Transcriptional biomarkers of steroidogenesis and trophoblast differentiation in the placenta in relation to prenatal phthalate exposure

Association of phthalate exposure with reproductive outcomes among infertile couples undergoing in vitro fertilization: A systematic review

Human fertility is impacted by changes in lifestyle and environmental deterioration. To increase human fertility, assisted reproductive technology (ART) has been extensively used around the globe. As early as 2009, the Endocrine Society released its first scientific statement on the potential adverse effects of environmental endocrine-disrupting chemicals (EDCs) on human health and disease development. Chemicals known as phthalates, frequently employed as plasticizers and additives, are common EDCs. Numerous studies have shown that phthalate metabolites in vivo exert estrogen-like or anti-androgenic effects in both humans and animals. They are associated with the progression of a range of diseases, most notably interference with the reproductive process, damage to the placenta, and the initiation of chronic diseases in adulthood. Phthalates are ingested by infertile couples in a variety of ways, including household products, diet, medical treatment, etc. Exposure to phthalates may exacerbate their infertility or poor ART outcomes, however, the available data on phthalate exposure and ART pregnancy outcomes are sparse and contradictory. Therefore, this review conducted a systematic evaluation of 16 papers related to phthalate exposure and ART pregnancy outcomes, to provide more aggregated results, and deepen our understanding of reproductive outcomes in infertile populations with phthalate exposure.

Seasonal variation in urinary PAH metabolite levels and associations with neonatal birth outcomes

Previous studies have demonstrated that exposure to polycyclic aromatic hydrocarbons (PAHs) can affect maternal and infant health. However, the conclusions regarding the effects of seasonal PAH exposure on maternal and infant health have been inconsistent. To further elucidate this issue, this study included data from 2282 mother-infant pairs in the Zuni birth cohort. The objective was to investigate the association between maternal late-pregnancy urinary PAH metabolite concentrations and neonatal birth outcomes during the heating and non-heating seasons. The results demonstrated that PAH exposure in Zunyi was primarily dominated by 2-OHNAP and 1-OHNAP and that the concentrations of PAH metabolites were significantly higher during the heating season. Furthermore, PAH metabolite exposure was found to affect neonatal birth weight, birth length, and parity index with seasonal differences. Further dose-effect analyses revealed nonlinear relationships and seasonal differences between PAH metabolites and neonatal birth weight, birth length, and parity index. Bayesian kernel mechanism regression modeling demonstrated that the inverted U-shaped relationship between PAH metabolites and neonatal birth weight and parity index was exclusive to the heating season. Consequently, it can be posited that maternal exposure to PAH metabolites during late pregnancy exerts a detrimental influence on neonatal growth and development, which is further compounded by the use of heating fuels. This highlights the necessity to either control or alter the use of heating fuels during pregnancy.

Associations of Serum Perfluoroalkyl Substances and Placental Human Chorionic Gonadotropin in Early Pregnancy, Measured in the UPSIDE Study in Rochester, New York

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widely detected in pregnant women and associated with adverse outcomes related to impaired placental function. Human chorionic gonadotropin (hCG) is a dimeric glycoprotein hormone that can indicate placental toxicity.

OBJECTIVES

Our aim was to quantify the association of serum PFAS with placental hCG, measured as an intact molecule (hCG), as free alpha-(hCG α ) and beta-subunits (hCG β ), and as a hyperglycosylated form (h-hCG), and evaluate effect measure modification by social determinants and by fetal sex.

METHODS

Data were collected from 326 pregnant women enrolled from 2015 to 2019 in the UPSIDE study in Rochester, New York. hCG forms were normalized for gestational age at the time of blood draw in the first trimester [multiple of the median (MoM)]. Seven PFAS were measured in second-trimester maternal serum. Multivariate imputation by chained equations and inverse probability weighting were used to evaluate robustness of linear associations. PFAS mixture effects were estimated by Bayesian kernel machine regression.

RESULTS

Perfluorohexane sulfonic acid (PFHxS) [hCG β : 0.29 log MoM units per log PFHxS; 95% confidence interval (CI): 0.08, 0.51] and perfluorodecanoic acid (PFDA) (hCG: - 0.09 ; 95% CI: - 0.16 , - 0.02 ) were associated with hCG in the single chemical and mixture analyses. The PFAS mixture was negatively associated with hCG α and positively with hCG β . Subgroup analyses revealed that PFAS associations with hCG differed by maternal race/ethnicity and education. Perfluoropentanoic acid (PFPeA) was associated with hCG β only in Black participants (- 0.23 ; 95% CI: - 0.37 , - 0.09 ) and in participants with high school education or less (- 0.14 ; 95% CI: - 0.26 , - 0.02 ); conversely, perfluorononanoic acid (PFNA) was negatively associated with hCG α only in White participants (- 0.15 ; 95% CI: - 0.27 , - 0.03 ) and with hCG β only in participants with a college education or greater (- 0.19 ; 95% CI: - 0.36 , - 0.01 ). These findings were robust to testing for selection bias, confounding bias, and left truncation bias where PFAS detection frequency was < 100 % . Two associations were negative in male (and null in female) pregnancies: Perfluoroundecanoic acid (PFUnDA) with hCG α , and PFNA with h-hCG.

CONCLUSIONS

Evidence was strongest for the association between PFHxS and PFDA with hCG in all participants and for PFPeA and PFNA within subgroups defined by social determinants and fetal sex. PFAS mixture associations with hCG α and hCG β differed, suggesting subunit-specific types of toxicity and/or regulation. Future studies will evaluate the biological, clinical and public health significance of these findings. https://doi.org/10.1289/EHP12950.

Racial and Ethnic Disparities in Phthalate Exposure and Preterm Birth: A Pooled Study of Sixteen U.S. Cohorts

BACKGROUND

Phthalate exposures are ubiquitous during pregnancy and may contribute to racial and ethnic disparities in preterm birth.

OBJECTIVES

We investigated race and ethnicity in the relationship between biomarkers of phthalate exposure and preterm birth by examining: a) how hypothetical reductions in racial and ethnic disparities in phthalate metabolites might reduce the probability of preterm birth; and b) exposure-response models stratified by race and ethnicity.

METHODS

We pooled individual-level data on 6,045 pregnancies from 16 U.S. cohorts. We investigated covariate-adjusted differences in nine urinary phthalate metabolite concentrations by race and ethnicity [non-Hispanic White (White, 43%), non-Hispanic Black (Black, 13%), Hispanic/Latina (38%), and Asian/Pacific Islander (3%)]. Using g-computation, we estimated changes in the probability of preterm birth under hypothetical interventions to eliminate disparities in levels of urinary phthalate metabolites by proportionally lowering average concentrations in Black and Hispanic/Latina participants to be approximately equal to the averages in White participants. We also used race and ethnicity-stratified logistic regression to characterize associations between phthalate metabolites and preterm birth.

RESULTS

In comparison with concentrations among White participants, adjusted mean phthalate metabolite concentrations were consistently higher among Black and Hispanic/Latina participants by 23%-148% and 4%-94%, respectively. Asian/Pacific Islander participants had metabolite levels that were similar to those of White participants. Hypothetical interventions to reduce disparities in metabolite mixtures were associated with lower probabilities of preterm birth for Black [13% relative reduction; 95% confidence interval (CI): - 34 % , 8.6%] and Hispanic/Latina (9% relative reduction; 95% CI: - 19 % , 0.8%) participants. Odds ratios for preterm birth in association with phthalate metabolites demonstrated heterogeneity by race and ethnicity for two individual metabolites (mono-n-butyl and monoisobutyl phthalate), with positive associations that were larger in magnitude observed among Black or Hispanic/Latina participants.

CONCLUSIONS

Phthalate metabolite concentrations differed substantially by race and ethnicity. Our results show hypothetical interventions to reduce population-level racial and ethnic disparities in biomarkers of phthalate exposure could potentially reduce the probability of preterm birth. https://doi.org/10.1289/EHP12831.

Placental inflammatory cytokines mRNA expression and preschool children's cognitive performance: a birth cohort study in China

BACKGROUND

The immunologic milieu at the maternal-fetal interface has profound effects on propelling the development of the fetal brain. However, accessible epidemiological studies concerning the association between placental inflammatory cytokines and the intellectual development of offspring in humans are limited. Therefore, we explored the possible link between mRNA expression of inflammatory cytokines in placenta and preschoolers' cognitive performance.

METHODS

Study subjects were obtained from the Ma'anshan birth cohort (MABC). Placental samples were collected after delivery, and real-time quantitative polymerase chain reaction (RT-qPCR) was utilized to measure the mRNA expression levels of IL-8, IL-1β, IL-6, TNF-α, CRP, IFN-γ, IL-10, and IL-4. Children's intellectual development was assessed at preschool age by using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV). Multiple linear regression and restricted cubic spline models were used for statistical analysis.

RESULTS

A total of 1665 pairs of mother and child were included in the analysis. After adjusting for confounders and after correction for multiple comparisons, we observed that mRNA expression of IL-8 (β =  - 0.53; 95% CI, - 0.92 to - 0.15), IL-6 (β =  - 0.58; 95% CI, - 0.97 to - 0.19), TNF-α (β =  - 0.37; 95% CI, - 0.71 to - 0.02), and IFN-γ (β =  - 0.31; 95% CI, - 0.61 to - 0.03) in the placenta was negatively associated with preschoolers' full scale intelligence quotient (FSIQ). Both higher IL-8 and IL-6 were associated with lower children's low fluid reasoning index (FRI), and higher IFN-γ was associated with lower children's working memory index (WMI). After further adjusting for confounders and children's age at cognitive testing, the integrated index of six pro-inflammatory cytokines (index 2) was found to be significantly and negatively correlated with both the FSIQ and each sub-dimension (verbal comprehension index (VCI), visual spatial index (VSI), FRI, WMI, processing speed index (PSI)). Sex-stratified analyses showed that the association of IL-8, IFN-γ, and index 2 with children's cognitive development was mainly concentrated in boys.

