can be divided into persistent and non-persistent depending on their degree of degradation, due to the recent uptick in research studies in this area, we have chosen to focus on the research pertaining to the detrimental effects on reproductive health of exposure to several EDCs that are widely encountered in daily life over the past six years, specifically bisphenol A (BPA), phthalates (PAEs), polychlorinated biphenyls (PCBs), parabens, pesticides, heavy metals, and so on. By focusing on the impact of EDCs on the hypothalamic-pituitary-gonadal (HPG) axis, which leads to the occurrence and development of reproductive system diseases, this review aims to provide new insights into the molecular mechanisms of EDCs' damage to human health and to encourage further in-depth research to clarify the potentially harmful effects of EDC exposure through various other mechanisms. Ultimately, it offers a scientific basis to enhance EDCs risk management, an endeavor of significant scientific and societal importance for safeguarding reproductive health.

Associations of Exposure to Air Pollution during the Male Programming Window and Mini-Puberty with Anogenital Distance and Penile Width at Birth and at 1 Year of Age in the Multicenter U.S. TIDES Cohort

BACKGROUND

Ambient air pollution may be a developmental endocrine disruptor. In animal models, gestational and perinatal exposure to diesel exhaust and concentrated particulate matter alters anogenital distance (AGD), a marker of prenatal androgen activity, in both sexes. Little is known in humans.

OBJECTIVES

We examined exposure to fine particulate matter (PM 2.5 ) and nitrogen dioxide (NO 2 ) in relation to human AGD at birth and at 1 year of age, focusing on exposures during critical windows of reproductive development: the male programming window (MPW; gestational weeks 8-14) and mini-puberty (postnatal months 1-3).

METHODS

The Infant Development and Environment Study (TIDES) recruited first trimester pregnant women (n = 687 ) at four U.S. sites (Minneapolis, Minnesota; Rochester, New York; San Francisco, California; and Seattle, Washington) from 2010 to 2012. We measured anus to clitoris (AGD-AC) and anus to fourchette (AGD-AF) in female infants at birth; in males, we measured anus to penis (AGD-AP), anus to scrotum (AGD-AS), and penile width at birth and at 1 year of age. Using advanced spatiotemporal models, we estimated maternal exposure to PM 2.5 and NO 2 in the MPW and mini-puberty. Covariate-adjusted, sex-stratified linear regression models examined associations between PM 2.5 and NO 2 and AGD.

RESULTS

In males, a 1 - μ g / m 3 increase in PM 2.5 exposure during the MPW was associated with shorter AGD at birth, but a longer AGD at 1 year of age (e.g., birth AGD-AP: β = - 0.35 mm ; 95% CI: - 0.62 , - 0.07 ; AGD-AS: β = 0.37 mm ; 95% CI: 0.02, 0.73). Mini-pubertal PM 2.5 exposure was also associated with shorter male AGD-AP (β = - 0.50 mm ; 95% CI: - 0.89 , - 0.11 ) at 1 year of age. Although not associated with male AGD measures, 1 -ppb increases in NO 2 exposure during the MPW (β = - 0.07 mm ; 95% CI: - 0.02 , - 0.12 ) and mini-puberty (β = - 0.04 mm ; 95% CI: - 0.08 , 0.01) were both associated with smaller penile width at 1 year of age. Results were similar in multipollutant models, where we also observed that in females AGD-AC was inversely associated with PM 2.5 exposure, but positively associated with NO 2 exposure.

DISCUSSION

PM 2.5 and NO 2 exposures during critical pre- and postnatal windows may disrupt reproductive development. More work is needed to confirm these novel results and clarify mechanisms. https://doi.org/10.1289/EHP12627.

Occurrence, placental transfer, and health risks of emerging endocrine-disrupting chemicals in pregnant women

Previous studies demonstrated that many environmental chemicals can cross the human placental barrier. However, the risk regarding gestational exposure of emerging endocrine-disrupting chemicals (EDCs) is unclear. In this study, the occurrence of 24 EDCs, such as bisphenol A analogs, parabens, triclocarban, and triclosan, was investigated in serum and urine samples from Chinese pregnant women. Some metabolites were determined in matched serum-urine pairs (n = 75) to perform a comprehensive assessment of exposure. The placental transfer efficiency (PTE) of the detected chemicals was determined in matched maternal-cord serum pairs (n = 110). The mean PTEs of the chemicals showed a large variation from 43.1% to 171.0%. The potential effects of physicochemical properties, molecular structures, and biological factors on PTE were investigated using multiple linear regression models and molecular docking. We found that the PTE of methyl paraben, ethyl paraben, and propyl paraben was associated with their increasing alkyl chain lengths. Furthermore, a comprehensive exposure assessment of EDCs showed that 62.7% of pregnant women had a health index > 1, which indicted potential health risks during pregnancy. However, toxicity and the underlying mechanisms of these EDCs remain to be further studied.

