Prenatal exposure to perfluoroalkyl substances and birth outcomes in a Spanish birth cohort

Per- and polyfluoroalkyl substances (PFAS) and fetal growth: A nation-wide register-based study on PFAS in drinking water

BACKGROUND

There is inconclusive evidence for an association between per- and polyfluoroalkyl substances (PFAS) and fetal growth.

OBJECTIVES

We conducted a nation-wide register-based cohort study to assess the associations of the estimated maternal exposure to the sum (PFAS4) of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) with birthweight as well as risk of small- (SGA) and large-for-gestational-age (LGA).

MATERIALS AND METHODS

We included all births in Sweden during 2012-2018 of mothers residing ≥ four years prior to partus in localities served by municipal drinking water where PFAS were measured in raw and drinking water. Using a one-compartment toxicokinetic model we estimated cumulative maternal blood levels of PFAS4 during pregnancy by linking residential history, municipal PFAS water concentration and year-specific background serum PFAS concentrations in Sweden. Individual birth outcomes and covariates were obtained via register linkage. Mean values and 95 % confidence intervals (CI) of β coefficients and odds ratios (OR) were estimated by linear and logistic regressions, respectively. Quantile g-computation regression was conducted to assess the impact of PFAS4 mixture.

RESULTS

Among the 248,804 singleton newborns included, no overall association was observed for PFAS4 and birthweight or SGA. However, an association was seen for LGA, multivariable-adjusted OR 1.08 (95% CI: 1.01-1.16) when comparing the highest PFAS4 quartile to the lowest. These associations remained for mixture effect approach where all PFAS, except for PFOA, contributed with a positive weight.

DISCUSSIONS

We observed an association of the sum of PFAS4 - especially PFOS - with increased risk of LGA, but not with SGA or birthweight. The limitations linked to the exposure assessment still require caution in the interpretation.

Prenatal exposure to poly- and perfluoroalkyl substances and postpartum depression in women with twin pregnancies

BACKGROUND

Women with multiple pregnancies are vulnerable to experience postpartum depression (PPD). Emerging evidence indicates an association between poly- and perfluoroalkyl substances (PFAS) exposure and PPD in women delivering singletons. The health risks of PFAS may also be present in women delivering twins.

OBJECTIVE

To estimate the impacts of prenatal PFAS exposure on the risk of PPD in women with twin pregnancies.

METHODS

Our study included 150 mothers who gave birth to twins and were enrolled in the Wuhan Twin Birth Cohort. The concentrations of maternal plasma PFAS were measured in each trimester and averaged. Eight individual PFAS were included in analyses. We used Edinburgh Postnatal Depression Scale to evaluate maternal depression at early pregnancy and 1 and 6 months after childbirth. The outcome was dichotomized using a cutoff value of ≥10 for main analyses. Associations were examined using multiple informant models and modified Poisson regressions. PFAS mixture effects were estimated using quantile g-computation.

RESULTS

Using quantile g-computation models, a quartile increase in the PFAS mixture during the first, second, third, and average pregnancy was significantly associated with a relative risk (RR) of 1.73 (95% CI: 1.42, 2.12), 1.54 (95% CI: 1.27, 1.84), 1.75 (95% CI: 1.49, 2.08), and 1.63 (95% CI: 1.35, 1.97) for PPD at 6 months after childbirth, respectively. The results of the single-PFAS models also indicated significant positive associations between individual PFAS and PPD at both 1 and 6 months.

CONCLUSIONS

The first study of women with twin pregnancies suggests that prenatal exposure to PFAS increases PPD risk up to 6 months postpartum. Twin pregnant women should receive long-term follow-up after delivery and extensive social support.

Maternal and Paternal Preconception Serum Concentrations of Per and Polyfluoroalkyl Substances in Relation to Birth Outcomes

Prenatal per and polyfluoroalkyl substances (PFAS) exposure is associated with adverse birth outcomes. There is an absence of evidence on the relationship between maternal and paternal preconception PFAS exposure and birth outcomes. This study included 312 mothers and 145 fathers with a singleton live birth from a preconception cohort of subfertile couples seeking fertility treatment at a U.S. clinic. PFAS were quantified in serum samples collected before conception. Gestational age (GA) and birthweight (BW) were abstracted from delivery records. We also assessed low birthweight (BW < 2500 g) and preterm birth (GA < 37 completed weeks). We utilized multivariable linear regression, logistic regression, and quantile-based g computation to examine maternal or paternal serum concentrations of individual PFAS and mixture with birth outcomes. Maternal serum concentrations of perfluorooctanesulfonate (PFOS), perfluorohexanesulfonate (PFHxS), and the total PFAS mixture were inversely associated with birthweight. Maternal PFOS concentration was associated with a higher risk of low birthweight. Conversely, paternal PFOS and PFHxS concentrations were imprecisely associated with higher birthweight. No associations were found for gestational age or preterm birth. The findings have important implications for preconception care. Future research with larger sample sizes would assist in validating these findings.

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

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

Prenatal per- and polyfluoroalkyl substances (PFAS) exposure in relation to preterm birth subtypes and size-for-gestational age in the LIFECODES cohort 2006-2008

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals widely used in consumer and industrial products. Numerous studies have linked prenatal PFAS exposures to increased risks of adverse pregnancy outcomes such as preterm birth (PTB) and small-for-gestational age (SGA).However, limited evidence is available for the effects of PFAS on PTB subtypes and large-for-gestational age (LGA).

OBJECTIVE

To examine the associations of PFAS with PTB [overall, placental (pPTB), spontaneous (sPTB)], BW Z-score, and size-for-gestational age (SGA, LGA).

METHODS

Our nested case-control study included 128 preterm cases and 373 term controls from the LIFECODES cohort between 2006 and 2008 (n = 501). Plasma concentrations of nine PFAS were measured in early pregnancy samples. Logistic regression was used to assess individual PFAS-birth outcome associations, while Bayesian Kernel Machine Regression (BKMR) was used to evaluate the joint effects of all PFAS. Effect modification by fetal sex was examined, and stratified analyses were conducted to obtain fetal sex-specific estimates.

RESULTS

Compared to term births, the odds of pPTB were higher from an interquartile range increase in perfluorodecanoic acid (PFDA) (OR = 1.60, 95% CI: 1.00-2.56), perfluorononanoic acid (PFNA) (OR = 1.67, 95% CI: 1.06-2.61), and perfluoroundecanoic acid (PFUA) (OR = 1.77, 95% CI: 1.00-3.12), with stronger associations observed in women who delivered males. BKMR analysis identified PFNA as the most important PFAS responsible for pPTB (conditional PIP = 0.78), with increasing ORs at higher percentiles of PFAS mixture. For LGA, positive associations were observed with PFDA and perfluorooctanoic acid in females only, and with PFUA in males only. BKMR analysis showed increasing, but null effects of PFAS mixture on LGA.

CONCLUSIONS

The effect of prenatal exposure to single and multiple PFAS on PTB and LGA depended on fetal sex. Future studies should strongly consider examining PTB subtypes and sex-specific effects of PFAS on pregnancy outcomes.

Prenatal Exposure to PFAS, Associations with Preterm Birth and Modification by Maternal Estrogen Levels: The Maoming Birth Study

BACKGROUND

Estrogens play a critical role in parturition, and poly- and perfluoroalkyl substances (PFAS), which have estrogenic effects, have been associated with preterm birth. However, the impact of estrogens on the association between PFAS and preterm birth is unknown.

