Prenatal low-level phenol exposures and birth outcomes in China

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.

Toxicological Impact of Bisphenol A on Females' Reproductive System: Review Based on Experimental and Epidemiological Studies

The study encompassing research papers documented in the last two decades pertaining to the possible influence of bisphenol A (BPA) on the fertility of females are appraised with emphasis on the influence of BPA in reproductive organs (uterus and ovaries) and pregnancy outcomes including discussion on the reproductive process (implantation, estrous cycle, hormone secretion); outcomes reveal a connection amongst BPA and female infertility. Ovary, uterus, and its shape as well as function can alter a person's ability to become pregnant by influencing the hypothalamus-pituitary axis in the ovarian model. Additionally, implantation and the estrous cycle may be affected by BPA. However, more research is warranted to comprehend the underlying action mechanisms and to promptly identify any imminent reproductive harm.

Environmental exposure and child health in China

Chinese children are exposed to broad environmental risks ranging from well-known hazards, such as pesticides and heavy metals, to emerging threats including many new man-made chemicals. Although anecdotal evidence suggests that the exposure levels in Chinese children are substantially higher than those of children in developed countries, a systematic assessment is lacking. Further, while these exposures have been linked to a variety of childhood diseases, such as respiratory, endocrine, neurological, behavioral, and malignant disorders, the magnitude of the associations is often unclear. This review provides a current epidemiologic overview of commonly reported environmental contaminants and their potential impact on children's health in China. We found that despite a large volume of studies on various topics, there is a need for more high-quality research and better-coordinated regional and national data collection. Moreover, prevention of such diseases will depend not only on training of environmental health professionals and enhanced research programs, but also on public education, legislation, and networking.

Exposure to endocrine disrupting chemicals (bisphenols, parabens, and triclosan) and their associations with preterm birth in humans

Preterm birth in humans (PTB), defined as birth prior to 37 weeks of gestation, is one of the most important causes of neonatal morbidity and mortality and is associated with adverse health outcomes later in life. Attributed to many different etiological factors, estimated 15.1 million or 11.1% of births each year are preterm, which is more than 1 per 10 livebirths globally. Environmental pollution is a well-established risk factor that could influence the pathogenesis of PTB. Increasing evidence has shown an association between maternal exposure to endocrine disrupting chemicals (EDCs) and PTB. This scoping review aims to summarize current research on the association between EDC exposure and PTB in humans. Database PubMed was used to identify articles discussing the effect of selected EDCs, namely bisphenol A, bisphenol S, bisphenol F, parabens, and triclosan, found in plastics, cosmetics and other personal care products, on PTB occurrence. Regardless of some inconsistences in the findings across studies, the reviewed studies suggest a potential association between involuntary exposure to reviewed EDCs and the risk of PTB. However, further studies are needed to delineate exact correlations and mechanisms through which EDC exposure causes PTB so that efficient preventative measures could be implemented. Until then, health care providers should inform women about possible EDC exposure thus empowering them to make healthy choices and at the same time decrease the EDC negative effects.

Effects of prenatal single and mixed bisphenol exposure on bone mineral density in preschool children: A population-based prospective cohort study

Exposure to bisphenols can affect bone mineral density (BMD) in animals and humans. However, the effects of maternal exposure to bisphenols during pregnancy on bone health in preschool children remain unknown. We aimed to assess the effects of prenatal exposure to single and multiple bisphenols on bone health in preschool children. A total of 230 mother-child pairs were included in this study. Generalized linear regression, restricted cubic spline (RCS), principal component analysis (PCA), and Bayesian kernel machine regression (BKMR) were utilized to assess the relationship between bisphenol levels and bone health in preschool children. Each natural log (Ln) unit increase in tetrabromobisphenol A was related to a 0.007 m/s (95 % CI: -0.015, 0.000) decrease in Ln-transformed speed of sound (SOS) among girls. Decreased BMD Z scores in preschool children were found only in the high bisphenol S exposure group (β = -0.568; 95 % CI: -1.087, -0.050) in boys. The risk of low BMD (BMDL) was significantly higher in the middle-exposure group (OR = 4.695; 95 % CI: 1.143, 24.381) and high-exposure group of BPS (OR = 6.165, 95 % CI: 1.445, 33.789) compared with the low-exposure group in boys. In girls, the risk of BMDL decreased with increasing bisphenol A concentration (OR = 0.413, 95 % CI: 0.215, 0.721). RCS analysis revealed a U-shaped nonlinear correlation between BPB concentration and BMDL in girls (P-overall = 0.011, P-nonlinear = 0.009). In PCA, a U-shaped dose-response relationship was found between PC2 and the risk of BMDL (P-overall = 0.048, P-nonlinear = 0.032), and a significant association was only noted in girls when stratified by sex. The BKMR model revealed a horizontal S-shaped curve relationship between bisphenol mixtures and BMDL in girls. The results indicated that prenatal exposure to single and mixed bisphenols can affect BMD in preschool children, exerting nonmonotonic and child sex-specific effects.

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.

Urinary neonicotinoid insecticides and adiposity measures among 7-year-old children in northern China: A cross-sectional study

BACKGROUND

Neonicotinoid insecticides (NEOs) are emerging synthetic insecticides used in various pest management regimens worldwide. Toxicology studies have indicated the obesogenic potential of NEOs, but their associations with adiposity measures are largely unknown.

OBJECTIVES

We aimed to assess urinary levels of NEOs/metabolites and their associations with children's adiposity measures, and to further investigate the potential role of oxidative stress.

METHODS

This study included 380 children who participated in the 7th year's follow-up of the Laizhou Wan Birth Cohort in northern China. Urinary levels of seven NEOs and two metabolites and a biomarker of lipid peroxidation named 8-iso-prostaglandin-F2α (8-iso-PGF2α) were detected. A total of nine indicators of adiposity were measured. Body mass index (BMI) z-score ≥85th percentile was defined as overweight/obesity, and waist-to-height ratio (WHtR) ≥0.5 was considered as abdominal obesity. Multiple linear regression, binary logistic regression and mediation analysis were performed.