Endocrine disrupting compounds in the baby's world - A harmful environment to the health of babies

Globally, there has been a significant increase in awareness of the adverse effects of chemicals with known or suspected endocrine-acting properties on human health. Human exposure to endocrine disrupting compounds (EDCs) mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Although it is difficult to assess the full impact of human exposure to EDCs, it is well known that timing of exposure is of importance and therefore infants are more vulnerable to EDCs and are at greater risk compared to adults. In this regard, infant safety and assessment of associations between prenatal exposure to EDCs and growth during infancy and childhood has been received considerable attention in the last years. Hence, the purpose of this review is to provide a current update on the evidence from biomonitoring studies on the exposure of infants to EDCs and a comprehensive view of the uptake, the mechanisms of action and biotransformation in baby/human body. Analytical methods used and concentration levels of EDCs in different biological matrices (e.g., placenta, cord plasma, amniotic fluid, breast milk, urine, and blood of pregnant women) are also discussed. Finally, key issues and recommendations were provided to avoid hazardous exposure to these chemicals, taking into account family and lifestyle factors related to this exposure.

Cumulative Exposure to Phthalates and Their Alternatives and Associated Female Reproductive Health: Body Burdens, Adverse Outcomes, and Underlying Mechanisms

The global birth rate has recently shown a decreasing trend, and exposure to environmental pollutants has been identified as a potential factor affecting female reproductive health. Phthalates have been widely used as plasticizers in plastic containers, children's toys, and medical devices, and their ubiquitous presence and endocrine-disrupting potential have already raised particular concerns. Phthalate exposure has been linked to various adverse health outcomes, including reproductive diseases. Given that many phthalates are gradually being banned, a growing number of phthalate alternatives are becoming popular, such as di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), di(2-ethylhexyl) adipate (DEHA), and di(2-ethylhexyl) terephthalate (DEHTP), and they are beginning to have a wide range of environmental effects. Studies have shown that many phthalate alternatives may disrupt female reproductive function by altering the estrous cycle, causing ovarian follicular atresia, and prolonging the gestational cycle, which raises growing concerns about their potential health risks. Herein, we summarize the effects of phthalates and their common alternatives in different female models, the exposure levels that influence the reproductive system, and the effects on female reproductive impairment, adverse pregnancy outcomes, and offspring development. Additionally, we scrutinize the effects of phthalates and their alternatives on hormone signaling, oxidative stress, and intracellular signaling to explore the underlying mechanisms of action on female reproductive health, because these chemicals may affect reproductive tissues directly or indirectly through endocrine disruption. Given the declining global trends of female reproductive capacity and the potential ability of phthalates and their alternatives to negatively impact female reproductive health, a more comprehensive study is needed to understand their effects on the human body and their underlying mechanisms. These findings may have an important role in improving female reproductive health and in turn decreasing the number of complications during pregnancy.

Prenatal exposure to phthalates and polybrominated diphenyl ethers on neonatal health: A birth cohort study in Guangxi, China

Few epidemiological studies have focused on prenatal phthalates (PAEs) and polybrominated diphenyl ethers (PBDEs) exposure to neonatal health in China. This study aimed to assess the associations between prenatal PAEs and PBDEs exposure and neonatal health in Guangxi, a Zhuang autonomous region of China. Concentrations of 4 PAEs metabolites (mPAEs) and 5 PBDEs congeners were measured in the serum of 267 healthy pregnant women. Birth outcomes and clinical data of neonates were collected after delivery. Mono-(2-Ethylhexyl) phthalate (MEHP) (81.52%) and BDE47 (35.21%) were the mPAEs and PBDEs congeners with the highest detection rate in serum. Prenatal exposures to mono-n-butyl phthalate (MBP), MEHP, and ΣmPAEs were negatively associated with birth weight (BW), birth length (BL), and gestational age (GA). Higher exposures to MBP, MEHP, and ΣmPAEs were associated with an increased odds ratio (OR) for low birth weight (LBW), but exposure to BDE28 exhibited the opposite effect. Moreover, higher exposures to MBP, MEHP, ΣmPAEs, BDE99, and ΣPBDEswere associated with an increased OR for premature birth (PTB) (P < 0.05). In contrast to MBP exposure, BDE28 exposure was associated with a higher OR for neonatal jaundice (NNJ) (P < 0.05). The interaction analysis showed a positive interaction between monoethyl phthalate (MEP) and BDE28 on the risk of NNJ and positive interaction between ΣmPAEs and BDE47 on the risk of NNJ. In addition, there are ethnicity-specific associations of prenatal PBDEs exposure with neonatal health in individuals of Zhuang and Han nationalities, and boy neonates were more sensitive to prenatal PBDEs exposure than girl neonates. The results revealed that prenatal exposure to mPAEs and PBDEs might have adverse effects on neonatal development, and the effects might be ethnicity- and sex-specific.