OBJECTIVE

The objective of this study is to investigate if estrogens modified the association between PFAS and preterm birth, using a nested case-control study design.

METHODS

A total of 371 preterm births and 508 controls were selected from a birth cohort study in China between 2016 and 2018. Perfluorobutanoic acid (PFBA), perfluorohexanesulfonic acid (PFHxS) and its branched isomer, perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and its branched isomer, and perfluorononanoic acid (PFNA) were quantified in maternal serum (mean gestational age of 32 wk). Estradiol and estriol were quantified in cord serum. Preterm birth was defined as live delivery at < 37 gestational weeks. Causal mediation analysis was used to estimate the mediation and interaction effects of estrogen on the association between PFAS and preterm birth. Latent profile analysis was used to identify important estrogen profiles. Multiple linear regression was used to estimate associations between PFAS and preterm birth and interactions between PFAS and estrogens on preterm birth.

RESULTS

Overall, higher odds ratios (ORs) of preterm birth were associated with each 1 ln-unit PFAS increase: PFBA [1.20, 95% confidence interval (CI): 1.14, 1.26], PFNA (1.30, 95% CI: 1.21, 1.39), PFOA (1.98, 95% CI: 1.54, 2.55), and PFOS (1.91, 95% CI: 1.76, 2.07) and its branched isomer (1.91, 95% CI: 1.90, 1.92). We detected statistically significant interactions between cord estradiol and PFAS on preterm birth, while no mediation effects of cord estrogen were observed. The ORs of PFOS (4.29, 95% CI: 1.31, 8.25), its branched isomer (6.71, 95% CI: 1.06, 11.91), and preterm birth were greater for participants with high cord estrogen levels than for participants with low cord estrogen levels.

DISCUSSION

Our findings suggest that estrogen modified the association between maternal PFAS exposure and preterm birth. Further studies on maternal PFAS exposure and preterm birth, taking interaction effects of cord estrogens into account, are warranted. https://doi.org/10.1289/EHP11377.

Low transplacental transfer of PFASs in the small-for-gestational-age (SGA) new-borns: Evidence from a Chinese birth cohort

Early life in utero exposure to per- and polyfluoroalkyl substances (PFASs) and infiltration through the placenta into cord blood pose significant risk to fetal development. Accumulating knowledge suggests that PFASs pass through the placenta in multiple transportation ways, not limiting to passive transport but also active transport or facilitated diffusion. Therefore, we propose that the transplacental transfer efficiency (TTE) could be re-evaluated as traditional cord to maternal ratio-based method might overlook certain biological or health information from the mother and fetus. In this study, we investigated 30 PFAS chemicals in paired maternal and cord serum from 195 births classified as small-for-gestational-age (SGA) and matched appropriate-for-gestational-age (AGA). PFASs were ubiquitously detected in the maternal and serum samples, with PFOA, PFOS, 6:2 Cl-PFESA and other dominant compounds. We adopted a modified TTE estimation method (TTEm), taking into consideration of the total burden mass of PFASs in the blood from mother to fetus. Using the modified TTEm, a significant (p < 0.05) decrease was observed in the PFAS transplacental transfer potential in SGA (1.6%-11.3%) compared to AGA (2.3%-21.1%), suggesting a reverse association between TTE and SGA birth risk. This is the first study attempted to re-evaluate the TTE of PFAS and indicates that TTEm might be more advantageous to reflect the transplacental transfer potency of chemicals particularly when transportation mechanisms are multi-faceted.

Xeno-estrogenic activity of real-life mixtures of perfluoroalkylated substances in human placenta homogenates

Humans are simultaneously exposed to complex chemical mixtures, and its combined effect can affect human health. As part of the HBM4EU project, the actual mixture of perfluoroalkylated substances (PFAS) in 25 human placenta samples was extracted by chromatographic methods and assessed for xeno-estrogenic activity using two in-vitro bioassays: the estrogen receptor transactivity and the E-Screen assay. Most of the PFAS extracts displayed xeno-estrogenic activity, in one or both assays. The xeno-estrogenic activities in the two bioassays were not correlated, but both assays showed an overall negative correlation with placenta concentrations of single PFAS. Xeno-estrogenic activities were significantly related to maternal characteristics; being higher in young, smokers and primiparous women, but not with fetal growth (birth weight, birth length, head circumference, gestational age, placenta weight). The presented extraction method can be used to study the combined effect of real-life mixtures of PFAS in relation to health outcomes in large-scale human biomonitoring studies.

Fetal Glucocorticoid Mediates the Association between Prenatal Per- and Polyfluoroalkyl Substance Exposure and Neonatal Growth Index: Evidence from a Birth Cohort Study

Glucocorticoid plays a key role in the growth and organ maturation of fetus. However, the effect of glucocorticoid on the association between per- and polyfluoroalkyl substance (PFAS) exposure and fetal growth is still unknown. We detected cord cortisol (active glucocorticoid in human) and 34 PFAS concentrations in the maternal serum samples, which were collected from 202 mother-fetus pairs in the Maoming Birth Cohort from 2015 to 2018. The mediation effect of cord cortisol on the association between maternal PFAS and the neonatal growth index (NGI) was estimated. We found that higher PFAS concentrations were associated with lower NGI in terms of ponderal index, birth weight (BW), head circumference (HC), and its z-scores (BWZ and HCZ) (P < 0.05). Fetal cortisol could mediate 12.6-27.3% of the associations between PFAS and NGI. Specifically, cord cortisol mediated the association between branched perfluorooctane sulfonate (branched PFOS) and HCZ by 20.4% and between perfluorooctanoate (PFOA) and HCZ by 27.3%. Our findings provide the first epidemiological data evincing that fetal cortisol could mediate the association between prenatal PFAS exposure and fetal growth. Further investigations are recommended to elucidate the interactions among cord cortisol, PFAS, and fetal growth.

Associations between maternal exposure to perfluoroalkylated substances (PFASs) and infant birth weight: a meta-analysis

The objective of this study was to determine the associations between maternal exposure to PFASs and infant birth weight and to explore evidence for a possible dose-response relationship. Four databases including PubMed, Embase, Web of Science, and Medline before 20 September 2022 were systematically searched. A fixed-effect model was used to estimate the change in infant birth weight (g) associated with PFAS concentrations increasing by 10-fold. Dose-response meta-analyses were also conducted when possible. The study follows the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A total of 21 studies were included. Among these studies, 18 studies examined the associations between PFOA and birth weight, 17 studies reported PFOS, and 11 studies discussed PFHxS. Associations between PFHxS (ES = -5.67, 95% CI: -33.92 to 22.59, P = 0.694) were weaker than those for PFOA and PFOS (ES = -58.62, 95% CI: -85.23 to -32.01, P < 0.001 for PFOA; ES = -54.75, 95% CI: -84.48 to -25.02, P < 0.001 for PFOS). The association was significantly stronger in the high median PFOS concentration group (ES = -107.23, 95% CI: -171.07 to -43.39, P < 0.001) than the lower one (ES = -29.15, 95% CI: -63.60 to -5.30, P = 0.097; meta-regression, P = 0.045). Limited evidence of a dose-response relationship was found. This study showed negative associations between maternal exposure to PFASs and infant birth weight. Limited evidence of a dose-response relationship between exposure to PFOS and infant birth weight was found. Further studies are needed to find more evidence.

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.