RESULTS

Six NEOs [imidacloprid (IMI, 99.7%), clothianidin (CLO, 98.9%), dinotefuran (DIN, 97.6%), thiamethoxam (THM, 95.5%), acetamiprid (ACE, 82.9%), thiacloprid (THD, 77.6%)] and two metabolites [N-desmethyl-acetamiprid (N-DMA, 100.0%), 6-chloronicotinic acid (6-CINA, 97.9%)] exhibited high detection rates. Multiple linear regressions showed positive associations of waist circumference with urinary levels of IMI and THM, of WHtR with IMI and THM levels, and of body fat percentage with 6-CINA levels. In contrast, exposure to N-DMA was negatively associated with body fat percentage and fat mass index. Binary logistic regressions further revealed that higher IMI levels were associated with overweight/obesity (OR = 1.556, 95% CI: 1.100, 2.201) and abdominal obesity (OR = 1.478, 95% CI: 1.078, 2.026) in children. 8-iso-PGF2α demonstrated 27.92%, 69.52% and 35.37% mediating effects in the positive associations of IMI, THD and THM with WHtR, respectively. Sex modified the associations of DIN with body fat mass (p_int = 0.032), body fat percentage (p_int = 0.009), fat mass index (p_int = 0.037) and the overweight/obesity rate (p_int = 0.046), with negative associations in girls and nonsignificant positive associations in boys.

CONCLUSIONS

School-age children in northern China were widely exposed to NEOs/metabolites. Urinary levels of NEOs/metabolites were associated with adiposity measures through the mediating role of 8-iso-PGF2α. These associations were mixed, and a sex-specific effect might exist.

Prenatal Exposure to Bisphenol A: Is There an Association between Bisphenol A in Second Trimester Amniotic Fluid and Fetal Growth?

Background and Objectives: Fetal growth abnormalities increase the risk of negative perinatal and long-term outcomes. Bisphenol A (BPA) is a ubiquitous endocrine-disrupting chemical to which humans may be exposed in a number of ways, such as from the environment, via various consumer products, and through the individual's diet. Since the compound possesses estrogen-mimicking properties and exerts epigenetic and genotoxic effects, it has been associated with harmful effects impacting the entire spectrum of human life, including, vitally, the intrauterine period. We investigated the role of maternal exposure to BPA in abnormal fetal growth velocity, both impaired and excessive. Materials and Methods: Amniotic fluid samples were collected from 35 women who underwent amniocentesis early in the second trimester due to medical reasons. Pregnancies were followed until delivery, and birth weights were recorded. The amniotic fluid samples were subsequently divided into three groups based on fetal birth weight, as follows: AGA (appropriate for gestational age), SGA (small for gestational age), and LGA (large for gestational age). Amniotic fluid BPA levels were determined by gas chromatography coupled with mass spectrometry. Results: BPA was detected in 80% (28/35) of our amniotic fluid samples. Median concentration was 281.495 pg/mL and ranged from 108.82 pg/mL to 1605.36 pg/mL. No significant association was observed between the study groups regarding BPA concentration. A significant positive correlation between amniotic fluid BPA concentration and birth weight centile (r = 0.351, p-value = 0.039) was identified. BPA levels were also inversely associated with gestational age in pregnancies at term (between 37 and 41 weeks) (r = -0.365, p-value = 0.031). Conclusions: Our findings suggest that maternal exposure to BPA during the early second trimester of pregnancy can potentially contribute to increased birthweight percentiles and to decreased gestational age in pregnancies at term.

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.

Multiple mediation effects on association between prenatal triclosan exposure and birth outcomes

BACKGROUND

Triclosan is a broad-spectrum antimicrobial, and was thought to affect intrauterine development, but the mechanism remains unclear.

OBJECTIVE

To explore the association between prenatal triclosan exposure and birth outcomes.

METHODS

Based on 726 mother-child pairs from the Sheyang Mini Birth Cohort Study (SMBCS), we used the available (published) data of triclosan in maternal urines, the hormones including thyroid-related hormones, gonadal hormones in cord blood, and adipokines, trimethylamine-N-oxide (TMAO) and its precursors in cord blood to explore possible health effects of triclosan on birth outcomes through assessing different hormones and parameters, using Bayesian mediation analysis.

RESULTS

Maternal triclosan exposure was associated with ponderal index (β = 0.317) and head circumference (β = -0.172) in generalized linear models. In Bayesian mediation analysis of PI model, estradiol (β = 0.806) and trimethylamine (TMA, β = 0.164) showed positive mediation effects, while total thyroxine (TT4, β = -0.302), leptin (β = -2.023) and TMAO (β = -0.110) showed negative mediation effects. As for model of head circumference, positive mediation effects were observed in free thyroxine (FT4, β = 0.493), TMA (β = 0.178), and TMAO (β = 0.683), negative mediation effects were observed in TT4 (β = -0.231), testosterone (β = -0.331), estradiol (β = -1.153), leptin (β = -2.361), choline (β = -0.169), betaine (β = -0.104), acetyl-L-carnitine (β = -0.773).

CONCLUSION

The results indicated triclosan can affect intrauterine growth by interfering thyroid-related hormones, gonadal hormones, adipokines, TMAO and its precursors.

Association of preconception mixtures of phenol and phthalate metabolites with birthweight among subfertile couples

Although parental preconception exposure to some phenols and phthalates have been associated with reduced birthweight, few studies have examined these chemicals as complex mixtures.

Prenatal pyrethroid exposure and lung function among school-aged children

BACKGROUND

Previous epidemiological evidence mainly focused on the adverse effects of prenatal exposure to pyrethroid insecticides (PYRs) on respiratory health during childhood. It remains unclear whether the PYR exposures can also impact on children's lung function.

OBJECTIVES

To explore the potential effects of prenatal PYR exposures on lung function in a population of Chinese children.

METHODS

This study included 233 mother-child dyads from the Laizhou Wan Birth Cohort (LWBC), Shandong province, northern China, between September 2010 and December 2013. Three metabolites of PYRs [3-phenoxybenzoic acid (3-PBA), and cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-DCCA and trans-DCCA)] were measured using gas chromatography-mass spectrometry (GC-MS) in maternal urine samples collected at recruitment. Lung function was assessed with spirometry in children aged 6-8 years. Multivariable linear regression and generalized linear models (GLMs) assessed the associations of prenatal PYR exposures with lung function in children.

