Maternal serum levels of perfluoroalkyl substances and organochlorines and indices of fetal growth: a Scandinavian case-cohort study

Exploring the levels of persistent organic pollutants in umbilical cord blood and their connection to gestational age and birth weights in Şanlıurfa, Turkey

BACKGROUND

Controversy surrounds the impact of persistent organic pollutants (POPs) on fetal development. This study aimed to investigate levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in umbilical cord blood from Şanlıurfa mothers in Turkey, exploring associations with gestational age and birth weight.

METHODS

Participants included voluntary mothers pregnant with a single fetus, providing details on maternal factors. Cord blood samples were collected immediately after delivery. Samples were extracted with a modified QuEChERS method, and OCPs (17 pesticides) and PCBs (11 congeners) compound levels were analyzed with a gas chromatograph/mass spectrometry. Detection frequencies and levels of POPs by single pollutant type and pollutant groups were calculated and compared according to gestational duration and birth weight. We used partial least squares discriminant analysis to identify the key chemicals and distinguish their respective statuses.

RESULTS

Among 120 infants, 35 were preterm but appropriate for gestational age, 35 were term but small for gestational age (SGA), and 50 were term and appropriate for gestational age (AGA). Beta HCH, Oxy-Chlordan, and PCB 28, were not detected in cord blood samples. Half of the samples contained at least 4 types of OCPs, with a median OCP level of 38.44 ng/g. Among the DDT, 2,4'-DDE was found at the highest concentration in cord plasma samples. The PCB congeners with a frequency exceeding 50% were ranked in the following order: 151, 149, 138, 146. The median level of ∑PCBs was 5.93 ng/g. Male infants born at term with SGA status exhibited lower levels of ∑DDTs, ∑OCPs compared to male infants born preterm or at term with AGA status. Di-ortho-substituted PCBs and hexachlorinated PCBs were higher in male infants born at term with SGA status than male infants born preterm with AGA status.

CONCLUSION

Overall, exposure to DDT and PCBs demonstrates varying effects depending on gestational duration and birth weight, with exposure levels also differing by gender. This underscores the necessity for studies across diverse populations that investigate the combined effects of multiple pollutant exposures on gestational age, birth weight, and gender simultaneously.

Association between pre- and postnatal exposure to endocrine-disrupting chemicals and birth and neurodevelopmental outcomes: an extensive review

Endocrine-disrupting chemicals (EDCs) are natural or synthetic chemicals that mimic, block, or interfere with the hormones in the body. The most common and well- studied EDCs are bisphenol A, phthalates, and persistent organic pollutants including polychlorinated biphenyls, polybrominated diphenyl ethers, per- and polyfluoroalkyl substances, other brominated flame retardants, organochlorine pesticides, dioxins, and furans. Starting in embryonic life, humans are constantly exposed to EDCs through air, diet, skin, and water. Fetuses and newborns undergo crucial developmental processes that allow adaptation to the environment throughout life. As developing organisms, they are extremely sensitive to low doses of EDCs. Many EDCs can cross the placental barrier and reach the developing fetal organs. In addition, newborns can be exposed to EDCs through breastfeeding or formula feeding. Pre- and postnatal exposure to EDCs may increase the risk of childhood diseases by disrupting the hormone-mediated processes critical for growth and development during gestation and infancy. This review discusses evidence of the relationship between pre- and postnatal exposure to several EDCs, childbirth, and neurodevelopmental outcomes. Available evidence suggests that pre- and postnatal exposure to certain EDCs causes fetal growth restriction, preterm birth, low birth weight, and neurodevelopmental problems through various mechanisms of action. Given the adverse effects of EDCs on child development, further studies are required to clarify the overall associations.

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

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

Maternal Serum Concentrations of Per- and Polyfluoroalkyl Substances in Early Pregnancy and Small for Gestational Age in Southern Sweden

Small for gestational age (SGA) is considered an adverse birth outcome. Per- and polyfluoralkyl substances (PFAS) have become increasingly investigated as contributing environmental factors, thus far with inconclusive results. The current study aimed to investigate the hypothesized association between increased maternal PFAS levels in early pregnancy and an increased risk for SGA birth. This population-based study used data from a sample of children born in Scania, Southern Sweden, between 1995 and 2009. Two groups were compared: cases born with SGA (n = 298) and non-SGA controls (n = 580). The cases consisted of two subgroups: one included women whose children's growth in late pregnancy was in the lowest quartile, and another included women from the remaining growth quartiles. Corresponding maternal serum samples were collected from a biobank and analyzed for concentrations of four types of PFAS: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS) using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The results were combined with information from birth registers and analyzed using Mann-Whitney U-tests and logistic regression-unadjusted as well as adjusted for potential confounders. In conclusion, elevated maternal concentrations of PFAS were not associated with an increased risk of SGA birth. However, significant ORs were observed in a subgroup analysis restricted to women of Nordic origin (unadjusted OR 3.2 and adjusted OR 2.4) for PFHxS.

Maternal pesticide exposure and risk of preterm birth: A systematic review and meta-analysis

BACKGROUND

Maternal pesticide exposure might be associated with adverse pregnancy outcomes through triggering inflammation and oxidative stress and disrupting endocrine functions. Yet the association between prenatal pesticide exposure and risk of preterm birth remains inconclusive.

OBJECTIVES

To conduct a systematic review and meta-analysis of human observational studies using the Office of Health Assessment and Translation (OHAT) framework to explore the association of per ten-fold increase of pesticide concentrations in maternal biological samples during pregnancy with risk of preterm birth and length of gestational age at birth.

DATA SOURCE

Five English (PubMed, Embase, Cochrane Library, Web of Science and Scopus) and 3 Chinese databases (China national knowledge infrastructure (CNKI), Wanfang Data, and Chinese Biomedical Literature Database (CBM)) were searched till Jan 18th, 2023.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

To be included, pesticide exposure should be measured in maternal biological samples during pregnancy and in log-transformed forms. The primary outcome was preterm birth and the secondary outcome was gestational age at birth.

STUDY APPRAISAL, SYNTHESIS METHODS AND CONFIDENCE ASSESSMENT

Quality of studies was evaluated using OHAT Risk of Bias Tool. Evidence was quantitatively synthesized with Correlated and Hierarchical Effects (CHE) model. The confidence rating in the body of evidence was done using OHAT.

RESULTS

A total of 21 studies reported by 18 papers were included, with 7 studies for preterm birth and 19 for gestational age at birth. The meta-analysis found a ten-fold increase of pesticide concentrations was potentially associated with risk of preterm birth (pooled OR = 1.28; 95%CI: 0.93, 1.78) and shortened gestational age at birth (β = -0.10; 95%CI: -0.21, 0.01). Sampling biospecimens in different trimesters was identified as a potential modifier in the association between pesticide exposure and length of gestational age (F = 2.77, P < 0.05). For studies that collected samples at any time during pregnancy, pesticide exposure was found to be associated with shortened length of gestational age (β = -0.43; 95%CI: -0.81, -0.06). The confidence rating in the body of evidence was "moderate" and "very low" for preterm birth and gestational age at birth, respectively.

CONCLUSION

Our result suggested moderate evidence of an association between pesticide exposure and higher risk of preterm birth. Yet more studies are still needed with larger sample size and careful considerations of confounders and accuracy of outcome measurements. Attention is also required on other pesticide compounds in addition to organochlorine and organophosphorus pesticides, and on windows of susceptibility.