CONCLUSIONS

Evidence of an association between low cognitive performance and high expression of placental inflammatory cytokines (IL-8, IL-6, TNF-α, and IFN-γ) was found, highlighting the potential importance of intrauterine placental immune status in dissecting offspring cognitive development.

Prenatal exposure to phthalates and emotional/behavioral development in young children

INTRODUCTION

Endocrine disrupting chemicals (EDCs) such as phthalates, found in our daily environment, are nowadays suggested to be associated with adverse outcomes. Prenatal exposure was found associated with neurodevelopmental complications such as behavioral difficulties in school age children.

AIM

To explore the association between intrauterine exposure to phthalates and emotional/behavioral development of 24 months old toddlers.

METHODS

Women were recruited at 11-18 weeks of gestation and provided spot urine samples, analyzed for phthalate metabolites (DEHP, DiNP, MBzBP). Offspring were examined at 24 months of age, using standard maternal report, regarding developmental and behavioral problems (CBCL, ASQ-3, HOME questionnaires) (N = 158). To explore the associations between metabolite levels and developmental outcomes, multivariate GLM analysis (General Linear Model) was used according to tertiles and developmental scores on each developmental outcome.

RESULTS

Associations of Di-(2-ethylhexyl) phthalate (DEHP) maternal exposure with behavioral-developmental outcomes were found only in boys. Compared with boys with lower DEHP maternal exposure, boys with high DEHP maternal exposure had lower developmental score in personal social abilities in the ASQ-3 questionnaire (50.68 + 8.06 and 44.14 + 11.02, high and low DEHP, respectively, p = 0.03), and more internalizing problems (for example, emotionally reactive score in high and low DEHP: 53.77 + 7.41 and 50.50 + 1.19, respectively, p = 0.029; anxious or depressed score: 53.38 + 5.01 and 50.75 + 1.34, respectively, p = 0.009; and somatic complaints scores 64.03 + 10.1 and 55.84 + 7.84, respectively, p = 0.003), and externalizing problems (49.28 + 8.59 and 43.33 + 9.11, respectively, p = 0.039). No differences were found in the development and behavior problems between high and low DEHP maternal exposure level in girls.

CONCLUSION

Maternal DEHP metabolite concentrations measured in first trimester urine was associated with children's emotional/behavioral developmental problems in 24-months old boys, supporting accumulating evidence of DEHP as a potentially harming chemical and call for environmental attention.

Determination of Polycyclic Aromatic Hydrocarbons (PAHs) and Phthalates in Human Placenta by Mixed Hexane/Ether Extraction and Gas Chromatography-Mass Spectrometry/Mass Spectrometry (GC-MS/MS)

In this study, we evaluated the extraction effect of three different extractants, namely hexane + ether (v/v = 3:1), acetonitrile and ethyl acetate, on polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in placenta detected and analysed by triple quadrupole gas chromatography-mass spectrometry (GC-MS/MS). The results showed that n-hexane + ether (v/v = 3:1) had the highest extraction efficiency. Under the optimal conditions, the limits of detection (LOD) for the 10 PAHs were 0.003-0.0167 μg/L with relative standard deviations (RSD) of 1.4-5.48% and detection rates of 68.19-107.05%, and the correlation coefficients were (R2, 0.9982-0.9999). The LODs for the nine PAEs were 0.0015-3.5714 μg/L and the correlation coefficients were (R2, 0.9982-0.9999). The limits of detection (S/N = 3) for the nine PAHs were 0.0015-0.5714 μg/L with relative standard deviations (RSD) of 3.15-8.37%, and the detection rates were 80.45-112.59% with correlations of (R2, 0.9972-0.9998). The method was applied to the analysis of PAHs and phthalates in placenta samples from pregnant women. The method's accuracy and applicability were demonstrated. In comparison with other methods for the detection of PAEs and PAHs, the method proposed in this paper has a wider linear range, lower minimum detection limit and comparable recovery with good correlation. This paper is dedicated to providing another method for improving the performance of extracting solid tissues.

Impact of Chemicals on the Age of Menarche: A Literature Review

A growing body of evidence suggests that chemicals interfere with the age of onset of menarche. We conducted a review in order to demonstrate the relationship between several categories of chemicals and menarche. We searched for English language papers using the Medline/PubMed database until April 2023. The chemical factors found to affect menarche were prenatal and antenatal smoke, phthalates, phenols, organochlorines, perfluoroalkyls and polyfluoroalkyls, metals, air pollutants and polybrominated diphenyl ethers. Low or high exposure to each chemical compound could affect the age of menarche, leading to early or delayed menarche. Furthermore, the results show that intrauterine exposure may have a different impact from antenatal exposure. There is evidence that endocrine-disrupting chemicals affect the age of menarche, but more research needs to be conducted.

Long-term exposure to di(2-ethylhexyl) phthalate, diisononyl phthalate, and a mixture of phthalates alters estrous cyclicity and/or impairs gestational index and birth rate in mice

Phthalates are found in plastic food containers, medical plastics, and personal care products. However, the effects of long-term phthalate exposure on female reproduction are unknown. Thus, this study investigated the effects of long-term, dietary phthalate exposure on estrous cyclicity and fertility in female mice. Adult female CD-1 mice were fed chow containing vehicle control (corn oil) or 0.15-1500 ppm of di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), or a mixture of phthalates (Mix) containing DEHP, DiNP, benzyl butyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, and diethyl phthalate. Measurements of urinary phthalate metabolites confirmed effective delivery of phthalates. Phthalate consumption for 11 months did not affect body weight compared to control. DEHP exposure at 0.15 ppm for 3 and 5 months increased the time that the mice spent in estrus and decreased the time the mice spent in metestrus/diestrus compared to control. DiNP exposure (0.15-1500 ppm) did not significantly affect time in estrus or metestrus/diestrus compared to control. Mix exposure at 0.15 and 1500 ppm for 3 months decreased the time the mice spent in metestrus/diestrus and increased the time the mice spent in estrus compared to control. DEHP (0.15-1500 ppm) or Mix (0.15-1500 ppm) exposure did not affect fertility-related indices compared to control. However, long-term DiNP exposure at 1500 ppm significantly reduced gestational index and birth rate compared to control. These data indicate that chronic dietary exposure to phthalates alters estrous cyclicity, and long-term exposure to DiNP reduces gestational index and birth rate in mice.

The effect of phthalates exposure during pregnancy on asthma in infants aged 0 to 36 months: a birth cohort study

This cohort study sought to investigate the effects of phthalates exposure during pregnancy on offspring asthma and its association with placental stress and inflammatory factor mRNA expression levels. A total of 3474 pregnant women from the China Ma'anshan birth cohort participated in this study. Seven phthalate metabolites were detected in urine samples during pregnancy by solid phase extraction-high-performance liquid chromatography tandem mass spectrometry. Placenta stress and inflammation mRNA expression were assessed by real-time quantitative polymerase chain reaction (RT-qPCR). Early pregnancy may be the critical period when phthalates exposure increases the risk of asthma in infants and young children, and there is a certain gender difference in the risk of asthma in infants and young children. Moreover, through the placenta stress and inflammatory factor associated with infant asthma found anti-inflammatory factor of interleukin-10 (IL-10) mRNA expression will reduce the risk of 36-month-old male infant asthma. The expression of interleukin-4(IL-4) and macrophage (M2) biomarker cluster of differentiation 206(CD206) mRNA reduced the risk of asthma in 18-month-old female infants. Placental stress and inflammatory response were analyzed using mediating effects. Tumor necrosis factor-α (TNFα) showed a complete mediating effect between mono-benzyl phthalate (MBzP) exposure in early pregnancy and asthma in 12-month-old males, and IL-10 also showed a complete mediating effect between mono-n-butyl phthalate (MBP) exposure in early and late pregnancy and asthma in 36-month-old males. In summary, exposure to phthalates during pregnancy may contribute to the development of asthma in infants, which may be associated with placental stress and inflammation.

A study on the association of placental and maternal urinary phthalate metabolites

BACKGROUND

Phthalate exposure in pregnancy is typically estimated using maternal urinary phthalate metabolite levels. Our aim was to evaluate the association of urinary and placental tissue phthalates, and to explore the role of maternal and pregnancy characteristics that may bias estimates.

METHODS

Fifty pregnancies were selected from the CANDLE Study, recruited from 2006 to 2011 in Tennessee. Linear models were used to estimate associations of urinary phthalates (2nd, 3rd trimesters) and placental tissue phthalates (birth). Potential confounders and modifiers were evaluated in categories: temporality (time between urine and placenta sample), fetal sex, demographics, social advantage, reproductive history, medication use, nutrition and adiposity. Molar and quantile normalized phthalates were calculated to facilitate comparison of placental and urinary levels.

RESULTS

Metabolites detectable in >80% of both urine and placental samples were MEP, MnBP, MBzP, MECPP, MEOHP, MEHHP, and MEHP. MEP was most abundant in urine (geometric mean [GM] 7.00 ×102 nmol/l) and in placental tissue (GM 2.56 ×104 nmol/l). MEHP was the least abundant in urine (GM 5.32 ×101 nmol/l) and second most abundant in placental tissue (2.04 ×104 nmol/l). In aggregate, MEHP differed the most between urine and placenta (2.21 log units), and MEHHP differed the least (0.07 log units). MECPP was positively associated between urine and placenta (regression coefficient: 0.31 95% CI 0.09, 0.53). Other urine-placenta metabolite associations were modified by measures of social advantage, reproductive history, medication use, and adiposity.