Human serum paraben levels and their associations with rheumatoid arthritis: a case-control study from Hangzhou, China

Parabens are widely used in consumer products resulting in frequent exposure to humans. To date, little is known about the association between human paraben exposure and rheumatoid arthritis (RA). In this study, a case-control study (n = 290) was conducted in Hangzhou, China, aiming to quantify the concentrations of methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), and butyl paraben (BuP) in serum samples and to determine their associations with RA risks. MeP (mean 4.7 ng/mL, range <0.05-20 ng/mL) was the predominant paraben in human serum, followed by PrP (1.9 ng/mL, <0.12-24 ng/mL), EtP (1.4 ng/mL, <0.09-10 ng/mL), and BuP (1.09 ng/mL, <0.10-10 ng/mL). With 1-unit increase of MeP concentrations in human serum, the levels of rheumatoid factors, anticyclic citrullinated peptide antibody, and immunoglobulin G will increase by 0.19 unit (95% confidence intervals [CI]: 0.12-0.46), 0.30 unit (95% CI: 0.26-0.58), and 0.24 unit (95% CI: 0.21-0.30) in the adjusted model, respectively. One-unit increase of MeP and PrP concentrations in human serum was associated with an increase of 0.15 (95% CI: 0.037-0.28) and 0.20 (95% CI: 0.10-0.32) in the C-reactive protein concentrations. In addition, an association between serum MeP levels and the incidence of RA (odds ratios (OR)_crude = 1.33, CI: 1.11-1.62, p = 0.03; OR_adjusted = 1.86, CI: 1.32-2.63, p = 0.02) was positive and significant. Based on the measurements of serum paraben concentrations, this work supports the evidence for the significant associations among paraben exposure, change of specific immune marker, and RA risks.

Estimated daily intake of phthalates, parabens, and bisphenol A in hospitalised very low birth weight infants

Very low birth weight infants (VLBW, birth weight (BW) < 1500 g) are exposed to phthalates, parabens and bisphenol A (BPA) early in life. We estimated daily intake (EDI) of these excipients in 40 VLBW infants the first and fifth week of life while hospitalised. Based on urinary samples collected in 2010, EDI was calculated and compared to the tolerable daily intake (TDI) with hazard quotients (HQs) evaluated. A HQ > 1 indicates that EDI exceeded TDI with increased risk of adverse health effects. EDI was higher in VLBW infants compared to term-born infants and older children. VLBW infants born at earlier gestational age (GA), or with lower BW, had higher EDI than infants born at later GA or with higher BW. First week median EDI for BPA was higher than TDI in 100% of infants, in 75% for di(2-ethylhexyl) phthalate (DEHP), 90% for the sum of butyl benzyl phthalate (BBzP), di-n-butyl phthalate (DnBP), DEHP and di-iso-nonyl phthalate (DiNP) = ∑BBzP+DnBP+DEHP+DiNP, and in 50% of infants for propylparaben (PrPa), indicating increased risk of adverse effects. Fifth week EDI remained higher than TDI in all infants for BPA, in 75% for DEHP and ∑BBzP+DnBP+DEHP+DiNP, and 25% of infants for PrPa, indicating prolonged risk. Maximum EDI for di-iso-butyl phthalate was higher than TDI suggesting risk of adverse effects at maximum exposure. VLBW infants born earlier than 28 weeks GA had higher EDI, above TDI, for PrPa compared to infants born later than 28 weeks GA. Infants with late-onset septicaemia (LOS) had higher EDI for DEHP, ∑BBzP+DnBP+DEHP+DiNP and BPA, above TDI, compared to infants without LOS. More 75% of the infants' EDI for DEHP and ∑BBzP+DnBP+DEHP+DiNP, 25% for PrPa, and 100% of infants' EDI for BPA, were above TDI resulting in HQs > 1, indicating increased risk of adverse health effects.

Association between parabens concentrations in human amniotic fluid and the offspring birth size: A Sub-study of the PERSIAN birth cohort

OBJECTIVE

Parabens are extensively used, and cause widespread exposure of the general population including pregnant women and developing fetuses to these pollutants. In this study, we aimed to investigate the association between the maternal exposure of parabens to study their transfer passed through the placental barrier to amniotic fluid; the second objective was to determine the association of paraben concentration in the amniotic fluid with the offspring birth size.

METHODS

This cross-sectional study was conducted from June 2019 to March 2021 in Isfahan, Iran. Samples of amniotic fluid were collected as set from 128 pregnant women at Cesarean section. The amniotic fluid concentrations of four parabens including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were determined using gas chromatography tandem mass spectroscopy (GC-Mass).