RESULTS

Among the PYR metabolites, 3-PBA (81.5%) were most frequently detected, followed by trans-DCCA (55.4%) and cis-DCCA (21.9%). The 3-PBA concentration was associated with a 1% decrease in FEV₁/FVC in the highest quartiles of exposure compared to the lowest quartile, with a potential dose response association (p-trend = 0.085). Our findings provide a suggestive effect modification by sex, with girls being more susceptible than the boys (p-trend = 0.011). However, there were no associations between the trans-DCCA concentration and lung function parameters.

CONCLUSION

Prenatal 3-PBA concentrations were associated with a modest decrease in FEV₁/FVC among school-aged children, and the association was slightly more pronounced for the girls than for the boys.

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.

Gestational triclosan exposure and infant birth weight: A systematic review and meta-analysis

BACKGROUND

Exposure to triclosan, an antimicrobial chemical used in some personal care and cleaning products, has been associated with reduced birth weight in some, but not all epidemiological studies.

OBJECTIVES

We conducted a systematic review and meta-analysis to characterize the relation of gestational triclosan exposure with infant birth weight and identify sources of heterogeneity between studies.

METHODS

We identified original studies measuring urinary triclosan concentrations during pregnancy and reporting their association with infant birth weight, gestational age (GA) adjusted birth weight (g), or GA-standardized birth weight z-scores. Using a random effects model, we estimated differences in these outcomes per 10-fold increase in triclosan concentrations and considered triclosan levels and infant sex as sources of heterogeneity. Using Navigation Guide Methods, we evaluated risk of bias within individual studies and across the body of evidence.

RESULTS

Among thirteen studies, median triclosan concentrations varied by almost 2-orders of magnitude (0.6-29 ng/mL), with higher concentrations in North American and some European studies compared to Asian ones. Associations between triclosan and birth weight (β:-20 g; 95% CI:-65, 26; n = 6) were stronger than those for GA-adjusted birth weight (β:-12 g; 95% CI:-29, 5; n = 9). Triclosan was not associated with GA-standardized birth weight z-scores (β:-0.04; 95% CI:-0.16, 0.07; n = 5). The association between triclosan and GA-adjusted birth weight was stronger in studies with median triclosan values ≥10 ng/mL compared to studies with median values < 10 ng/mL (β:-27 g; 95% CI:-61, 7; n = 4 vs. β:6g; 95% CI:-20, 31; n = 5). With a limited number of studies, we observed suggestive evidence that inverse associations were more apparent in studies with ≥ 2 prospective triclosan measures compared to those with one measure.

DISCUSSION

Available evidence, with "low" risk of bias, provides limited evidence that triclosan exposure and reduces infant birth weight. We observed stronger inverse associations between triclosan concentrations and birth weight in populations with higher triclosan exposure.

Bisphenol A exposure and abnormal glucose tolerance during pregnancy: systematic review and meta-analysis

In the present work, a systematic review and meta-analysis were performed to examine the probable relation between maternal exposure to bisphenol A (BPA), as estrogen-disrupting compounds, and gestational diabetes mellitus (GDM), and impaired glucose tolerance (IGT). We comprehensively searched three electronic databases to retrieve published studies on maternal exposure to BPA and GDM/IGT, through February 2021. Cochran's Q test and I2 statistics were employed for testing heterogeneity across studies. DerSimonian and Liard random-effects model was used to determine the pooled estimates. Otherwise, the fixed-effects model with inverse-variance weights was applied. Sensitivity analysis was performed to determine the robustness of the results by excluding each study from the pooled estimate. The potential publication bias was examined using Begg's and Egger's tests. The pooled odds ratio did not show BPA exposure to be a significant risk factor for GDM (OR = 0.90, 95% CI = 0.62-1.33, I2: 50.7%). Also, no significant association was observed between BPA exposure and risk of IGT (OR = 0.93, 95% CI = 0.40-2.18, I2: 11.5%). Based on the findings of this study, no association was found between exposure to BPA during pregnancy and the risk of GDM/IGT. Albeit no heterogeneity was found between studies.

REPRODUCTIVE TOXICOLOGY: Pregnancy exposure to endocrine disrupting chemicals: implications for women's health

Women are ubiquitously exposed to non-persistent endocrine disrupting chemicals (EDCs) from food contact materials and personal care products. Understanding the impacts of exposure to these chemicals on pregnancy and long-term health outcomes in women is a critical area of research that has been largely overlooked. This brief review focuses on the epidemiologic literature exploring associations of non-persistent EDCs - including phthalates, parabens, bisphenols, and triclosan - with maternal pregnancy outcomes and long-term health outcomes in women. We focus on the challenges of this research, particularly assessing non-persistent EDC exposures, aspects of study design, and statistical approaches. We conclude by reviewing the best practices for non-persistent EDC research with regards to pregnancy and women's health. Though limited, we found some evidence indicating that exposure to non-persistent EDCs is associated with pregnancy health. However, findings from these studies have been inconsistent and require corroboration. Recent studies have also proposed that non-persistent EDC exposures in pregnancy may adversely affect postnatal maternal health. To date, only a few studies have been conducted and have only focused on postpartum weight. More research is needed in this area to inform efforts to promote optimal health across the lifespan of women.

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.

Association of BPA exposure during pregnancy with risk of preterm birth and changes in gestational age: A meta-analysis and systematic review

The associations of bisphenol A exposure during pregnancy with risk of preterm birth (PTB) and changes in gestational age have remained controversial. To conduct the meta-analysis, the relevant studies were searched through PubMed, OVID, and Web of Science from inception through June ‎17, ‎2020. Data were independently extracted and analyzed using odds ratio (OR) or regression coefficient (β) and their 95% confidence intervals (CIs). We identified 668 references and included 7 studies for preterm birth and 9 studies for gestational age. The included studies reported that the median or geometric mean (GM) of maternal urinary BPA ranged from 0.48 to 6.44 ng/ml. The meta-analysis estimated OR to be 1.36 (95% CI: 1.03, 1.69) for preterm birth associated with maternal urinary BPA exposure during pregnancy. In the subgroup analysis based on BPA exposure level, a significant association was observed between preterm birth and higher BPA exposure among the populations had BPA median or GM concentrations higher than 2.16 ng/ml (OR: 1.92; 95% CI: 1.38, 2.47). In the subgroup analyses by maternal urinary BPA exposure assessed in different trimesters, a significant association of preterm birth was only observed with BPA assessed in the third trimester (OR: 1.62; 95% CI: 1.15, 2.09). In addition, higher maternal urinary BPA exposure during pregnancy was associated with decreased gestational age by 0.50 (-0.87, -0.13) days, and the subgroup analyses also showed that only BPA exposure in the third trimester was associated with decreased gestational age by 1.36 (-2.21, -0.52) days. This meta-analysis demonstrated that higher BPA exposure was associated with an increased risk of preterm birth and decreased length of gestational age, and suggested that BPA exposure in the third trimester of pregnancy may be a critical susceptible period of preterm birth.