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

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

Serum Concentrations of Selected Poly- and Perfluoroalkyl Substances (PFASs) in Pregnant Women and Associations with Birth Outcomes. A Cross-Sectional Study from Southern Malawi

Pervasive exposure to per-and polyfluoroalkyl substances (PFASs) shows associations with adverse pregnancy outcomes. The aim of the present study was to examine the determinants of different serum PFAS concentrations in late pregnancy and their relationship with birth outcomes in southern Malawi. The sample included 605 pregnant women with a mean age of 24.8 years and their offspring from three districts in the southern region of Malawi. Six PFAS were measured in serum from third-trimester women. The serum PFAS concentrations were assessed with head circumference, birth length, birth weight, gestational age and ponderal index. Participants living in urban areas had significantly higher serum levels of PFOA, PFNA and SumPFOS, while SumPFHxS concentrations were higher in women from rural settings. High PFOA, PFNA and SumPFHxS concentrations were generally inversely associated with head circumference. Birth length was negatively associated with PFOA and PFNA while SumPFHxS was negatively associated with birth weight. SumPFOS was inversely associated with gestational age. Urban area of residence was the strongest predictor for high PFAS concentrations in the maternal serum and was generally associated with adverse birth outcomes. The results highlight the need to investigate SumPFHxS further as it follows a pattern that is different to similar compounds and cohorts.

Association of single and multiple prefluoroalkyl substances exposure with preterm birth: Results from a Chinese birth cohort study

BACKGROUND

Perfluoroalkyl substances (PFASs) are persistent organic pollutants that may lead the adverse birth outcomes, including preterm birth (PTB). However, previous studies have reported inconsistent results on the association between PFASs and PTB, and lack of the epidemiological evidence regarding the effect of PFASs mixture on PTB. This study aimed to explore association of individual and multiple exposure to PFASs with PTB.

METHODS

The study subjects were consisted of 1341 pregnant women from Guangxi Zhuang Birth Cohort in Guangxi, China, from June 2015 to April 2019. Nine PFASs concentrations in the maternal serum were examined by ultrahigh liquid performance chromatography-tandem mass spectrometry, and the gestational weeks were obtained from medical records. We applied binary logistics regression model to explore correlation between individual PFAS and PTB and inspected the combined effect of PFASs mixture on PTB by applying Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regression models.

RESULTS

In adjusted logistics regression model, perfluorooctane sulfonate (PFOS), perfluoroheptanoic acid (PFHpA), perfluorobutanesulfonic acid (PFBS), ∑perfluorinated sulfonic acids (PFSA), and ∑PFASs were positively associated with the risk of PTB. In contrast, perfluoroundecanoic acid (PFUnA), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA) were negatively associated with the risk of PTB. These associations of n PFOS and PFHpA with PTB were found to be more pronounced in male infants. Restricted cubic splines (RCSs) showed an inverse U-shaped relationship between PFBS and PTB. Analysis from BKMR model showed a positive association between PFASs mixture and PTB, and no evidence of interactions among the nine PFASs were detected. Additionally, PFHpA, PFOS, and PFBS were identified as the main contributors for the effect of PFASs mixture on increasing the risk of PTB by BKMR and WQS models.

CONCLUSION

Prenatal exposure to higher levels of PFASs mixture was associated with higher risk of PTB.

Polychlorinated Biphenyls (PCBs) in the Environment: Occupational and Exposure Events, Effects on Human Health and Fertility

In the last decade or so, polychlorinated biphenyls (PCBs) garnered renewed attention in the scientific community due to new evidence pointing at their continued presence in the environment and workplaces and the potential human risks related to their presence. PCBs move from the environment to humans through different routes; the dominant pathway is the ingestion of contaminated foods (fish, seafood and dairy products), followed by inhalation (both indoor and outdoor air), and, to a lesser extent, dust ingestion and dermal contact. Numerous studies reported the environmental and occupational exposure to these pollutants, deriving from building materials (flame-retardants, plasticizers, paints, caulking compounds, sealants, fluorescent light ballasts, etc.) and electrical equipment. The highest PCBs contaminations were detected in e-waste recycling sites, suggesting the need for the implementation of remediation strategies of such polluted areas to safeguard the health of workers and local populations. Furthermore, a significant correlation between PCB exposure and increased blood PCB concentrations was observed in people working in PCB-contaminated workplaces. Several epidemiological studies suggest that environmental and occupational exposure to high concentrations of PCBs is associated with different health outcomes, such as neuropsychological and neurobehavioral deficits, dementia, immune system dysfunctions, cardiovascular diseases and cancer. In addition, recent studies indicate that PCBs bioaccumulation can reduce fertility, with harmful effects on the reproductive system that can be passed to offspring. In the near future, further studies are needed to assess the real effects of PCBs exposure at low concentrations for prolonged exposure in workplaces and specific indoor environments.

Sexually Dimorphic Accumulation of Persistent Organic Pollutants in Fetuses

Living in an industrialized era, we are exposed to man-made chemicals including persistent organic pollutants (POPs). Previous studies have shown associations of POP exposure with adverse outcomes in humans, wildlife, and the environment, making it a global concern. Exposure during sensitive windows of susceptibility such as fetal development is of particular concern because of the potential increased risk of developing diseases in childhood and adulthood. However, there are limited studies on the sexual dimorphism of POP accumulation during the prenatal period. In this mini-review, we focus on differences in POP concentrations in the placenta and fetal tissues between males and females. We also show the sexually dimorphic adverse outcomes of prenatal exposure to POPs. Overall, our summary shows that males may accumulate higher concentrations of POPs in the placenta and fetal tissues compared to females, although studies are sparse and inconsistent. In addition, there are differences in adverse health outcomes associated to prenatal POP exposure according to sex. Hence, we highly urge researchers investigating the health effects of POP exposure to consider sexual dimorphism in their studies.

Association Between Exposure to Per- and Polyfluoroalkyl Substances and Birth Outcomes: A Systematic Review and Meta-Analysis

Background

A large body of emerging evidence suggests that per- and polyfluoroalkyl substances (PFAS) affect birth outcomes in various pathways, but the evidence is inconsistent. Therefore, this study aimed to systematically review the epidemiological evidence on PFAS exposure and birth outcomes.

Methods

Three electronic databases were searched for epidemiological studies through February 13, 2021. We used random-effects meta-analysis for eight birth outcome indicators to calculate summary effect estimates for various exposure types. The risk of bias and the overall quality and level of evidence for each exposure-outcome pair were assessed.

Results

The initial search identified 58 potentially eligible studies, of which 46 were ultimately included. Many PFAS were found to have previously unrecognized statistically significant associations with birth outcomes. Specifically, birth weight (BW) was associated with PFAS, with effect sizes ranging from −181.209 g (95% confidence interval (CI) = −360.620 to −1.798) per 1 ng/ml increase in perfluoroheptanesulfonate (PFHpS) to −24.252 g (95% CI = −38.574 to −9.930) per 1 ln (ng/ml) increase in perfluorodecaoic acid (PFDA). Similar patterns were observed between other PFAS and birth outcomes: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) with birth length (BL) and ponderal index (PI), PFOS and perfluorododecanoic acid (PFDoDA) with head circumference (HC), PFHpS with gestational age (GA), and perfluorononanoic acid (PFNA) and PFHpS with preterm birth (PTB). Additionally, PFDA showed a statistically significant association with small for gestational age (SGA). The level of the combined evidence for each exposure-outcome pair was considered to be “moderate”.

Conclusion

This study showed that PFAS exposure was significantly associated with increased risks of various adverse birth outcomes and that different birth outcome indicators had different degrees of sensitivity to PFAS. Further studies are needed to confirm our results by expanding the sample size, clarifying the effects of different types or doses of PFAS and the time of blood collection on birth outcomes, and fully considering the possible confounders.