CONCLUSION

Phthalates were ubiquitous in 50 full-term placental samples, as has already been shown in maternal urine. MEP and MEHP were the most abundant. Measurement and comparison of urinary and placental phthalates can advance knowledge on phthalate toxicity in pregnancy and provide insight into the validity and accuracy of relying on maternal urinary concentrations to estimate placental exposures.

IMPACT STATEMENT

This is the first report of correlations/associations of urinary and placental tissue phthalates in human pregnancy. Epidemiologists have relied exclusively on maternal urinary phthalate metabolite concentrations to assess exposures in pregnant women and risk to their fetuses. Even though it has not yet been confirmed empirically, it is widely assumed that urinary concentrations are strongly and positively correlated with placental and fetal levels. Our data suggest that may not be the case, and these associations may vary by phthalate metabolite and associations may be modified by measures of social advantage, reproductive history, medication use, and adiposity.

Applying the adverse outcome pathway concept for assessing non-monotonic dose responses: biphasic effect of bis(2-ethylhexyl) phthalate (DEHP) on testosterone levels

Male reproduction is one of the primary health endpoints identified in rodent studies for some phthalates, such as DEHP (Bis(2-ethylhexyl) phthalate), DBP (Dibutyl phthalate), and BBP (Benzyl butyl phthalate). The reduction in testosterone level was used as an intermediate key event for grouping some phthalates and to establish a reference point for risk assessment. Phthalates, and specifically DEHP, are one of the chemicals for which the greatest number of non-monotonic dose responses (NMDRs) are observed. These NMDRs cover different endpoints and situations, often including testosterone levels. The presence of NMDR has been the subject of some debate within the area of chemical risk assessment, which is traditionally anchored around driving health-based guidance values for apical endpoints that typically follow a clear monotonic dose-response. The consequence of NMDR for chemical risk assessment has recently received considerable attention amongst regulatory agencies, which confirmed its relevance particularly for receptor-mediated effects. The present review explores the relationship between DEHP exposure and testosterone levels, investigating the biological plausibility of the observed NMDRs. The Adverse Outcome Pathway (AOP) concept is applied to integrate NMDRs into Key Event Relationships (KERs) for exploring a mechanistic understanding of initial key events and possibly associated reproductive and non-reproductive adverse outcomes.

Exposure to endocrine-disrupting chemicals and risk of gestational hypertension and preeclampsia: A systematic review and meta-analysis

Prenatal exposure to endocrine-disrupting chemicals has been linked to gestational hypertension (GH) and preeclampsia (PE). However, the results were conflicting and inconclusive. We conducted a systematic review and meta-analysis for an overview of these relationships. We searched PubMed, and Google Scholar for studies investigating bisphenol A, phthalates, and per or poly-fluoroalkyl substances and GH or PE. Pooled odds ratio (OR) with a 95% confidence interval (CI) were calculated for risk estimate using the generic inverse variance method. A total of 14 studies were included in the present analysis. The pooled results demonstrated that perfluorooctanoic acid (PFOA, OR:1.20, 95% CI: 1.04, 1.39), perfluoro octane sulfonic acid (PFOS, (OR:1.23, 95% CI: 1.10, 1.38), and perfluononanoic acid (PFNA, OR:1.20, 95% CI: 1.03, 1.40) were significantly associated with an increased risk of PE. There was no significant association observed with perfluoro hexane sulfonic acid (PFHxS), perfluoro decanoic acid (PFDA), perfluoro heptanoic acid (PFHpA), and perfluoro undecanoic acid (PFUnDA) and PE. For GH, a statistically significant positive association was found with PFOA (OR:1.18, 95% CI: 1.01, 1.39) and PFHxS (OR:1.15, 95% CI: 1.02, 1.29). Among various phthalates analysed only mono-ethyl phthalate (MEP, OR:1.37, 95% CI: 1.11, 1.70) showed an association with GH. From our analysis, bisphenol A exposure during pregnancy did not show a significant association with the risk of PE. Our findings indicated that exposure to PFASs such as PFOA, PFOS, and PFNA during pregnancy is associated with an increased risk of PE and PFOA and PFHxS with GH. We also found that MEP was associated with GH. Most of the results were unstable in sensitivity analysis. Since most of these associations have limited evidence, more research is needed to confirm these findings.

The Placental Function Beyond Pregnancy: Insights from Latin America

Currently, more than 100,000 papers had been published studying the placenta in both physiological and pathological contexts. However, relevant health conditions affecting placental function, mostly found in low-income countries, should be evaluated deeper. This review will raise some - of what we think necessary - points of discussion regarding challenging topics not fully understood, including the paternal versus maternal contribution on placental genes imprinting, placenta-brain communication, and some environmental conditions affecting the placenta. The discussions are parts of an international effort to fulfil some gaps observed in this area, and Latin-American research groups currently evaluate that.

The effect of endocrine-disrupting chemicals on placental development

Endocrine-disrupting chemicals (EDCs) or endocrine disruptors are substances that are either naturally occurring or artificial and are released into the natural environment. Humans are exposed to EDCs through ingestion, inhalation, and skin contact. Many everyday household items, such as plastic bottles and containers, the liners of metal food cans, detergents, flame retardants, food, gadgets, cosmetics, and pesticides, contain endocrine disruptors. Each hormone has a unique chemical makeup and structural attributes. The way that endocrine hormones connect to receptors is described as a "lock and key" mechanism, with each hormone serving as the key (lock). This mechanism is enabled by the complementary shape of receptors to their hormone, which allows the hormone to activate the receptors. EDCs are described as exogenous chemicals or compounds that have a negative impact on organisms' health by interacting with the functioning of the endocrine system. EDCs are associated with cancer, cardiovascular risk, behavioural disorders, autoimmune abnormalities, and reproductive disorders. EDCs exposure in humans is highly harmful during critical life stages. Nonetheless, the effect of EDCs on the placenta is often underestimated. The placenta is especially sensitive to EDCs due to its abundance of hormone receptors. In this review, we evaluated the most recent data on the effects of EDCs on placental development and function, including heavy metals, plasticizers, pesticides, flame retardants, UV filters and preservatives. The EDCs under evaluation have evidence from human biomonitoring and are found in nature. Additionally, this study indicates important knowledge gaps that will direct future research on the topic.

Associations between Prenatal Exposure to Phthalates and Features of the Metabolic Syndrome in Males from Childhood into Adulthood

Phthalate metabolites are detectable within the majority of the population. Evidence suggests that a prenatal exposure to phthalates may be associated with the subsequent risks of obesity and elevated blood pressure. We hypothesised that a prenatal exposure to phthalates would lead to an increase in adverse cardiometabolic parameters through childhood and adulthood. The maternal serum phthalate measurements from the stored samples taken from Gen1 mothers at 18 and 34 weeks gestation were examined in relation to the cardiometabolic measures in 387 male offspring from the Raine Study. Data from the Gen2 follow-ups between 3 and 27 years were used. The primary outcomes were analysed longitudinally using linear mixed models for the repeated measures. Non-alcoholic fatty liver disease (NAFLD) was assessed at 17 years using logistic regression. A consistent positive relationship was observed between a prenatal exposure to mono-carboxy-iso-octyl phthalate (MCiOP) through adolescence into adulthood with systolic blood pressure. There were no other consistent cardiovascular associations. Mid-levels of prenatal exposures to Mono-n-butyl phthalate (MnBP) were associated with a greater incidence of NAFLD. Detectable Mono-3-carboxypropyl phthalate (MCPP) was associated with a lower serum HDL-C through late childhood into adulthood, while a higher prenatal exposure to mono-iso-butyl phthalate (MiBP), was associated with a higher LDL-C at 22 years of age. A mid-level prenatal exposure to mono-2-ethylhexyl phthalate (MEHP) metabolites was associated with higher insulin in adulthood, while a higher prenatal exposure to the sum of the Di-(2-ethyl-hexyl) phthalate (DEHP) and Di-iso-nonyl phthalate (DiNP) metabolites was associated with higher fasting serum glucose in adulthood. In conclusion, our study demonstrated that higher prenatal phthalate exposures to some phthalate metabolites was associated with some adverse metabolic profiles through adolescence into adulthood, although the consistent themes were limited to a few metabolites and the outcomes of systolic blood pressure, fasting insulin and glucose.

Associations Between Prenatal Urinary Biomarkers of Phthalate Exposure and Preterm Birth: A Pooled Study of 16 US Cohorts

Importance

Phthalate exposure is widespread among pregnant women and may be a risk factor for preterm birth.

Objective

To investigate the prospective association between urinary biomarkers of phthalates in pregnancy and preterm birth among individuals living in the US.

Design, Setting, and Participants

Individual-level data were pooled from 16 preconception and pregnancy studies conducted in the US. Pregnant individuals who delivered between 1983 and 2018 and provided 1 or more urine samples during pregnancy were included.

Exposures

Urinary phthalate metabolites were quantified as biomarkers of phthalate exposure. Concentrations of 11 phthalate metabolites were standardized for urine dilution and mean repeated measurements across pregnancy were calculated.

Main Outcomes and Measures

Logistic regression models were used to examine the association between each phthalate metabolite with the odds of preterm birth, defined as less than 37 weeks of gestation at delivery (n = 539). Models pooled data using fixed effects and adjusted for maternal age, race and ethnicity, education, and prepregnancy body mass index. The association between the overall mixture of phthalate metabolites and preterm birth was also examined with logistic regression. G-computation, which requires certain assumptions to be considered causal, was used to estimate the association with hypothetical interventions to reduce the mixture concentrations on preterm birth.