RESULTS

The pointed parabens were extracted from yielded clear supernatant using a dispersive liquid-liquid microextraction (DLLME) method. Four paraben derivatives including MP (normal: 0.68 ± 0.7; overweight: 1.40 ± 1.76; obese: 0.30 ± 0.26; p-value: 0.275), EP (normal: 0.14 ± 0.09; overweight: 0.72 ± 0.72; obese: 0.38 ± 0.05; p-value: 0.434), PP (normal: 0.05 ± 0.05; overweight: 0.06 ± 0.06; obese: 0.20 ± 0.17; p-value: 0.770), and BP (normal: 2.89 ± 1.80; overweight: 3.89 ± 6.48; obese: 5.80 ± 7.56; p-value: 0.341) were simultaneously detected in samples of maternal amniotic fluid using GC-MS. In 92.2% (n = 118) of pregnant women, the paraben derivatives (MP, EP, PP, BP) were detected. We found that considerable levels of MP, EP, PP, and BP existed in 22.6% (n = 29), 21.9% (n = 28), 29.7% (n = 38), and 85.2% (n = 109) of samples, respectively. In addition, the correlation between paraben concentrations in amniotic fluid and birth size was investigated. The results showed that an inverse significant association between MP and head circumference, chest, hip, and arm circumference. While a positive correlation between MP and height of newborn was observed. Similar correlations were observed for EP and weight, height, head circumference, chest, hip, and arm.

CONCLUSION

The current study indicated that parabens have been detected in amniotic fluid samples and a strong/possible correlation between exposure of pregnant women to parabens and the birth size of newborns.

Sex-specific associations between maternal exposure to parabens, phenols and phthalates during pregnancy and birth size outcomes in offspring

Current evidence on the effects of prenatal exposure to endocrine disrupting chemicals on birth size remains largely inconclusive. We aimed to investigate sex-specific associations between maternal exposure to parabens, phenols and phthalates during pregnancy and birth weight, length and head/abdominal circumferences. We performed a prospective study of 88 pregnant women who underwent amniocentesis in the period 2012 to 2014. Maternal urine samples were collected during pregnancy in weeks 12 to 36 (median: 18 weeks). The concentrations of parabens, phenols and individual phthalate diester metabolites were analyzed by isotope-diluted liquid chromatography-tandem mass spectrometry and osmolality adjusted. Linear regression models estimated the associations between urinary levels of selected compounds (tertile(T2-T3)_medium/high versus T1_low exposure) and birth size, stratified by offspring sex. A total of three parabens, two phenols, four individual phthalate metabolites and four sums of diester metabolites were detectable above limits of detection in at least 60% of urine samples. Overall, we observed few statistically significant associations, but medium/high exposure to bisphenol A (BPA) in male offspring was associated with statistically significant lower birth size across most outcomes [birth weight: -428 g (95% CI -756 to -99.4); birth length: -1.76 cm (95% CI -3.28 to -0.25); abdominal circumference: -1.97 cm (95% CI -3.55 to -0.39)]. Similarly, medium/high exposure to methyl paraben (MeP) in male offspring was associated with lower birth weight (-661 g, 95% CI -1251 to -70.7) and length (-3.11 cm, 95% CI -5.76 to -0.46) compared to low exposure. None of these associations were statistically significant in female offspring. Across all compounds, individual exposures were associated with more negative estimates of birth weight for male than for female offspring. Our study indicates that prenatal exposure to BPA and MeP may negatively affect birth size outcomes, with a possible sex effect. Given the small sample size, these findings need to be replicated in future larger studies.

Single and mixed effects of prenatal exposure to multiple bisphenols on hemoglobin levels and the risk of anemia in pregnant women

INTRODUCTION

Bisphenols have endocrine-disrupting effects, which may disrupt hemoglobin (Hb) homeostasis and lead to anemia. However, the effects of bisphenols on anemia remain unknown. Therefore, we assessed the effects of single- and multiple-exposure to bisphenols on Hb levels and anemia of pregnant women.

METHODS

The study involved 2035 pregnant women from Guangxi Zhuang Birth Cohort in China. Generalized linear regression, principal component analysis (PCA), quantile g-computation (Qgcomp), and Bayesian kernel machine regression (BKMR) were performed to examine the effects of serum bisphenols on Hb levels and the risk of anemia.

RESULTS

After adjustment, elevated bisphenol A (BPA) levels were correlated with decreased Hb concentrations (β = -0.51; 95%CI: -0.92, -0.10) in the first trimester, and these correlations were more sensitive in mothers of males. Compared with the low-exposure group, bisphenol B (BPB) levels in the high-exposure group led to a 1.52 g/L (95%CI: -3.01, -0.03) decrease in Hb levels in the second trimester; tetrabromobisphenol A (TBBPA) levels in the high-exposure group led to a higher the risk of anemia in the third trimester (OR = 1.46; 95%CI: 1.07, 1.99); bisphenol F (BPF) in the high-exposure group led to lower Hb levels (β = -2.42; 95%CI:-4.69, -0.14) in mothers of male fetuses in the third trimester. Qgcomp showed that elevated levels of bisphenol mixture was correlated with (β = -1.42; 95%CI: -2.61, -0.24) decrease in Hb levels in the second trimester. PCA revealed a negative association between PC2 and Hb levels in the first trimester (β = -0.89; 95%CI: -1.61, -0.17). Similarly, a negative relationship was observed between PC1 and Hb levels in the third trimester among mothers with male fetuses (β = -1.00; 95%CI: -1.94, -0.06).