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

Associations between exposure to perfluoroalkyl substances and birth outcomes: A meta-analysis

Although previous meta-analyses have shown that prenatal PFASs exposure is associated with reduction in birth weight, effects of prenatal PFASs exposure on birth outcomes have not been fully explored. We conducted a meta-analysis of 23 eligible studies searched from Embase, PubMed, and Web of Science before March 21, 2021 to analyze the association between prenatal PFASs exposure and birth outcomes, including premature birth (PTB), low birth weight (LBW), small for gestational age (SGA) and miscarriage. Odds ratio (OR) and corresponding confidence intervals were extracted for analysis. According to the heterogeneity of the included studies, fixed-effects (I² ≤ 50%) and random-effects (I² > 50%) models were applied respectively. The significant associations between PFOS and PTB (pooled OR = 1.54, 95% CI: 1.20-1.98), PFOA and miscarriage (pooled OR = 1.40, 95% CI: 1.15-1.70), and PFOS and LBW (pooled OR = 1.52, 95% CI: 1.19-1.94) were obtained. There were differences between included studies with different study regions, sampling time, and samples type used for PFASs assessment. These findings may provide insight in risk assessment and decision-making in producing products that contain PFASs.

High in Utero Exposure to Perfluoroalkyl Substances from Drinking Water and Birth Weight: A Cohort Study among Infants in Ronneby, Sweden

In 2013, the drinking water for one-third of the households in Ronneby, Sweden, was found to be contaminated by perfluorinated alkyl substances (PFAS, >10,000 ng/L) from Aqueous Film Forming Foam (AFFF). In utero PFAS exposure can influence birth weight, but little is known about the effects at very high levels. This study aimed to examine the association between in utero PFAS exposure and birth weight. Infants with mothers from Ronneby exposed to contaminated water at home (high exposure) and infants with mothers from Ronneby not exposed to contaminated water at home (low exposure) were compared to infants with mothers from Blekinge county excluding Ronneby (referents). All infants born in Blekinge county 1995–2013 were included (n = 30,360). Differences in birth weight were only seen among infants born after 2005. For boys, Ronneby high exposure had a lower mean birth weight than referents (−54 g, 95% CI −97; −11). For girls, Ronneby high exposure had a higher mean birth weight than referents (47 g, 95% CI 4; 90). There were no differences in birth weight between referents and Ronneby low exposure. In conclusion, high exposure to PFAS may influence birth weight in a sex-specific way, although the effect estimates were relatively small.

Association of maternal exposure to perfluoroalkyl and polyfluroalkyl substances with infant growth from birth to 12 months: A prospective cohort study

BACKGROUND

Although maternal perfluoroalkyl and polyfluroalkyl substances (PFASs) were associated with adverse birth outcomes, much less is known about their impact on infant growth during early infancy.

OBJECTIVES

We investigated the association between maternal PFASs exposure and infant growth during the first 12 months of life.

METHODS

Participating 2395 pregnancies were recruited from Shanghai Birth Cohort between 2013 and 2016. Ten PFASs were quantified from maternal plasma collected during early pregnancy (median, 15 gestational weeks). We measured infant length, weight, and head circumference at birth, 42 days, 6 months, and 12 months. Linear mixed regression model was used to estimate the associations between PFAS concentrations and repeated measurements of infant growth. Effect modification by infant sex was estimated.

RESULTS

Elevated perfluoroheptanoic acid (PFHpA) concentration was negatively associated with infant length-for-age Z score (LAZ) (β = -0.06, 95% confidence interval (CI): -0.11, -0.01) during the first year. Adverse associations were also observed for perfluorobutane sulfonate (PFBS) and weight-for-length Z score (WFL) (β = -0.02, 95% CI: -0.04, -0.00) and BMI-for-age Z score (BAZ) (β = -0.02, 95% CI: -0.04, -0.00). However, perfluorododecanoic acid (PFDoA) was positively associated with WFL (β = 0.03, 95% CI: 0.00, 0.06) and BAZ (β = 0.03, 95% CI: 0.00, 0.06). The adverse association of PFHpA and LAZ was more pronounced among males (β = -0.06; 95% CI: -0.11, -0.00) than females (β = 0.06; 95% CI: 0.01, 0.12).

CONCLUSIONS

In our study, negative associations were found for maternal PFHpA exposure and infant LAZ, PFBS and WFL and BAZ. Meanwhile, maternal PFDoA exposure was positively related with WFL and BAZ. The adverse association of maternal PFHpA exposure and infant LAZ was more pronounced among males. The results should be interpreted with caution, further prospective cohort studies with longitudinal and detailed measures are warranted to confirm these findings.

Relationships between maternal perfluoroalkyl substance levels, polymorphisms of receptor genes, and adverse birth outcomes in the Hokkaido birth cohort study, Japan

We assessed the associations between perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) levels in third trimester maternal serum, the maternal genotypes of genes encoding nuclear receptors, and birth outcomes. We studied a prospective birth cohort of healthy pregnant Japanese women (n = 372) recruited in Sapporo between July 2002 and October 2005. We analyzed PFOS and PFOA levels using liquid chromatography-tandem mass spectrometry and analyzed 13 single nucleotide polymorphisms (SNPs) of proliferator-activated receptor alpha, gamma, gamma coactivator 1A, delta, constitutive androstane receptor, liver X receptor alpha, and beta (LXRB) using real-time polymerase reaction (PCR). We employed multiple linear regression models to establish the influences of log₁₀-transformed PFOS and PFOA levels and maternal genotypes on birth size. In female infants, we identified interactions between PFOS levels, the maternal genotype of LXRB (rs1405655), and birth weight. The estimated mean changes in birth weight in response to PFOS levels, the maternal genotype LXRB (rs1405655)-TC/CC (compared to TT), and their interactions were -502.9 g (95 % confidence interval [CI] = -247.3, -758.5 g), -526.3 g (95 % CI = -200.7, -852.0 g), and 662.1 g (95 % CI = 221.0, 1,103.2 g; p_int = 0.003), respectively. Interactions between PFOS levels and the maternal genotype of LXRB (rs1405655) also significantly affected birth chest circumference and the Ponderal index (p_int = 0.037 and 0.005, respectively). Thus, interactions between PFOS levels and the maternal genotype of LXRB (rs1405655) affects birth sizes in female infants. We found that certain SNPs modify the effects of PFOS levels on birth size.

Impact of intra-uterine life on future health

Since the emergence of the concept of developmental origins of health and disease (DOHaD), suggested by Barker in the 1980s, numerous epidemiological studies in humans have confirmed the relationship between maternal obesity during pregnancy and the risk of offspring developing various chronic adult illnesses. These effects of intrauterine life are independent of inheritance of disease susceptibility genes and/or socio-economic factors. Regarding potential mechanisms, recent data from animal models suggests a role of insulin resistance early in development. Another potential mechanism, in the case of maternal obesity, is increased placental nutrient transfer. The DOHaD concept also includes fetal exposure to environmental endocrine disruptors (EEDs). A Danish group for the first time recently analyzed EED passage across the placenta in humans throughout pregnancy. This study showed different levels of bioaccumulation depending on the fetal organ, with greater vulnerability in male than female fetuses. Recent clinical studies suggested an association between fetal exposure to particular EEDs and precocious puberty, increased incidence of cryptorchidism and impaired sperm quality in adulthood. These modifications of the in-utero environment also appear to be responsible for epigenetic changes that are transmittable over several generations. A recent example of this is the demonstration of the transmission of polycystic ovary syndrome (PCOS) in mice. In summary, an increasing number of examples of the impact of intrauterine life on the health of offspring have appeared in recent years, illustrating the important role that endocrinologists can play in preventing particular pathologies in future generations.

Per- and polyfluoroalkyl substances exposure during pregnancy and adverse pregnancy and birth outcomes: A systematic review and meta-analysis

BACKGROUND

Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy has been suggested to be associated with adverse pregnancy and birth outcomes; however, the findings have been inconsistent. We aimed to conduct a systematic review and meta-analysis to provide an overview of these associations.

METHODS

The online databases PubMed, EMBASE and Web of Science were searched comprehensively for eligible studies from inception to February 2021. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using random- or fixed-effects models, and dose-response meta-analyses were also conducted when possible.