Newborn metabolomic signatures of maternal per- and polyfluoroalkyl substance exposure and reduced length of gestation

Marginalized populations experience disproportionate rates of preterm birth and early term birth. Exposure to per- and polyfluoroalkyl substances (PFAS) has been reported to reduce length of gestation, but the underlying mechanisms are unknown. In the present study, we characterized the molecular signatures of prenatal PFAS exposure and gestational age at birth outcomes in the newborn dried blood spot metabolome among 267 African American dyads in Atlanta, Georgia between 2016 and 2020. Pregnant people with higher serum perfluorooctanoic acid and perfluorohexane sulfonic acid concentrations had increased odds of an early birth. After false discovery rate correction, the effect of prenatal PFAS exposure on reduced length of gestation was associated with 8 metabolomic pathways and 52 metabolites in newborn dried blood spots, which suggested perturbed tissue neogenesis, neuroendocrine function, and redox homeostasis. These mechanisms explain how prenatal PFAS exposure gives rise to the leading cause of infant death in the United States.

Association between perfluoroalkyl and polyfluoroalkyl substances exposure and fetal overgrowth: A prospective birth cohort study conducted in China

BACKGROUND

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) has been associated with gestational diabetes mellitus, obesity or overweight in childhood, but data on fetal overgrowth outcomes including macrosomia and large for gestational age (LGA) and among gestational age diverse infants remain scarce.

OBJECTIVE

To evaluate the association between maternal PFASs exposure and macrosomia and LGA, with exploration of the interaction between PFASs exposure and gestational age on fetal overgrowth.

METHODS

A total of 1441 mother-infants pairs from Guangxi Zhuang Birth Cohort of China were analyzed. Nine PFASs were measured in maternal serum using ultra-high liquid performance chromatographytandem mass spectrometry. Multivaraible logistical regression and generalized additive models were performed for individual PFAS exposures, piecewise regression analysis was used to estimate the breakpoint values for the non-linear dose-response relationships. Bayesian Kernel Machine Regression was performed for PFASs mixture.

RESULTS

In single pollutant models, maternal PFDA and PFOA exposure showed U-shaped relationship with macrosomia and LGA. When PFDA concentration exceeded 0.32 ng/mL was significantly positively associated with risks of LGA and macrosomia (OR=4.66, 95%CI: 1.26, 17.17; OR=14.43, 95%CI: 2.64, 79.02; respectively), while a negatively association was observed when level below 0.32 ng/mL. When PFOA concentration exceeded 1.20 ng/mL was significantly associated with increased risk of macrosomia (OR=7.75, 95%CI: 1.36, 44.06). In mixed exposure models, mixture of PFASs was positively associated with macrosomia, as well as associated with LGA when all the PFASs were at their 30th percentile or below. The maximum risk of LGA was reached when concentrations of PFUnA, PFDA, or PFBS were at the highest concentrations and the gestational age at the minimum of this study.

CONCLUSIONS

Maternal exposure to PFDA, PFOA and PFASs mixture were non-monotonically associated with macrosomia and LGA, the direction of the associations depends on the level of exposure.

Maternal Serum, Cord and Human Milk Levels of Per- and Polyfluoroalkyl Substances (PFAS), Association with Predictors and Effect on Newborn Anthropometry

BACKGROUND

The understanding of per- and polyfluoroalkyl substances (PFAS) health effects is rapidly advancing among critical populations. Therefore, the objective of this study was to assess PFAS serum levels among Lebanese pregnant women, cord serum and human milk levels, their determinants, and effects on newborn anthropometry.

METHODS

We measured concentrations of six PFAS (PFHpA, PFOA, PFHxS, PFOS, PFNA and PFDA) using liquid chromatography MS/MS for 419 participants, of which 269 had sociodemographic, anthropometric, environmental and dietary information.

RESULTS

The percentage of detection for PFHpA, PFOA, PFHxS and PFOS was 36.3-37.7%. PFOA and PFOS levels (95th percentile) were higher than HBM-I and HBM-II values. While PFAS were not detected in cord serum, five compounds were detected in human milk. Multivariate regression showed that fish/shellfish consumption, vicinity to illegal incineration and higher educational level were associated with an almost twice higher risk of elevated PFHpA, PFOA, PFHxS and PFOS serum levels. Higher PFAS levels in human milk were observed with higher eggs and dairy products consumption, in addition to tap water (preliminary findings). Higher PFHpA was significantly associated with lower newborn weight-for-length Z-score at birth.

CONCLUSIONS

Findings establish the need for further studies, and urgent action to reduce exposure among subgroups with higher PFAS levels.

Perfluorooctane sulfonic acid modulates expression of placental steroidogenesis-associated genes and hormone levels in pregnant rats

Perfluorooctane sulfonate (PFOS) is a widespread and persistent chemical in the environment. Reports show that PFOS is a potential endocrine disruptor; however, the possible effects of PFOS on placental endocrine function are unclear. This study aimed to investigate the endocrine-disrupting effects of PFOS on the placenta in pregnant rats and its potential mechanism. Pregnant rats from gestational days 4-20 were exposed to 0, 10, and 50 μg/mL PFOS through drinking water followed by analysis of various biochemical parameters. PFOS dose-dependently decreased fetal and placental weight in both sexes, with a specific decrease in weight of labyrinth but not junctional layer. Plasma progesterone (↑166%), aldosterone (↑201%), corticosterone (↑205%), testosterone (↑45%), luteinizing hormone (↑49%) levels were significantly increased, while estradiol (↓27%), prolactin (↓28%) and hCG (↓62%) levels were reduced in groups exposed to higher doses of PFOS. Real-time quantitative reverse transcriptase-polymerase chain reaction analysis revealed a significant increase in mRNA levels of placental steroid biosynthesis enzymes, including Cyp11A1 and 3β-HSD1 in male placenta and StAR, Cyp11A1, 17β-HSD1 and 17β-HSD3 in female placenta of PFOS dams. Cyp19A1 expression in ovaries was significantly decreased in PFOS dams. mRNA levels for placental steroid metabolism enzyme UGT1A1 increased in male but not in female placenta of PFOS dams. These results suggest that the placenta is a target tissue of PFOS and PFOS-induced dysregulation in steroid hormone production might be related to the altered expression of hormone biosynthesis and metabolism enzyme genes in the placenta. This hormone disruption might affect maternal health and fetal growth.

Association of Early Pregnancy Perfluoroalkyl and Polyfluoroalkyl Substance Exposure With Birth Outcomes

Importance

Prenatal perfluoroalkyl and polyfluoroalkyl substances (PFAS) have been linked to adverse birth outcomes. Previous research showed that higher folate concentrations are associated with lower blood PFAS concentrations in adolescents and adults. Further studies are needed to explore whether prenatal folate status mitigates PFAS-related adverse birth outcomes.

Objective

To examine whether prenatal folate status modifies the negative associations between pregnancy PFAS concentrations, birth weight, and gestational age previously observed in a US cohort.

Design, Setting, and Participants

In a prospective design, a prebirth cohort of mothers or pregnant women was recruited between April 1999 and November 2002, in Project Viva, a study conducted in eastern Massachusetts. Statistical analyses were performed from May 24 and October 25, 2022.

Exposure

Plasma concentrations of 6 PFAS compounds were measured in early pregnancy (median gestational week, 9.6). Folate status was assessed through a food frequency questionnaire and measured in plasma samples collected in early pregnancy.

Main Outcomes and Measures

Birth weight and gestational age, abstracted from delivery records; birth weight z score, standardized by gestational age and infant sex; low birth weight, defined as birth weight less than 2500 g; and preterm birth, defined as birth at less than 37 completed gestational weeks.