CONCLUSIONS

Prenatal exposure to single and mixed bisphenols may decrease Hb levels and increase the risk of anemia during pregnancy, the associations may be greater in mothers with male fetuses than those with female fetuses.

New insights on the effects of endocrine-disrupting chemicals on children

OBJECTIVE

Endocrine disrupting chemicals (EDCs) are present in many areas and materials of the common life, and exposure to these chemicals can occur from products to personal care, from air and food. This review aims to summarize the more recent epidemiological findings for the impact of EDCs on endocrine system health in children, including effects in growth, metabolism, sexual development, and reproduction.

SOURCES

The MEDLINE database (PubMed) was searched on August 24th, 2021, filtering for EDCs, endocrine disruptors, children, and humans.

SUMMARY OF THE FINDINGS

Intrauterine exposure of EDCs can have transgenerational effects, thus laying the foundation for disease in later life. The dose-response relationship may not always be predictable as even low-level exposures that may occur in everyday life can have significant effects on a susceptible individual. Although individual compounds have been studied in detail, the effects of a combination of these chemicals are yet to be studied to understand the real-life situation where human beings are exposed to a "cocktail effect" of these EDCs. Epidemiological studies in humans suggest EDCs' effects on prenatal growth, thyroid function, glucose metabolism, obesity, puberty, and fertility mainly through epigenetic mechanisms.

CONCLUSIONS

EDCs cause adverse effects in animals, and their effects on human health are now known and irrefutable. Because people are typically exposed to multiple endocrine disruptors, assessing public health effects is difficult. Legislation to ban EDCs and protect especially pregnant women and young children is required and needs to be revised and adjusted to new developments on a regular basis.

Contribution of prenatal endocrine-disrupting chemical exposure to genital anomalies in males: The pooled results from current evidence

The etiology of hypospadias and cryptorchidism, which are the two most common genital anomalies in males, has not been elucidated. Although prenatal exposure to endocrine-disrupting chemicals (EDCs) may increase the risks of hypospadias and cryptorchidism, the associations have not been confirmed. Therefore, we performed a meta-analysis to establish the relationships between prenatal exposure to EDCs and male genital anomalies. A systematic search of PubMed, EMbase, and Cochrane Library CENTRAL for relevant published studies providing quantitative data on the associations between prenatal EDCs exposure and hypospadias/cryptorchidism in humans was conducted. In total, sixteen case-controlled studies were included. Prenatal exposure to overall EDCs was associated with an increased risk of hypospadias in males (OR, 1.34, 95 % CI 1.12 to 1.60). Although there was no statistically significant association between overall EDCs exposure and cryptorchidism (OR, 1.11, 95 % CI 0.99 to 1.24), exposure to phenol substances was associated with an increased risk of cryptorchidism (OR, 1.81, 95 % CI, 1.12 to 2.93). Using the GRADE tool, we found the overall evidence to be of moderate certainty. In conclusion, the current evidence suggests prenatal EDCs exposure may increase the risk of hypospadias in males.

Prenatal exposure to phenols and benzophenones in relation to markers of male reproductive function in adulthood

INTRODUCTION

Environmental exposure during fetal life may disrupt testicular development. In humans, a limited number of studies have investigated whether these adverse effects persist into adulthood. Using data from a prospective, population-based birth cohort study, The Copenhagen Mother-Child cohort, the objective was to assess if there is an association between fetal exposure to selected phenols and benzophenones and markers of testicular function in adult men.

METHODS

Pregnant women were recruited in 1997-2001. Their sons were examined clinically at 18-20 years of age, with focus on adult markers of reproductive function (anogenital distance (AGD), semen quality and reproductive hormones). In total, 101 18-20-year-old men were included, whose mothers during pregnancy had a serum sample drawn and analyzed for bisphenol A (BPA) and seven other simple phenols, as well as six benzophenones. To investigate the association between chemical levels (in tertiles, T1-T3) in relation to markers of reproductive function, univariate and multiple linear regression analyses were performed.

RESULTS

In fully adjusted analyses, increased levels of luteinizing hormone (LH) were observed with higher fetal exposure to BPA (percentage difference (95%CI)) (T2: 12% (-8%,36%) and T3: 33% (10%,62%), compared to T1) and benzophenone-3 (BP-3) (T2: 21% (-2%,49%), T3: 18% (-4%,45%)), while no clear association was seen to total testosterone (TT). Higher levels of BPA and BP-3 were associated with a lower TT/LH ratio, although only significant for BPA (p-trend=0.01). No associations were seen to AGD or markers of semen quality.