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.

Effect of Maternal Triclosan Exposure on Neonatal Birth Weight and Children Triclosan Exposure on Children's BMI: A Meta-Analysis

Background: Triclosan (TCS) is an environmental chemical with endocrine disrupting effects and can enter the body through the skin or oral mucosa. Human data about the effect of TCS exposure during pregnancy on neonatal birth weight and TCS exposure during childhood on children's growth are scarce.

Objectives: To investigate the association between maternal urinary TCS level and neonatal birth weight, as well as children's urinary TCS level and children's body mass index (BMI).

Methods: A systematic literature search was conducted using PubMed, Cochrane Library, and Web of Science. Finally, seven epidemiological articles with 5,006 participants from September 25, 2014 to August 10, 2018 were included in the meta-analysis to identify the relationship between maternal exposure to TCS and neonatal birth weight. On the other hand, three epidemiological articles with 5,213 participants from July 22, 2014 to September 1, 2017 were included in another meta-analysis to identify the relationship between children's exposure to TCS and children's BMI. We used Stata 16.0 to test the heterogeneity among the studies and calculating the combined effect value 95% confidence interval (CI) of the selected corresponding models.

Results: TCS exposure during pregnancy was not significant associated with neonatal birth weight. The results of forest plots were as follows: ES (Estimate) = 0.41 (95% CI: −11.97–12.78). Children's urinary TCS level was also irrelevant associated with children's BMI: ES = 0.03 (95% CI: −0.54–0.60).

Conclusions: This meta-analysis demonstrated that there was no significant association between maternal TCS level and neonatal birth weight, also there has no relationship between children's urinary TCS level and children's BMI.

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.

Endocrine disrupting chemicals: Impacts on human fertility and fecundity during the peri-conception period

It is becoming increasingly difficult to avoid exposure to man-made endocrine disrupting chemicals (EDCs) and environmental toxicants. This escalating yet constant exposure is postulated to partially explain the concurrent decline in human fertility that has occurred over the last 50 years. Controversy however remains as to whether associations exist, with conflicting findings commonly reported for all major EDC classes. The primary aim of this extensive work was to identify and review strong peer-reviewed evidence regarding the effects of environmentally-relevant EDC concentrations on adult male and female fertility during the critical periconception period on reproductive hormone concentrations, gamete and embryo characteristics, as well as the time to pregnancy in the general population. Secondly, to ascertain whether individuals or couples diagnosed as sub-fertile exhibit higher EDC or toxicant concentrations. Lastly, to highlight where little or no data exists that prevents strong associations being identified. From the greater than 1480 known EDCs, substantial evidence supports a negative association between exposure to phthalates, PCBs, PBDEs, pyrethroids, organochloride pesticides and male fertility and fecundity. Only moderate evidence exists for a negative association between BPA, PCBs, organochloride pesticides and female fertility and fecundity. Overall fewer studies were reported in women than men, with knowledge gaps generally evident for both sexes for all the major EDC classes, as well as a paucity of female fertility studies following exposure to parabens, triclosans, dioxins, PFAS, organophosphates and pyrethroids. Generally, sub-fertile individuals or couples exhibit higher EDC concentrations, endorsing a positive association between EDC exposure and sub-fertility. This review also discusses confounding and limiting factors that hamper our understanding of EDC exposures on fertility and fecundity. Finally, it highlights future research areas, as well as government, industry and social awareness strategies required to mitigate the negative effects of EDC and environmental toxicant exposure on human fertility and fecundity.

Associations of urinary phenolic environmental estrogens exposure with blood glucose levels and gestational diabetes mellitus in Chinese pregnant women

BACKGROUND

Endocrine-disrupting chemicals (EDCs) are considered to be related to diabetes, but studies of the association between phenolic EDCs and gestational diabetes mellitus (GDM) are limited.

OBJECTIVES

To assess associations of maternal urinary bisphenol A (BPA), nonylphenol (NP), and 2-tert-octylphenol (2-t-OP) with GDM occurrence.

METHODS

A cross-sectional study was performed among 390 Chinese women at 24-28 weeks of gestation. GDM was diagnosed with a 2-h 75-g oral glucose tolerance test (OGTT). BPA, NP, and 2-t-OP concentrations were determined in urine samples. Linear and logistic regression tests evaluated associations of BPA, NP, and 2-t-OP with blood glucose levels and GDM prevalence.

RESULTS

The 2-t-OP concentrations in GDM patients were significantly higher than in non-GDM women with median values of 2.23 μg/g Cr and 1.79 μg/g Cr, respectively. No significant difference was observed in BPA and NP. Urinary 2-t-OP was positively associated with blood glucose levels after adjustment for several confounding factors and urinary BPA and NP. Higher 2-t-OP levels were associated with higher odds of GDM (OR: 5.78; 95% CI: 2.04, 16.37), whereas higher NP levels were associated with lower odds (OR: 0.22; 95% CI: 0.05, 0.85) in the adjusted models. In addition, compared to the first quartile of 2-t-OP, the adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for GDM in the second, third, and fourth quartiles were 2.81 (1.23, 6.42), 3.01 (1.30, 6.93), and 5.49 (2.24, 13.46), respectively.

CONCLUSION

Our study indicates that, for the first time to our knowledge, exposure to 2-t-OP is associated with a higher risk of GDM. However, higher NP exposure is associated with lower GDM risk. Further studies are necessary to affirm the associations of 2-t-OP and NP with GDM, and to elucidate the causality of these findings.

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.

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.