FINDINGS

A total of 29 studies (32,905 participants) were included. The pooled results demonstrated that perfluorooctane sulfonate (PFOS) exposure during pregnancy was linearly associated with increased preterm birth risk (pooled OR per 1-ng/ml increase: 1.01, 95% CIs: 1.00-1.02, P = 0.009) and perfluorononanoate (PFNA) and perfluorooctanoate (PFOA) exposure showed inverted U-shaped associations with preterm birth risk (P values for the nonlinear trend: 0.025 and 0.030). Positive associations were also observed for exposure to perfluorodecanoate (PFDA) and miscarriage (pooled OR per 1-ng/ml increase: 1.87, 95% CIs: 1.15-3.03) and PFOS and preeclampsia (pooled OR per 1-log increase: 1.27, 95% CIs: 1.06-1.51), whereas exposure to perfluoroundecanoate (PFUnDA) was inversely associated with preeclampsia risk (pooled OR per 1-log increase: 0.81, 95% CIs: 0.71-0.93). Based on individual evidence, detrimental effects were observed between PFDA exposure and small for gestational age and between PFOA and PFOS and intrauterine growth restriction. No significant associations were found between pregnancy PFAS exposure and other adverse pregnancy outcomes (i.e., gestational diabetes mellitus, pregnancy-induced hypertension, low birth weight, and large and small for gestational age).

INTERPRETATION

Our findings indicated that PFOS, PFOA and PFNA exposure during pregnancy might be associated with increased preterm birth risk and that PFAS exposure might be associated with the risk of miscarriage and preeclampsia. Due to the limited evidence obtained for most associations, additional studies are required to confirm these findings.

The Aryl hydrocarbon receptor mediates reproductive toxicity of polychlorinated biphenyl congener 126 in rats

Polychlorinated biphenyls (PCBs) are endocrine disrupting chemicals with documented, though mechanistically ill-defined, reproductive toxicity. The toxicity of dioxin-like PCBs, such as PCB126, is mediated via the aryl hydrocarbon receptor (AHR) in non-ovarian tissues. The goal of this study was to examine the uterine and ovarian effects of PCB126 and test the hypothesis that the AHR is required for PCB126-induced reproductive toxicity. Female Holzman-Sprague Dawley wild type (n = 14; WT) and Ahr knock out (n = 11; AHR-/-) rats received a single intraperitoneal injection of either corn oil vehicle (5 ml/kg: WT_O and AHR-/-_O) or PCB126 (1.63 mg/kg in corn oil: WT_PCB and AHR-/-_PCB) at four weeks of age. The estrous cycle was synchronized and ovary and uterus were collected 28 days after exposure. In WT rats, PCB126 exposure reduced (P < 0.05) body and ovary weight, uterine gland number, uterine area, progesterone, 17β-estradiol and anti-Müllerian hormone level, secondary and antral follicle and corpora lutea number but follicle stimulating hormone level increased (P < 0.05). In AHR-/- rats, PCB126 exposure increased (P ≤ 0.05) circulating luteinizing hormone level. Ovarian or uterine mRNA abundance of biotransformation, and inflammation genes were altered (P < 0.05) in WT rats due to PCB126 exposure. In AHR-/- rats, the transcriptional effects of PCB126 were restricted to reductions (P < 0.05) in three inflammatory genes. These findings support a functional role for AHR in the female reproductive tract, illustrate AHR's requirement in PCB126-induced reprotoxicity, and highlight the potential risk of dioxin-like compounds on female reproduction.

Praegnatio Perturbatio-Impact of Endocrine-Disrupting Chemicals

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

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

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

The association between perfluoroalkyl substances and lipid profile in exposed pregnant women in the Veneto region, Italy

BACKGROUND

Residents of a large area of North-Eastern Italy were exposed for decades to high concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFAS) via drinking water. Serum PFAS levels have been consistently associated with elevated serum lipids, but few studies have been conducted among pregnant women, and none has stratified analyses by trimester of gestation. Elevated serum lipid levels during pregnancy can have both immediate and long-lasting effects on pregnant women and the developing fetus. We evaluated the association between perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluoro-hexanesulfonate (PFHxS) levels in relation to lipid profiles in highly-exposed pregnant women.

METHODS

A cross-sectional analysis was conducted in 319 pregnant women (age 14-48 years) enrolled in the Regional health surveillance program. Non-fasting blood samples were obtained in any trimester of pregnancy and analyzed for PFOA, PFOS and PFHxS, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C). Low-density lipoprotein cholesterol (LDL-C) was calculated. The associations between ln-transformed PFAS (and categorized into quartiles) and lipids were assessed using generalized additive models. Analyses were adjusted for potential confounders and stratified according to pregnancy trimester.

RESULTS

The geometric means of PFOA, PFOS and PFHxS were 14.78 ng/mL, 2.67 ng/mL and 1.89 ng/mL, respectively. The plasma levels of TC, HDL-C and LDL-C increased steadily throughout the trimesters. In the 1st trimester, PFOS was positively associated with TC and PFHxS with HDL-C. In the 3rd trimester, instead, an inverse relationship was seen between PFOA and PFHxS and both TC and LDL-C.

CONCLUSIONS

Results suggest the associations between PFAS concentrations and lipid profiles in pregnant women might differ by trimesters of pregnancy. In the first trimester, patterns are similar to those of non-pregnant women, while they differ late in pregnancy. Different independent behavior of PFAS and lipid levels throughout the pregnancy might explain our observations. These findings support the ubiquitous exposure to PFAS and possible influence on lipid metabolisms during pregnancy and suggest a careful evaluation of the timing of PFAS measurement, when examining effects of PFAS during pregnancy on gestational outcomes related to serum lipids amounts.

Early-Life Exposure to Per- and Poly-Fluorinated Alkyl Substances and Growth, Adiposity, and Puberty in Children: A Systematic Review

Per- or polyfluoroalkyl substances (PFAS), a family of synthetic polyfluorinated compounds, are widely used in consumer products. Ubiquitous exposures to PFAS, in consideration of their persistence, bioaccumulation potential, and toxicities have led to concerns regarding possible harmful effects during critical periods of development in early-life and long-term consequences on health. The potential effects of PFAS depend on various factors including the type of PFAS and the timing and level of exposure. We performed a systematic review of the epidemiologic literature to assess the effects of early-life PFAS exposure on prenatal and postnatal growth, adiposity, and puberty in children and adolescents. For birth size, most studies indicated that prenatal PFAS exposure, in particular long-chain PFAS, may impair fetal growth, albeit some reports of null associations with maternal PFAS. For growth within 2 years of age, prenatal PFAS exposure showed no associations with height and either null or negative associations with weight. However, postnatal PFAS exposures were inversely related to height and weight at 2 years in a cross-sectional study. For postnatal adiposity, prenatal PFAS may mostly have negative associations with body mass index in the first 2 years of life, but positive relationships with adiposity in childhood and adolescence, although some studies showed null associations. For puberty, the evidence for associations between early-life PFAS exposure and pubertal development or sex hormone levels were limited and inconclusive. From experimental studies, plausible mechanisms through which PFAS may affect early-life growth and puberty include PFAS-induced activation of peroxisome proliferator-activated receptor, alterations of thyroid or steroid hormone synthesis and metabolism, and their weak estrogenic or anti-androgenic properties. Although the published literature suggests possible effects of PFAS exposures on early-life growth, adiposity, and puberty, current human evidence is limited in establishing PFAS-induced effects on early-life physical development. Further investigation is warranted to clarify PFAS-induced effects on growth and physical development in consideration of the critical time-window of exposure, concomitant exposure to chemical mixtures including various PFAS types, and possible non-monotonic dose-response relationship for growth and adiposity trajectories.

Early-life exposure to multiple persistent organic pollutants and metals and birth weight: Pooled analysis in four Flemish birth cohorts

BACKGROUND AND AIMS

Prenatal chemical exposure has frequently been associated with reduced fetal growth although results have been inconsistent. Most studies associate single pollutant exposure to this health outcome, even though this does not reflect real life situations as humans are exposed to many pollutants during their life time. The objective of this study is to investigate the association between prenatal exposure to a mixture of persistent environmental chemicals and birth weight using multipollutant models.