Results

The cohort included a total of 1400 mother-singleton pairs. The mean (SD) age of the mothers was 32.21 (4.89) years. Most of the mothers were White (73.2%) and had a college degree or higher (69.1%). Early pregnancy plasma perfluorooctanoic acid concentration was associated with lower birth weight and birth weight z score only among mothers whose dietary folate intake (birth weight: β, -89.13 g; 95% CI, -166.84 to -11.42 g; birth weight z score: -0.13; 95% CI, -0.26 to -0.003) or plasma folate concentration (birth weight: -87.03 g; 95% CI, -180.11 to 6.05 g; birth weight z score: -0.14; 95% CI, -0.30 to 0.02) were below the 25th percentile (dietary: 660 μg/d, plasma: 14 ng/mL). No associations were found among mothers in the higher folate level groups, although the tests for heterogeneity did not reject the null. Associations between plasma perfluorooctane sulfonic acid and perfluorononanoate (PFNA) concentrations and lower birth weight, and between PFNA and earlier gestational age were noted only among mothers whose prenatal dietary folate intake or plasma folate concentration was in the lowest quartile range. No associations were found among mothers in higher folate status quartile groups.

Conclusions and Relevance

In this large, US prebirth cohort, early pregnancy exposure to select PFAS compounds was associated with adverse birth outcomes only among mothers below the 25th percentile of prenatal dietary or plasma folate levels.

Pregnancy-related hemodynamic biomarkers in relation to trimester-specific maternal per - and polyfluoroalkyl substances exposures and adverse birth outcomes

The fate of environmental chemicals in maternal and fetal tissues might be affected by pregnancy-related hemodynamic changes that occur across gestation. Specifically, hemodilution and renal function are hypothesized to confound associations between per- and polyfluoroalkyl substances (PFAS) exposure measures in late pregnancy with gestational length and fetal growth. We sought to analyze two pregnancy-related hemodynamic biomarkers, creatinine and estimated glomerular filtration rate (eGFR), as confounders of the trimester-specific relationships between maternal serum PFAS concentrations and adverse birth outcomes. Participants were enrolled in the Atlanta African American Maternal-Child Cohort between 2014 and 2020. Biospecimens were collected at up to two timepoints, which were categorized into the 1st trimester (N = 278; 11 mean weeks gestation), 2nd trimester (N = 162; 24 mean weeks gestation), and 3rd trimester (N = 110; 29 mean weeks gestation). We quantified six PFAS in serum, creatinine in serum and urine, and eGFR using the Cockroft-Gault equation. Multivariable regression models estimated the associations between single PFAS and their sum with gestational age at delivery (weeks), preterm birth (PTB, <37 gestational weeks), birthweight z-scores, and small for gestational age (SGA). Primary models were adjusted for sociodemographics. We additionally adjusted for serum creatinine, urinary creatinine, or eGFR in the confounding assessments. An interquartile range increase in perfluorooctanoic acid (PFOA) produced a non-significant reduction in birthweight z-score during the 1st and 2nd trimesters (β = -0.01 g [95% CI = -0.14, 0.12] and β = -0.07 g [95% CI = -0.19, 0.06], respectively) whereas the relationship was significant and positive during the 3rd trimester (β = 0.15 g; 95% CI = 0.01, 0.29). Trimester-specific effects were similar for the other PFAS and adverse birth outcomes, which persisted after adjusting for creatinine or eGFR. The relationships between prenatal PFAS exposure and adverse birth outcomes were not strongly confounded by renal function or hemodilution. However, 3rd trimester samples consistently exhibited different effects than those collected during the 1st and 2nd trimesters.

Systematic review and meta-analysis of birth weight and PFNA exposures

We used a systematic review that included risk of bias and study sensitivity analysis to identify 34 studies examining changes in birth weight (BWT) in relation to PFNA biomarker measures (e.g., maternal serum/plasma or umbilical cord samples). We fit a random effects model of the overall pooled estimate and stratified estimates based on sample timing and overall study confidence. We conducted a meta-regression to further examine the impact of gestational age at biomarker sample timing. We detected a -32.9 g (95%CI: -47.0, -18.7) mean BWT deficit per each ln PFNA increase from 27 included studies. We did not detect evidence of publication bias (p_E = 0.30) or between-study heterogeneity in the summary estimate (p_Q = 0.05; I² = 36%). The twelve high confidence studies yielded a smaller pooled effect estimate (β = -28.0 g; 95%CI: -49.0, -6.9) than the ten medium (β = -39.0 g; 95%CI: -61.8, -16.3) or four low (β = -36.9 g; 95%CI: -82.9, 9.1) confidence studies. The stratum-specific results based on earlier pregnancy sampling periods in 11 studies showed smaller deficits (β = -22.0 g; 95%CI: -40.1, -4.0) compared to 10 mid- and late-pregnancy (β = -44.2 g; 95%CI: -64.8, -23.5) studies and six post-partum studies (β = -42.9 g; 95%CI: -88.0, 2.2). Using estimates of the specific gestational week of sampling, the meta-regression showed results consistent with the categorical sample analysis, in that as gestational age at sampling time increases across these studies, the summary effect estimate of a mean BWT deficit got larger. Overall, we detected mean BWT deficits for PFNA that were larger and more consistent across studies than previous PFAS meta-analyses. Compared to studies with later sampling, BWT deficits were smaller but remained sizeable for even the earliest sampling periods. Contrary to earlier meta-analyses for PFOA and PFOS, BWT deficits that were detected across all strata did not appear to be fully explained by potential bias due to pregnancy hemodynamics from sampling timing differences.

Birth Outcomes in Relation to Prenatal Exposure to Per- and Polyfluoroalkyl Substances and Stress in the Environmental Influences on Child Health Outcomes (ECHO) Program

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are persistent and ubiquitous chemicals associated with risk of adverse birth outcomes. Results of previous studies have been inconsistent. Associations between PFAS and birth outcomes may be affected by psychosocial stress.

OBJECTIVES

We estimated risk of adverse birth outcomes in relation to prenatal PFAS concentrations and evaluate whether maternal stress modifies those relationships.

METHODS

We included 3,339 participants from 11 prospective prenatal cohorts in the Environmental influences on the Child Health Outcomes (ECHO) program to estimate the associations of five PFAS and birth outcomes. We stratified by perceived stress scale scores to examine effect modification and used Bayesian Weighted Sums to estimate mixtures of PFAS.

RESULTS

We observed reduced birth size with increased concentrations of all PFAS. For a 1-unit higher log-normalized exposure to perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS), we observed lower birthweight-for-gestational-age z-scores of β = - 0.15 [95% confidence interval (CI): - 0.27 , - 0.03 ], β = - 0.14 (95% CI: - 0.28 , - 0.002 ), β = - 0.22 (95% CI: - 0.23 , - 0.10 ), β = - 0.06 (95% CI: - 0.18 , 0.06), and β = - 0.25 (95% CI: - 0.37 , - 0.14 ), respectively. We observed a lower odds ratio (OR) for large-for-gestational-age: OR PFNA = 0.56 (95% CI: 0.38, 0.83), OR PFDA = 0.52 (95% CI: 0.35, 0.77). For a 1-unit increase in log-normalized concentration of summed PFAS, we observed a lower birthweight-for-gestational-age z-score [- 0.28 ; 95% highest posterior density (HPD): - 0.44 , - 0.14 ] and decreased odds of large-for-gestational-age (OR = 0.49 ; 95% HPD: 0.29, 0.82). Perfluorodecanoic acid (PFDA) explained the highest percentage (40%) of the summed effect in both models. Associations were not modified by maternal perceived stress.

