Maternal urinary bisphenol A levels and infant low birth weight: A nested case-control study of the Health Baby Cohort in China

High Levels of BPA and BPF Exposure during Pregnancy Are Associated with Lower Birth Weight in Shenyang in Northeast China

Animal studies indicate that bisphenol A (BPA) has obesogenic effects. Recent experiments reported similar endocrine-disrupting effects of bisphenol F (BPF) and bisphenol S (BPS), which are substitutes of BPA. The aim of this study was to investigate the exposure levels of these bisphenols in pregnant women and their effects on the physical development of infants aged 0-12 months. This study recruited pregnant women who gave birth at a hospital between February 2019 and September 2020. Urine samples from these pregnant women in the third trimester of pregnancy were detected by using ultrahigh-performance liquid chromatography-triple quadruple mass spectrometry. Follow-ups at 6 and 12 months of age were conducted by telephone by pediatricians using a structured questionnaire. Multiple linear regressions were used to determine the associations between bisphenol concentrations and infant weight. A total of 113 mother-child pairs had complete questionnaires and urine samples as well as data on newborns aged 6 months and 12 months. The detection rates of urinary BPA, BPF, and BPS in pregnant women were 100, 62.83, and 46.02%, respectively. Their median levels are 5.84, 0.54, and 0.07 μg/L, respectively. Increased urinary BPA and BPF concentrations during pregnancy were significantly associated with lower birth weight (standardized regression coefficients [β] = -0.081 kg, 95% confidence interval [CI]: -0.134 to -0.027; β = -0.049 kg, 95% CI: -0.097 to -0.001). In addition, urinary BPA and BPF concentrations during pregnancy were positively associated with weight growth rate from 0 to 6 months (β = 0.035 kg/mouth, 95% CI: 0.00-0.064; β = 0.028 kg/mouth, 95% CI: 0.006-0.050), especially in female infants (β = 0.054 kg/mouth, 95% CI: 0.015-0.093; β = 0.035 kg/mouth, 95% CI: 0.005-0.065). Therefore, maternal BPA and BPF levels during pregnancy were negatively correlated with birth weight and positively correlated with the growth rate of infant weight at 0-6 months of age, especially in female infants.

Associations of prenatal exposure to bisphenols with BMI growth trajectories in offspring within the first two years: evidence from a birth cohort study in China

BACKGROUND

Prenatal bisphenol exposure has been reported to be associated with lower birth weight and obesity-related indicators in early childhood. These findings warrant an investigation of the relationship between prenatal bisphenol exposure and the dynamic growth of offspring. This study aimed to evaluate the relationship of maternal bisphenol concentration in urine with the body mass index (BMI) growth trajectory of children aged up to two years and to identify the critical exposure periods.

METHODS

A total of 826 mother-offspring pairs were recruited from Wuhan Children's Hospital between November 2013 and March 2015. Maternal urine samples collected during the first, second, and third trimesters were analyzed for bisphenol A (BPA), bisphenol S, and bisphenol F (BPF) concentrations. Measurements of length and weight were taken at 0, 1, 3, 6, 8, 12, 18, and 24 months. Children's BMI was standardized using the World Health Organization reference, and group-based trajectory modeling was used to identify BMI growth trajectories. The associations between prenatal bisphenol exposure and BMI growth trajectory patterns were assessed using multinomial logistic regression models.

RESULTS

The BMI growth trajectories of the 826 children were categorized into four patterns: low-stable (n = 134, 16.2%), low-increasing (n = 142, 17.2%), moderate-stable (n = 350, 42.4%), and moderate-increasing (n = 200, 24.2%). After adjusting for potential confounders, we observed that prenatal exposure to BPA during the second trimester [odds ratio (OR) = 2.20, 95% confidence interval (CI) = 1.09-4.43] and BPF during the third trimester (OR = 3.28, 95% CI = 1.55-6.95) at the highest quartile concentration were associated with an increased likelihood of the low-increasing BMI trajectory. Furthermore, in the subgroup analysis by infant sex, the positive association between the highest quartile of prenatal average urinary BPF concentration during the whole pregnancy and the low-increasing BMI trajectory was found only in girls (OR = 2.82, 95% CI = 1.04-7.68).

CONCLUSION

Our study findings suggest that prenatal exposure to BPA and BPF (a commonly used substitute for BPA) is associated with BMI growth trajectories in offspring during the first two years, increasing the likelihood of the low-increasing pattern. Video Abstract (MP4 120033 kb).

Associations of prenatal exposure to bisphenols with infant anthropometry: A prospective cohort study

BACKGROUND

Bisphenols (BPs) have been shown to exhibit developmental toxicities. Epidemiological evidence on prenatal BPs exposure and infant growth primarily confined scopes to specific BPs and birth outcomes, with few studies focusing on infant growth and reporting inconsistent findings. The joint effect of prenatal exposure to BPs mixture on infant growth was rarely studied.

OBJECTIVE

This study examined associations of prenatal exposure to individual bisphenol A (BPA) and its analogues (bisphenol F [BPF], bisphenol S [BPS], bisphenol AF [BPAF], and tetrachlorobisphenol A [TCBPA]) and their mixture with infant growth.

METHODS

Urinary concentrations of BPs in pregnant women were quantified. Weight, body mass index, skinfold thickness, and circumference measurements of infants were collected at birth, 6 and 12 months of age, rapid growth and overweight were further defined. Multiple linear regression models and Bayesian kernel machine regression models (BKMR) were used to analyze associations of exposure to individual BPs and BPs mixture with infants' anthropometric measurements, and to identify the important components among mixture. The risks for rapid growth and overweight of each BP were determined using modified Poisson regression models.

RESULTS

A general profile of higher prenatal BPs exposure (mainly BPA, BPF, and BPS) associated with higher anthropometric measurements and higher risks of overweight during infancy was found. We also observed higher risks of rapid growth in infants following prenatal BPs exposure, with risk ratios ranging from 1.46 to 1.91. The joint effect of BPs mixture and single effect of each BP from the BKMR models were consistent with findings from the linear regression models, further suggesting that associations in girls were generally driven by BPA, BPF, or BPS, while in boys mainly by BPF.

CONCLUSION

Prenatal exposure to BPs and their mixture could increase anthropometric measurements of offspring during infancy, with implications of altered growth trajectory in future.

The potential impact of nano- and microplastics on human health: Understanding human health risks

Plastics are used all over the world. Unfortunately, due to limited biodegradation, plastics cause a significant level of environmental pollution. The smallest recognized to date are termed nanoplastics (1 nm [nm] up to 1 μm [μm]) and microplastics (1 μm-5 mm). These nano- and microplastics can enter the human body through the respiratory system via inhalation, the digestive tract via consumption of contaminated food and water, or penetration through the skin via cosmetics and clothes contact. Bioaccumulation of plastics in the human body can potentially lead to a range of health issues, including respiratory disorders like lung cancer, asthma and hypersensitivity pneumonitis, neurological symptoms such as fatigue and dizziness, inflammatory bowel disease and even disturbances in gut microbiota. Most studies to date have confirmed that nano- and microplastics can induce apoptosis in cells and have genotoxic and cytotoxic effects. Understanding the cellular and molecular mechanisms of plastics' actions may help extrapolate the risks to humans. The article provides a comprehensive review of articles in databases regarding the impact of nano- and microplastics on human health. The review included retrospective studies and case reports of people exposed to nanoplastics and microplastics. This research highlights the need for further research to fully understand the extent of the impact of plastics on human health.

The associations between maternal and fetal exposure to endocrine-disrupting chemicals and asymmetric fetal growth restriction: a prospective cohort study

Recent evidence has revealed associations between endocrine-disrupting chemicals (EDCs) and placental insufficiency due to altered placental growth, syncytialization, and trophoblast invasion. However, no epidemiologic study has reported associations between exposure to EDCs and asymmetric fetal growth restriction (FGR) caused by placenta insufficiency. The aim of this study was to evaluate the association between EDC exposure and asymmetric FGR. This was a prospective cohort study including women admitted for delivery to the Maternal Fetal Center at Seoul St. Mary's Hospital between October 2021 and October 2022. Maternal urine and cord blood samples were collected, and the levels of bisphenol-A (BPA), monoethyl phthalates, and perfluorooctanoic acid in each specimen were analyzed. We investigated linear and non-linear associations between the levels of EDCs and fetal growth parameters, including the head circumference (HC)/abdominal circumference (AC) ratio as an asymmetric parameter. The levels of EDCs were compared between fetuses with and without asymmetric FGR. Of the EDCs, only the fetal levels of BPA showed a linear association with the HC/AC ratio after adjusting for confounding variables (β = 0.003, p < 0.05). When comparing the normal growth and asymmetric FGR groups, the asymmetric FGR group showed significantly higher maternal and fetal BPA levels compared to the normal growth group (maternal urine BPA, 3.99 μg/g creatinine vs. 1.71 μg/g creatinine [p < 0.05]; cord blood BPA, 1.96 μg/L vs. -0.86 μg/L [p < 0.05]). In conclusion, fetal exposure levels of BPA show linear associations with asymmetric fetal growth patterns. High maternal and fetal exposure to BPA might be associated with asymmetric FGR.