METHODS

We combined exposure biomarker data measured in cord blood samples of 1579 women from four Flemish birth cohorts collected over a 10 years' time period. The common set of available and detectable exposure measures in these cohorts are three polychlorinated biphenyls (PCB) congeners (138, 153 and 180), hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (p,p'-DDE) and the metals cadmium and lead. Multiple linear regression (MLR), Bayesian Information Criterion (BIC), penalized regression using minimax concave penalty (MCP) and Bayesian Adaptive Sampling (BAS) were applied to assess the influence of multiple pollutants in a single analysis on birth weight, adjusted for a priori selected covariates.

RESULTS

In the pooled dataset, a median (P25-P75) birth weight and gestational age of 3420 (3140-3700) grams and 39 (39-40) weeks was observed respectively. The median contaminant levels in cord blood were: 15.8, 26.5, 18.0, 16.9 and 91.5 ng/g lipid for PCB 138, PCB 153, PCB 180, HCB and p,p'-DDE, respectively, 0.075 µg/L for cadmium and 9.7 µg/L for lead. According to the applied statistical methods for multipollutant assessment, p,p'-DDE and PCB 180 were most consistently associated with birth weight. In addition, PCB 153 was selected when applying MCP and BAS. An inverse association with birth weight was found for the PCB congeners, while an increased birth weight was observed for elevated levels of p,p'-DDE.

CONCLUSIONS

Assessing the health risk of combinations of exposure biomarkers reflects better real-world situations and thereby allows more effective risk assessment. Our results add to the existing evidence based on detrimental effects of PCBs on birth weight and indicate a possible increase in birth weight due to p,p'-DDE (while correcting for PCBs).

Co-exposure to PCB126 and PFOS increases biomarkers associated with cardiovascular disease risk and liver injury in mice

Polychlorinated biphenyl (PCB)126 and perfluorooctane sulfonic acid (PFOS) are halogenated organic pollutants of high concern. Exposure to these chemicals is ubiquitous, and can lead to potential synergistic adverse effects in individuals exposed to both classes of chemicals. The present study was designed to identify interactions between PCB126 and PFOS that might promote acute changes in inflammatory pathways associated with cardiovascular disease and liver injury. Male C57BL/6 mice were exposed to vehicle, PCB126, PFOS, or a mixture of both pollutants. Plasma and liver samples were collected at 48 h after exposure. Changes in the expression of hepatic genes involved in oxidative stress, inflammation, and atherosclerosis were investigated. Plasma and liver samples was analyzed using untargeted lipidomic method. Hepatic mRNA levels for Nqo1, Icam1, and PAI1 were significantly increased in the mixture-exposed mice. Plasma levels of PAI1, a marker of fibrosis and thrombosis, were also significantly elevated in the mixture-exposed group. Liver injury was observed only in the mixture-exposed mice. Lipidomic analysis revealed that co-exposure to the mixture enhanced hepatic lipid accumulation and elevated oxidized phospholipids levels. In summary, this study shows that acute co-exposure to PCB126 and PFOS in mice results in liver injury and increased cardiovascular disease risk.

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

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

Perfluorooctane sulfonic acid (PFOS) exposure during pregnancy increases blood pressure and impairs vascular relaxation mechanisms in the adult offspring

Perfluorooctanesulfonate (PFOS) is a persistent environmental agent. We examined whether PFOS exposure during pregnancy alters blood pressure in male and female offspring, and if this is related to sex-specific changes in vascular mechanisms. PFOS was administered through drinking water (50 μg/mL) to pregnant Sprague-Dawley rats from gestational day 4 until delivery. PFOS-exposure decreased maternal weight gain but did not significantly alter feed and water intake in dams. The male and female pups born to PFOS mothers were smaller in weight by 29 % and 27 %, respectively. The male PFOS offspring remained smaller through adulthood, but the female PFOS offspring exhibited catch-up growth. The blood pressure at 12 and 16 weeks of age was elevated at similar magnitude in PFOS males and females than controls. Mesenteric arterial relaxation to acetylcholine was reduced in both PFOS males and females, but the extent of decrease was greater in females. Relaxation to sodium-nitroprusside was reduced in PFOS females but unaffected in PFOS males. Vascular eNOS expression was not changed, but phospho(Ser¹¹⁷⁷)-eNOS was decreased in PFOS males. In PFOS females, both total eNOS and phospho(Ser¹¹⁷⁷)-eNOS expression were reduced. In conclusion, PFOS exposure during prenatal life (1) caused low birth weight followed by catch-up growth only in females (2) lead to hypertension of similar magnitude in both males and females; (2) decreased endothelium-dependent vascular relaxation in males but suppressed both endothelium-dependent and -independent relaxation in females. The endothelial dysfunction is associated with reduced activity of eNOS in males and decreased expression and activity of eNOS in females.

Assessment of perfluoroalkyl substances in placenta by coupling salt assisted liquid-liquid extraction with dispersive liquid-liquid microextraction prior to liquid chromatography-tandem mass spectrometry

The widespread use of perfluoroalkyl substances (PFAS) is resulting in a broad human exposure to these endocrine disrupting chemicals (EDCs), prompting biomonitoring research to evaluate its magnitude and impact, especially during critical windows of exposure such as fetal and perinatal periods. This study was focused on developing a method to determine 10 PFAS in placental tissue by combining salt-assisted liquid-liquid extraction with dispersive liquid-liquid microextraction and using liquid chromatography-tandem mass spectrometry. Chemometric strategies were applied to optimize the experimental parameters. The limit of quantification was 0.02 ng g^-1 for all analytes, and the inter-day variability (as relative standard deviation) ranged from 7.9% to 13.8%. Recoveries ranged from 88.2% to 113.9%. The suitableness of the procedure was demonstrated by assessing the targeted compounds in 20 placenta samples. The highest concentrations were recorded for perfluorooctanoic acid and perfluorooctane sulfonate, with maximum concentrations of 0.62 and 1.02 ng g^-1 and median concentrations of 0.13 and 0.53 ng g^-1, respectively. Median concentrations of the other PFAS ranged from detected values to 0.08 ng g^-1. This analytical procedure yields useful data on fetal exposure to PFAS.

Exposure to per- and polyfluorinated alkyl substances in pregnant Brazilian women and its association with fetal growth

Research pertaining to exposure of humans to per- and polyfluorinated alkyl substances (PFASs) has received considerable public and regulatory attention in recent years. Although several studies have reported exposure to PFASs by populations in North America and western Europe, such information is still scarce in Latin America, including Brazil. In this study, concentrations of thirteen PFASs were determined in whole blood collected during the second trimester from 252 pregnant Brazilian women. This is a nested case-control study within the Brazilian Ribeirao Preto and Sao Luiz Birth Cohort Study (BRISA) with selected birth outcomes cases (n = 63) and matched controls (n = 189). PFASs concentrations were associated with conditions including preeclampsia, birth weight (BW), preterm birth, and intrauterine growth restriction (IUGR). Among PFASs measured, perfluorooctane sulfonate (PFOS) was found at the highest concentration (range: 1.06-106 ng mL^-1 with a median value of 3.41 ng mL^-1) which was followed by perfluorooctanoic acid (PFOA, range: 0.11-2.77 ng mL^-1 with a median value of 0.20 ng mL^-1). A significant positive association of PFOS and PFOA concentrations with fetal growth restriction (p < 0.05) was found. This is the first study to assess whole blood concentrations of PFASs and their effect on fetal growth in pregnant Brazilian women.