CONCLUSION

In conclusion, high exposure to BPA and BP-3 was associated with a compensated reduced Leydig cell function but no other changes in markers of reproductive health. As maternal levels of BPA and BP-3 were not correlated, separate effects may be at play. Larger studies on long-term reproductive consequences of prenatal exposures are warranted to validate our findings.

Presence of parabens, phenols and phthalates in paired maternal serum, urine and amniotic fluid

OBJECTIVE

To examine whether selected endocrine disrupting chemicals were present in pregnant women and passed through the placental barrier to amniotic fluid, potentially exposing the developing fetus.

METHODS

Paired samples of maternal serum, urine and amniotic fluid were concurrently collected (<1 h) from 200 pregnant women (age >18 years) with a singleton pregnancy and undergoing amniocentesis between gestational weeks 12 - 36. The concentration of six different parabens, seven phenols, 31 metabolites from 15 phthalate diesters and the polychlorinated substance triclocarban were analyzed by isotope diluted TurboFlow-liquid chromatography-tandem mass spectrometry.

RESULTS

Concentrations of all included compounds were highest in maternal urine followed by serum, and lowest in amniotic fluid. Of the six parabens measured in amniotic fluid, methylparaben (MeP) and ethylparaben (EtP) were detectable most often (87% and 33% of the samples, respectively). Of the seven phenols measured, three (2,4-dichlorphenol, 2,5-dichlorphenol, 2-propylphenol) were detectable in the range of 14-21% of the amniotic fluid samples, at low concentrations (<0.12 ng/ml). Two secondary phthalates metabolites, mono-(2-carboxymethyl-hexyl) phthalate and mono-carboxy-iso-octyl phthalate were each present in ≤15% of the amniotic fluid samples at concentrations 2-5 times lower than in maternal serum and 20-100 times lower than in maternal urine. A modest statistically significant correlation between the levels of MeP and EtP was detected in paired maternal urine-amniotic fluid samples was detected (Spearman r_MeP: 0.246; r_EtP: 0.364). Likewise, the concentration of mono-ethyl phthalate (MEP) in paired maternal urine and amniotic fluid samples indicated a modest statistically significant correlation (Spearman r_MEP: 0.264), driven by detectable levels of MEP in only 3% of the amniotic fluid samples.

CONCLUSIONS

In general, the included parabens, phenols and phthalates were effectively metabolized and excreted via the urine, which was the matrix that reflected the highest detectable levels. The detectable levels of several included parabens and phthalates in human amniotic fluid calls for further investigations of the toxicokinetic and potential endocrine disrupting properties of individual and multiple endocrine disruptors in order to better assess the risk to the developing fetus.

Endocrine-Disrupting Chemicals and Child Health

While definitions vary, endocrine-disrupting chemicals (EDCs) have two fundamental features: their disruption of hormone function and their contribution to disease and disability. The unique vulnerability of children to low-level EDC exposures has eroded the notion that only the dose makes the thing a poison, requiring a paradigm shift in scientific and policy practice. In this review, we discuss the unique vulnerability of children as early as fetal life and provide an overview of epidemiological studies on programming effects of EDCs on neuronal, metabolic, and immune pathways as well as on endocrine, reproductive, and renal systems. Building on this accumulating evidence, we dispel and address existing myths about the health effects of EDCs with examples from child health research. Finally, we provide a list of effective actions to reduce exposure, and subsequent harm that are applicable to individuals, communities, and policy-makers. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Praegnatio Perturbatio-Impact of Endocrine-Disrupting Chemicals

The burden of adverse pregnancy outcomes such as preterm birth and low birth weight is considerable across the world. Several risk factors for adverse pregnancy outcomes have been identified. One risk factor for adverse pregnancy outcomes receiving considerable attention in recent years is gestational exposure to endocrine-disrupting chemicals (EDCs). Humans are exposed to a multitude of environmental chemicals with known endocrine-disrupting properties, and evidence suggests exposure to these EDCs have the potential to disrupt the maternal-fetal environment culminating in adverse pregnancy and birth outcomes. This review addresses the impact of maternal and fetal exposure to environmental EDCs of natural and man-made chemicals in disrupting the maternal-fetal milieu in human leading to adverse pregnancy and birth outcomes-a risk factor for adult-onset noncommunicable diseases, the role lifestyle and environmental factors play in mitigating or amplifying the effects of EDCs, the underlying mechanisms and mediators involved, and the research directions on which to focus future investigations to help alleviate the adverse effects of EDC exposure.

Prenatal paraben exposure and anogenital distance and reproductive hormones during mini-puberty: A study from the Odense Child Cohort

BACKGROUND

Parabens are added to personal care products as antimicrobial preservatives. They have been suggested to have endocrine disrupting abilities. Prenatal exposure to parabens has been associated with reproductive endpoints including reduced male anogenital distance (AGD, distance from anus to genitals), which is sensitive to prenatal anti-androgenic exposure.