Impact of prenatal triclosan exposure on gestational age and anthropometric measures at birth: A systematic review and meta-analysis

Background:

Exposure to endocrine disrupting chemicals such as triclosan (TCS) leads to disrupting the endocrine system and consequently effect on the birth outcomes. The findings of studies in this field are controversial.

Materials and Methods:

This systematic review and meta analysis was conducted based on the identified published papers in Scopus, Web of Science, and PubMed up to November 2019. All steps, including searching, screening, data extracting, and quality assessment, were done by two independent researchers.

Results:

Finally 15 published papers selected. The number of participants in whom the association of TCS exposure was assessed with birth weight, birth length, birth head circumference, and gestational age were 9112, 4311, 2854, and 3181 mother infant pairs, respectively. The pooled analysis showed that TCS exposure during pregnancy leads to increasing the birth weight for boys with β= 3.97 and 95% confidence interval (CI) (−3.98, 11.92), and girls with β= 5.37, 95% CI (−6.00, 16.75), but the association was not statistically significant. In addition, according to fixed effects models, the TCS exposure was not significantly associated with birth length (−0.008, 95% CI [−0.049, 0.034]), birth head circumference (−0.01, 95% CI [−0.08, 0.06]), and gestational age (−0.005, 95% CI [−0.017, 0.006]). Likewise, analysis for data segregated by gender of infants revealed similar results.

Conclusion:

The obtained results depicted that the TCS exposure during pregnancy period was associated with higher birth weight for boys and girls. No significant association was observed for TCS exposure with variation of birth length, head circumference, and gestational age duration. In fact, the results showed the evidence of null associations between maternal TCS exposure and birth outcomes.

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.

Prenatal urinary concentrations of environmental phenols and birth outcomes in the mother-infant pairs of Tehran Environment and Neurodevelopmental Disorders (TEND) cohort study

Daily exposure to environmental phenols can lead to potential undesirable effects on the health of pregnant women and fetuses. The present study is aimed to evaluate the relationship between maternal urinary concentrations of phenols in pregnancy and anthropometric birth outcomes. The studied population comprised of 189 pregnant women participating in the Tehran Environment and Neurodevelopmental Disorders (TEND) prospective cohort study, which had been ongoing since March 2016 in some hospitals and health care delivery centers in Tehran, Iran. Concentrations of bisphenol-A, triclosan, 4-nonylphenol, and parabens were determined in spot urine samples of pregnant mothers in the first trimester. Weight, length, and head circumference at birth were also extracted from the mothers' delivery files. Multivariable linear regression was used to examine the relationship between log-concentrations of phenols and birth outcomes. When we analyzed all samples regardless of neonates' gender, none of the urinary concentrations of phenols were associated with weight and length at birth. Indeed, in sex-stratified adjusted models, one log-unit increase of butylparaben was related to a 283.6 g (95% CI: 23, 544) increase in boys' birth weight. Prenatal urinary concentration of triclosan and propylparaben was respectively related to a decrease of 4.8 cm (95% C: -8.5, -1.1) in boys' length and 0.9 cm (95%CI: -1.8, -0.04) in girls' length. In the adjusted models for estimating the changes in head circumference, one log-unit increase of triclosan, methylparaben, and butylparaben led to a reduction of 1.6 cm (95% CI: -3.17, 0.03), increase of 0.8 cm (95% CI: -0.01, 1.6) and 0.7 cm (95% CI: 0.08, 1.4) in head circumference at birth respectively. Our results suggested that prenatal triclosan and parabens exposure might be associated with head circumference at birth. Furthermore, we observed a sexually dimorphic pattern between maternal triclosan and parabens exposure during pregnancy and fetal growth. However, these findings must be interpreted while taking into account the limitations of this study.

Association of prenatal exposure to phenols and parabens with birth size: A systematic review and meta-analysis

Phenols and parabens are endocrine-disrupting chemicals and are widely used in daily life products due to their antibacterial action. Previous studies suggest associations of prenatal exposure to phenols and parabens with fetal development; however, such findings are rare and inconsistent. The aim of this review and meta-analysis is to estimate the associations between maternal exposure to phenols and parabens and birth size. We identified 21 relevant studies that met the inclusion criteria through databases of PubMed, Cochrane, EMBASE and Qvid Medline. The last search was in July 3, 2019. The heterogeneity and possibility of publication bias among included studies were assessed by Q-statistic and Begg's test, respectively. Meta-analysis revealed that prenatal exposure to triclosan [number of studies (n) = 12, regression coefficient (β) = -0.04 g; 95% confidence interval (CI): -0.139, 0.059], benzophenone-3 (n = 10, β = -0.001 g; 95% CI: -0.013, 0.012), bisphenol A (n = 9, β = -0.049 g; 95% CI: -0.199, 0.101), 2-4-dichlorophenols (n = 6, β = -14.124 g; 95% CI: -29.971, 1.723), 2-5-dichlorophenols (n = 6, β = -0.061 g; 95% CI: -0.196, 0.074) and parabens were negatively associated with fetal birth weight. Most of them were insignificant. Inconsistent and insignificant associations were detected between exposure to phenols and parabens and other birth outcomes. Subgroup analysis suggested that heterogeneity in our meta-analysis was mainly attributed to the studies conducted in developed countries and samples collected in the second trimester. Insignificant and controversial associations of maternal exposure to phenols and parabens with birth size were observed in our study. The study design and methods of the included studies are inconsistent, and the effects of environmental pollutants on human health are complex. Further cohort studies with large samples and a consistent approach are thus required to evaluate the associations of maternal exposure to phenols and parabens with birth size.

Association between prenatal exposure to bisphenol a and birth outcomes: A systematic review with meta-analysis

BACKGROUND

Previous studies investigated the relation of prenatal exposure to bisphenol A (BPA) and birth outcomes, but these results were inconsistent. The aim of this study was to investigate the relation of prenatal exposure to BPA and birth outcomes, provide comprehensive results based on current studies.

METHODS

The PubMed, Cochrane databases, and Web of Science databases were searched systematically by two researchers respectively from their inceptions to Oct. 2018, using the following keywords "bisphenol A, birth weight, birth length, head circumference, gestational age, birth outcomes". We extracted β coefficient and 95% confidence interval (CI) or β coefficient and standard deviation (SD) from included study. The subgroup analysis was performed to evaluate the potential heterogeneity between studies. We conducted sensitivity analysis by excluding the each individual study to assess the results whether were stable. Finally, the publication bias was performed by accumulative forest plot.