Identifying Risk Factors for Levels of Per- and Polyfluoroalkyl Substances (PFAS) in the Placenta in a High-Risk Pregnancy Cohort in North Carolina

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS), a ubiquitous class of chemicals, is associated with adverse outcomes such as pre-eclampsia, low infant birth weight, and later-life adiposity. The objectives of this study were to examine PFAS levels in the placenta and identify sociodemographic risk factors in a high-risk pregnancy cohort (n = 122) in Chapel Hill, North Carolina. Of concern, PFOS, PFHxS, PFHpS, and PFUnA were detected above the reporting limit in 99, 75, 55, and 49% of placentas, respectively. Maternal race/ethnicity was associated with significant differences in PFUnA levels. While the data from this high-risk cohort did not provide evidence for an association with hypertensive disorders of pregnancy, fetal growth, or gestational age, the prevalence of detectable PFAS in the placenta suggests a need to biomonitor for exposure to PFAS during pregnancy. Future research should investigate factors underlying the differences in PFAS levels in association with a mother's race/ethnicity, as well as potential effects on pregnancy and child health.

Exposure to PFAS and small for gestational age new-borns: A birth records study in Veneto Region (Italy)

BACKGROUND

Perfluoroalkylated substances (PFAS) in serum are inversely associated with fetal growth. Small for gestational age (SGA) is a measure based on birth weight and gestational age at birth and represents a good indicator of fetal growth but it has been used only in a small number of studies. We examined the association between PFAS exposure and the risk of severe SGA in a PFAS contaminated area in the Veneto Region (North-East of Italy).

METHODS

A retrospective cohort study has been developed including all singleton live births reported in the Veneto Region Birth Registry between 2003 and 2018 to mothers living in the contaminated and in a control area. We estimated the association between mothers' area of residence and severe SGA using crude RR (and 95% CI) and stepwise logistic regression, including all the maternal characteristics.

RESULTS

The study included 105,114 singleton live births. The occurence of severe SGA was 3.44% in the contaminated area and 2.67% in the control area. The multivariate analysis confirmed that living in the contaminated area significantly increased the odds of severe SGA (adjusted OR 1.27 (95% C.I. 1.16, 1.39)).

CONCLUSIONS

The findings suggest that living in a contaminated area by PFAS plays a role in affecting fetal growth and support the hypothesis that PFAS exposure is a risk factor for SGA. Individual data on exposure are needed to confirm the direct association.

Birth weight and perfluorooctane sulfonic acid: a random-effects meta-regression analysis

Supplemental Digital Content is available in the text.

Perfluorooctane sulfonic acid (PFOS) is a ubiquitous environmental contaminant. Most people in developed countries have detectable serum concentrations. Lower birth weight has been associated with serum PFOS in studies world-wide, many of which have been published only recently.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

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

Associations of Exposure to Perfluoroalkyl Substances With Thyroid Hormone Concentrations and Birth Size

BACKGROUND

Adequate thyroid function during pregnancy is essential for optimal fetal growth. Gestational exposure to perfluoroalkyl substances (PFAS) can negatively affect birth size and disrupt maternal and neonatal thyroid function, although the interrelationship is unclear.

OBJECTIVE

We aimed to quantify the associations between maternal serum-PFAS concentrations and birth weight, birth length, and cranial circumference. We also aimed to estimate associations between PFAS and thyroid hormone (TH) concentrations, thereby elucidating whether THs potentially mediate the associations between PFAS concentrations and birth size.

METHODS

We studied a population-based prospective cohort of 172 mother-singleton pairs from the Faroe Islands. Twelve PFAS were measured in maternal serum obtained at 34 weeks of gestation. THs were measured in maternal and cord serum. Associations between PFAS concentrations and birth size and TH concentrations were estimated using multivariable linear regressions. Sex-stratified analyses along with a mediation analysis were performed to estimate potential mediating effects of THs in the association between PFAS and birth outcomes.

RESULTS

Several PFASs were negatively associated with birth weight, length, and head circumference, and a general positive association between maternal serum-PFASs and cord serum-thyroid-stimulating hormone (TSH; also known as thyrotropin) was found. For instance, a doubling in perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) was associated with a 53% (95% CI, 18%-99%) and 40% (95% CI, 8%-81%) increases in TSH concentrations, respectively. There was little evidence of sexually dimorphic associations. Overall, THs were not found to mediate associations between PFASs and birth size.

CONCLUSION

In this study, several PFASs were negatively associated with birth size and increased THs; however, this did not explain lower birth weight among children exposed to PFAS.

Metabolomics study and meta-analysis on the association between maternal pesticide exposome and birth outcomes

BACKGROUND

Pregnant women are exposed to a number of pesticides which are widely used in China. Their potential risks on reproduction and infants are still unknown.

OBJECTIVE

We aimed to investigate whether infant's birth weight and length of gestation were associated with levels of various pesticides in maternal blood based on Nanjing Medical University (NMU) affiliated hospitals data and meta-analysis, and also to explore the possible intermediate metabolomics pathways.

METHODS

Eligible subjects (n = 102) were included in this study from the affiliated hospitals of NMU. Gas chromatography tandem mass spectrometry (GC/MS) and Q-Exactive mass spectrometer (QE) were used to detect 37 pesticides (9 organophosphorus pesticides, 7 organochlorine pesticides, 5 carbamate pesticides, and 16 others) and 161 metabolites (53 in animo acid metabolism 47 in lipid metabolism, 18 in carbohydrate metabolism, 14 in nucleotide metabolism and 29 in other metabolisms) in maternal blood, respectively. Multi-linear regression and Bayesian kernel machine regression (BKMR) were performed to identify the association of single/mixed pesticide exposure in maternal blood with birth weight and length of gestation. Moreover, we conducted a meta-analysis including additional 2497 subjects to evaluate whether exposure to key pesticide, β-hexachlorocyclohexane (β-HCH) was associated with decreased birth weight globally. Mediation analysis was used to explore the metabolic alteration mediating the association between key pesticide exposure and birth outcomes.

RESULTS

We found that decreased birth weight was significantly associated with increasing levels of mecarbam and β-HCH. We did not find any association between length of gestation and these pesticides. Among pesticides with detection rate more than 50%, BKMR analysis found an overall negative association of mixed pesticides exposure with birth weight, and verified that β-HCH was the key pesticide for such effect. Meta-analysis revealed a significantly negative association between exposure to β-HCH and birth weight. Metabolomics identified three metabolites and five metabolites as significant mediators for the effect of mecarbam and β-HCH, respectively, among which glyceraldehyde and its related glycerolipid metabolism and thyroxine and its related thyroid hormone metabolism were found to be the mostly enriched mediating metabolic pathway.

CONCLUSIONS

Based on the comprehensive pesticide exposome and metabolome wide associational study combined with meta-analysis, we found that prenatal exposure to β-HCH and mecarbam decreased birth weight via disrupting thyroid hormone metabolism and glyceraldehyde metabolism, providing new insights into the toxic effects of exposure to pesticides on birth outcomes.

Oestrogenic Endocrine Disruptors in the Placenta and the Fetus

Endocrine disrupting chemicals (EDCs) are exogenous substances that interfere with the stability and regulation of the endocrine system of the body or its offspring. These substances are generally stable in chemical properties, not easy to be biodegraded, and can be enriched in organisms. In the past half century, EDCs have gradually entered the food chain, and these substances have been frequently found in maternal blood. Perinatal maternal hormone levels are unstable and vulnerable to EDCs. Some EDCs can affect embryonic development through the blood-fetal barrier and cause damage to the neuroendocrine system, liver function, and genital development. Some also effect cross-generational inheritance through epigenetic mechanisms. This article mainly elaborates the mechanism and detection methods of estrogenic endocrine disruptors, such as bisphenol A (BPA), organochlorine pesticides (OCPs), diethylstilbestrol (DES) and phthalates (PAEs), and their effects on placenta and fetal health in order to raise concerns about the proper use of products containing EDCs during pregnancy and provide a reference for human health.