OBJECTIVES

To study the associations between maternal paraben concentrations in second trimester urine and AGD and reproductive hormone concentrations at 3 months of age in offspring.

METHODS

Pregnant women from Odense, Denmark were included in early pregnancy from 2010 to 12, and their children are being followed up. Fasting spot urine samples from 536 pregnant women were analyzed for methylparaben (MeP), ethyl-paraben (EtP), iso-propylparaben (i-PrP), n-propylparaben (n-PrP), n-butylparaben (n-BuP) and benzylparaben (BzP) by liquid chromatography tandem mass spectrometry and thereafter osmolarity adjusted. Three months after expected date of birth, AGD was measured in 452 children, and serum concentrations of follicle stimulating hormone (FSH), luteinizing (LH), testosterone, dehydroepiandrosterone-sulphate (DHEAS), androstenedione and 17-hydroxyprogesterone (17-OHP) were measured in 198 children. Maternal paraben exposure was categorized into tertiles or below and above level of detection, and sex-stratified multiple linear regression analyses were performed with AGD or reproductive hormones as outcomes.

RESULTS

Most pregnant women had low concentrations of parabens in urine, but 10% exceeded the threshold for adverse estrogenic effects. Higher maternal paraben exposure was associated with shorter AGD in male offspring and longer AGD in girls, although only significant for MeP in boys. In addition, FSH, LH, DHEAS, 17-OHP concentrations were lower in girls with high prenatal paraben exposure, whereas no consistent pattern was found in boys.

DISCUSSION

The endocrine disrupting abilities of parabens may affect humans at vulnerable time periods during development, which may have long term impact on reproductive function. This is the first study to find these associations in girls and our findings need confirmation.

Impact of gestational exposure to endocrine disrupting chemicals on pregnancy and birth outcomes

With the advent of industrialization, humans are exposed to a wide range of environmental chemicals, many with endocrine disrupting potential. As successful maintenance of pregnancy and fetal development are under tight hormonal control, the gestational exposure to environmental endocrine disrupting chemicals (EDC) have the potential to adversely affect the maternal milieu and support to the fetus, fetal developmental trajectory and birth outcomes. This chapter summarizes the impact of exposure to EDCs both individually and as mixtures during pregnancy, the immediate and long-term consequences of such exposures on the mother and fetus, the direct and indirect mechanisms through which they elicit their effects, factors that modify their action, and the research directions to focus future investigations.

Endocrine disrupting chemicals and breast cancer: a systematic review of epidemiological studies

BACKGROUND

Endocrine-disrupting compounds (EDCs) are ubiquitous substances that are found in our everyday lives, including pesticides, plasticizers, pharmaceutical agents, personal care products, and also in food products and food packaging. Increasing epidemiological evidence suggest that EDCs may affect the development or progression of breast cancer and consequently lead to lifelong harmful health consequences, especially when exposure occurs during early life in humans. Yet so far no appraisal of the available evidence has been conducted on this topic.

OBJECTIVE

To systematically review all the available epidemiological studies about the association of the levels of environmental exposures of EDCs with breast cancer risk.

METHODS

The search was performed in accordance with the PRISMA guidelines. We retrieved articles from PubMed (MEDLINE) until 10 March 2021. The key words used in this research were: "Endocrine disruptor(s)" OR "Endocrine disrupting chemical(s)" OR any of the EDCs mentioned below AND "Breast cancer" to locate all relevant articles published. We included only cohort studies and case-control studies. All relevant articles were accessed in full text and were evaluated and summarized in tables.

RESULTS

We identified 131 studies that met the search criteria and were included in this systematic review. EDCs reviewed herein included pesticides (e.g. p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (DDE), atrazine, 2,3,7,8-tetrachloridibenzo-p-dioxin (TCDD or dioxin)), synthetic chemicals (e.g. bisphenol A (BPA), phthalates, per- and polyfluoroalkyl substances (PFAS), parabens, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), contraceptive pills), phytoestrogens (e.g. genistein, resveratrol), and certain mycotoxins (e.g. zearalenone). Most studies assessed environmental EDCs exposure via biomarker measurements.

CONCLUSION

We identified certain EDC exposures could potentially elevate the risk of breast cancer. As majority of EDCs are highly persistent in the environment and bio-accumulative, it is essential to assess the long-term impacts of EDC exposures, especially multi-generational and transgenerational. Also, since food is often a major route of exposure to EDCs, well-designed exposure assessments of potential EDCs in food and food packing are necessary and their potential link to breast cancer development need to be carefully evaluated for subsequent EDC policy making and regulations.