Results

The final analytic sample included 6045 participants (mean [SD] age, 29.1 [6.1] years). Overall, 802 individuals (13.3%) were Black, 2323 (38.4%) were Hispanic/Latina, 2576 (42.6%) were White, and 328 (5.4%) had other race and ethnicity (including American Indian/Alaskan Native, Native Hawaiian, >1 racial identity, or reported as other). Most phthalate metabolites were detected in more than 96% of participants. Higher odds of preterm birth, ranging from 12% to 16%, were observed in association with an interquartile range increase in urinary concentrations of mono-n-butyl phthalate (odds ratio [OR], 1.12 [95% CI, 0.98-1.27]), mono-isobutyl phthalate (OR, 1.16 [95% CI, 1.00-1.34]), mono(2-ethyl-5-carboxypentyl) phthalate (OR, 1.16 [95% CI, 1.00-1.34]), and mono(3-carboxypropyl) phthalate (OR, 1.14 [95% CI, 1.01-1.29]). Among approximately 90 preterm births per 1000 live births in this study population, hypothetical interventions to reduce the mixture of phthalate metabolite levels by 10%, 30%, and 50% were estimated to prevent 1.8 (95% CI, 0.5-3.1), 5.9 (95% CI, 1.7-9.9), and 11.1 (95% CI, 3.6-18.3) preterm births, respectively.

Conclusions and Relevance

Results from this large US study population suggest that phthalate exposure during pregnancy may be a preventable risk factor for preterm delivery.

Phthalate Exposures and Placental Health in Animal Models and Humans: A Systematic Review

Phthalates are ubiquitous compounds known to leach from the plastic products that contain them. Due to their endocrine-disrupting properties, a wide range of studies have elucidated their effects on reproduction, metabolism, neurodevelopment, and growth. Additionally, their impacts during pregnancy and on the developing fetus have been extensively studied. Most recently, there has been interest in the impacts of phthalates on the placenta, a transient major endocrine organ critical to maintenance of the uterine environment and fetal development. Phthalate-induced changes in placental structure and function may have significant impacts on the course of pregnancy and ultimately, child health. Prior reviews have described the literature on phthalates and placental health; however to date, there has been no comprehensive, systematic review on this topic. Here, we review 35 papers (24 human and 11 animal studies) and summarize phthalate exposures in relation to an extensive set of placental measures. Phthalate-related alterations were reported for placental morphology, hormone production, vascularization, histopathology, and gene/protein expression. The most consistent changes were observed in vascular and morphologic endpoints, including cell composition. These changes have implications for pregnancy complications such as preterm birth and intrauterine growth restriction as well as potential ramifications for children's health. This comprehensive review of the literature, including common sources of bias, will inform the future work in this rapidly expanding field.

Killing two birds with one stone: Pregnancy is a sensitive window for endocrine effects on both the mother and the fetus

Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be "imprinted" in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.

Phthalate Esters in Tap Water, Southern Thailand: Daily Exposure and Cumulative Health Risk in Infants, Lactating Mothers, Pregnant and Nonpregnant Women

Human exposure to phthalate esters (PAEs) via drinking water has generated public health concerns due to their endocrine disruptive abilities. This study reports on the occurrence and fate of six PAEs in raw and tap water samples collected from provincial waterworks located in Songkhla Province, Southern Thailand. In addition, the daily exposure and cumulative health risk of susceptible populations due to drinking tap water were evaluated by using four different reference dose (RfDs) sources. The maximum concentrations of PAEs in raw water were between 1.68 and 4.84 and 0.52 and 1.24 µg/L in tap water. Moreover, the levels of PAEs in the tap water samples indicated the poor PAEs removal efficiency of the conventional treatment process (59.9-69.1%). The contribution of water to the daily intake of PAEs did not exceed 0.37% in all the groups. Furthermore, both the individual and cumulative risk assessment showed negligible noncarcinogenic and antiandrogenic risk for all the groups. Nevertheless, the cumulative risk showed an increasing trend in the order of infants > lactating mothers > pregnant women > nonpregnant women, suggesting that infants are more vulnerable. In additional, the newly proposed RfDAA yielded higher hazard quotient and hazard index estimates, which indicates it is a more sensitive tool than other RfDs for the assessment of the individual and mixture risk of pollutants. The carcinogenic risk of DEHP was acceptable in every group. However, we recommend a future cumulative risk assessment of vulnerable groups considering their simultaneous exposure to all chemicals that have antiandrogenic effects via tap water.

Role of epidemiology in risk assessment: a case study of five ortho-phthalates

BACKGROUND

The association between environmental chemical exposures and chronic diseases is of increasing concern. Chemical risk assessment relies heavily on pre-market toxicity testing to identify safe levels of exposure, often known as reference doses (RfD), expected to be protective of human health. Although some RfDs have been reassessed in light of new hazard information, it is not a common practice. Continuous surveillance of animal and human data, both in terms of exposures and associated health outcomes, could provide valuable information to risk assessors and regulators. Using ortho-phthalates as case study, we asked whether RfDs deduced from male reproductive toxicity studies and set by traditional regulatory toxicology approaches sufficiently protect the population for other health outcomes.

METHODS

We searched for epidemiological studies on benzyl butyl phthalate (BBP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), dicyclohexyl phthalate (DCHP), and bis(2-ethylhexyl) phthalate (DEHP). Data were extracted from studies where any of the five chemicals or their metabolites were measured and showed a statistically significant association with a health outcome; 38 studies met the criteria. We estimated intake for each phthalate from urinary metabolite concentration and compared estimated intake ranges associated with health endpoints to each phthalate's RfD.

RESULT

For DBP, DIBP, and BBP, the estimated intake ranges significantly associated with health endpoints were all below their individual RfDs. For DEHP, the intake range included associations at levels both below and above its RfD. For DCHP, no relevant studies could be identified. The significantly affected endpoints revealed by our analysis include metabolic, neurodevelopmental and behavioral disorders, obesity, and changes in hormone levels. Most of these conditions are not routinely evaluated in animal testing employed in regulatory toxicology.

CONCLUSION

We conclude that for DBP, DIBP, BBP, and DEHP current RfDs estimated based on male reproductive toxicity may not be sufficiently protective of other health effects. Thus, a new approach is needed where post-market exposures, epidemiological and clinical data are systematically reviewed to ensure adequate health protection.

A Comprehensive Assessment of Associations between Prenatal Phthalate Exposure and the Placental Transcriptomic Landscape

BACKGROUND

Phthalates are commonly used endocrine-disrupting chemicals that are ubiquitous in the general population. Prenatal phthalate exposure may alter placental physiology and fetal development, leading to adverse perinatal and childhood health outcomes.

OBJECTIVE

We examined associations between prenatal phthalate exposure in the second and third trimesters and the placental transcriptome at birth, including genes and long noncoding RNAs (lncRNAs), to gain insight into potential mechanisms of action during fetal development.

METHODS

The ECHO PATHWAYs consortium quantified 21 urinary phthalate metabolites from 760 women enrolled in the CANDLE study (Shelby County, TN) using high-performance liquid chromatography-tandem mass spectrometry. Placental transcriptomic data were obtained using paired-end RNA sequencing. Linear models were fitted to estimate separate associations between maternal urinary phthalate metabolite concentration during the second and third trimester and placental gene expression at birth, adjusted for confounding variables. Genes were considered differentially expressed at a Benjamini-Hochberg false discovery rate (FDR) p<0.05. Associations between phthalate metabolites and biological pathways were identified using self-contained gene set testing and considered significantly altered with an FDR-adjusted p<0.2.

RESULTS

We observed significant associations between second-trimester phthalate metabolites mono (carboxyisooctyl) phthalate (MCIOP), mono-2-ethyl-5-carboxypentyl phthalate, and mono-2-ethyl-5-oxohexyl phthalate and 18 genes in total, including four lncRNAs. Specifically, placental expression of NEAT1 was associated with multiple phthalate metabolites. Third-trimester MCIOP and mono-isobutyl phthalate concentrations were significantly associated with placental expression of 18 genes and two genes, respectively. Expression of genes within 27 biological pathways was associated with mono-methyl phthalate, MCIOP, and monoethyl phthalate concentrations.

DISCUSSION

To our knowledge, this is the first genome-wide assessment of the relationship between the placental transcriptome at birth and prenatal phthalate exposure in a large and diverse birth cohort. We identified numerous genes and lncRNAs associated with prenatal phthalate exposure. These associations mirror findings from other epidemiological and in vitro analyses and may provide insight into biological pathways affected in utero by phthalate exposure. https://doi.org/10.1289/EHP8973.

Endocrine-Disrupting Chemicals and Disorders of Penile Development in Humans

This paper reviews the current knowledge on the environmental effects on penile development in humans. The specific focus is on endocrine-disrupting chemicals (EDCs), a heterogeneous group of natural or manmade substances that interfere with endocrine function, and whether they can induce hypospadias and micropenis in male neonates. Epidemiological data and animal observations first raised suspicions about environmental effects, leading to the testis dysgenesis syndrome (TDS) hypothesis. More recent research has provided stronger indications that TDS may indeed be the result of the direct or indirect effects of EDCs. Drawing on epidemiological and toxicological studies, we also report on the effects of maternal diet and substances like pesticides, phthalates, bisphenol A, and polychlorinated biphenyls. Proximity to contamination hazards and occupational exposure are also suspected to contribute to the occurrence of hypospadias and micropenis. Lastly, the cumulative effects of EDCs and the possibility of transgenerational effects, with the penile development of subsequent generations being affected, raise concerns for long-term public health.

Placental outcomes of phthalate exposure

Proper placental development and function relies on hormone receptors and signaling pathways that make the placenta susceptible to disruption by endocrine disrupting chemicals, such as phthalates. Here, we review relevant research on the associations between phthalate exposures and dysfunctions of the development and function of the placenta, including morphology, physiology, and genetic and epigenetic effects. This review covers in vitro studies, in vivo studies in mammals, and studies in humans. We also discuss important gaps in the literature. Overall, the evidence indicates that toxicity to the placental and maternal-fetal interface is associated with exposure to phthalates. Further studies are needed to better elucidate the mechanisms through which phthalates act in the placenta as well as additional human studies that assess placental disruption through pregnancy with larger sample sizes.