Evidence Implicating Non-Dioxin-Like Congeners as the Key Mediators of Polychlorinated Biphenyl (PCB) Developmental Neurotoxicity

Despite being banned from production for decades, polychlorinated biphenyls (PCBs) continue to pose a significant risk to human health. This is due to not only the continued release of legacy PCBs from PCB-containing equipment and materials manufactured prior to the ban on PCB production, but also the inadvertent production of PCBs as byproducts of contemporary pigment and dye production. Evidence from human and animal studies clearly identifies developmental neurotoxicity as a primary endpoint of concern associated with PCB exposures. However, the relative role(s) of specific PCB congeners in mediating the adverse effects of PCBs on the developing nervous system, and the mechanism(s) by which PCBs disrupt typical neurodevelopment remain outstanding questions. New questions are also emerging regarding the potential developmental neurotoxicity of lower chlorinated PCBs that were not present in the legacy commercial PCB mixtures, but constitute a significant proportion of contemporary human PCB exposures. Here, we review behavioral and mechanistic data obtained from experimental models as well as recent epidemiological studies that suggest the non-dioxin-like (NDL) PCBs are primarily responsible for the developmental neurotoxicity associated with PCBs. We also discuss emerging data demonstrating the potential for non-legacy, lower chlorinated PCBs to cause adverse neurodevelopmental outcomes. Molecular targets, the relevance of PCB interactions with these targets to neurodevelopmental disorders, and critical data gaps are addressed as well.

Maternal serum levels of perfluoroalkyl substances in early pregnancy and offspring birth weight

BACKGROUND

Perfluoroalkyl substances (PFASs) are widespread, bioaccumulating, and persistent and show placental transfer. Emerging research indicates associations between prenatal exposure and low birth weight. The aim of this study was to assess the associations between first trimester exposure to PFASs and birth weight (BW) in the Swedish Environmental, Longitudinal, Mother and child, Asthma and allergy (SELMA) study and examine whether associations differ between girls and boys.

METHODS

Eight PFASs were analyzed in maternal serum (median: 10 weeks of pregnancy). Associations between prenatal PFAS exposure and birth outcomes with BW, BW for gestational age, and birth small for gestational age (SGA) were assessed in 1533 infants, adjusted for potential confounders and stratified by sex.

RESULTS

Increased maternal perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were associated with lower BW, lower BW for gestational age, and SGA birth. Associations were significant only in girls, where prenatal exposure in the upper quartile was associated with a 93-142-g lower BW when compared with that of the lowest quartile exposure. The associations were not mediated by effects on gestational age.

CONCLUSIONS

We found associations between prenatal exposure for five different PFASs and birth weight, with more pronounced associations in girls than in boys.

Review of the Effects of Perinatal Exposure to Endocrine-Disrupting Chemicals in Animals and Humans

Maternal exposure to endocrine-disrupting chemicals (EDCs) is associated with long-term hormone-dependent effects that are sometimes not revealed until maturity, middle age, or adulthood. The aim of this study was to conduct descriptive reviews on animal experimental and human epidemiological evidence of the adverse health effects of in utero and lactational exposure to selected EDCs on the first generation and subsequent generation of the exposed offspring. PubMed, Web of Science, and Toxline databases were searched for relevant human and experimental animal studies on 29 October 29 2018. Search results were screened for relevance, and studies that met the inclusion criteria were evaluated and qualitative data extracted for analysis. The search yielded 73 relevant human and 113 animal studies. Results from studies show that in utero and lactational exposure to EDCs is associated with impairment of reproductive, immunologic, metabolic, neurobehavioral, and growth physiology of the exposed offspring up to the fourth generation without additional exposure. Little convergence is seen between animal experiments and human studies in terms of the reported adverse health effects which might be associated with methodologic challenges across the studies. Based on the available animal and human evidence, in utero and lactational exposure to EDCs is detrimental to the offspring. However, more human studies are necessary to clarify the toxicological and pathophysiological mechanisms underlying these effects.

Exposure to Persistent Organic Pollutants and Birth Characteristics: The Upstate KIDS Study

BACKGROUND

Prenatal exposure to persistent organic pollutants (POPs) may be associated with obesogenic effects in offspring. Our study is the first to investigate associations between concentrations of POPs from newborn dried blood spots (DBS) and birth characteristics.

METHODS

Concentrations of 10 polychlorinated biphenyl congeners (PCBs), polybrominated diphenyl ether-47 (PBDE-47), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) were measured from DBSs collected at birth from 2,065 singleton infants. DBS samples were pooled in groups of five and assayed together to reach limits of detection. Differences in risk of large for gestational age (LGA, defined as >90th percentile of birth weight for sex and gestational age), small for gestational age (SGA, <10th), and preterm birth (gestational age <37 weeks) were estimated using logistic regression per unit (ng/ml) increase in concentration of each chemical, adjusting for individual-level covariates, including maternal age, race/ethnicity, prepregnancy BMI, education, parity, smoking, and infant sex while assuming a gamma distribution and using multiple imputation to account for pools.

RESULTS

There were 215 (11.3%) singletons born LGA, 158 (7.5%) born SGA, and 157 (7.6%) born preterm. Higher concentrations of POPs were positively associated with slightly higher risk of LGA and higher birth weight.

CONCLUSIONS

Relationships between POPs measured in newborn DBS and birth size were mixed. Pooled analysis methods using DBS could address challenges in limits of detection and costs for population-based research.

In utero exposure to endocrine disrupting chemicals, micro-RNA profiles, and fetal growth: a pilot study protocol

Background: The developing fetus is particularly vulnerable to the effects of endocrine disrupting chemicals (EDCs). Molecular fingerprints of EDCs can be identified via microRNA (miRNA) expression profiles and may be etiologically implicated in the developmental origin of disease (DOHaD).

Methods/design: This pilot study includes pregnant women at high risk (smoking at conception), and low risk (non-smoking at conception) for SGA birth (birthweight<10^th percentile for gestational age). We have randomly selected 12 mothers (3 high-risk SGA birth, 3 low-risk SGA birth, 3 high-risk non-SGA birth, 3 low-risk non-SGA birth), with EDC measurements from gestational week 17. All offspring are female. We aim to test the stability of our samples (maternal serum, cord blood, placenta tissue), observe the differential expression of miRNA profiles over time (gestational weeks 17, 25, 33, 37, birth), and study the consistency between maternal EDC measures and miRNA expression profiles across our repeated measures.

Expected impact of the study for Public Health: Results from this pilot study will inform the development of a larger cohort wide analysis, and will impact the current state of knowledge in the fields of public health, epigenetics, and the DOHaD.

Adverse effects of hexaclorobenzene exposure in children and adolescents

BACKGROUND

Hexachlorobenzene (HCB: C₆Cl₆) is a persistent, bioaccumulative chemical formerly used worldwide in pesticide mixtures but also produced as a by-product in the chemical and metallurgical industry. Despite current international restrictions in the use and production of HCB, the majority of the general population still show detectable levels of HCB, which raises concerns on the potential health implications of the exposure.

OBJECTIVE

To compile and synthesize the available scientific evidence regarding the adverse effects of exposure to HCB in children and adolescents.

METHODS

A review of the literature focused on the adverse effects of HCB exposure in children. Eligible studies were systematically screened from searches in Medline, Scopus and Ebsco-host databases. A total of 62 studies were finally included.

RESULTS AND DISCUSSION

In our search we found evidences of potential health effects linked to HCB exposure at different levels (e.g. neurotoxic, nephrotoxic, immunotoxic, hepatotoxic and toxicogenomic), although the conclusions are still contradictory. Further prospective research is needed, considering the special vulnerability of children and adolescent population as well as the ubiquity of the exposure.