RESULTS

Seven studies with 3004 participants met the inclusion criteria. BPA had significant positively association with birth weight (β = 21.92, 95%CI: 1.50-42.35, P = .04). No significant associations were found between BPA and birth length, head circumference and gestational age (All of P > .05).

CONCLUSION

This meta-analysis demonstrated that the BPA was positively associated with birth weight. Therefore, further studies are needed to investigate the critical sensitive period of influencing fetal development and to investigate the difference on gender.

Unhealthy Levels of Phthalates and Bisphenol A in Mexican Pregnant Women with Gestational Diabetes and Its Association to Altered Expression of miRNAs Involved with Metabolic Disease

Several studies indicate that bisphenol A (BPA) and phthalates may have a role in the development of metabolic diseases using different molecular pathways, including epigenetic regulatory mechanisms. However, it is unclear whether exposure to these chemicals modifies serum levels of miRNAs associated with gestational diabetes mellitus (GDM) risk. In the present study, we evaluated the serum levels of miRNAs associated with GDM (miR-9-5p, miR-16-5p, miR-29a-3p and miR-330-3p) and urinary levels of phthalate metabolites (mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP) and mono(2-ethyl hexyl) phthalate (MEHP)) and bisphenol A in GDM patients and women without GDM during the second trimester of gestation. We observed higher levels of miR-9-5p, miR-29a-3p and miR-330-3p in sera of patients with GDM compared to non-diabetic subjects. Phthalates were detected in 97–100% of urine samples, while BPA only in 40%. Urinary MEHP and BPA concentrations were remarkably higher in both study groups compared to previously reported data. Unadjusted MEHP levels and adjusted BPA levels were higher in non-diabetics than in GDM patients (p = 0.03, p = 0.02). We found positive correlations between adjusted urinary MBzP levels and miR-16-5p expression levels (p < 0.05), adjusted MEHP concentrations and miR-29a-3p expression levels (p < 0.05). We also found negative correlations between unadjusted and adjusted MBP concentrations and miR-29a-3p expression levels (p < 0.0001, p < 0.05), unadjusted MiBP concentrations and miR-29a-3p expression levels (p < 0.01). Urinary MEHP levels reflect a striking exposure to di(2-ethylhexyl) phthalate (DEHP) in pregnant Mexican women. This study highlights the need for a regulatory strategy in the manufacture of several items containing endocrine disruptors in order to avoid involuntary ingestion of these compounds in the Mexican population.

Variations, Determinants, and Coexposure Patterns of Personal Care Product Chemicals among Chinese Pregnant Women: A Longitudinal Study

Exposure to mixtures of personal care product chemicals (PCPCs) is commonplace among the Chinese population; yet, limited data are available on the variations, determinants, and coexposure patterns of PCPCs, particularly among pregnant women at multiple time points during gestation. Here, we measured concentrations of 11 most common PCPCs (five parabens, five benzophenones, and triclosan) in 2823 urine samples collected from 941 pregnant women over three trimesters. Based on the quantification results, we calculated the intraclass correlation coefficient (ICC) to assess within-person variability of targeted compounds, applied linear mixed mode models to explore associations between urinary concentrations of PCPCs and exposure-related factors, and used percentile analysis to evaluate exposure to specific or multiple chemicals at one or three trimesters. Seven targeted compounds: methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), 4-hydroxybenzophenone (4-OH-BP), 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), and triclosan (TCS) were detected in over 66% of samples. The median urinary concentrations (ng/mL) of MeP, EtP, PrP, 4-OH-BP, BP-1, BP-3, and TCS were 15.44, 0.49, 0.61, 0.16, 0.25, 0.53, and 0.48, respectively. We observed that benzophenones (ICC: 0.46-0.55) and triclosan (ICC: 0.50) were less variable than parabens (ICC: 0.35-0.40). Urinary levels of parabens were related to physical activity frequency; urinary levels of benzophenones were associated with the refurbishment of homes and household income, and urinary levels of triclosan were contingent upon the personal basic information (prepregnancy body mass index and age). Notably, higher levels of benzophenones and triclosan but lower paraben levels were observed in summer than in winter. Both coexposure to high percentiles of multiple pollutants at one trimester and exposure to one pollutant at high-dose through three trimesters were rare in the study population. Our findings suggest that these exposure-related factors should be taken into consideration, and health risks should be assessed on mixtures of pollutants in future epidemiological studies.

Bisphenol a: A narrative review of prenatal exposure effects on adipogenesis and childhood obesity via peroxisome proliferator-activated receptor gamma

There is significant evidence of globally ubiquitous prenatal exposures to bisphenol A (BPA). Childhood obesity as an epidemic has been a global concern for over a decade. Experimental models and epidemiological evidence suggest that BPA may act as an obesogen during adipogenesis. Results from stem cell models and birth cohort studies support the developmental origins of health and disease theory. While literature reviews have presented a variety of potential mechanisms of BPA action during adipogenesis, there remains no consensus. This review is the first to explore the proliferator-activated receptor gamma (PPARγ) mechanism in detail. This review will also examine the obesogenic effect of prenatal exposure to BPA during critical windows of vulnerability. Although vast experimental literature exists, there is limited epidemiological evidence to support the hypothesis for the obesogenic effect of BPA. The primary goal of this review is to provide researchers with a roadmap of existing research and suggestions for future directions for analyzing the relationship between prenatal BPA exposures and childhood obesity.

Fetal growth in environmental epidemiology: mechanisms, limitations, and a review of associations with biomarkers of non-persistent chemical exposures during pregnancy

BACKGROUND

Non-persistent chemicals, such as phthalates, environmental phenols, organophosphate pesticides, and others, are challenging to study because of their ubiquity in the environment, diverse exposure routes, and high temporal variability of biomarkers. Nonetheless, there is interest in understanding how gestational exposure to these chemicals may affect fetal growth, as perturbations to normal fetal growth are related to a plethora of adverse health outcomes in childhood and adulthood.