Bisphenol chemicals in colostrum from Shanghai, China during 2006-2019: Concentration, temporal variation, and potential influence on birth parameters

Bisphenol A (BPA) and its alternatives bisphenol S (BPS) and bisphenol F (BPF) are identified as endocrine disruptors that have negative impacts on infant growth. Their temporal variations in human milk and potential effects on fetal growth are not well known. In this study, colostrum collecting at four time points between 2006 and 2019 and paired urine in 2019 from Shanghai, China, were analyzed for eight bisphenols. The total concentrations in colostrum in 2019 were up to 3.43 ng/mL, with BPA being dominant, followed by BPS and BPF. BPA levels in colostrum noticeably decreased from 2010 to 2013. Additionally, obvious percentage changes in bisphenols were observed in 2019. The BPA concentrations in paired colostrum and urine were not significantly correlated. High levels of BPA in colostrum were linked to a significant reduction in birth head circumference in 2019 (p = 0.031). BPA and BPS in colostrum might have similar negative effect on fetal growth in 2019, but these effects were generally non-significant. Further studies are needed to testify the potential impact. The hazard indexes for infants in the first week of life were below 1, suggesting no obvious health risks. However, the high contribution from BPA still warrants further attention.

Bisphenol A induces placental ferroptosis and fetal growth restriction via the YAP/TAZ-ferritinophagy axis

Exposure to bisphenol A (BPA) during gestation leads to fetal growth restriction (FGR), whereby the underlying mechanisms remain unknown. Here, we found that FGR patients showed higher levels of BPA in the urine, serum, and placenta; meanwhile, trophoblast ferroptosis was observed in FGR placentas, as indicated by accumulated intracellular iron, impaired antioxidant molecules, and increased lipid peroxidation products. To investigate the role of ferroptosis in placental and fetal growth, BPA stimulation was performed both in vivo and in vitro. BPA exposure during gestation was associated with FGR in mice; also, it induces ferroptosis in mouse placentas and human placental trophoblast. Pretreatment with ferroptosis inhibitor ferritin-1 (Fer-1) alleviated BPA-induced oxidative damage and cell death. Notably, BPA reduced the trophoblastic expression of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), which regulated tissue growth and organ size. YAP or TAZ siRNA enhanced BPA-induced ferroptosis, suggesting that trophoblast ferroptosis is dependent on YAP/TAZ downregulation after BPA stimulation. Consistently, the protein levels of YAP/TAZ were also reduced in FGR placentas. Further results revealed that silencing YAP/TAZ promoted BPA-induced ferroptosis through autophagy. Pretreatment with autophagy inhibitor chloroquine (CQ) attenuated BPA-induced trophoblast ferroptosis. Ferritinophagy, an autophagic degradation of ferritin (FTH1), was observed in FGR placentas. Similarly, BPA reduced the protein level of FTH1 in placental trophoblast. Pretreatment with iron chelator desferrioxamine (DFO) and NCOA4 (an autophagy cargo receptor) siRNA weakened the ferroptosis of trophoblast after exposure to BPA, indicating that autophagy mediates ferroptosis in BPA-stimulated trophoblast by degrading ferritin. In summary, ferroptosis was featured in BPA-associated FGR and trophoblast injury; the regulation of ferroptosis involved the YAP/TAZ-autophagy-ferritin axis.

Bisphenol A induces placental ferroptosis and fetal growth restriction via the YAP/TAZ-ferritinophagy axis

Exposure to bisphenol A (BPA) during gestation leads to fetal growth restriction (FGR), whereby the underlying mechanisms remain unknown. Here, we found that FGR patients showed higher levels of BPA in the urine, serum, and placenta; meanwhile, trophoblast ferroptosis was observed in FGR placentas, as indicated by accumulated intracellular iron, impaired antioxidant molecules, and increased lipid peroxidation products. To investigate the role of ferroptosis in placental and fetal growth, BPA stimulation was performed both in vivo and in vitro. BPA exposure during gestation was associated with FGR in mice; also, it induces ferroptosis in mouse placentas and human placental trophoblast. Pretreatment with ferroptosis inhibitor ferritin-1 (Fer-1) alleviated BPA-induced oxidative damage and cell death. Notably, BPA reduced the trophoblastic expression of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), which regulated tissue growth and organ size. YAP or TAZ siRNA enhanced BPA-induced ferroptosis, suggesting that trophoblast ferroptosis is dependent on YAP/TAZ downregulation after BPA stimulation. Consistently, the protein levels of YAP/TAZ were also reduced in FGR placentas. Further results revealed that silencing YAP/TAZ promoted BPA-induced ferroptosis through autophagy. Pretreatment with autophagy inhibitor chloroquine (CQ) attenuated BPA-induced trophoblast ferroptosis. Ferritinophagy, an autophagic degradation of ferritin (FTH1), was observed in FGR placentas. Similarly, BPA reduced the protein level of FTH1 in placental trophoblast. Pretreatment with iron chelator desferrioxamine (DFO) and NCOA4 (an autophagy cargo receptor) siRNA weakened the ferroptosis of trophoblast after exposure to BPA, indicating that autophagy mediates ferroptosis in BPA-stimulated trophoblast by degrading ferritin. In summary, ferroptosis was featured in BPA-associated FGR and trophoblast injury; the regulation of ferroptosis involved the YAP/TAZ-autophagy-ferritin axis.

Influence of maternal endocrine disrupting chemicals exposure on adverse pregnancy outcomes: A systematic review and meta-analysis

Maternal endocrine disrupting chemicals (EDCs) exposure, the common environmental pollutants, was capable of involving in adverse pregnancy outcomes. However, the evidence of their connection is not consistent. Our goal was to comprehensively explore the risk of EDCs related to adverse pregnancy outcomes. One hundred and one studies were included from two databases before 2023 to explore the association between EDCs and adverse pregnancy outcomes including miscarriage, small for gestational age (SGA), low birth weight (LBW) and preterm birth (PTB). We found that maternal PFASs exposure was positively correlated with PTB (OR:1.13, 95% CI:1.04-1.23), SGA (OR:1.10, 95% CI:1.04-1.16) and miscarriage (OR:1.09, 95% CI:1.00-1.19). The pooled estimates also showed maternal PAEs exposure was linked with PTB (OR:1.16, 95% CI:1.11-1.21), SGA (OR:1.20, 95% CI:1.07-1.35) and miscarriage (OR:1.55, 95% CI:1.33-1.81). In addition, maternal exposure to some specific class of EDCs including PFOS, MBP, MEHP, DEHP, and BPA was associated with PTB. Maternal exposure to PFOS, PFOA, PFHpA was associated with SGA. Maternal exposure to BPA was associated with LBW. Maternal exposure to MMP, MEHP, MEHHP, MEOHP, BPA was associated with miscarriage. Maternal PFASs, PAEs and BPA exposure may increase adverse pregnancy outcomes risk according to our study. However, the limited number of studies on dose-response hampered further explanation for causal association.

Prenatal exposure to bisphenol A and neonatal health outcomes: A systematic review

Bisphenol A (BPA) is an endocrine-disrupting chemical substance responsible for the composition of polycarbonate plastics and epoxy resins. Early life and pregnancy are important windows of susceptibility. This review aimed to conduct a systematic assessment of human studies to comprehensively describe the association between prenatal BPA exposure and neonatal health outcomes. Literature was searched in Cochrane Library, Embase, PubMed, Scopus, and Web of Science published before November 2022, and were selected according to clear inclusion and exclusion criteria. The Newcastle-Ottawa scale (NOS) and Grades of Recommendation, Assessment, Development, and Evaluation guidelines (GRADE) were followed to grade the methodological quality of studies and the certainty of the evidence respectively. As a result, a total of 22259 participants from 45 trials were included. And the potential associations of prenatal exposure to BPA and neonatal health outcomes were mainly shown in four aspects: gestational age/preterm birth, physical health at birth, the incidence of systemic abnormalities or diseases, and other health outcomes. Although the certainty of the evidence was low to very low, the methodological quality of the included studies was high. Prenatal BPA exposure tended to have negative effects on most of the health outcomes in neonates but showed inconsistent results on physical health at birth. This systematic review is the first to comprehensively synthesize the existing evidence on the association between prenatal BPA exposure and neonatal health outcomes. In the future, further studies are still needed to verify these effects and elucidate the underlying mechanisms.