Exposure to alternative bisphenols BPS and BPF through breast milk: Noxious heritage effect during nursing associated with idiopathic infertility

There is increasing evidence that bisphenols BPS and BPF, which are analogues of BPA, have deleterious effects on reproduction even at extremely low doses. Indirect exposure via the maternal route (i.e. across the placenta and/or by breastfeeding) is underestimated, although it can be assumed to be a cause of idiopathic female infertility. Therefore, we hypothesised the deleterious effects of exposure to BPA analogues during breastfeeding on the ovarian and oocyte quality of offspring. A 15-day exposure period of pups was designed, whilst nursing dams (N ≥ 6 per experimental group) were treated via drinking water with a low (0.2 ng/g body weight/day) or moderate (20 ng/g body weight/day) dose of bisphenol, mimicking real exposure in humans. Thereafter, female pups were bred to 60 days and oocytes were collected. Immature oocytes were used in the in-vitro maturation assay; alternatively, in-vivo-matured oocytes were isolated and used for parthenogenetic activation. Both in-vitro- and in-vivo-matured oocytes were subjected to immunostaining of spindle microtubules (α-tubulin) and demethylation of histone H3 on the lysine K27 (H3K27me2) residue. Although very low doses of both BPS and BPF did not affect the quality of ovarian histology, spindle formation and epigenetic signs were affected. Notably, in-vitro-matured oocytes were significantly sensitive to both doses of BPS and BPF. Although no significant differences in spindle-chromatin quality were identified in ovulated and in-vivo-matured oocytes, developmental competence was significantly damaged. Taken together, our mouse model provides evidence that bisphenol analogues represent a risk to human reproduction, possibly leading to idiopathic infertility in women.

Endocrine Disrupting Chemicals and Reproductive Health in Boys and Men

Male reproductive health has declined as indicated by increasing rates of cryptorchidism, i.e., undescended testis, poor semen quality, low serum testosterone level, and testicular cancer. Exposure to endocrine disrupting chemicals (EDCs) has been proposed to have a role in this finding. In utero exposure to antiandrogenic EDCs, particularly at a sensitive period of fetal testicular development, the so-called 'masculinization programming window (MPW)', can disturb testicular development and function. Low androgen effect during the MPW can cause both short- and long-term reproductive disorders. A concurrent exposure to EDCs may also affect testicular function or damage testicular cells. Evidence from animal studies supports the role of endocrine disrupting chemicals in development of male reproductive disorders. However, evidence from epidemiological studies is relatively mixed. In this article, we review the current literature that evaluated relationship between prenatal EDC exposures and anogenital distance, cryptorchidism, and congenital penile abnormality called hypospadias. We review also studies on the association between early life and postnatal EDC exposure and semen quality, hypothalamic-pituitary-gonadal axis hormone levels and testicular cancer.

Endocrine disrupting chemicals and reproductive disorders in women, men, and animal models

This chapter covers the known effects of endocrine disrupting chemicals (EDCs) on reproductive disorders. The EDCs represented are highly studied, including plasticizers (bisphenols and phthalates), chemicals in personal care products (parabens), persistent environmental contaminants (polychlorinated biphenyls), and chemicals in pesticides or herbicides. Both female and male reproductive disorders are reviewed in the chapter. Female disorders include infertility/subfertility, irregular reproductive cycles, early menopause, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and uterine fibroids. Male disorders include infertility/subfertility, cryptorchidism, and hypospadias. Findings from both human and animal studies are represented.

Endocrine disruptors and pregnancy: Knowledge, attitudes and practice of perinatal health professionals. A French multicentre survey

INTRODUCTION

Endocrine disruptors (ED) such as phthalates or bisphenol A are ubiquitous and pregnant women and children are particularly vulnerable. Perinatal health professionals are well-placed to inform pregnant women about the risks. We set out to evaluate perinatal health professionals' knowledge of ED and the information they give during pregnancy.

MATERIAL AND METHODS

We invited midwives, obstetrician-gynecologists (OB/GYN), general practitioners (GP), and general medicine and OB/GYN residents to respond to a short Google survey between August and November 2018 by email using perinatal network.

RESULTS

Out of 4100 questionnaires sent, 1650 completed questionnaires were returned and analyzed. The participation rate was 41 % with the following distribution: midwives (n = 1215, 74 %), OB/GYN residents (n = 102, 6 %), OB/GYNs (n = 129, 8 %), GPs and residents in general medicine (n = 204, 12 %), in private and public hospitals in France. Only 181 of the respondents thought they were well-informed about ED including 160 midwives (11 %). Most of the responding professionals reported not to give any information during pregnancy (n = 946, 57.3 %). Midwives (n = 452, 37.2 %), people >50 years (n = 104, 41.6 %) and people working in private structures (n = 451, 34.9 %) were the most likely to give information, mainly orally. Overall, 346 (74.2 %) of the respondents considered that information about health risks of endocrine disruptors was important and most of them wished they were better informed (n = 1532, 92.9 %).

CONCLUSION

Our study suggests that perinatal health professionals do not have enough medical information, training or tools to communicate about the risks associated with ED to pregnant women and consequently cannot educate them. Research is needed to further explore the risks and support prevention of environmental exposure for pregnant women.