DISCUSSION

Our large, multi-cohort study of PFAS and adverse birth outcomes found a negative association between prenatal PFAS and birthweight-for-gestational-age, and the associations were not different in groups with high vs. low perceived stress. This study can help inform policy to reduce exposures in the environment and humans. https://doi.org/10.1289/EHP10723.

Nutritional Modulation of Associations between Prenatal Exposure to Persistent Organic Pollutants and Childhood Obesity: A Prospective Cohort Study

BACKGROUND

Prenatal exposure to persistent organic pollutants (POPs) may contribute to the development of childhood obesity and metabolic disorders. However, little is known about whether the maternal nutritional status during pregnancy can modulate these associations.

OBJECTIVES

The main objective was to characterize the joint associations and interactions between prenatal levels of POPs and nutrients on childhood obesity.

METHODS

We used data from to the Spanish INfancia y Medio Ambiente-Environment and Childhood (INMA) birth cohort, on POPs and nutritional biomarkers measured in maternal blood collected at the first trimester of pregnancy and child anthropometric measurements at 7 years of age. Six organochlorine compounds (OCs) [dichlorodiphenyldichloroethylene, hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and polychlorinated biphenyls 138, 153, 180] and four per- and polyfluoroalkyl substances (PFAS) were measured. Nutrients included vitamins (D, B12, and folate), polyunsaturated fatty acids (PUFAs), and dietary carotenoids. Two POPs-nutrients mixtures data sets were established: a) OCs, PFAS, vitamins, and carotenoids (n=660), and b) OCs, PUFAs, and vitamins (n=558). Joint associations of mixtures on obesity were characterized using Bayesian kernel machine regression (BKMR). Relative importance of biomarkers and two-way interactions were identified using gradient boosting machine, hierarchical group lasso regularization, and BKMR. Interactions were further characterized using multivariate regression models in the multiplicative and additive scale.

RESULTS

Forty percent of children had overweight or obesity. We observed a positive overall joint association of both POPs-nutrients mixtures on overweight/obesity risk, with HCB and vitamin B12 the biomarkers contributing the most. Recurrent interactions were found between HCB and vitamin B12 across screening models. Relative risk for a natural log increase of HCB was 1.31 (95% CI: 1.11, 1.54, pInteraction=0.02) in the tertile 2 of vitamin B12 and in the additive scale a relative excess risk due to interaction of 0.11 (95% CI: 0.02, 0.20) was found. Interaction between perfluorooctane sulfonate and β-cryptoxanthin suggested a protective effect of the antioxidant on overweight/obesity risk.

CONCLUSION

These results support that maternal nutritional status may modulate the effect of prenatal exposure to POPs on childhood overweight/obesity. These findings may help to develop a biological hypothesis for future toxicological studies and to better interpret inconsistent findings in epidemiological studies. https://doi.org/10.1289/EHP11258.

Maternal plasma perfluoroalkyl substances concentrations in early pregnancy and cardiovascular development in offspring: A prospective cohort study

BACKGROUND

High maternal plasma perfluoroalkyl substances (PFAS) concentrations has been associated with adverse birth outcomes, but data on early childhood cardiovascular health is limited. This study aimed to assess the potential association between maternal plasma PFAS concentrations during early pregnancy and cardiovascular development in offspring.

MATERIAL AND METHODS

Cardiovascular development was assessed through blood pressure measurement, echocardiography and carotid ultrasound examinations among 957 children from the Shanghai Birth Cohort aged at 4 years old. Maternal plasma concentrations of PFAS were measured at mean gestational age of 14.4 (SD:1.8) weeks. The joint associations between PFAS mixture concentrations and cardiovascular parameters were analyzed using a Bayesian kernel machine regression (BKMR). The potential association of individual PFAS chemicals concentrations was explored using multiple linear regression.

RESULTS

In BKMR analyses, carotid intima media thickness (cIMT), interventricular septum thickness in diastole and systole, posterior wall thicknesses in diastole and systole, and relative wall thickness were significantly lower when all log10-transformed PFAS were fixed at 75th percentile in comparison to at their 50th percentile[Estimated overall Risk:-0.31 (95%CI: -0.42, -0.20), -0.09 (95%CI: -0.11, -0.07), -0.21 (95%CI: -0.26, -0.16), -0.09 (95%CI: -0.11, -0.07), -0.07 (95%CI: -0.10, -0.04) and -0.005 (95%CI: -0.006, -0.004)].Furthermore, maternal plasma concentrations of individual short-chain PFAS was associated with a decrease in left ventricular wall thickness, intraventricular septum thickness and enlarged chamber volume, and long-chain with a decrease in cIMT.

CONCLUSIONS

Our findings suggest that maternal plasma PFAS concentrations during early pregnancy was adversely associated with cardiovascular development in offspring, including thinner cardiac wall thickness and cIMT.

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.

Perfluoroalkyl Mixture Exposure in Relation to Fetal Growth: Potential Roles of Maternal Characteristics and Associations with Birth Outcomes

Perfluoroalkyl substances (PFASs) exposure is suggested to interfere with fetal growth. However, limited investigations considered the roles of parity and delivery on PFASs distributions and the joint effects of PFASs mixture on birth outcomes. In this study, 506 birth cohorts were investigated in Hangzhou, China with 14 PFASs measured in maternal serum. Mothers with higher maternal ages who underwent cesarean section were associated with elevated PFASs burden, while parity showed a significant but diverse influence. A logarithmic unit increment in perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorononane sulfonate (PFNS) was significantly associated with a reduced birth weight of 0.153 kg (95% confidence interval (CI): -0.274, -0.031, p = 0.014), 0.217 kg (95% CI: -0.385, -0.049, p = 0.012), and 0.137 kg (95% CI: -0.270, -0.003, p = 0.044), respectively. Higher perfluoroheptanoic acid (PFHpA) and perfluoroheptane sulphonate (PFHpS) were associated with increased Apgar-1 scores. PFOA (Odds ratio (OR): 2.17, 95% CI: 1.27, 3.71, p = 0.004) and PFNS (OR:1.59, 95% CI: 1.01, 2.50, p = 0.043) were also risk factors to preterm birth. In addition, the quantile-based g-computation showed that PFASs mixture exposure was significantly associated with Apgar-1 (OR: 0.324, 95%CI: 0.068, 0.579, p = 0.013) and preterm birth (OR: 0.356, 95% CI: 0.149, 0.845, p = 0.019). In conclusion, PFASs were widely distributed in the maternal serum, which was influenced by maternal characteristics and significantly associated with several birth outcomes. Further investigation should focus on the placenta transfer and toxicities of PFASs.