Association between prenatal exposure to multiple persistent organic pollutants (POPs) and growth indicators in newborns

Despite the fact that many of persistent organic pollutants (POPs) have been banned for decades, they still constitute a group of harmful substances to human health. Prenatal exposure can have adverse effects on one's health as well as on their newborns. The present cross-sectional study, which includes 87% of the births registered in La Palma Island (Canary Islands, Spain) during 2016 (n = 447), aims to evaluate the potential adverse health effects exerted by a wide range of POPs on newborns. We quantified blood cord levels of twenty organochlorine pesticides, eighteen polychlorinated biphenyls (PCBs), eight bromodiphenyl ethers (BDEs), and sixteen polycyclic aromatic hydrocarbons (PAHs) using the method of gas chromatography-mass spectrometry. By groups, p,p'-DDE, PCB-28, BDE-47, and phenanthrene were the most frequently detected compounds (median values = 0.148, 0.107, 0.065, and 0.380 ng/mL, respectively). p,p'-DDE was found to be significantly associated with an increase in neonatal birth weight, with a special emphasis on girls. An inverse association between PCB-28 and PCB-52 with birth weight was observed, and these associations were determined by the gender. A similar trend was obtained for BDE-47 but not for any of the PAHs. When assessing the effect of mixtures, boys exhibiting ≥ 3 OCPs were at lower risk of having higher birth weight (OR = 0.25; 95% CI = 0.07 - 0.89; P = 0.032). The effect of these pollutants on birth weight does not go in the same direction, a fact that is conditioned by several factors, including the chemical nature of the substance or the gender of the newborn. Additional research is needed to understand the role of POPs on fetal development.

Early pregnancy exposure to endocrine disrupting chemical mixtures are associated with inflammatory changes in maternal and neonatal circulation

Endocrine disrupting chemicals (EDCs) are ubiquitous, and pregnancy is a sensitive window for toxicant exposure. EDCs may disrupt the maternal immune system, which may lead to poor pregnancy outcomes. Most studies investigate single EDCs, even though "real life" exposures do not occur in isolation. We tested the hypothesis that uniquely weighted mixtures of early pregnancy exposures are associated with distinct changes in the maternal and neonatal inflammasome. First trimester urine samples were tested for 12 phthalates, 12 phenols, and 17 metals in 56 women. Twelve cytokines were measured in first trimester and term maternal plasma, and in cord blood after delivery. Spearman correlations and linear regression were used to relate individual exposures with inflammatory cytokines. Linear regression was used to relate cytokine levels with gestational age and birth weight. Principal component analysis was used to assess the effect of weighted EDC mixtures on maternal and neonatal inflammation. Our results demonstrated that maternal and cord blood cytokines were differentially associated with (1) individual EDCs and (2) EDC mixtures. Several individual cytokines were positively associated with gestational age and birth weight. These observed associations between EDC mixtures and the pregnancy inflammasome may have clinical and public health implications for women of childbearing age.

Concentrations of perfluoroalkyl substances (PFASs) in human embryonic and fetal organs from first, second, and third trimester pregnancies

BACKGROUND

The persistent environmental contaminants perfluoroalkyl substances (PFASs) have gained attention due to their potential adverse health effects, in particular following early life exposure. Information on human fetal exposure to PFASs is currently limited to one report on first trimester samples. There is no data available on PFAS concentrations in fetal organs throughout all three trimesters of pregnancy.

METHODS

We measured the concentrations of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorohexane sulfonic acid (PFHxS) in human embryos and fetuses with corresponding placentas and maternal serum samples derived from elective pregnancy terminations and cases of intrauterine fetal death. A total of 78 embryos and fetuses aged 7-42 gestational weeks were included and a total of 225 fetal organs covering liver, lung, heart, central nervous system (CNS), and adipose tissue were analyzed, together with 71 placentas and 63 maternal serum samples. PFAS concentrations were assayed by liquid chromatography/triple quadrupole mass spectrometry.

RESULTS

All evaluated PFASs were detected and quantified in maternal sera, placentas and embryos/fetuses. In maternal serum samples, PFOS was detected in highest concentrations, followed by PFOA > PFNA > PFDA = PFUnA = PFHxS. Similarly, PFOS was detected in highest concentrations in embryo/fetal tissues, followed by PFOA > PFNA = PFDA = PFUnA. PFHxS was detected in very few fetuses. In general, PFAS concentrations in embryo/fetal tissue (ng/g) were lower than maternal serum (ng/ml) but similar to placenta concentrations. The total PFAS burden (i.e. the sum of all PFASs) was highest in lung tissue in first trimester samples and in liver in second and third trimester samples. The burden was lowest in CNS samples irrespective of fetal age. The placenta:maternal serum ratios of PFOS, PFOA and PFNA increased across gestation suggesting bioaccumulation in the placenta. Further, we observed that the ratios were higher in pregnancies with male fetuses compared to female fetuses.

CONCLUSIONS

Human fetuses were intrinsically exposed to a mixture of PFASs throughout gestation. The compounds were detected in all analyzed tissues, suggesting that PFASs reach and may affect many types of organs. Collectively, our results demonstrate that PFASs pass the placenta and deposit to embryo and fetal tissues, calling for risk assessment of gestational exposures.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food

The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in food. Regarding PFOS and PFOA occurrence, the final data set available for dietary exposure assessment contained a total of 20,019 analytical results (PFOS n = 10,191 and PFOA n = 9,828). There were large differences between upper and lower bound exposure due to analytical methods with insufficient sensitivity. The CONTAM Panel considered the lower bound estimates to be closer to true exposure levels. Important contributors to the lower bound mean chronic exposure were 'Fish and other seafood', 'Meat and meat products' and 'Eggs and egg products', for PFOS, and 'Milk and dairy products', 'Drinking water' and 'Fish and other seafood' for PFOA. PFOS and PFOA are readily absorbed in the gastrointestinal tract, excreted in urine and faeces, and do not undergo metabolism. Estimated human half-lives for PFOS and PFOA are about 5 years and 2-4 years, respectively. The derivation of a health-based guidance value was based on human epidemiological studies. For PFOS, the increase in serum total cholesterol in adults, and the decrease in antibody response at vaccination in children were identified as the critical effects. For PFOA, the increase in serum total cholesterol was the critical effect. Also reduced birth weight (for both compounds) and increased prevalence of high serum levels of the liver enzyme alanine aminotransferase (ALT) (for PFOA) were considered. After benchmark modelling of serum levels of PFOS and PFOA, and estimating the corresponding daily intakes, the CONTAM Panel established a tolerable weekly intake (TWI) of 13 ng/kg body weight (bw) per week for PFOS and 6 ng/kg bw per week for PFOA. For both compounds, exposure of a considerable proportion of the population exceeds the proposed TWIs.

Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food

The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in food. Regarding PFOS and PFOA occurrence, the final data set available for dietary exposure assessment contained a total of 20,019 analytical results (PFOS n = 10,191 and PFOA n = 9,828). There were large differences between upper and lower bound exposure due to analytical methods with insufficient sensitivity. The CONTAM Panel considered the lower bound estimates to be closer to true exposure levels. Important contributors to the lower bound mean chronic exposure were 'Fish and other seafood', 'Meat and meat products' and 'Eggs and egg products', for PFOS, and 'Milk and dairy products', 'Drinking water' and 'Fish and other seafood' for PFOA. PFOS and PFOA are readily absorbed in the gastrointestinal tract, excreted in urine and faeces, and do not undergo metabolism. Estimated human half-lives for PFOS and PFOA are about 5 years and 2-4 years, respectively. The derivation of a health-based guidance value was based on human epidemiological studies. For PFOS, the increase in serum total cholesterol in adults, and the decrease in antibody response at vaccination in children were identified as the critical effects. For PFOA, the increase in serum total cholesterol was the critical effect. Also reduced birth weight (for both compounds) and increased prevalence of high serum levels of the liver enzyme alanine aminotransferase (ALT) (for PFOA) were considered. After benchmark modelling of serum levels of PFOS and PFOA, and estimating the corresponding daily intakes, the CONTAM Panel established a tolerable weekly intake (TWI) of 13 ng/kg body weight (bw) per week for PFOS and 6 ng/kg bw per week for PFOA. For both compounds, exposure of a considerable proportion of the population exceeds the proposed TWIs.