Endocrine-disrupting chemicals and autoimmune diseases

Endocrine-disrupting chemicals (EDCs) widely exist in people's production and life which have great potential to damage human and animal health. Over the past few decades, growing attention has been paid to the impact of EDCs on human health, as well as immune system. So far, researchers have proved that EDCs (such as bisphenol A (BPA), phthalate, tetrachlorodibenzodioxin (TCDD), etc.) affect human immune function and promotes the occurrence and development of autoimmune diseases (ADs). Therefore, in order to better understand how EDCs affect ADs, we summarized the current knowledge about the impact of EDCs on ADs, and elaborated the potential mechanism of the impact of EDCs on ADs in this review.

Association between prenatal exposure to perfluoroalkyl substance mixtures and intrauterine growth restriction risk: A large, nested case-control study in Guangxi, China

Intrauterine growth restriction (IUGR) is an abnormal fetal growth pattern that can lead to neonatal morbidity and mortality. IUGR may be affected by prenatal exposure to environmental pollutants, including perfluoroalkyl substances (PFASs). However, research linking PFAS exposure to IUGR is limited, with inconsistent results. We aimed to investigate the association between PFAS exposure and IUGR by using nested casecontrol study based on Guangxi Zhuang Birth Cohort (GZBC), in Guangxi, China. A total of 200 IUGR cases and 600 controls were enrolled in this study. The maternal serum concentrations of nine PFASs were measured using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLCMS). The associations single and mixed effects of prenatal PFAS exposure on IUGR risk were assessed using conditional logistic regression (single-exposure), Bayesian kernel machine regression (BKMR) and quantile g-computation (qgcomp) models. In the conditional logistic regression models, the log10-transformed concentrations of perfluoroheptanoic acid (PFHpA, adjusted OR: 4.41, 95% CI: 3.03-6.41), perfluorododecanoic acid (PFDoA, adjusted OR: 1.94, 95% CI: 1.14-3.32), and perfluorohexanesulfonate (PFHxS, adjusted OR: 1.83, 95% CI: 1.15-2.91) were positively associated with risk of IUGR. In the BKMR models, the combined effect of PFASs was positively associated with IUGR risk. In the qgcomp models, we also found an increased IUGR risk (OR=5.92, 95% CI: 2.33-15.06) when all nine PFASs increased by one tertile as a whole, and PFHpA (43.9%) contributed the largest positive weights. These findings suggested prenatal exposure to single and mixtures of PFASs may increase IUGR risk, with the effect being largely driven by the PFHpA concentration.

Sex-specific effects of prenatal organophosphate ester (OPE) metabolite mixtures and adverse infant birth outcomes in the maternal and developmental risks from environmental and social stressors (MADRES) pregnancy cohort

BACKGROUND

Organophosphate esters (OPEs) are used as flame retardants and plasticizers in various consumer products. Limited prior research suggests sex-specific effects of prenatal OPE exposures on fetal development. We evaluated overall and sex-specific associations between prenatal OPE exposures and gestational age (GA) at birth and birthweight for gestational age (BW for GA) z-scores among the predominately low-income, Hispanic MADRES cohort.

METHODS

Nine OPE metabolite concentrations were measured in 421 maternal urine samples collected during a third trimester visit (GA = 31.5 ± 2.0 weeks). We examined associations between single urinary OPE metabolites and GA at birth and BW for GA z-scores using linear regression models and Generalized Additive Models (GAMs) and effects from OPE mixtures using Bayesian Kernel Machine Regression (BKMR). We also assessed sex-specific differences in single metabolite analyses by evaluating statistical interactions and stratifying by sex.

RESULTS

We did not find significant associations between individual OPE metabolites and birth outcomes in the full infant sample; however, we found that higher bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) was associated with earlier GA at birth among male infants (p = 0.04), and a nonlinear, inverted U-shape association between the sum of dibutyl phosphate and di-isobutyl phosphate (DNBP + DIBP) and GA at birth among female infants (p = 0.03). In mixtures analysis, higher OPE metabolite mixture exposures was associated with lower GA at birth, which was primarily driven by female infants. No associations were observed between OPE mixtures and BW for GA z-scores.

CONCLUSION

Higher BDCIPP and DNBP + DIBP concentrations were associated with earlier GA at birth among male and female infants, respectively. Higher exposure to OPE mixtures was associated with earlier GA at birth, particularly among female infants. However, we saw no associations between prenatal OPEs and BW for GA. Our results suggest sex-specific impacts of prenatal OPE exposures on GA at birth.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Human body burden of bisphenol A: a case study of lactating mothers in Florianopolis, Brazil

Exclusive breast milk is the diet recommended by the World Health Organization (WHO) until 6 months of age. However, breastfeeding has the potential of transferring certain toxic chemicals from the mother to the infant. Bisphenol A (BPA) is a synthetic chemical used as a monomer in polycarbonate plastics and epoxy resins. Information on BPA concentration in the breast milk of lactating mothers is very limited; thus, this study aimed to determine the concentration of BPA in the colostrum of 64 post-partum women at a university-affiliated tertiary hospital in South Brazil. The results showed that all the breast milk samples contained a high concentration of BPA with a median value of 34.18 ng/mL. Furthermore, the concentration of BPA in mothers was influenced by the consumption of foods packaged in plastic packaging, especially when the plastic is heated (p = 0.0182). The total daily intake of BPA in breastfed infants was 19.5 µg/kg/day and 28.5 µg/kg/day was recorded at the 95th percentile of body weight per day, which is higher than the maximum daily intake estimated by the European Authority of Food Safety. These data showed a high concentration of BPA in the breastmilk of the lactating mothers which might be through the use of plastic containers as food/drink packages. This is of public health importance as the high concentration of BPA in their breast milk can be an indicator of potentially serious health problems in these mothers and much more in the babies breastfed with BPA-contaminated breast milk.

Endocrine disruptor chemicals, adipokines and reproductive functions

The prevalence of adult obesity has risen markedly in recent decades. The endocrine system precisely regulates energy balance, fat abundance and fat deposition. Interestingly, white adipose tissue is an endocrine gland producing adipokines, which regulate whole-body physiology, including energy balance and reproduction. Endocrine disruptor chemicals (EDCs) include natural substances or chemicals that affect the endocrine system by multiple mechanisms and increase the risk of adverse health outcomes. Numerous studies have associated exposure to EDCs with obesity, classifying them as obesogens by their ability to activate different mechanisms, including the differentiation of adipocytes, increasing the storage of triglycerides, or elevating the number of adipocytes. Moreover, in recent years, not only industrial deception and obesity have intensified but also the problem of human infertility. Reproductive functions depend on hormone interactions, the balance of which may be disrupted by various EDCs or obesity. This review gives a brief summary of common EDCs linked with obesity, the mechanisms of their action, and the effect on adipokine levels, reproduction and connected disorders, such as polycystic ovarian syndrome, decrease in sperm motility, preeclampsia, intrauterine growth restriction in females and decrease of sperm motility in males.

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.

Cross-Generational Impacts of Diet Shift on Bisphenol Analogue Loads in Indo-Pacific Humpback Dolphins (Sousa chinensis)

Bisphenol analogues (BPs) are ubiquitous pollutants to marine organisms as endocrine disruptive chemicals. However, the residue contamination and the trophic transfer of BPs in the apex predator nearshore dolphins are poorly studied. Here, we measured the concentrations of six BPs, including bisphenol A (BPA), bisphenol AF (BPAF), bisphenol B (BPB), bisphenol F (BPF), bisphenol P (BPP), and bisphenol S (BPS) in the liver of Indo-Pacific humpback dolphin (Sousa chinensis) (n = 75) collected from the Pearl River Estuary during a period with significant dietary changes (2004-2020). BPA and BPAF were the dominant components of the residue ∑BPs in the liver, with a proportion of 80%. Sex, maturity, and stranding location had no significant effects on BP levels. The generalized additive models indicated that BPA levels in juveniles and adults decreased from 2004 to 2013 while increasing from 2013 to 2020. The temporal trend of BPA levels was likely driven by the shift of the dominant diet from Harpadon nehereus to Thryssa spp. The concurrent increase of BPA loads in calves and juveniles and adults over the recent decades suggested that the diet-mediated variations of maternal BPA levels could be redistributed to their offspring.

Association between human herpesvirus 6 (HHV-6) and cognitive function in the elderly population in Shenzhen, China

AIM

Human herpesvirus 6 (HHV-6) is neurophilic, and its relationship with Alzheimer's disease (AD) remains controversial. This study aimed to examine the relationships between HHV-6 and cognitive abilities in elderly people aged 60 years or above from communities in Shenzhen.

METHODS

We recruited participants from 10 community health service centers in Shenzhen. Participants were divided into case and control groups according to Mini-Mental State Examination (MMSE) scale standards and were included in this study with 1:1 matching based on sex and age (± 3 years). The HHV-6 gene was detected by real-time fluorescent quantitative PCR, and the HHV-6 copy number was quantified.