Association between phenols and thyroid hormones: The role of iodothyronine deiodinase genes

Previous literature on prenatal phenol exposure and thyroid hormone (TH) alteration is conflicting, and the possible mechanisms of action involved remain unclear. We aimed to examine the association between prenatal phenol exposure and levels of maternal and neonatal THs, as well as the possible role of iodothyronine deiodinase (DIO) gene polymorphisms in this relation. We studied 387 Spanish mother-neonate pairs with measurements of maternal phenols, total triiodothyronine (TT3) and free thyroxine (FT4), maternal and neonatal thyroid-stimulating hormone (TSH), and maternal genotypes for single nucleotide polymorphisms in the DIO1(rs2235544) and DIO2(rs12885300) genes. We implemented multivariate linear and weighted quantile sum (WQS) regressions to examine the association between phenols and THs (including sex-stratified models for neonatal TSH) and investigated effect modification of genotypes in the maternal phenol-TH associations. In single exposure models, we found negative associations between maternal triclosan (TCS) and neonatal TSH (% change [95%CI]: -2.95 [-5.70, -0.11], per twofold phenol increase) - stronger for girls - and less clearly for maternal ethylparaben (EPB) and TSH (-2.27 [-4.55, 0.07]). In phenol mixture models, we found no association with THs. In the genetic interaction models, we found some evidence of effect modification of DIO gene polymorphisms with stronger negative associations between methylparaben (MPB), propylparaben (PPB), butylparaben (BPB) and TT3 as well as bisphenol A (BPA) and FT4 for DIO1(rs2235544)-CC. Stronger inverse associations for genotypes DIO2(rs12885300)-CC and DIO2(rs12885300)-CT and positive ones for DIO2(rs12885300)-TT were also reported for BPA and FT4. In conclusion, we found some evidence of an association between phenols and TSH during pregnancy and at birth in single exposure models, the latter being stronger for girls. Since no association was observed between maternal levels of phenols and TT3 or FT4, the possible role of the genetic background in these associations warrants further investigation.

Dermal uptake: An important pathway of human exposure to perfluoroalkyl substances?

Per- and polyfluoroalkyl substances (PFAS) have been produced and used in a broad range of products since the 1950s. This class, comprising of thousands of chemicals, have been used in many different products ranging from firefighting foam to personal care products and clothes. Even at relatively low levels of exposure, PFAS have been linked to various health effects in humans such as lower birth weight, increased serum cholesterol levels, and reduced antibody response to vaccination. Human biomonitoring data demonstrates ubiquitous exposure to PFAS across all age groups. This has been attributed to PFAS-contaminated water and dietary intake, as well as inadvertent ingestion of indoor dust for adults and toddlers. In utero exposure and breast milk have been indicated as important exposure pathways for foetuses and nursing infants. More recently, PFAS have been identified in a wide range of products, many of which come in contact with skin (e.g., cosmetics and fabrics). Despite this, few studies have evaluated dermal uptake as a possible route for human exposure and little is known about the dermal absorption potential of different PFAS. This article critically investigates the current state-of-knowledge on human exposure to PFAS, highlighting the lack of dermal exposure data. Additionally, the different approaches for dermal uptake assessment studies are discussed and the available literature on human dermal absorption of PFAS is critically reviewed and compared to other halogenated contaminants, e.g., brominated flame retardants and its implications for dermal exposure to PFAS. Finally, the urgent need for dermal permeation and uptake studies for a wide range of PFAS and their precursors is highlighted and recommendations for future research to advance the current understanding of human dermal exposure to PFAS are discussed.

Prenatal Perfluorooctanoic Acid (PFOA) Exposure Is Associated With Lower Infant Birthweight Within the MADRES Pregnancy Cohort

Introduction

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent synthetic chemicals found in household products that can cross the placenta during pregnancy. We investigated whether PFAS exposure during pregnancy was associated with infant birth outcomes in a predominantly urban Hispanic population.

Methods

Serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in 342 prenatal biospecimens (mean gestational age: 21 ± 9 weeks) from participants in the ongoing Maternal And Developmental Risks from Environmental and Social Stressors (MADRES) cohort. PFAS compounds were modeled continuously or categorically, depending on the percentage of samples detected. The birth outcomes assessed were birthweight, gestational age at birth, and birthweight for gestational age (BW-for-GA) z-scores that accounted for parity or infant sex. Single pollutant and multipollutant linear regression models were performed to evaluate associations between PFAS exposures and birth outcomes, adjusting for sociodemographic, perinatal, and study design covariates.

Results

Maternal participants (n = 342) were on average 29 ± 6 years old at study entry and were predominantly Hispanic (76%). Infants were born at a mean of 39 ± 2 weeks of gestation and weighed on average 3,278 ± 522 g. PFOS and PFHxS were detected in 100% of the samples while PFNA, PFOA, and PFDA were detected in 70%, 65%, and 57% of the samples, respectively. PFAS levels were generally lower in this cohort than in comparable cohorts. Women with detected levels of PFOA during pregnancy had infants weighing on average 119.7 g less (95% CI -216.7, -22.7) than women with undetected levels of PFOA in adjusted single pollutant models. PFOA results were also statistically significant in BW-for-GA z-score models that were specific for sex or parity. In models that were mutually adjusted for five detected PFAS compounds, PFOA results remained comparable; however, the association was only significant in BW-for-GA z-scores that were specific for parity (β = -0.3; 95% CI -0.6, -0.01). We found no significant adjusted associations with the remaining PFAS concentrations and the birth outcomes assessed.

Conclusion

Prenatal exposure to PFOA was associated with lower birthweight in infants, suggesting that exposure to these chemicals during critical periods of development might have important implications for children's health.

Concentrations of per- and polyfluoroalkyl substances (PFAS) in human placental tissues and associations with birth outcomes

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants commonly detected in human serum. Previous studies have observed associations between maternal serum PFAS and adverse pregnancy and birth outcomes such as lower birth weight or pre-eclampsia; however, few studies have explored these associations with birth outcomes and placental tissue PFAS concentration. The placenta is a vital contributor to a healthy pregnancy and may be involved in the mechanism of PFAS reproductive toxicity. Our goal was to measure placental PFAS concentrations and examine associations with birth outcomes (e.g., birth weight, gestational duration). Placenta samples (n = 120) were collected during delivery from women enrolled in the Healthy Pregnancy, Healthy Baby cohort (HPHB) in Durham, North Carolina. All placenta samples contained detectable PFAS, with perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) being the most abundant and most frequently detected (all >96% detection frequency). While placental PFAS concentrations did not differ by infant sex, higher PFAS levels were observed in placenta from nulliparous women, suggesting that parity influences the accumulation of PFAS in the placenta. We used linear regression models to examine associations between placental PFAS and birth outcomes. After adjustment for parity, tobacco use, maternal age, and maternal race, we found that placental PFOS was associated with lower birth weight for gestational age in male infants and higher birth weight for gestational age in female infants. Similar findings were seen for PFNA for birth weight for gestational age. These differences in birth outcomes based on infant sex highlight a need to explore mechanistic differences in PFAS toxicity during gestation for male and female infants.

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.

Prenatal Exposure to Per- and Polyfluoroalkyl Substances and Child Growth Trajectories in the First Two Years

BACKGROUND

Pregnant women are ubiquitously exposed to per- and polyfluoroalkyl substances (PFAS). Prenatal exposure to PFAS has been associated with lower birth weight but also with excess adiposity and higher weight in childhood. These mixed findings warrant investigation of the relationship between PFAS and dynamic offspring growth.

OBJECTIVES

To investigate the association between prenatal PFAS exposure and early-life growth trajectories during the first 2 y.

METHODS

Pregnant women (n=3,426) were recruited from 2013 to 2016 from the Shanghai Birth Cohort (SBC) Study, and their children were followed up from birth to 2 y of age. Seven PFAS congeners were quantified in pregnant women's serum during the first trimester. Our study population was restricted to 1,350 children who had five repeated measurements for at least one anthropometric measure. Four anthropometric measures, including weight, length/height, weight-for-length, and head circumference, were evaluated at birth, 42 d, 6 months, 12 months, and 24 months, and standardized into z-scores using the World Health Organization reference. Trajectories of each measure were classified into five groups using group-based trajectory modeling. Multinomial logistic regression was used to estimate odds ratio (OR) and 95% confidence interval (CI) for trajectory groups according to log2-transformed PFAS concentrations, and the moderate-stable group was selected as the reference group for all measures.