Structural changes, increased hypoxia, and oxidative DNA damage in placenta due to maternal smokeless tobacco use

BACKGROUND

Smokeless tobacco (SLT) consumption during pregnancy is a well-recognized health risk that causes placental damage including hypoxia and oxidative damage. Although consumption of SLT by women varies from region to region, majority of tea leave pluckers consume SLT for relieving stress and pain. Still, the effects of SLT consumption have not been evaluated in tea garden workers (TGW). While previous studies have attempted to report effects of cigarette smoke using in vitro model, hypoxia-inducible factor (HIF)-1α expression in human placentae from pregnant women exposed to SLT has not been previously studied. This study was aimed to explore the effects of SLT consumption on placental structure, expression of HIF-1α and oxidative DNA damage in sample population of TGW.

METHODS

A total of 51 placentae were collected from SLT users and nonusers (n = 30 and 21, respectively) with full-term normal delivery, who were involved in the plucking of tea leaves during pregnancy in tea plantation. Low birth weight (LBW, i.e., weight <2,500 g) and normal birth weight (NBW) groups among both SLT user and nonuser were compared for the stated parameters. Placental tissues were processed for transmission electron microscopy (TEM) study and immunohistochemical analysis for the expression of HIF-1α and 8-hydroxy-2'-deoxyguanosine (8-OHdG).

RESULTS

Altered ultrastructural characteristics were observed in the tertiary villi of LBW group among SLT users which included endothelial cells protrusion into capillary lumen, degenerated nuclei, significant thickening of trophoblast basement membrane and vasculo-syncytial membrane, abnormalities of the microvilli, swollen or damaged mitochondria, and dilatation in endoplasmic reticulum cisternae. Furthermore, significant reduction in the perimeter, area, and number of the stromal capillary of the tertiary villi of placenta were found in LBW group as compared with NBW group from the SLT users. Enhanced expression for HIF-1α and oxidative DNA damage (8-OHdG) biomarker was observed in SLT users as compared with nonusers.

CONCLUSIONS

Maternal SLT exposure during pregnancy may be associated with villus hypoxia and consequently oxidative DNA damage. It is presumed that deleterious effect of SLT exposure on placenta could result in impairment of placental barrier, and restrict nutrient and oxygen supply from mother to fetus, and thus could be a cause of fetal growth restriction.

Endocrine disrupting chemicals (EDCs) and placental function: Impact on fetal brain development

Pregnancy is a critical time of vulnerability for the development of the fetal brain. Exposure to environmental pollutants at any point in pregnancy can negatively impact many aspects of fetal development, especially the organization and differentiation of the brain. The placenta performs a variety of functions that can help protect the fetus and sustain brain development. However, disruption of any of these functions can have negative impacts on both the pregnancy outcome and fetal neurodevelopment. This review presents current understanding of how environmental exposures, specifically to endocrine disrupting chemicals (EDCs), interfere with placental function and, in turn, neurodevelopment. Some of the key differences in placental development between animal models are presented, as well as how placental functions such as serving as a xenobiotic barrier and exchange organ, immune interface, regulator of growth and fetal oxygenation, and a neuroendocrine organ, could be vulnerable to environmental exposure. This review illustrates the importance of the placenta as a modulator of fetal brain development and suggests critical unexplored areas and possible vulnerabilities to environmental exposure.

Racial/Ethnic Disparities in Pregnancy and Prenatal Exposure to Endocrine-Disrupting Chemicals Commonly Used in Personal Care Products

PURPOSE OF REVIEW

Endocrine-disrupting chemical (EDC) exposure during pregnancy is linked to adverse maternal and child health outcomes that are racially/ethnically disparate. Personal care products (PCP) are one source of EDCs where differences in racial/ethnic patterns of use exist. We assessed the literature for racial/ethnic disparities in pregnancy and prenatal PCP chemical exposures.

RECENT FINDINGS

Only 3 studies explicitly examined racial/ethnic disparities in pregnancy and prenatal exposure to PCP-associated EDCs. Fifty-three articles from 12 cohorts presented EDC concentrations stratified by race/ethnicity or among homogenous US minority populations. Studies reported on phthalates and phenols. Higher phthalate metabolites and paraben concentrations were observed for pregnant non-Hispanic Black and Hispanic women. Higher concentrations of benzophenone-3 were observed in non-Hispanic White women; results were inconsistent for triclosan. This review highlights need for future research examining pregnancy and prenatal PCP-associated EDCs disparities to understand and reduce racial/ethnic disparities in maternal and child health.

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.

Associations between Prenatal Exposure to Phthalates and Timing of Menarche and Growth and Adiposity into Adulthood: A Twenty-Years Birth Cohort Study

Phthalates are ubiquitous environmental chemicals with endocrine disrupting properties and potentially obesogenic effects. We hypothesised that antenatal phthalate exposure may influence growth and adiposity patterns in girls through childhood into adolescence. Among 1342 Raine Study singleton females, 462 had maternal serum and at least one outcome available up to 20 years of age. Individuals’ maternal serum collected at 18 and 34 weeks gestation was pooled and analyzed for concentrations of 32 metabolites of 15 phthalate diesters. Cox regression and linear models were used to determine associations between maternal phthalate levels and age at menarche, change in height and weight z-scores between birth and two years, height from birth to 20 years, BMI from two to 20 years, deviation from mid-parental height at age 20 and DEXA scan measures at age 20. Weak negative associations were detected with some phthalate metabolites and change in height and weight z-score during infancy. Weak positive associations between some of the high molecular weight phthalate metabolites and height z-score were detected during childhood. While still within the normal range, age at menarche was slightly delayed in girls with higher prenatal exposure to the higher molecular weight phthalate metabolites. We derived some associations between prenatal phthalate exposure with early growth patterns and age at menarche.

The influence of prenatal exposure to phthalates on subsequent male growth and body composition in adolescence

Phthalates are ubiquitous environmental chemicals with predominantly anti-androgenic, and potentially obesogenic effects. We hypothesised that antenatal phthalate exposure may influence subsequent boy's growth and body composition through childhood and adolescence. Among 1399 singleton males from the Raine Study, 410 had maternal serum and at least one height, BMI or DEXA outcome available after birth and up to 20 years of age. Maternal serum collected at 18 and 34 weeks' gestation was pooled, and analyzed for concentrations of 32 metabolites of 15 phthalate diesters. Their serum concentrations were categorized into undetectable/detectable levels or tertiles. Linear mixed models were used to determine associations between maternal serum phthalate levels and longitudinal height and body mass index (BMI) z-scores in boys from birth to 20 years of age (n = 250 and n = 295 respectively). Linear regression was used to determine associations between maternal phthalate levels and deviation from mid-parental height (n = 177) and DEXA scan outcomes (n = 191) at the 20 year follow-up. Weak positive associations of participants height z-score increase were detected with exposure to some phthalate metabolites in particular to the lower molecular weight phthalate metabolites. Less consistent findings, by mixed model analyses, were detected for BMI and body composition, by dual energy X-ray absorptiometry (DEXA), with some positive associations of phthalate metabolites with BMI and some negative associations with DEXA fat tissue measures, although no consistent findings were evident. In conclusion, we derived some associations of childhood growth with prenatal phthalate exposure, particularly with respect to the lower molecular weight phthalate metabolites.

The impact of Di-(2-ethylhexyl) Phthalate and Mono(2-ethylhexyl) Phthalate in placental development, function, and pathophysiology

Di(2-ethylhexyl) phthalate (DEHP) is a chemical widely distributed in the environment as is extensively used in the plastic industry. DEHP is considered an endocrine disruptor chemical (EDC) and humans are inevitably and unintentionally exposed to this EDC through several sources including food, beverages, cosmetics, medical devices, among others. DEHP exposure has been associated and may be involved in the development of various pathologies; importantly, pregnant women are a particular risk group considering that endocrine alterations during gestation may impact fetal programming leading to the development of several chronic diseases in adulthood. Recent studies have indicated that exposure to DEHP and its metabolite Mono(2-ethylhexyl) phthalate (MEHP) may impair placental development and function, which in turn would have a negative impact on fetal growth. Studies performed in several trophoblastic and placental models have shown the negative impact of DEHP and MEHP in key processes related to placental development such as implantation, differentiation, invasion and angiogenesis. In addition, many alterations in placental functions like hormone signaling, metabolism, transfer of nutrients, immunomodulation and oxidative stress response have been reported. Moreover, clinical-epidemiological evidence supports the association between DEHP exposure and adverse pregnancy outcomes and pathologies. In this review, we aim to summarize for the first time current knowledge about the impact of DEHP and MEHP exposure on placental development and pathophysiology, as well as the mechanisms involved. We also remark the importance of exploring DEHP and MEHP effects in different trophoblast cell populations and discuss new perspectives regarding this topic.

Prenatal and early childhood exposure to phthalates and childhood behavior at age 7 years

BACKGROUND

Emerging evidence suggests that phthalate exposure may be associated with behavior problems in children and that these associations may be sex specific.

METHODS

In a follow up study of 411 inner-city minority mothers and their children, mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBzP), monoisobutyl phthalate (MiBP), monethyl phthalate (MEP) and four di-2-ethylhexyl phthalate metabolites (DEHP) were quantified in maternal urine samples collected during the third trimester and in child urine samples at ages 3 and 5 years. The Conners' Parent Rating Scale-Revised: Long Form (CPRS) and Child Behavior Checklist (CBCL) were administered to the mothers to assess children's behavior problems at 7 years of age. The analysis included children with available measures of CBCL, CPRS and phthalates measured in maternal urine. We performed both Quasi-Poisson regression and a mixture analysis using Weighted Quantile Sum(WQS) regression to assess the risk for CPRS scores and for internalizing and externalizing behaviors (from the CBCL) following intra-uterine exposure to the phthalate metabolites for boys and girls separately.