RESULTS

A total of 580 participants (cases, n = 290; controls, n = 290), matched for gender and age was included in this study. A positive HHV-6 test was not associated with a significant difference in global cognitive performance (OR_adjusted = 1.651, 95% CI = 0.671-4.062). After adjusting for gender, age, education, Pittsburgh Sleep Quality Index (PSQI) score, homocysteine (Hcy) and glycosylated hemoglobin (HbA1c), the results of multiple linear regression showed that there was a statistically negative correlation between HHV-6 copy number and orientation (β_adjusted = -0.974, p = 0.013), attention and calculation (β_adjusted = -1.840, p < 0.001), and language (β_adjusted = -2.267, p < 0.001). The restricted cubic spline (RCS) model results showed that there was a nonlinear dose-response relationship between HHV-6 log10-transformed copies and orientation (p_overall = 0.003, p_nonliner = 0.045), attention and calculation (p_overall < 0.001, p_nonliner < 0.001), and language (p_overall < 0.001, p_nonliner = 0.016).

CONCLUSIONS

HHV-6 infection significantly associated with orientation, attention and calculation, and language in elderly individuals.

Risk factors associated with low birth weight

OBJECTIVES

Low birth weight (LBW) is one of the major factors affecting child morbidity and mortality worldwide. Every day, approximately 800 women die from causes related to pregnancy and childbirth worldwide. Maternal ill health increases the risk of LBW. This study seeks to investigate determinants and incidence of LBW.

METHODS

This study was conducted based on the medical records of mothers and their 1,946 infants born in 2016-2019 at the Department of Gynaecology and Obstetrics of Louis Pasteur University Hospital in Košice. Data on mothers and newborn infants were obtained from the Reports on mothers at childbirth. The inclusion criteria were singleton births and birth weight > 500 g. The exclusion criteria were twins or multiple births, congenital anomalies and stillbirths, birth weight ≥ 4,000 g or ≤ 500 g, and Roma ethnicity. Roma children are more likely to be born prematurely, with low birth weight. Roma mothers have different lifestyle. Univariate analysis was employed to evaluate the association between the independent variables and LBW. Variables that were found to be statistically significant were then further analysed using multivariable logistic analysis for each dependent variable. The implementation of the research was approved by the Ethics Committee.

RESULTS

Of 1,946 newborns, 271 (13.90%) have low birth weight. The mean of birth weight at delivery was 3,068.62 (SD 671.16) grams. Factors that were associated with LBW were primary maternal education (OR = 2.98, 95% CI: 1.08-8.21, p = 0.034), marital status single (OR = 2.88, 95% CI: 1.68-4.94, p < 0.001), number of prenatal care visits less than 8 (OR = 1.62, 95% CI: 1.01-2.61, p = 0.047), and preterm birth (OR = 74.94, 95% CI: 45.44-123.61, p < 0.001).

CONCLUSION

The reducing of LBW requires strategies to improve maternal lifestyle, maternal care before, during and after birth and to strengthen social support.

Sex-specific effects of Bisphenol a on the signalling pathway of ESRRG in the human placenta

Bisphenol A (BPA) exposure during pregnancy is associated with low fetal weight, particularly in male fetuses. The expression of estrogen-related receptor gamma (ESRRG), a receptor for BPA in the human placenta, is reduced in fetal growth restriction. This study sought to explore whether ESRRG signaling mediates BPA-induced placental dysfunction and determine whether changes in the ESRRG signaling pathway are sex-specific. Placental villous explants from 18 normal term pregnancies were cultured with a range of BPA concentrations (1 nM–1 μM). Baseline BPA concentrations in the placental tissue used for explant culture ranged from 0.04 to 5.1 nM (average 2.3 ±1.9 nM; n = 6). Expression of ESRRG signaling pathway constituents and cell turnover were quantified. BPA (1 μM) increased ESRRG mRNA expression after 24 h in both sexes. ESRRG mRNA and protein expression was increased in female placentas treated with 1 μM BPA for 24 h but was decreased in male placentas treated with 1 nM or 1 μM for 48 h. Levels of 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) and placenta specific-1 (PLAC1), genes downstream of ESRRG, were also affected. HSD17B1 mRNA expression was increased in female placentas by 1 μM BPA; however, 1 nM BPA reduced HSD17B1 and PLAC1 expression in male placentas at 48 h. BPA treatment did not affect rates of proliferation, apoptosis, or syncytiotrophoblast differentiation in cultured villous explants. This study has demonstrated that BPA affects the ESRRG signaling pathway in a sex-specific manner in human placentas and a possible biological mechanism to explain the differential effects of BPA exposure on male and female fetuses observed in epidemiological studies.

Trimester two gestational exposure to bisphenol A and adherence to mediterranean diet are associated with adolescent offspring oxidative stress and metabolic syndrome risk in a sex-specific manner

Background

Exposure to prenatal bisphenol A (BPA) and Mediterranean Diet Score (MDS) has been linked to metabolic risk in child offspring. It remains unclear if independent and interactive effects persist in adolescence.

Methods

We examined prenatal BPA and MDS on adolescent offspring metabolic syndrome risk score (MRS) and 8-isoprostane (8-iso), a biomarker of oxidative stress. Data from maternal-adolescent dyads from a Mexico City cohort were utilized, including trimester-specific prenatal BPA from spot urine and MDS from food frequency questionnaires. Offspring socio-demographic data and biomarkers to estimate MRS and 8-iso were obtained during peri-adolescence.

Results

Adjusted linear regression models examined associations between trimester-specific BPA, MDS, and BPA^*MDS on outcomes. Sex-stratified analyses revealed a significant association between MDS with increased 8-iso (β = 0.064, p < 0.05), and a marginal association between trimester two BPA with increased 8-iso (β = 0.237), while MDS modified the marginal association between BPA and 8-iso in females (β = 0.046). A negative, marginal association was observed between trimester two BPA and MRS (β = - 0.728), while BPA ^* MDS was marginally, positively associated with MRS (β = 0.152) in males.

Conclusions

Study findings indicate that trimester two prenatal BPA and maternal adherence to a Mediterranean diet may have sexually dimorphic effects on adolescent offspring oxidative stress and metabolic syndrome risk.

Teratogenicity and toxicity of the new BPA alternative TMBPF, and BPA, BPS, and BPAF in chick embryonic development

Bisphenol A (BPA) is a widely known, yet controversial reproductive toxin, capable of inducing reproductive, developmental, and somatic growth defects across species. Due to scientific findings and public concern, companies have developed BPA alternatives remarkably similar to BPA. However, these alternatives have had much less testing and oversight, yet they are already being mass-produced and used across industries from plastics to food-contact coatings. The newest one, tetramethyl bisphenol F (TMBPF), is the least well-studied and has never been investigated in embryological models, however it continues to be mass produced and found in various products. Here, we used the chicken embryotoxicity screening test to compare the toxicities and potencies of several BPA analogs including TMBPF. We exposed developing chicken (Gallus gallus domesticus) embryos in ovo, from embryonic day 5 to 12 (E5-12), to increasing concentrations of BPA, bisphenol S (BPS), bisphenol AF (BPAF), and TMBPF, from 0.003 to 30 μM, and analyzed their developmental and toxic effects. The bisphenols significantly impaired development, growth, and survival in a dose-dependent manner, even at low, environmentally relevant concentrations of 3-30 nM. There was severely reduced growth and developmental delay, with exposed embryos averaging half the size and weight of control vehicle-treated embryos. The most common and severe dysmorphologies were craniofacial, eye, gastrointestinal, and body pigmentation abnormalities. The bisphenols caused dose-dependent toxicity with the lowest LC₅₀s (lethal concentration with 50% survival) ever demonstrated in chick embryos, at 0.83-2.92 μM. Notably, TMBPF was the second-most toxic and teratogenic of all chemicals tested (rank order of BPAF > TMBPF > BPS > BPA). These results underscore the adverse effects of BPA replacements on early embryo development and may have implications for reproductive health and disease across species, including pregnancy exposures in humans.