RESULTS

Higher prenatal exposure to PFAS was associated with elevated odds for the low-rising weight-for-age z-score (WAZ) trajectory, and the high-rising length-for-age z-score (LAZ) trajectory. Meanwhile, PFAS levels were associated with decreased odds for the low-rising and high-rising weight-for-length z-score (WLZ) trajectories. In addition, the associations of PFAS with growth trajectory groups differed by sex, where males had greater odds for the low-rising and low-stable WAZ trajectories and for the high-stable and low-rising WLZ trajectories. In contrast, inverse associations were consistently observed with trajectories of the high-stable, low-stable, and low-rising head-circumference-for-age z-score (HCZ) in relation to most individual PFAS congeners. PFAS mixtures analysis further confirmed the above findings.

DISCUSSION

Trajectory analysis approach provided insight into the complex associations between PFAS exposure and offspring growth. Future studies are warranted to confirm the present findings with trajectory modeling strategies and understand the clinical significance of these trajectory groups. https://doi.org/10.1289/EHP9875.

Association between maternal per- and polyfluoroalkyl substance exposure and newborn telomere length: Effect modification by birth seasons

BACKGROUND

Telomere length (TL) is an important biomarker of biological aging and disease that may be affected by prenatal exposure to environmental pollutants. Birth seasons have been linked to reproductive and immune-related diseases. Prenatal exposure to per- and polyfluoroalkyl substance (PFAS) has been associated with adverse birth outcomes, but the effects of PFAS and birth seasons on newborn TL are poorly understood.

OBJECTIVES

To explore the individual and combined effects of maternal PFAS exposure on newborn TL, with exploration of the interaction between PFAS and birth seasons on newborn TL.

METHODS

Between June 2015 and May 2018, a total of 499 mother-newborn pairs were recruited for a birth cohort study in Guangxi, China. Maternal blood samples were collected during pregnancy. Nine PFASs were measured by ultraperformance liquid chromatography-mass spectrometry. Newborn TL was assessed using quantitative real-time polymerase chain reaction. Modeling newborn TL as the outcome, multivariable linear regressions were performed for individual PFAS exposures, and Bayesian Kernel Machine Regressions were performed for PFAS mixtures. Furthermore, interaction analyses were conducted to evaluate the effect modification by birth seasons in these relationships.

RESULTS

For both single and multipollutant models, PFASs exposure were inversely associated with newborn TL, although none of the relationships were significant. The mixture of PFASs showed a potential positive trend of combined effect on newborn TL but non-statistically significant. Each ln-transformed unit concentration increase in PFOA was related to a 20.41% (95% CI: -30.44%, -8.93%) shorter TL in spring-born infants but not in those born in other birth seasons. Mothers in the middle and highest tertiles of PFOA exposure had 11.69% and 10.71% shorter TLs in spring-born infants, respectively.

CONCLUSION

Maternal PFAS exposure showed little association with newborn TL. The results suggested potential effect modification by birth season on the association between PFOA exposure and newborn TL.

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.

Longitudinal poly- and perfluoroalkyl substances (PFAS) levels in Dutch infants

BACKGROUND AND AIMS

Per- and polyfluoroalkyl substances (PFAS) are a potential hazard for public health. These man-made-chemicals are non-degradable with an elimination half-life of multiple years, causing accumulation in the environment and humans. Rodent studies demonstrated that PFAS are harmful, especially when present during the critical window in the first months of life. Because longitudinal data during infancy are limited, we investigated longitudinal plasma levels in infants aged 3 months and 2 years and its most important determinants.

METHODS

In 369 healthy term-born Dutch infants, we determined plasma PFOS, PFOA, PFHxS, PFNA and PFDA levels at age 3 months and 2 years, using liquid chromatography-electrospray-ionization-tandem-mass-spectrometry (LC-ESI-MS/MS). We studied the associations with maternal and child characteristics by multiple regression models.

RESULTS

At age 3 months, median plasma levels of PFOS, PFOA, PFHxS, PFNA and PFDA were 1.48, 2.40, 0.43, 0.23 and 0.07 ng/mL, resp. Levels decreased slightly until age 2 years to 1.30, 1.81, 0.40, 0.21 and 0.08 ng/mL, resp. Maternal age, first born, Caucasian ethnicity and exclusive breastfeeding were associated with higher infant's plasma levels at age 3 months. Levels at 3 months were the most important predictor for PFAS levels at age 2 years. Infants with exclusive breastfeeding during the first 3 months of life (EBF) had 2-3 fold higher levels throughout infancy compared to infants with exclusive formula feeding (EFF), with PFOA levels at 3 months 3.72 ng/mL versus 1.26 ng/mL and at 2 years 3.15 ng/mL versus 1.22 ng/mL, respectively.

CONCLUSION

Plasma PFAS levels decreased only slightly during infancy. Higher levels at age 3 months were found in Caucasian, first-born infants from older mothers and throughout infancy in EBF-infants. Our findings indicate that trans-placental transmission and breastfeeding are the most important determinants of PFAS exposure in early life.

LncRNA MEG3 alleviates PFOS induced placental cell growth inhibition through its derived miR-770 targeting PTX3

Perfluorooctane sulfonic acid (PFOS) is a persistent environmental pollutant. Exposure to PFOS has been associated with abnormal fetal development. The long non-coding RNA (lncRNA) has been showed to play a role in fetal growth restriction (FGR), preeclampsia (PE) and other pregnancy complications. Whether the lncRNA contributes to PFOS-induced toxicity in the placenta remains unknown. In this study, we investigated the function of lncRNA MEG3 and its derived miR-770 in PFOS-induced placental toxicity. Pregnant mice received gavage administration of different concentrations of PFOS (0.5, 2.5, and 12.5 mg/kg/day) from GD0 to GD17, and HTR-8/SVneo cells were treated with PFOS in the concentrations of 0, 10^-1, 1, 10 μM. We found that expression levels of miR-770 and its host gene MEG3 were reduced in mice placentas and HTR-8/SVneo cells with exposure of PFOS. A significant hypermethylation was observed at MEG3 promoter in placentas of mice gestational-treated with PFOS. We also confirmed that MEG3 and miR-770 overexpression alleviated the cell growth inhibition induced by PFOS. Furthermore, PTX3 (Pentraxin 3) was identified as the direct target of miR-770 and it was enhanced after PFOS exposure. In summary, our results suggested that MEG3 alleviate PFOS-induced placental cell inhibition through MEG3/miR-770/PTX3 axis.