RESULTS

Among boys, increases in in anxious-shy behaviors were associated with prenatal exposure to MBzP (Mean Ratio [MR] = 1.20, 95%CI 1.05-1.36) and MiBP (Mean Ratio (MR) = 1.22, 95%CI 1.02-1.47). Among girls, increases in perfectionism were associated with MBzP (MR = 1.15, 95%CI 1.01-1.30). In both boys and girls, increases in psychosomatic problems were associated with MiBP (MR = 1.28, 95%CI 1.02-1.60), and MnBP (MR = 1.28, 95%CI 1.02-1.59), respectively. Among girls, decreased hyperactivity was associated with two DEHP metabolites, mono(2-ethyl-5-oxohexyl) phthalate (MR = 0.83, 95%CI 0.71-0.98) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MR = 0.85, 95%CI 0.72-0.99). Using weighted Quantile Sum logistic regression, no associations were found between the Weighted Quantile Sum (WQS) of phthalate metabolites and CPRS scores or externalizing and internalizing behaviors. Nonetheless, when the analysis was performed separately for DEHP and non-DEHP metabolites significant associations were found between the WQS of DEHP metabolites and social problems in boys (OR = 2.15, 95%CI 1.13-4.06, p-value = 0.02) anxious-shy problems in girls (OR = 2.19, 95%CI 1.15-4.16, p = 0.02), and emotional lability problems in all children (OR = 0.61, 95%CI 0.38-0.97, p = 0.04). MEHP and MEOHP were the most highly weighted DEHP metabolites in WQS mixture. The analysis performed with CBCL scale corroborated these associations.

CONCLUSION

Concentration of non-DEHP metabolites was associated with anxious-shy behaviors among boys. DEHP phthalate metabolites were associated with decreased hyperactivity and impulsivity among girls on CPRS scores. These findings lend further support to the adverse associations between prenatal phthalate exposure and childhood outcomes, and clearly suggest that such associations are sex and mixture specific.

Sex-specific difference in placental inflammatory transcriptional biomarkers of maternal phthalate exposure: a prospective cohort study

Previous epidemiologic research has shown that phthalate exposure in pregnant women is related to birth outcomes in a sex-specific manner. These outcomes may be mediated by placental inflammation, which is the proposed biological mechanism. This is the first study to address the relationship between phthalate exposure and gene expression in placental inflammation in a sex-specific manner. We performed quantitative PCR to measure placental inflammatory mRNAs (CRP, TNF-α, IL-1β, IL-6, IL-10, MCP-1, IL-8, CD68, and CD206) in 2469 placentae that were sampled at birth. We estimated the associations between mRNA and urinary phthalate monoesters using multiple linear regression models. Mono-n-butyl phthalate (MBP) was correlated with higher IL-1β, IL-6, and CRP expression in placentae of male fetuses and with higher IL-6, CRP, MCP-1, IL-8, IL-10, and CD68 expression in placentae of female fetuses. Mono benzyl phthalate (MBzP) increased the expression of TNF-α, MCP-1, and CD68 only in placentae of male fetuses. Mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) was negatively correlated with CRP, MCP-1, and CD68 in placentae of female fetuses. Maternal phthalate exposure was associated with inflammatory variations in placental tissues. The associations were stronger in placentae of male than of female fetuses. Compared with the other metabolites, MBP plays a strong role in these associations. The placenta is worth being further investigated as a potential mediator of maternal exposure-induced disease risk in children.

Placenta Disrupted: Endocrine Disrupting Chemicals and Pregnancy

Endocrine disrupting chemicals (EDCs) are chemicals that can interfere with normal endocrine signals. Human exposure to EDCs is particularly concerning during vulnerable periods of life, such as pregnancy. However, often overlooked is the effect that EDCs may pose to the placenta. The abundance of hormone receptors makes the placenta highly sensitive to EDCs. We have reviewed the most recent advances in our understanding of EDC exposures on the development and function of the placenta such as steroidogenesis, spiral artery remodeling, drug-transporter expression, implantation and cellular invasion, fusion, and proliferation. EDCs reviewed include those ubiquitous in the environment with available human biomonitoring data. This review also identifies critical gaps in knowledge to drive future research in the field.

Plastics derived endocrine-disrupting compounds and their effects on early development

Despite the fact that the estrogenic effects of bisphenols were first described 80 years ago, recent data about its potential negative impact on birth outcome parameters raises a strong rationale to investigate further. The adverse health effects of plastics recommend to measure the impacts of endocrine-disrupting compounds (EDCs) such as bisphenols (BPA, BPS, BPF), bis(2-ethylhexyl) phthalate, and dibutyl phthalate (DBP) in human health. Exposure to these compounds in utero may program the diseases of the testis, prostate, kidney and abnormalities in the immune system, and cause tumors, uterine hemorrhage during pregnancy and polycystic ovary. These compounds also control the processes of epigenetic transgenerational inheritance of adult-onset diseases by modulating DNA methylation and epimutations in reproductive cells. The early developmental stage is the most susceptible window for developmental and genomic programming. The critical stages of the events for a normal human birth lie between the many transitions occurring between spermatogenesis, egg fertilization and the fully formed fetus. As the cells begin to grow and differentiate, there are critical balances of hormones, and protein synthesis. Data are emerging on how these plastic-derived compounds affect embryogenesis, placentation and feto-placental development since pregnant women and unborn fetuses are often exposed to these factors during preconception and throughout gestation. Impaired early development that ultimately influences fetal outcomes is at the center of many developmental disorders and contributes an independent risk factor for adult chronic diseases. This review will summarize the current status on the impact of exposure to plastic derived EDCs on the growth, gene expression, epigenetic and angiogenic activities of the early fetal development process and their possible effects on birth outcomes.

Immune Cells in the Uterine Remodeling: Are They the Target of Endocrine Disrupting Chemicals?

Sufficient uterine remodeling is essential for fetal survival and development. Pathologies related to poor remodeling have a negative impact on maternal and fetal health even years after birth. Research of the last decades yielded excellent studies demonstrating the key role of immune cells in the remodeling processes. This review summarizes the current knowledge about the relevance of immune cells for uterine remodeling during pregnancy and further discusses immunomodulatory effects of man-made endocrine disrupting chemicals on immune cells.

Biomimetic Micropatterned Adhesive Surfaces To Mechanobiologically Regulate Placental Trophoblast Fusion

The placental syncytiotrophoblast is a giant multinucleated cell that forms a tree-like structure and regulates transport between mother and baby during development. It is maintained throughout pregnancy by continuous fusion of trophoblast cells, and disruptions in fusion are associated with considerable adverse health effects including diseases such as preeclampsia. Developing predictive control over cell fusion in culture models is hence of critical importance in placental drug discovery and transport studies, but this can currently be only partially achieved with biochemical factors. Here, we investigate whether biophysical signals associated with budding morphogenesis during development of the placental villous tree can synergistically direct and enhance trophoblast fusion. We use micropatterning techniques to manipulate physical stresses in engineered microtissues and demonstrate that biomimetic geometries simulating budding robustly enhance fusion and alter spatial patterns of synthesis of pregnancy-related hormones. These findings indicate that biophysical signals play a previously unrecognized and significant role in regulating placental fusion and function, in synergy with established soluble signals. More broadly, our studies demonstrate that biomimetic strategies focusing on tissue mechanics can be important approaches to design, build, and test placental tissue cultures for future studies of pregnancy-related drug safety, efficacy, and discovery.

Using Experimental Models to Assess Effects of Bisphenol A (BPA) and Phthalates on the Placenta: Challenges and Perspectives

The placenta is critical for all aspects of fetal development. Bisphenol A (BPA) and phthalates are endocrine disruptors with ubiquitous exposure in pregnant women-their effects on the placenta is an area of growing research interest. Therefore, our objectives were to (1) summarize research related to the effects BPA or phthalates on placental outcomes in animal and cell models, and (2) evaluate the challenges for using such models to study the impacts of these chemicals on placental endpoints. Overall, studies in cells and animal models suggest that BPA and phthalates impact placental hormones, some epigenetic endpoints, increase inflammation and oxidative stress, and decrease cell viability and nutrient transfer. However, few animal or cell studies have assessed these outcomes at concentrations relevant to humans. Furthermore, it is unclear whether effects of BPA/phthalates on the placenta in animal models mediate fetal outcomes, as most studies have dosed after the earliest stages of placental and fetal development. It is also unclear whether effects of these chemicals are sex-specific, as few studies have considered placental sex. Finally, while there is substantial evidence for effects of mono-(2-ethylhexyl) phthalate (the major metabolite of di-(2-ethylhexyl) phthalate), on placental endpoints in cells, little is currently known about effects of other phthalates to which pregnant women are exposed. Moving forward, these limitations will need to be addressed to help us understand the precise mechanisms of action of these chemicals within the placenta, and how these reported perturbations impact fetal health.

Phthalate exposure and female reproductive and developmental outcomes: a systematic review of the human epidemiological evidence

OBJECTIVE

We performed a systematic review of the epidemiology literature to identify the female reproductive and developmental effects associated with phthalate exposure.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

Six phthalates were included in the review: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), and diethyl phthalate (DEP). The initial literature search (of PubMed, Web of Science, and Toxline) included all studies of female reproductive and developmental effects in humans, and outcomes were selected for full systematic review based on data availability.

STUDY EVALUATION AND SYNTHESIS METHODS

For each outcome, studies were evaluated using criteria defined a priori for risk of bias and sensitivity by two reviewers using a domain-based approach. Evidence was synthesized by outcome and phthalate and strength of evidence was summarized using a structured framework.