Association of maternal exposure to bisphenol A with her β-hCG level and neonatal anthropometric measures

Bisphenol A (BPA) is one of the organic compounds that might interfere with estrogenic receptors, which would make difficulties in pregnancy hormones and fetal growth. Human chorionic gonadotropin (β-hCG) is one of the important pregnancy hormones that might be affected by environmental pollutants. The aim of this study is to investigate the probable impacts of maternal exposure to BPA on anthropometric measures of newborns. This cross-sectional study was conducted in 2019-2020 in Isfahan, Iran. During the first trimester of pregnancy, we measured the urinary BPA concentration and serum β-hCG level of 120 pregnant women, who were randomly selected from participants of a birth cohort. BPA concentration was measured using gas chromatography-mass spectrometry (GC-MS). Serum blood sample was derived and used for β-hCG analysis. Anthropometric measurement of neonates was conducted at the time of birth. BPA and β-hCG level were grouped by quartiles, and their associations with birth weight, height, and head circumference were tested using multiple linear regression model. The adjustment was done for urine creatinine, gender, and gestational age, as well as maternal age, body mass index, and education level. Data of 119 pairs of mothers and infants were available for the present study. The mean (SD) age of mothers was 29.19 (5.75) years; 56.3% of newborns were boys. Geometric mean of urinary BPA and β-hCG concentrations were 0.36 ng/g crea. (creatinine) and 17736 mIU/ml, respectively. Across the BPA tertiles, the differences in mean values were not significant for none of the anthropometric measurements and gestational age (GA). Furthermore, no significant association existed between unadjusted and adjusted tertiles of BPA and β-hCG with abovementioned birth outcomes. It seems that the non-significant association found in this study is because of low levels of urinary BPA levels than in other studies; the adverse effects on infants might be related to high concentration of BPA passed from placenta. Future longitudinal studies with large sample size are necessary to document the adverse health effects of maternal exposure to endocrine disruptor chemicals including BPA.

Urinary Concentrations of Bisphenol Mixtures during Pregnancy and Birth Outcomes: The MAKE Study

Bisphenols are endocrine disruptors that may be associated with altered fetal growth in humans, and they have similar biological functions to mimic hormones. In addition, aggregated chemicals showed an adverse effect although individual concentration was at a low level. However, most studies between bisphenols and birth outcomes have focused on the effect of individual bisphenol. Thus, we explored the associations of urinary bisphenol mixtures with birth outcomes. We conducted a prospective birth cohort study in South Korea. One hundred eighty mother-infant pairs were recruited from 2017 to 2019. Bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS) in one spot urine were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. We used two statistical approaches to examine potential associations of BPA, BPF, and BPS with birth weight and gestational age: (1) multivariable linear regression; (2) Bayesian kernel machine regression (BKMR). The geometric means of BPA, BPF, and BPS were 2.1, 0.2, and 0.1 μg/L, respectively. In stratified linear analyses by each median value, a higher BPF was positively associated with birth weight (g) (β = 125.5; 95% CI: 45.0 to 205.9). Mixture analyses using BKMR suggested an inverse association between bisphenol mixtures and birth weight. Our findings suggest that in utero bisphenol exposure may influence birth weight and that such relationships may differ considering non-linearity and the combined effect.

The associations of birth outcome differences in twins with prenatal exposure to bisphenol A and its alternatives

BACKGROUND

Bisphenol A (BPA) and its alternatives, including BPF and BPS, exhibit endocrine disruption activities. However, the effects of bisphenols on fetal growth in twins remain unclear.

OBJECTIVE

To explore the associations of prenatal BPA, BPF, and BPS exposure with birth outcome differences in twins.

METHODS

We recruited 289 twin pregnant women who visited the hospital for prenatal examination during the first trimester from 2013 to 2016. Urinary bisphenol levels were determined during the first, second, and third trimesters. The associations of maternal exposure to bisphenols with birth outcome differences in twins were analyzed after stratification by different trimesters. We applied the multiple informant model to estimate trimester-specific associations between urinary bisphenol concentrations and birth outcome differences in twins.

RESULTS

We found low reproducibility (ICC<0.40) for maternal urinary BPA and moderate reproducibility (0.40 < ICC<0.75) for BPF and BPS. Urinary BPA concentrations were positively associated with within-pair twin birth weight difference when comparing the third vs. the first tertile in each of the three trimesters (i.e., 133.06 g, 95% CI: 68.19, 197.94; 144.5 g, 95%CI: 81.82-207.18 g; and 135.04 g, 95%CI: 71.37-198.71 g for the 1st, 2nd, and 3rd trimester, respectively). The effect of urinary BPA concentration on increased birth length difference within-pair twins were also observed across different trimesters (All P for trends < 0.05). Urinary BPA levels were positively associated with the within-pair birth weight and birth length differences across pregnancy trimesters (All of Type 3 P for values < 0.05).

CONCLUSION

Maternal BPA exposure appeared to influence birth wight and birth length differences in twins. Our results warrant further confirmation.

A Systematic Review of Bisphenol A from Dietary and Non-Dietary Sources during Pregnancy and Its Possible Connection with Fetal Growth Restriction: Investigating Its Potential Effects and the Window of Fetal Vulnerability

Bisphenol A (BPA), a ubiquitous endocrine-disrupting chemical (EDC), is increasingly hypothesized to be a factor contributing to changes in fetal growth velocity. BPA exposure may be environmental, occupational, and/or dietary, with canned foods and plastic bottles contributing significantly. Our systematic review aims to evaluate the current literature and to investigate the role of BPA in abnormal fetal growth patterns. A search was conducted in the PubMed and Cochrane databases. A total of 25 articles met the eligibility criteria and were included in this systematic review. Eleven of them failed to show a clear relationship between BPA and abnormal fetal growth. The majority of the remaining studies (9/14) found an inverse association of BPA with indicators of fetal growth, whereas three studies suggested increased fetal growth, and two studies produced contradictory findings. Of note, both of the studies that collected a sample (amniotic fluid) directly reflecting BPA concentration in the fetus during the first half of pregnancy revealed an inverse association with birth weight. In conclusion, there is mounting evidence that combined exposure to BPA from dietary and non-dietary sources during pregnancy may contribute to abnormal fetal growth; a tendency towards fetal growth restriction was shown, especially when exposure occurs during the first half.

Prenatal Bisphenol a Exposure, DNA Methylation, and Low Birth Weight: A Pilot Study in Taiwan

Prenatal exposure to bisphenol A (BPA) may increase the risk of abnormal birth outcomes, and DNA methylation might mediate these adverse effects. This study aimed to investigate the effects of maternal BPA exposure on maternal and fetal DNA methylation levels and explore whether epigenetic changes are related to the associations between BPA and low birth weight. We collected urine and blood samples originating from 162 mother-infant pairs in a Taiwanese cohort study. We measured DNA methylation using the Illumina Infinium HumanMethylation 450 BeadChip in 34 maternal blood samples with high and low BPA levels based on the 75th percentile level (9.5 μg/g creatinine). Eighty-seven CpGs with the most differentially methylated probes possibly interacting with BPA exposure or birth weight were selected using two multiple regression models. Ingenuity pathway analysis (IPA) was utilized to narrow down 18 candidate CpGs related to disease categories, including developmental disorders, skeletal and muscular disorders, skeletal and muscular system development, metabolic diseases, and lipid metabolism. We then validated these genes by pyrosequencing, and 8 CpGs met the primer design score requirements in 82 cord blood samples. The associations among low birth weight, BPA exposure, and DNA methylation were analyzed. Exposure to BPA was associated with low birth weight. Analysis of the epigenome-wide findings did not show significant associations between BPA and DNA methylation in cord blood of the 8 CpGs. However, the adjusted odds ratio for the dehydrogenase/reductase member 9 (DHRS9) gene, at the 2nd CG site, in the hypermethylated group was significantly associated with low birth weight. These results support a role of BPA, and possibly DHRS9 methylation, in fetal growth. However, additional studies with larger sample sizes are warranted.

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.

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.

Human biomonitoring of bisphenol A along pregnancy: An exposure reconstruction of the EXHES-Spain cohort

This study was aimed at reconstructing the exposure to bisphenol (BPA) of 60 pregnant women from the EXHES-Spain cohort. A biomonitoring study was conducted by determining BPA levels in urine samples over the three trimesters of pregnancy. Moreover, the correlations between BPA levels and the role of different potential exposure sources, with special emphasis on the dietary intake, were also studied. Urine samples were subjected to dispersive liquid-liquid microextraction and the subsequent analysis via gas chromatography-mass spectrometry. BPA was detected in 76% of the urine samples. A significant decrease of urinary BPA levels was observed along pregnancy, as mean concentrations of creatinine-adjusted BPA were 4.64, 4.84 and 2.51 μg/g in the first, second and third trimester, respectively. This decrease was essentially associated with changes in the dietary habits of the pregnant women, including a lower intake of canned food and drinks. However, the potential role of other pregnancy-related biochemical or physiological factors should not be disregarded. Very interestingly, significant differences in urine BPA levels were found according to the fruit consumption pattern, as women who ate more citrus fruits showed lower BPA concentrations in urine. The reconstructed exposure to BPA was estimated in 0.072, 0.069 and 0.038 μg BPA/kg of body weight/day in the first, second and third trimesters, respectively. These values are far below the temporary tolerable daily intake (t-TDI) established by the EFSA.

The effect of plastic bottled water consumption on outcomes of ICSI cycles undertaken for unexplained infertility

RESEARCH QUESTION

Do bisphenol A (BPA) levels in maternal urine, serum and follicular fluid affect embryo quality and intracytoplasmic sperm hinjection (ICSI) cycle outcomes in women with unexplained infertility?