METHODS

The purpose of this review is to describe the state of the science on this topic. We searched PubMed for studies that included both 1) biomarkers of non-persistent chemicals collected during pregnancy and 2) fetal growth outcomes measured at birth (e.g., birth weight) or by ultrasound in utero (e.g., estimated fetal weight).

RESULTS

The bulk of the literature we found uses biomarkers measured at a single time point in pregnancy and birth weight as the primary measure of fetal growth. There is a small, but growing, body of research that uses ultrasound measures to assess fetal growth during pregnancy. In addition to summarizing the findings of the publications we identified, we describe inconsistencies in methodology, areas for improvement, and gaps in existing knowledge that can be targeted for improvement in future work. This literature is characterized by variability in methodology, likely contributing to the inconsistency of results reported. We further discuss maternal, placental, and fetal pathways by which these classes of chemicals may affect fetal growth.

CONCLUSIONS

To improve understanding of how everyday chemical exposures affect fetal growth, and ultimately lifelong health outcomes, mechanisms of toxicant action should be considered alongside improved study designs for future hypothesis-driven research.

The associations between prenatal exposure to triclocarban, phenols and parabens with gestational age and birth weight in northern Puerto Rico

BACKGROUND

Prenatal exposure to certain xenobiotics has been associated with adverse birth outcomes. We examined the associations of triclocarban, phenols and parabens in a cohort of 922 pregnant women in Puerto Rico, the Puerto Rico Testsite for Exploring Contamination Threats Program (PROTECT).

METHODS

Urinary triclocarban, phenols and parabens were measured at three time points in pregnancy (visit 1: 16-20 weeks, visit 2: 20-24 weeks, visit 3: 24-28 weeks gestation). Multiple linear regression (MLR) models were conducted to regress gestational age and birthweight z-scores against each woman's log average concentrations of exposure biomarkers. Logistic regression models were conducted to calculate odds of preterm birth, small or large for gestational age (SGA and LGA) in association with each of the exposure biomarkers. An interaction term between the average urinary biomarker concentration and infant sex was included in models to identify effect modification. The results were additionally stratified by study visit to look for windows of vulnerability. Results were transformed into the change in the birth outcome for an inter-quartile-range difference in biomarker concentration (Δ).

RESULTS

Average benzophenone-3, methyl- and propyl-paraben concentrations were associated with an increase in gestational age [(Δ 1.90 days; 95% CI: 0.54, 3.26); (Δ 1.63; 95% CI: 0.37, 2.89); (Δ 2.06; 95% CI: 0.63, 3.48), respectively]. Triclocarban was associated with a suggestive 2-day decrease in gestational age (Δ - 1.96; 95% CI: -4.11, 0.19). Bisphenol A measured at visit 1 was associated with a suggestive increase in gestational age (Δ 1.37; 95% CI: -0.05, 2.79). Triclosan was positively associated with gestational age among males, and negatively associated with gestational age among females. Methyl-, butyl- and propyl-paraben were associated with significant 0.50-0.66 decreased odds of SGA. BPS was associated with an increase in the odds of SGA at visit 3, and a suggestive increase in the odds of LGA at visit 1.

CONCLUSION

Benzophenone-3, methyl-paraben and propyl-paraben were associated with an increase in gestational age. Concentrations of triclocarban, which were much higher than reported in other populations, were associated with a suggestive decrease in gestational age. The direction of the association between triclosan and gestational age differed by infant sex. Parabens were associated with a decrease in SGA, and BPS was associated with both SGA and LGA depending on the study visit. Further studies are required to substantiate these findings.

Concentrations of endocrine disrupting chemicals in newborn blood spots and infant outcomes in the upstate KIDS study

BACKGROUND

Novel methodologies to quantify infant exposures to endocrine disrupting chemicals (EDCs) for population-based studies are needed.

OBJECTIVES

We used newborn dried blood spots to quantify three EDCs and their associations with infant outcomes in the Upstate KIDS Cohort.

METHODS

We measured bisphenol A (BPA), perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in 2071 singleton and 1040 twin infants born to mothers in New York State. We log transformed concentrations after rescaling by their standard deviations and modeled each in relation to gestational age, birthweight, length, head circumference and Ponderal Index (PI) using linear regression techniques. All models were adjusted for maternal age, body mass index, education, infertility treatment and parity. Generalized estimating equations with robust standard errors were used to assess the associations for twins.

RESULTS

Chemicals were largely quantified above the limits of detection (>99% for PFOS and PFOA; 90% for BPA). Overall, we observed no significant associations between PFASs and birth size irrespective of plurality of birth. However, among twins, BPA was associated with decreases in gestational age (adjusted β = -0.09 weeks; 95% Confidence Interval (CI): -0.16, -0.02) and birthweight (adjusted β = -32.52 g; 95% CI: -60.99, -4.05), head circumference (adjusted β = -0.18 cm; 95% CI: -0.38, -0.02) and increased PI in singletons (adjusted β = 0.02 cm; 95% CI: 0.004, 0.04).

CONCLUSION

We observed negative associations between BPA and birth size in twins. Our findings demonstrate the feasibility of newborn dried blood spots for quantifying neonatal exposure at the population level.

The association of repeated measurements of prenatal exposure to triclosan with fetal and early-childhood growth

BACKGROUND

Triclosan (TCS) is known to possess endocrine disrupting properties and metabolize rapidly in the human body. Human data concerning repeated measurements of TCS throughout pregnancy in relation to fetal and childhood growth are sparse.

OBJECTIVES

We investigated the associations between multiple measurements of maternal urinary concentrations of TCS during pregnancy and fetal and early-childhood growth.

METHODS

The study population included 850 mother-infant pairs who participated in a prenatal cohort established between 2014 and 2015 in Wuhan. Prenatal TCS exposure was measured in a complete series of urine samples collected at the first, second and third trimesters. General linear models and generalized estimating equation models were applied to evaluate the associations of the averaged maternal urinary concentrations of TCS over trimesters and trimester-specific urinary TCS with the z-scores of estimated fetal weight, head circumference, abdominal circumference, and femur length at 16, 24, and 31 gestational weeks, weight and length at birth, and weight and height at 0.5, 1, and 2 years of age.