RESULTS

The primary outcomes reviewed here are (number of included/excluded studies in parentheses): pubertal development (5/13), time to pregnancy (3/4), preterm birth (8/12), and spontaneous abortion (5/0). Among these outcomes, preterm birth had moderate evidence of a positive association with phthalate exposure (specifically DEHP, DBP, and DEP). Exposure levels for BBP, DIBP, and DINP were generally lower than for the phthalates with an observed effect, which may partially explain the difference due to lower sensitivity. Other phthalate/outcome combinations were considered to have slight or indeterminate evidence of an association.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Overall, these results support that some phthalates may be associated with higher odds of preterm birth in humans, though there is some remaining inconsistency. More evidence is needed on the mechanism and relevant exposure window for this association. The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Hazards of diisobutyl phthalate (DIBP) exposure: A systematic review of animal toxicology studies

BACKGROUND

Biomonitoring studies indicate a trend towards increased human exposure to diisobutyl phthalate (DIBP), a replacement for dibutyl phthalate (DBP). Recent reviews have found DIBP to be a male reproductive toxicant, but have not evaluated other hazards of DIBP exposure.

OBJECTIVE

To inform chemical risk assessment, we performed a systematic review to identify and characterize outcomes within six broad hazard categories (male reproductive, female reproductive, developmental, liver, kidney, and cancer) following exposure of nonhuman mammalian animals to DIBP or the primary metabolite, monoisobutyl phthalate (MIBP).

METHODS

A literature search was conducted in four online scientific databases [PubMed, Web of Science, Toxline, and Toxic Substances Control Act Test Submissions 2.0 (TSCATS2)], and augmented by review of regulatory sources as well as forward and backward searches. Studies were identified for inclusion based on defined PECO (Population, Exposure, Comparator, Outcome) criteria. Studies were evaluated using criteria defined a priori for reporting quality, risk of bias, and sensitivity using a domain-based approach. Evidence was synthesized by outcome and life stage of exposure, and strength of evidence was summarized into categories of robust, moderate, slight, indeterminate, or compelling evidence of no effect, using a structured framework.

RESULTS

Nineteen toxicological studies in rats or mice met the inclusion criteria. There was robust evidence that DIBP causes male reproductive toxicity. Male rats and mice exposed to DIBP during gestation had decreased testosterone and adverse effects on sperm or testicular histology, with additional phthalate syndrome effects observed in male rats. There was also evidence of androgen-dependent and -independent male reproductive effects in rats and mice following peripubertal or young adult exposure to DIBP or MIBP, but confidence was reduced because of concerns over risk of bias and sensitivity in the available studies. There was also robust evidence that DIBP causes developmental toxicity; specifically, increased post-implantation loss and decreased pre- and postnatal growth. For other hazards, evidence was limited by the small number of studies, experimental designs that were suboptimal for evaluating outcomes, and study evaluation concerns such as incomplete reporting of methods and results. There was slight evidence for female reproductive toxicity and effects on liver, and indeterminate evidence for effects on kidney and cancer.

CONCLUSION

Results support DIBP as a children's health concern and indicate that male reproductive and developmental toxicities are hazards of DIBP exposure, with some evidence for female reproductive and liver toxicity. Data gaps include the need for more studies on male reproductive effects following postnatal and adult exposure, and studies to characterize potential hormonal mechanisms in females.

Disruption of ergosterol and tryptophan biosynthesis, as well as cell wall integrity pathway and the intracellular pH homeostasis, lead to mono-(2-ethylhexyl)-phthalate toxicity in budding yeast

Endocrine disrupting chemicals (EDCs) are substances in the environment, food, and consumer products that interfere with hormone homeostasis, metabolism or reproduction in humans and animals. One such EDC, the plasticizer di-(2-ethylhexyl)-phthalate (DEHP), exerts its function through its principal bioactive metabolite, mono-(2-ethylhexyl)-phthalate (MEHP). To fully understand the effects of MEHP on cellular processes and metabolism as well as to assess the impact of genetic alteration on the susceptibility to MEHP-induced toxicity, we screened MEHP-sensitive mutations on a genome-scale in the eukaryotic model organism Saccharomyces cerevisiae. We identified a total of 96 chemical-genetic interactions between MEHP and gene mutations in this study. In response to MEHP treatment, most of these gene mutants accumulated higher intracellular MEHP content, which correlated with their MEHP sensitivity. Twenty-seven of these genes are involved in the metabolism, twenty-two of them play roles in protein sorting, and ten of them regulate ion homeostasis. Functional categorization of these genes indicated that the biosynthetic pathways of both ergosterol and tryptophan, as well as cell wall integrity and the intracellular pH homeostasis, were involved in the protective response of yeast cells to the MEHP toxicity. Our study demonstrated that a collection of yeast gene deletion mutants is useful for a functional toxicogenomic analysis of EDCs, which could provide important clues to the effects of EDCs on higher eukaryotic organisms.

Impacts of bisphenol A (BPA) and phthalate exposures on epigenetic outcomes in the human placenta

The placenta guides fetal growth and development. Bisphenol A (BPA) and phthalates are widespread environmental contaminants and endocrine disruptors, and the placental epigenetic response to these chemicals is an area of growing research interest. Therefore, our objective was to summarize research linking BPA or phthalate exposure to placental outcomes in human pregnancies, with a particular focus on epigenetic endpoints. In PubMed, studies were selected for review (without limiting start date and ending on 1 May 2018) if they reported any direct effects of BPA or phthalates on the placenta in humans. Collectively, available studies suggest that BPA and phthalate exposures are associated with changes to placental micro-RNA expression, DNA methylation, and genomic imprinting. Furthermore, several studies suggest that fetal sex may be an important modifier of placental outcomes in response to these chemicals. Studies in humans demonstrate associations of BPA and phthalate exposure with adverse placental outcomes. Moving forward, more studies should consider sex differences (termed "placental sex") in the measured outcomes, and should utilize appropriate statistical approaches to assess modification by fetal sex. Furthermore, more consistent sample collection and molecular outcome assessment paradigms will be indispensable for making progress in the field. These advances, together with improved non-invasive tools for measuring placental function and outcomes across pregnancy, will be critical for understanding the mechanisms driving placental epigenetic disruption in response to BPA and phthalates, and how these disruptions translate into placental and fetal health.

Effects of selective serotonin-reuptake inhibitors (SSRIs) on human villous trophoblasts syncytialization

Selective serotonin-reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants during pregnancy. The human placenta is a highly specialized organ supporting normal growth and development of the fetus. Therefore, this study aims to analyze the effects of SSRIs on villous cytotrophoblasts cells, using BeWo cells and human placental trophoblast cells in primary culture. The SSRIs fluoxetine and its metabolite norfluoxetine, sertraline and venlafaxine did not affect BeWo cell proliferation and viability, nor the percentage of M30-positive (apoptotic) primary trophoblast cells. None of the SSRIs affected basal or forskolin-stimulated BeWo cell fusion, whereas sertraline and venlafaxine increased the fusion of primary villous trophoblasts. Sertraline and venlafaxine also modified human chorionic gonadotropin beta (β-hCG) secretion by BeWo cells, whereas none of the SSRIs affected β-hCG secretion in primary trophoblasts. Norfluoxetine increased CGB (chorionic gonadotropin beta) and GJA1 (gap junction protein alpha 1) levels of gene expression (biomarkers of syncytialization) in BeWo cells, whereas in primary trophoblasts none of the SSRIs tested affected the expression of these genes. This study shows that SSRIs affect villous trophoblast syncytialization in a structure- and concentration-dependent manner and suggests that certain SSRIs may compromise placental health. In addition, it highlights the importance of using primary trophoblast cells instead of "trophoblast -like" cell lines to assess the effects of medications on human villous trophoblast function.

Impacts of prenatal triclosan exposure on fetal reproductive hormones and its potential mechanism

BACKGROUND

Triclosan (TCS) has been widely detected in pregnant women. The reproductive endocrine-disrupting effects of TCS have been observed in humans and animals. Little is known about the potential impact of prenatal TCS exposure on fetal reproductive development as well as its potential mechanism.

OBJECTIVES

We investigated the potential effect of prenatal TCS exposure on fetal reproductive hormones in cord blood and its potential mechanism in relation to placental steroidogenic enzymes.

METHODS

Urinary TCS was detected among 537 healthy pregnant women from a prospective cohort in China. Four reproductive hormones in cord blood, namely E₂ (n=430), T (n=424), LH (n=428) and FSH (n=373), and three steroidogenic enzymes in placenta, namely P450arom (n=233), 3β-HSD (n=227) and 17β-HSD (n=222), were measured.

RESULTS

Prenatal TCS exposure was associated with increased testosterone concentrations in cord blood in a dose-dependent manner. Infants with prenatal TCS levels >0.6μg/L had, on average, a 0.23ng/mL (95% CI: 0.05, 0.45, p=0.02) higher testosterone concentrations in cord blood compared to those with prenatal TCS levels <0.1μg/L. Of note, prenatal TCS exposure was associated with increased testosterone and decreased E₂ concentrations in cord blood among male infants. Adverse associations were found between the prenatal TCS exposure and concentrations of three placental steroidogenic enzymes. 3β-HSD and P450arom demonstrated mediating effects in the association between prenatal TCS exposure and testosterone concentrations in cord blood.

CONCLUSIONS

Our findings suggested potential impacts of prenatal TCS exposure on reproductive hormones in cord blood mediated by steroidogenic enzymes, and male infants were more vulnerable.