DESIGN

Prospective study conducted between 1 April 2019 and 30 September 2019. The study cohort consisted of 82 women aged between 23 and 33 years who underwent intracytoplasmic sperm injection owing to unexplained infertility and provided urine, blood and follicular fluid samples on the day of oocyte retrieval. Consumption of drinking water from plastic carboys or bottles at home were considered as chronic BPA exposure. Demographic features and IVF outcomes of the patients were collected.

RESULTS

Among the 82 women with unexplained infertility, clinical pregnancy was achieved in 22 (26.8%) patients after the IVF and embryo transfer cycle. The patients who consumed tap water had statistically significantly lower BPA values in three body fluids compared with patients who consumed plastic bottled water (all P < 0.001). Women who had grade 1 embryos transferred had lower serum BPA values than women who had grade 2 embryos transferred (10.8 ± 5.2 versus 26.9 ± 22 ng/ml, P = 0.003). Serum and follicular fluid BPA levels were statistically significantly higher in women who failed to achieve clinical pregnancy (P < 0.001, P = 0.006, respectively) and obtain a live birth (both P = 0.007).

CONCLUSIONS

A negative relationship was found between serum and follicular fluid BPA levels and embryo quality, clinical pregnancy and live birth in these women. In addition, the BPA levels of women who consume tap water at home were lower than those who use plastic bottled water.

Multisystemic alterations in humans induced by bisphenol A and phthalates: Experimental, epidemiological and clinical studies reveal the need to change health policies

A vast amount of evidence indicates that bisphenol A (BPA) and phthalates are widely distributed in the environment since these compounds are mass-produced for the manufacture of plastics and plasticizers. These compounds belong to a large group of substances termed endocrine-disrupting chemicals (EDC). It is well known that humans and living organisms are unavoidably and unintentionally exposed to BPA and phthalates from food packaging materials and many other everyday products. BPA and phthalates exert their effect by interfering with hormone synthesis, bioavailability, and action, thereby altering cellular proliferation and differentiation, tissue development, and the regulation of several physiological processes. In fact, these EDC can alter fetal programming at an epigenetic level, which can be transgenerational transmitted and may be involved in the development of various chronic pathologies later in the adulthood, including metabolic, reproductive and degenerative diseases, and certain types of cancer. In this review, we describe the most recent proposed mechanisms of action of these EDC and offer a compelling selection of experimental, epidemiological and clinical studies, which show evidence of how exposure to these pollutants affects our health during development, and their association with a wide range of reproductive, metabolic and neurological diseases, as well as hormone-related cancers. We stress the importance of concern in the general population and the urgent need for the medical health care system to closely monitor EDC levels in the population due to unavoidable and involuntary exposure to these pollutants and their impact on human health.

Cumulative health risks for bisphenols using the maximum cumulative ratio among Chinese pregnant women

Bisphenol A and its alternatives are frequently detected in environmental and human samples, but studies associated with the pattern of combined health hazards from the exposure to the bisphenol mixtures are lacking, particularly for pregnant women. Here, we recruited 941 pregnant women with a full set of urine samples in the three trimesters collected under a cohort study project in Wuhan, China, between 2014 and 2015. We measured the concentrations of 8 bisphenols in 2823 urine samples, and calculated the average concentrations of bisphenols, which were detected in over 50% of samples, once during each trimester of pregnancy. We calculated the maximum cumulative ratio (MCR) on basis of estimated daily intake (EDI), hazard quotient (HQ), hazard index (HI) of three major bisphenols, including bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS), to find which one or mixtures drive risks. Participants were categorized into four groups according to their maximum HQ, HI and MCR values. We found negative relationships between log(MCR-1) and log(HI) with the slope (-0.6431). Percentage of HQ of BPA in HI ranged from 37.1% (<25th percentiles of HI) to 75.5% (>95th percentiles of HI) indicating the upward trend of dominance by BPA at increasing HI ranges. The cumulative health risks of bisphenol exposures largely originated from the health hazards of BPA and BPS, particularly BPA. The intervention for regulation on the production and application of BPA and its alternatives are urgent, and China should consider national regulation on these chemicals based on its risk to human health.

Independent and combined effects of Bisphenol A and Diethylhexyl Phthalate on gestational outcomes and offspring development in Sprague-Dawley rats

Bisphenol A (BPA) and Diethylhexyl Phthalate (DEHP) are well-studied endocrine disrupting chemicals (EDCs), however, the effects of mixtures of these EDCs are not. To assess the consequences of prenatal exposure to a mixture of these EDCs, dams were orally administered either saline (control), BPA (5 μg/kg BW/day), high dose DEHP (HD-D; 7.5 mg/kg BW/day), or a combination of BPA with HD-D in experiment 1; saline, BPA (5 μg/kg BW/day), low-dose DEHP (LD-D; 5 μg/kg BW/day) or a combination of BPA with LD-D in experiment 2. Gestational weights, number of abortions, litter size and weights, number of live births and stillbirths were recorded. Morphometric measures were obtained at birth and body weight, food and water intake were monitored weekly from postnatal weeks 3-12. Offspring were sacrificed at 16-24 weeks of age and organ weights were measured. The abortion rate of dams exposed to HD-D and the mixtures, BPA + LD-D and BPA + HD-D were higher at 9, 14 and 27% respectively. Prenatal exposure to BPA or HD-D significantly decreased relative thymus weights in male but not female offspring. Apoptotic cells were detected in thymus sections of both male and female offspring prenatally exposed to DEHP. Relative heart weights increased in BPA + HD-D exposed male offspring compared to the other groups. The results indicate that a mixture of BPA and DEHP, produced a pronounced effect on pregnancy outcomes. Male offspring appear to be more susceptible to the programming effects of these EDCs or their mixture suggesting a need to reconsider the possible additive, antagonistic or synergistic effects of EDC mixtures.

Sex-specific associations of prenatal exposure to bisphenol A and its alternatives with fetal growth parameters and gestational age

BACKGROUND

Bisphenol A (BPA) can cause detrimental effects on fetal growth. However, the effects of BPA alternatives, such as bisphenol F (BPF) and bisphenol S (BPS), on fetal growth are less known.

OBJECTIVE

To investigate the relationships of prenatal BPA, BPF, and BPS exposures with fetal growth parameters and gestational age.

METHODS

Urinary BPA, BPF, and BPS were measured in 1,197 pregnant women before delivery in a Chinese cohort. The associations of prenatal exposure to BPA, BPF, and BPS with fetal growth parameters and gestational age were examined, and associations stratified by fetal sex were also conducted. We used a restricted cubic splines (RCS) model to examine the dose-response associations between exposures and outcomes.

RESULTS

Maternal urinary BPA and BPF were negatively related to birth length (-0.30 cm, 95% CI: -0.44, -0.15 and -0.21 cm, 95% CI: -0.36, -0.07 comparing the extreme exposure groups, respectively, both p for trends < 0.01). These associations were more pronounced in girls with inverted U-shaped dose-response relationships. Maternal urinary BPA and BPF were positively related to ponderal index (0.05 g/cm³ × 100, 95% CI: 0.01, 0.09 and 0.04 g/cm³ × 100, 95% CI: 0.01, 0.08 comparing the extreme exposure groups, respectively, both p for trends = 0.02), and maternal urinary BPS was associated with shorter gestational age (-0.20 weeks, 95% CI: -0.37, -0.03 comparing the extreme exposure groups, p for trend = 0.02). These associations were only observed in girls and exhibited a linear dose-response relationship.

CONCLUSIONS

Prenatal BPA, BPF, and BPS exposures were associated with detrimental effects on fetal growth parameters, and stronger effects were noted in female infants.

Environmental Endocrine-Disrupting Chemical Exposure: Role in Non-Communicable Diseases

The exponential growth of pollutant discharges into the environment due to increasing industrial and agricultural activities is a rising threat for human health and a biggest concern for environmental health globally. Several synthetic chemicals, categorized as potential environmental endocrine-disrupting chemicals (EDCs), are evident to affect the health of not only livestock and wildlife but also humankind. In recent years, human exposure to environmental EDCs has received increased awareness due to their association with altered human health as documented by several epidemiological and experimental studies. EDCs are associated with deleterious effects on male and female reproductive health; causes diabetes, obesity, metabolic disorders, thyroid homeostasis and increase the risk of hormone-sensitive cancers. Sewage effluents are a major source of several EDCs, which eventually reach large water bodies and potentially contaminate the drinking water supply. Similarly, water storage material such as different types of plastics also leaches out EDCs in drinking Water. Domestic wastewater containing pharmaceutical ingredients, metals, pesticides and personal care product additives also influences endocrine activity. These EDCs act via various receptors through a variety of known and unknown mechanisms including epigenetic modification. They differ from classic toxins in several ways such as low-dose effect, non-monotonic dose and trans-generational effects. This review aims to highlight the hidden burden of EDCs on human health and discusses the non-classical toxic properties of EDCs in an attempt to understand the magnitude of the exposome on human health. Present data on the environmental EDCs advocate that there may be associations between human exposure to EDCs and several undesirable health outcomes that warrants further human bio-monitoring of EDCs.