RESULTS

In overall infants, we did not observe any significant association of the averaged maternal urinary concentrations of TCS over trimesters with ultrasound parameters and size at birth. However, a positive association of borderline statistical significance was found between averaged prenatal TCS exposure and the third-trimester estimated fetal weight z-score in girls in sex-stratified analyses (β = 0.054, 95% CI: -0.005, 0.113, p = 0.07). Moreover, averaged prenatal TCS exposure was positively associated with 2 year-old weight z-score among total infants (β = 0.046, 95% CI: 0.005, 0.087). After stratifying by sex, the same association was observed in girls with more prominent estimation (β = 0.062, 95% CI: 0.000, 0.124), whereas the association weakened and became not significant in boys (β = 0.033, 95% CI: -0.024, 0.089). TCS exposure at 1st and 2nd-trimester were positively associated with weight z-score at 2 years, in both overall and female infants.

CONCLUSIONS

Prenatal exposure to triclosan was associated with elevated third-trimester estimated fetal weight and 2 year-old weight z-score in girls, and the early and middle stage of pregnancy may be the windows of vulnerability. Apart from these findings, we did not find strong evidence for prenatal triclosan exposure in relation to fetal and early-childhood growth.

Maternal and paternal preconception exposure to bisphenols and size at birth

STUDY QUESTION

Are maternal and paternal preconception urinary bisphenol A (BPA) or bisphenol S (BPS) concentrations associated with offspring birth size?

SUMMARY ANSWER

Maternal-but not paternal-preconception urinary BPA concentrations were associated with lower birth size among couples seeking fertility evaluation.

WHAT IS KNOWN ALREADY

Prenatal BPA exposure has been previously associated with reduced birth size in some but not all epidemiologic studies. However, the potential effect of BPA exposure before conception in either parent is unknown. Data on BPS is practically absent.

STUDY DESIGN, SIZE, DURATION

Ongoing prospective preconception cohort of women and men seeking fertility evaluation between 2005 and 2016 in a large fertility center in an academic hospital in Boston, MA, USA.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We examined the association between maternal and paternal preconception, as well as maternal prenatal urinary BPA and BPS concentrations, and size at birth among 346 singletons from couples recruited in the Environment and Reproductive Health (EARTH) Study using multivariable linear regression. Infant birth weight and head circumference were abstracted from delivery records. Mean preconception and prenatal exposures were estimated by averaging urinary ln-BPA and ln-BPS concentrations in multiple maternal and paternal urine samples collected before pregnancy, and maternal pregnancy samples collected in each trimester.

MAIN RESULTS AND THE ROLE OF CHANCE

Maternal preconception urinary BPA concentrations were inversely associated with birth weight and head circumference in adjusted models: each ln-unit increase was associated with a decrease in birth weight of 119 g (95% CI: -212, -27), and a head circumference decrease of 0.72 cm (95% CI: -1.3, -0.1). Additional adjustment by gestational age or prenatal BPA exposure modestly attenuated results. Women with higher prenatal BPA concentrations had infants with lower mean birth weight (-75 g, 95% CI: -153, 2) although this did not achieve statistical significance. Paternal preconception urinary BPA concentrations were not associated with either birth weight or head circumference. No consistent patterns emerged for BPS concentrations measured in either parent.

LIMITATIONS, REASONS FOR CAUTION

We observed a strong negative association between maternal-but not paternal-preconception BPA concentrations and offspring birth size among a subfertile population. Although these results are overall consistent with prior studies on prenatal BPA exposure, these findings may not be generalizable to women without fertility concerns.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that the unexplored maternal preconception period may be a sensitive window for BPA effects on birth outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

Work supported by Grants (ES R01 009718, ES 022955 and ES 000002) from the National Institute of Environmental Health Sciences (NIEHS). C.M. was supported by a post-doctoral fellowship award from the Canadian Institutes of Health Research. There are no competing interests to declare.

Association between bisphenol a exposure and idiopathic central precocious puberty (ICPP) among school-aged girls in Shanghai, China

BACKGROUND

Bisphenol A (BPA) is a well-known and widely used endocrine disrupter, but data on its association with childhood reproductive development are limited.

OBJECTIVES

We investigated the possible relationship between exposure to BPA and idiopathic central precocious puberty (ICPP) in school-aged girls.

METHODS

We conducted a 1:1 matched case-control study in Shanghai, China, between July 2011 and September 2012. This study included 136 school-aged (6 to 9 years old) girls diagnosed with ICPP and 136 controls matched for age and body mass index (BMI). We measured the urinary BPA concentrations of all the girls and examined the association with odds of having ICPP. Laboratory examinations including serum estradiol (E2) levels, basal and gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels, bone ages (BA), and uterine and ovarian sizes were conducted in the ICPP girls.

RESULTS

Median concentrations of urinary BPA in the ICPP and control groups were 6.35 and 1.17 μg/g creatinine (Cr), respectively (p < 0.001). After adjustment for confounders, compared to those with the lowest concentrations of BPA, the highest concentrations were associated with a 9.08-fold increased odds of having ICPP [odds ratio (OR) = 9.08, (95% confidence interval (CI): 2.83-29.15)]. In the ICPP group, modest negative correlation was present between urinary BPA concentrations (μg/g Cr) and peak FSH levels [β = -0.090 (95% CI: -0.178, -0.003), p = 0.044].

CONCLUSIONS

Our findings suggest that BPA exposure is associated with increased odds of having ICPP in school-aged girls, and the potential mechanism may be attributable to the relatively low FSH levels.

The association between prenatal bisphenol A exposure and birth weight: a meta-analysis

The association between prenatal BPA exposure and birth weight is controversial. Here, a meta-analysis was performed to estimate the association between prenatal BPA exposure and birth weight. We searched literature addressing the association of interest in relevant databases. Data were independently extracted and analyzed using partial regression coefficient (β) and/or odds ratio (OR) and their 95% confidence intervals (CIs). We identified 140 references and included 8 studies. Based on the results of meta-analysis, the association between prenatal BPA exposure and continuous birth weight was estimated to be 4.42 g (95% CI: -8.83 to 17.67 g) when comparing the highest vs. the lowest BPA concentration. Findings from this study indicated that prenatal BPA exposure was not statistically associated with continuous birth weight. However, more evidence, based on large prospective cohort studies, is required to provide conclusive evidence on whether or not prenatal BPA exposure is associated with birth weight.