The Possible Impact of Antenatal Exposure to Ubiquitous Phthalates Upon Male Reproductive Function at 20 Years of Age

Phthalates are ubiquitous environmental endocrine-disrupting chemicals suspected to interfere with developmental androgen action leading to adverse effects on male reproductive function. Prenatal exposure studies in rodents show cryptorchidism, hypospadias and reduced testicular volume (TV), testosterone and anogenital distance in males. It is postulated that there is a developmental window in utero when phthalate exposure has the most potent adverse effects. Some human studies show associations between prenatal phthalate exposure and reduced calculated "free" serum testosterone in infant boys and shorter anogenital distance. However, there are no data available yet which link antenatal exposure to long-term effects in men. We aimed to correlate antenatal phthalate exposure with adult TV, semen parameters and serum reproductive hormone concentrations. 913 men from the Western Australian (Raine) Pregnancy Cohort were contacted aged 20-22 years. 423 (56%) agreed to participate; 404 underwent testicular ultrasound examination; 365 provided semen samples, and reproductive hormones were measured in 384. Maternal antenatal serum phthalate metabolite measurements were available for 185 and 111 men, who provided serum and semen, respectively. Maternal serum collected at 18 and 34 weeks gestation, stored at -80°C, was pooled and analyzed for 32 phthalate metabolites by liquid chromatography-tandem mass spectrometry. TV was calculated, semen analysis performed by WHO approved methods, and serum concentrations of gonadotrophins, inhibin B, and testosterone measured. Eleven phthalate metabolites were detected. Primary and secondary metabolites of di-(2-ethyl-hexyl) phthalate (DEHP) and di-iso-nonyl phthalate (DiNP) were positively correlated. After correction for adult height, BMI, presence of a varicocele and exposure to maternal smoking mono-iso-nonyl phthalate (MiNP) (r = -0.22) and sums of DEHP and DiNP metabolites (r = -0.24) and the sum of the metabolites of the high molecular weight phthalates (r = -0.21) were negatively correlated with TV (all p < 0.05). After adjustment for BMI adult serum total testosterone was positively associated with exposure to the following antenatal serum phthalate metabolites: mono-(2-ethylhexyl) phthalate (r = 0.26), MiNP (r = 0.18), the sum of metabolites for DEHP (r = 0.21) and DiNP (r = 0.18), and the sum of high molecular phthalates (r = 0.20) (p = 0.0005 to p = 0.02). Given sample size, storage duration and confounding through postnatal exposures, further studies are required.

Prenatal phthalate exposure and placental size and shape at birth: A birth cohort study

OBJECTIVE

There is concern over the potential placental effects of prenatal phthalate exposure, and the potential adverse effects of prenatal phthalate exposure require further study; however, few data are available in humans. We investigated the associations between phthalate exposure in each trimester and both placental size and shape at birth.

METHODS

We measured the urinary concentrations of phthalate metabolites among 2725 pregnant women in the Ma'anshan Birth Cohort. Before collecting urine samples from each of the three trimesters, the pregnant women were interviewed via questionnaires. Placental information was obtained from hospital records. We estimated the sex-specific associations between urinary phthalate concentrations in each trimester and both placental size and shape at birth using adjusted multiple regression. A linear mixed model was used for the repeated measures analysis with subject-specific random intercepts and slopes for gestational age at sample collection to test the effect of phthalate levels on placental size and shape and to estimate the effect sizes.

RESULTS

Overall, placental breadth increased by 0.148cm (95% CI: 0.078, 0.218) with each 1 ln-concentration increase in MBP in the first trimester. The difference between placental length and breadth (length-breadth) decreased by 0.086cm (95% CI: -0.159, -0.012) and 0.149cm (95% CI: -0.221, -0.076) with each 1 ln-concentration increase in MMP and MBP, respectively, in the first trimester. In the second trimester, placental thickness increased by 0.017cm (95% CI: 0.006, 0.027), 0.020cm (95% CI: 0.004, 0.036), 0.028cm (95% CI: 0.007, 0.048), and 0.035cm (95% CI: 0.018, 0.053) with each 1 ln-concentration increase in MMP, MBP, MEOHP, and MEHHP, respectively. In the third trimester, placental thickness increased by 0.037cm (95% CI: 0.019, 0.056) and 0.019cm (95% CI: 0, 0.037) with each 1 ln-concentration increase in MBP and MEHP, respectively. Multiple linear regression for each offspring sex indicated that prenatal phthalate exposure increased placental thickness in both the first and second trimesters in males, whereas the corresponding relationship was close to null in females. Linear mixed models (LMMs) yielded similar results.

CONCLUSION

Our results suggest the presence of associations between prenatal phthalate exposure and placental size and shape. Exposure to certain phthalates may cause the placenta to become thicker and more circular. Associations appeared stronger for the subsample representing male offspring than those for the subsample representing female offspring. Given the few studies on this topic, additional research is warranted.

An Investigation of the Single and Combined Phthalate Metabolite Effects on Human Chorionic Gonadotropin Expression in Placental Cells

BACKGROUND

Observational studies have reported associations between maternal phthalate levels and adverse outcomes at birth and in the health of the child. Effects on placental function have been suggested as a biologic basis for these findings.

OBJECTIVE

We evaluated the effects of phthalates on placental function in vitro by measuring relevant candidate genes and proteins.

MATERIALS AND METHODS

Human trophoblast progenitor cells were isolated at 7-14 wk of pregnancy (two female and three male concepti), and villous cytotrophoblast cells (vCTBs) were isolated at 15-20 wk (three female and four male concepti). Cells were cultured in vitro with four phthalate metabolites and their combination at concentrations based on levels found previously in the urine of pregnant women: mono-n-butyl (MnBP, 200 nM), monobenzyl (MBzP, 3μM), mono-2-ethylhexyl (MEHP, 700 nM), and monoethyl (MEP, 1.5μM) phthalates. mRNA levels of CGA, CGB, PPARG, CYP19A1, CYP11A1, PTGS2, EREG, and the intracellular β subunit of human chorionic gonadotropin (hCGβ) and peroxisome proliferator activated receptor γ (PPARγ) were measured in the cellular extracts, and protein levels for four forms of secreted hCG were measured in the conditioned media.

RESULTS

Previously reported associations between maternal phthalates and placental gene expression were reproduced experimentally: MnBP with CGA, MBzP with CYP11A1, and MEHP with PTGS2. CGB and hCGβ were up-regulated by MBzP. In some cases, there were marked, even opposite, differences in response by sex of the cells. There was evidence of agonism in female cells and antagonism in male cells of PPARγ by simultaneous exposure to multiple phthalates.

CONCLUSIONS

Concentrations of MnBP, MBzP and MEHP similar to those found in the urine of pregnant women consistently altered hCG and PPARγ expression in primary placental cells. These findings provide evidence for the molecular basis by which phthalates may alter placental function, and they provide a preliminary mechanistic hypothesis for opposite responses by sex. https://doi.org/10.1289/EHP1539.

Facts about phthalate toxicity in humans and their occurrence in alcoholic beverages

Phthalates are esters of phthalic acid and aliphatic alcohol added to plastic to improve its softness, flexibility, and extensibility. They easily migrate from plastic products into the environment because of their physical and chemical properties. This review summarises their characteristics, distribution in the environment, monitoring, use, toxic effects on human health, regulatory limits in different matrices and products, and tolerable daily intake. The studies we have reviewed suggest that phthalates have a potential to affect reproduction and development in humans. Due to the inconsistent data, further studies are needed and, in the meantime, precautionary policies must be implemented. Here we draw attention to the methods of determining phthalate levels in alcoholic beverages and reported levels in plum spirits produced in Croatia. Legally produced and moderately consumed plum spirits do not seem to increase the risk of phthalate toxicity for human health. We conclude with recommendations for the effective monitoring of phthalate exposure in humans and for the implementation of alternative materials in alcohol production.

Maternal urinary phthalates and sex-specific placental mRNA levels in an urban birth cohort

BACKGROUND

Prenatal urinary concentrations of phthalates in women participants in an urban birth cohort were associated with outcomes in their children related to neurodevelopment, autoimmune disease risk, and fat mass at 3,5,7, and 8 years of life. Placental biomarkers and outcomes at birth may offer biologic insight into these associations. This is the first study to address these associations with candidate genes from the phthalate and placenta literature, accounting for sex differences, and using absolute quantitation methods for mRNA levels.

METHODS

We measured candidate mRNAs in 180 placentas sampled at birth (HSD17B1, AHR, CGA, CYP19A1, SLC27A4, PTGS2, PPARG, CYP11A1) by quantitative PCR and an absolute standard curve. We estimated associations of log_e mRNA with quartiles of urinary phthalate monoesters using linear mixed models. Phthalate metabolites (N = 358) and mRNAs (N = 180) were transformed to a z-score and modeled as independent, correlated vectors in relation to large for gestational age (LGA) and gestational diabetes mellitus (GDM).

RESULTS

CGA was associated with 4 out of 6 urinary phthalates. CGA was 2.0 log_e units lower at the 3^rd vs. 1^st quartile of mono-n-butyl phthalate (MnBP) (95% confidence interval (CI): -3.5, -0.5) in male placentas, but 0.6 log_e units higher (95% CI: -0.8, 1.9) in female placentas (sex interaction p = 0.01). There was an inverse association of MnBP with PPARG in male placentas (-1.1 log_e units at highest vs. lowest quartile, 95% CI: -2.0, -0.1). CY19A1, CYP11A1, CGA were associated with one or more of the following in a sex-specific manner: monobenzyl phthalate (MBzP), MnBP, mono-iso-butyl phthalate (MiBP). These 3 mRNAs were lower by 1.4-fold (95% CI: -2.4, -1.0) in male GDM placentas vs. female and non-GDM placentas (p-value for interaction = 0.04). The metabolites MnBP/MiBP were 16% higher (95% CI: 0, 22) in GDM pregnancies.

CONCLUSIONS

Prenatal concentrations of certain phthalates and outcomes at birth were modestly associated with molecular changes in fetal placental tissue during pregnancy. Associations were stronger in male vs. female placentas, and associations with MnBP and MiBP were stronger than other metabolites. Placental mRNAs are being pursued further as potential mediators of exposure-induced risks to the health of the child.