Urinary bisphenol A and its interaction with ESR1 genetic polymorphism associated with non-small cell lung cancer: findings from a case-control study in Chinese population

Bisphenol A (BPA), a well-known endocrine disruptor, was reported to promote migration and invasion of lung cancer cells, but findings in human study is absent. A case-control study in Chinese population was conducted to evaluate the association between BPA exposure and non-small cell lung cancer (NSCLC), and explore the interaction between BPA exposure and estrogen-related genetic polymorphism on NSCLC. BPA concentrations were measured in urine samples using an UHPLC-MS method and rs2046210 in estrogen receptor α (ESR1) gene was genotyped by TaqMan genotyping system. Logistic regression was performed to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for the association analyses. As a result, 615 NSCLC cases and 615 healthy controls were enrolled from Wuhan, central China. The mean age was 58.0 (SD: 7.9) years old for controls and 59.2 (SD: 8.8) years old for cancer cases. The creatinine-adjusted BPA levels were significantly higher in NSCLC cases than that in healthy controls (median: 0.97 vs 0.73 μg/L, P < 0.001). Exposure to high levels of BPA was significantly associated with NSCLC (adjusted OR = 1.91, 95%CI: 1.39-2.62, P < 0.001 for the highest quartile). We also observed a shallow concave dose-response relationship about the overall association between BPA and NSCLC. Moreover, interaction analyses showed that BPA exposure interacted multiplicatively with rs2046210, with a marginal P value (P = 0.049), to contribute to NSCLC. In conclusion, exposure to high levels BPA may be associated with NSCLC and the relationship may be modified by genetic polymorphism in ESR1.

Different temporal trends of exposure to Bisphenol A among international travelers between Los Angeles and Beijing

Recent studies suggested a significant downward trend in population's exposure to bisphenol A (BPA) in the United States. However, the temporal trend of BPA exposure remains unclear in China - a populous country with substantial industrial activities but less efforts made to phase out BPA in consumer products. In addition, it is unclear to what extent a visit from the United States to China could affect human exposure to BPA. In this natural experiment, we measured the concentration of total BPA in 418 urine samples repeatedly collected from 55 Los Angeles residents before, during, and after they spent 10 weeks in Beijing from 2012 to 2017. We found that traveling from Los Angeles to Beijing led to a 2.91-fold (95% CI: 2.43 to 3.50) increase in urinary BPA levels, which fully returned to baseline after study participants came back to Los Angeles. From 2012 to 2017, urinary BPA concentrations decreased in Los Angeles by 25.5% per year (95% CI: -30.8% to -19.8%; p < 0.001) but did not change in Beijing (p = 0.24). Consequently, the concentration ratio of urinary BPA between Beijing and Los Angeles increased from 1.23 (95% CI: 0.82 to 1.85) in 2012 to 4.05 (95% CI: 2.75 to 5.97) in 2017. These results indicate that BPA exposures may increase among international travelers to China. Additional efforts are needed to reduce population's exposure to BPA in China.

Association of prenatal exposure to bisphenols and birth size in Zhuang ethnic newborns

Prenatal exposure to bisphenol A (BPA) and its analogues can affect fetal growth and development. However, epidemiologic findings were inconsistent and there was a lack of study for BPA analogues. We aimed to examine the associations between prenatal exposure to BPA, bisphenol B (BPB), bisphenol F (BPF), bisphenol S (BPS), and tetrabromobisphenol A (TBBPA) and birth size. 2023 mother-infant pairs were included in this study. The associations between serum bisphenol levels and birth size were analyzed by multivariate linear regression models. After adjusting for covariates, one log10-unit increase in serum BPA was correlated with a 32.10 g (95% CI: -61.10, -3.10) decrease in birth weight for all infants, and the inverse association was only observed in males when stratified analysis by gender. Additionally, higher BPF concentrations were associated with decreasing birth weight (P for trend = 0.031), ponderal index (P for trend = 0.021), and birth weight Z-scores (P for trend = 0.039) in all infants, and the inverse associations were also only observed in males when stratified analysis by gender. Similarly, higher TBBPA levels were also correlated with decreased birth weight (P for trend = 0.023). However, after gender stratification, higher TBBPA concentrations were associated with a decrease in birth weight (P for trend = 0.007), birth length (P for trend = 0.026), and birth weight Z-scores (P for trend = 0.039) in males. Our data suggested an inverse association of prenatal exposure to BPA, BPF, and TBBPA and birth size, which may be more pronounced in male infants.

Association between maternal lifestyle factors and low birth weight in preterm and term births: a case-control study

Background

It has been reported that lifestyle factors may affect birth weight; however, few studies have explored the association between lifestyle factors and low birth weight in preterm and term births in China. The objective of this study was to explore the effect of lifestyle on low birth weight in preterm and term births.

Methods

This case-control study was conducted in fourteen hospitals in Jiangmen, Guangdong Province. Data were collected from August 2015 to May 2016 using a standard questionnaire. Data were analysed using logistic regression.

Results

Women who delivered preterm and were physically active (1–3 times per week and ≥ 4 times per week) had reduced odds of having low birth weight babies (aOR = 0.584, 95%CI = 0.394–0.867 and, aOR = 0.516, 95%CI = 0.355–0.752, respectively). Pregnant women who had insufficient gestational weight gain had increased odds of having low birth weight babies (aOR = 2.272, 95%CI = 1.626–3.176). Women exposed to passive smoking had an increased risk of delivering low birth weight infants (aOR = 1.404, 95%CI = 1.057–1.864). Insufficient gestational weight gain and excessive gestational weight gain were both significantly associated with low birth weight (aOR = 1.484, 95%CI = 1.103–1.998 and aOR = 0.369, 95%CI = 0.236–0.577, respectively) for term deliveries. In addition, parity, history of low birth weight, antenatal care and gestational hypertension were significantly associated with the likelihood of low birth weight.

Conclusion

Pregnant women without exercise contraindications should remain physically active. Pregnant women should be aware of the negative effects of smoke and be aware of strategies to protect themselves from passive smoke exposure. Hospitals should inform pregnant women of the importance appropriate gestational weight gain. These recommendations should be put into practice to decrease the prevalence of low birth weight infants.

Associations of lifestyle factors with phthalate metabolites, bisphenol A, parabens, and triclosan concentrations in breast milk of Korean mothers

The toxicity of endocrine disruptors depends on the synergistic interactions of biological, environmental, and behavioral factors. The specific effects of diet, consumer product use, and behaviors, however, are debated in the literature, particularly with regard to endocrine disruptors found in breast milk. This study aimed to measure the levels of phthalate metabolites, bisphenol A, parabens, and triclosan in breast milk and to investigate their associations with various lifestyle factors. The breast milk samples as well as surveys were collected from 221 first-time mothers throughout South Korea and each sample was analyzed for the presence of 15 endocrine disruptors. Phthalate metabolites were detected in 5.4-83.3% of the samples, with median concentrations of 0.08-1.72 μg/L, while bisphenol A, parabens, and triclosan were detected in 25.8-88.2% of the samples, with median concentrations of 0.12-1.47 μg/L. High levels of endocrine disruptors were associated with frequent consumption of fish and cup noodles; the use of plastic and disposable food containers; the use of air fresheners, lotions and make-up; the purchase of new furniture; and socioeconomic status. We also observed the potential role of moderate walking activity on the reduction of these chemicals in breast milk. Our data provide evidence of the potential effects of diet, consumer products, and behavior on the presence of phthalate metabolites, bisphenol A, parabens, and triclosan in breast milk. Future studies should include community or regional impact on a mothers' exposure to endocrine disruptors, to assess the joint contribution of both individual and neighborhood factors.

Prenatal exposure to bisphenol a and its analogues (bisphenol F and S) and ultrasound parameters of fetal growth

BACKGROUND

Bisphenol A (BPA) has been shown to affect normal fetal growth, but human evidence on its analogues (BPF and BPS) is limited.

OBJECT

To examine the associations between prenatal exposure to BPA and its analogues (BPF and BPS) and ultrasound parameters of fetal growth.

METHODS

We measured urinary BPA, BPF, and BPS concentrations among 322 pregnant women during late pregnancy from a cohort study in Wuhan, China. Fetal biparietal diameter (BPD), head circumference (HC), femur length (FL), and abdominal circumference (AC) were measured by ultrasonography. The associations of maternal urinary BPA, BPF, and BPS concentrations with ultrasound parameters of fetal growth were estimated by multivariable adjusted models.

RESULTS

We observed a gender difference in association of maternal urinary BPA concentrations and fetal HC (P for interaction = 0.003); each ln-unit increase in maternal urinary BPA concentration was associated with a mean decrease of 0.10 cm (95%CI: 0.18, -0.02) among boys and a mean increase of 0.14 cm (95%CI: 0.00, 0.28) among girls for HC. The associations were robust for urinary BPA concentrations modeled as tertiles or including urinary BPA, BPF, and BPS into mutual adjustment models. We did not observe robust associations between maternal urinary BPF and BPS concentrations and ultrasound parameters of fetal growth, though an inverse association with AC and a positive association with FL were estimated for maternal urinary BPF concentrations modeled as continuous variables.

CONCLUSIONS

Prenatal exposure to BPA but not BPF and BPS was sex-specifically associated with certain fetal growth parameters.

Neuro-toxic and Reproductive Effects of BPA

Background:

Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. It has recognized activity as an endocrine-disrupting chemical and has suspected roles as a neurological and reproductive toxicant. It interferes in steroid signaling, induces oxidative stress, and affects gene expression epigenetically. Gestational, perinatal and neonatal exposures to BPA affect developmental processes, including brain development and gametogenesis, with consequences on brain functions, behavior, and fertility.

Methods:

This review critically analyzes recent findings on the neuro-toxic and reproductive effects of BPA (and its ana-logues), with focus on neuronal differentiation, synaptic plasticity, glia and microglia activity, cognitive functions, and the central and local control of reproduction.

Results:

BPA has potential human health hazard associated with gestational, peri- and neonatal exposure. Beginning with BPA’s disposition, this review summarizes recent findings on the neurotoxicity of BPA and its analogues, on neuronal dif-ferentiation, synaptic plasticity, neuro-inflammation, neuro-degeneration, and impairment of cognitive abilities. Furthermore, it reports the recent findings on the activity of BPA along the HPG axis, effects on the hypothalamic Gonadotropin Releas-ing Hormone (GnRH), and the associated effects on reproduction in both sexes and successful pregnancy.

Conclusion:

BPA and its analogues impair neuronal activity, HPG axis function, reproduction, and fertility. Contrasting re-sults have emerged in animal models and human. Thus, further studies are needed to better define their safety levels. This re-view offers new insights on these issues with the aim to find the “fil rouge”, if any, that characterize BPA’s mechanism of action with outcomes on neuronal function and reproduction.

Prenatal Exposure to Organophosphate Flame Retardants and the Risk of Low Birth Weight: A Nested Case-Control Study in China

Organophosphate flame retardants (OPFRs), used as flame retardants and plasticizers, have been suggested to impair fetal growth and development in toxicological studies, but epidemiological data are extremely limited. This study was designed to explore whether prenatal exposure to OPFRs was associated with an increased risk of low birth weight (LBW) using a nested case-control design based on the ongoing prospective birth cohort in Wuhan, China. A total of 113 cases and 226 matched controls recruited from this cohort project in 2014-2016 were included. OPFR metabolite concentrations in maternal urine samples collected in the third trimester were determined, and birth outcomes were extracted from medical records. Compared with the lowest tertile of diphenyl phosphate (DPHP) concentrations, pregnant women with the highest tertile of DPHP had a 4.62-fold (95% confidence interval (CI): 1.72, 12.40) significantly increased risk for giving birth to LBW infants, with a significant dose-response relationship (p-trend < 0.01). After stratification by newborn sex, the significant positive association of DPHP levels with LBW risk was merely observed among female newborns. Our results suggest a positive association between maternal urinary DPHP concentrations and LBW risk for the first time, and the effect appears be sex-specific.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Involvement of the Endocrine-Disrupting Chemical Bisphenol A (BPA) in Human Placentation

Background: Endocrine-disrupting chemicals (EDCs) are environmental chemicals/toxicants that humans are exposed to, interfering with the action of multiple hormones. Bisphenol A (BPA) is classified as an EDC with xenoestrogenic activity with potentially adverse effects in reproduction. Currently, a significant knowledge gap remains regarding the complete spectrum of BPA-induced effects on the human placenta. As such, the present study examined the effects of physiologically relevant doses of BPA in vitro. Methods: qRT-PCR, Western blotting, immunofluorescence, ELISA, microarray analyses, and bioinformatics have been employed to study the effects of BPA using nonsyncytialised (non-ST) and syncytialised (ST) BeWo cells. Results: Treatment with 3 nM BPA led to an increase in cell number and altered the phosphorylation status of p38, an effect mediated primarily via the membrane-bound estrogen receptor (GPR30). Nonbiased microarray analysis identified 1195 and 477 genes that were differentially regulated in non-ST BeWo cells, whereas in ST BeWo cells, 309 and 158 genes had altered expression when treated with 3 and 10 nM, respectively. Enriched pathway analyses in non-ST BeWo identified a leptin and insulin overlap (3 nM), methylation pathways (10 nM), and differentiation of white and brown adipocytes (common). In the ST model, most significantly enriched were the nuclear factor erythroid 2-related factor 2 (NRF2) pathway (3 nM) and mir-124 predicted interactions with cell cycle and differentiation (10 nM). Conclusion: Collectively, our data offer a new insight regarding BPA effects at the placental level, and provide a potential link with metabolic changes that can have an impact on the developing fetus.

Urinary bisphenol A concentration is correlated with poorer oocyte retrieval and embryo implantation outcomes in patients with tubal factor infertility undergoing in vitro fertilisation

Bisphenol A (BPA) is a substance ubiquitously present in the environment, and its toxicity on reproductive function has been well characterised in animal models. However, it is still controversy about the effects of BPA exposure on human female reproduction. Therefore, in the present study, the associations of urinary BPA concentration with the outcomes of in vitro fertilisation (IVF) and embryo transfer from fresh and frozen cycles were analysed in the same cohort. 351 women who underwent IVF treatment from September 2013 to October 2016, at the Centre of Reproductive Medicine in the Women's Hospital School of Medicine at Zhejiang University were recruited. Single-spot urine samples were collected on the day of oocyte retrieval to detect BPA using solid-phase extraction and liquid chromatography coupled with tandem mass spectrometry. A multivariable generalised linear mixed model was used to evaluate the association between the urinary BPA concentration and IVF outcomes. After adjustment for age, body mass index, baseline follicle-stimulating hormone level, baseline oestradiol level, and antral follicle count, a significant decrease in the number of retrieved oocytes and in the rates of clinical pregnancy and implantation was observed in the patients with a high urinary BPA concentration. We concluded that BPA exposure exert negative effects on oocyte retrieval and embryo implantation in women undergoing IVF.

Trimester-specific, gender-specific, and low-dose effects associated with non-monotonic relationships of bisphenol A on estrone, 17β-estradiol and estriol

BACKGROUND

Bisphenol A (BPA) may cause some adverse effects on human health by mimicking estrogen activities. In vitro andanimalstudies have observed the non-monotonic associations between BPA and natural estrogens, but the evidence in human study is lacking, particularly at multiple points in time during pregnancy.

OBJECTIVE

We aimed to examine the relationships between BPA and estrogens in the three trimesters among Chinese pregnant women and their gender variations.

METHODS

This study included 851 participants from a birth cohort conducted in Wuhan, China between 2014 and 2015. We measured concentrations of BPA and three estrogens (estrone (E1), 17β-estradiol (E2) and estriol (E3)) in urine samples collected in the three trimesters of pregnancy (mean for each visit: 13.0, 23.6, and 35.9 weeks' gestation). We calculated the estimated daily intakes using urinary BPA concentrations and compared them with the tolerable intake value to assess potential health risks. We used multivariate linear regression models stratified by trimester and gender to explore trimester-specific and gender-specific associations of BPA with E1, E2, and E3.

RESULTS

We found the decreased levels of estrogens (β < 0, P < 0.05) in the upper BPA quartiles over three trimesters, except for the elevated levels of E3 (β = 0.20, 95% CI: 0.02, 0.38) in the highest BPA quartile in the 2nd trimester. There were significant non-linear associations (overall associations P < 0.05, non-linear associations P < 0.05) between BPA and E3 in the three trimesters. In the gender-stratified analysis, we observed significant negative relationships (β < 0, P < 0.05) between BPA and E2 among mothers carrying male fetuses in the 1st trimester and significant associations between BPA and E3 among mothers carrying female fetuses in the 2nd trimester. However, we found no significant relationship between BPA and E2 among mothers carrying female fetuses over three trimesters.

CONCLUSIONS

Our findings support experimental evidence of non-monotonic relationships between BPA and three major estrogens, even at low doses of BPA. Mothers delivering male fetuses may be more sensitive to E2 at early pregnancy, and those delivering female fetuses may be more susceptive to E3 at mid-pregnancy.