Maternal exposure to endocrine disrupting chemicals (EDCs) and preterm birth: A systematic review, meta-analysis, and meta-regression analysis

Preterm birth is the second most common cause of death in children under 5 years of age. The etiology of preterm birth has not yet been elucidated. Although maternal exposure to endocrine disrupting chemicals (EDCs) may increase the risk for preterm birth, associations have not been confirmed. We performed a meta-analysis to elucidate the relationships between maternal exposure to EDCs and preterm birth. A systematic search of PubMed, Ovid-EMBASE, and the Cochrane Library (CENTRAL) for relevant published studies providing quantitative data on the association between maternal EDC exposure and preterm birth in humans was conducted in July 2021. To calculate the overall estimates, we pooled the adjusted regression coefficients with 95% confidence intervals (CIs) from each study by the inverse variance method. A total of 59 studies were included. The pooled results indicated that maternal exposure to metals (OR, 1.23; 95% CI, 1.17 to 1.29) and phthalates (OR, 1.31; 95% CI, 1.21 to 1.42) was related to an increased risk for preterm birth. Specifically, maternal exposure to lead, cadmium, chromium, copper and manganese appeared to be correlated with an elevated risk for preterm birth. Additionally, maternal exposure to monoethyl phthalate (MEP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), monobenzyl phthalate (MBzP), and di (2-ethylhexyl) phthalate (DEHP) was also associated with preterm birth. In conclusion, maternal exposure to metals and phthalates may increase the risk for preterm birth based on current evidence.

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.

Associations of paternal and maternal per- and polyfluoroalkyl substances exposure with cord serum reproductive hormones, placental steroidogenic enzyme and birth weight

BACKGROUND

Maternal per- and polyfluoroalkyl substances (PFAS) exposure has been associated with placental function and fetal growth measures. However, few studies have simultaneously investigated paternal and maternal exposure effects.

OBJECTIVES

We evaluated the associations of paternal or maternal PFAS levels with placental function and fetal growth measures.

METHODS

We studied six PFAS measured in matched parental serums collected within 3 days before delivery in a birth cohort from LaiZhouWan, China. Outcomes evaluated include cord serum estradiol (n = 351), testosterone (n = 349), placental P450aromatase (n = 125), and birth weight (n = 369). Multiple linear regression was applied to estimate the associations for these outcomes according to paternal or maternal PFAS level after adjusting for socio-demographic confounders. Co-adjustment analysis of both paternal and maternal PFAS in the same model was performed.

RESULTS

Maternal and paternal PFAS levels were correlated (Spearman's r = 0.23-0.45). Maternal PFAS were associated with increased estradiol (e.g.

, PFOA

β = 0.03, 95%CI: 0.00, 0.07), testosterone (e.g.

, PFUA

β = 0.14, 95%CI: 0.00, 0.27), and P450aromatase (e.g.

, PFOA

β = 0.13, 95%CI: 0.04, 0.22). Maternal PFAS were also associated with a lower mean of birth weight but the estimated 95% CI included the null. Paternal PFAS were not associated with any of the outcomes evaluated.

CONCLUSIONS

Several maternal PFAS were associated with fetal steroid hormones and placental enzymes. Despite a correlation of PFAS level within the couples, no association was found for paternal PFAS exposure on these outcomes. The findings suggest the intrauterine PFAS exposure effect on fetal endocrine hormones and growth is unlikely to be confounded by exposure sources or familial factors shared within the couples.

The relationship between maternal perfluoroalkylated substances exposure and low birth weight of offspring: a systematic review and meta-analysis

Some studies have shown that maternal perfluoroalkylated substances (PFAS) exposure may be associated with low birth weight (LBW) of offspring. We conducted a meta-analysis to assess the association between maternal PFASs exposure and LBW in offspring. The researchers searched PubMed, Science Direct, Scopus, Google Scholar, Web of Science, and Embase to find all the articles before October 2020. The Newcastle-Ottawa Scale was used to evaluate the quality of the studies. Finally, six articles were included for meta-analysis. Our meta-analysis showed no significant correlation between maternal perfluorooctanoic acid (PFOA) exposure and LBW of offspring: odds ratio (OR) = 0.90, 95% confidence interval (95% CI) = 0.80-1.01, with low heterogeneity (I² = 18.4%, P = 0.289); there was a significant positive correlation between maternal perfluorooctane sulfonate (PFOS) exposure and LBW of offspring (OR = 1.32, 95% CI = 1.09-1.55) with no heterogeneity (I² = 0.00%, P = 0.570). The grouping analysis of PFOS showed was a significant positive correlation between maternal PFOS exposure and LBW of offspring in American (OR = 1.44, 95% CI = 1.15-1.72). This study provided a systematic review and meta-analysis evidence for the relationship between maternal PFASs exposure and LBW of offspring through a small number of studies. Researchers should conduct further studies between different regions.

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.

Association between maternal exposure to perfluoroalkyl and polyfluoroalkyl substances and risks of adverse pregnancy outcomes: A systematic review and meta-analysis

Perfluoroalkyl and polyfluoroalkyl substances (PFASs), a class of persistent endocrine-disrupting chemicals, are widely used in consumer products due to their unique amphiphilic properties. Previous epidemiological studies suggest association of maternal PFASs exposure and adverse pregnancy outcomes, while evidences about the association are inconsistent. The aim of this systematic review and meta-analysis is to assess the relationship of maternal PFASs exposure and adverse pregnancy outcomes. Twenty-one relevant studies were identified from three databases before 2020. The quality, heterogeneity and possibility of publication bias of included studies were evaluated by Newcastle-Ottawa Scale, Q-statistic and Begg's test, respectively. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were obtained by means of random-effects meta-analysis models. Meta-analysis results revealed that maternal exposure to perfluorooctane sulfonic acid (PFOS) may have a positive association with preterm birth (OR = 1.20, 95% CI: 1.04, 1.38). The pooled estimates also showed limited evidence of association between maternal perfluorononanoic acid (PFNA) exposure and miscarriage (OR = 1.48, 95% CI: 0.92, 2.38) with obvious heterogeneity (I² = 93.9, p < 0.01). However, no such significant associations were found between the other PFASs and miscarriage, stillbirth and preterm birth. In addition, the subgroup analyses showed that studies on the relationship of maternal PFASs exposure and miscarriage were mainly contributed by developed countries. The meta-analysis results indicated maternal exposure to PFOS can increase the risk of preterm birth. The results of the included studies are inconsistent and the effects of PFASs on human health are complex. Further studies with enough samples are required to verify these findings.

Prenatal perfluoroalkyl substance exposure and neuropsychological development throughout childhood: The INMA Project

BACKGROUND

Perfluoroalkyl substances (PFASs) have been related to neurodevelopmental toxicity in animals. However, human studies are inconclusive.

OBJECTIVES

To evaluate the association between prenatal PFAS exposure and neuropsychological development during childhood.

METHODS

1240 mother-child pairs from the Spanish INMA Project were analyzed. Perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorononanoic acid (PFNA) were measured in first-trimester maternal plasma. Neuropsychological development was assessed at 14 months, 4-5 and 7 years covering four domains: general cognitive, general motor, attention, and working memory. Associations were studied by means of multivariable regression analyses.

RESULTS

PFHxS, PFOA, PFOS, and PFNA medians were: 0.6, 2.4, 6.1, and 0.7 ng/mL. Higher PFAS prenatal exposure was associated with worse motor development at 14 months, especially in the case of PFHxS (β[95%CI]: -1.49[-2.73, -0.24]) and to a lesser extent PFOS (-1.25[-2.62, 0.12]). There was also a marginal positive association between general cognitive development at 4-5 years and PFOS (1.17[-0.10, 2.43]) and PFNA (0.99[-0.13, 2.12]). No clear associations for other neuropsychological outcomes or any sex differences were found.

DISCUSSION

This study shows no clear-cut evidence of an association between prenatal PFAS exposure and adverse neuropsychological development in children up to the age of 7 years.

Maternal Perfluoroalkyl Substances, Thyroid Hormones, and DIO Genes: A Spanish Cross-sectional Study

Results of studies on perfluoroalkyl substances (PFASs) and thyroid hormones (THs) are heterogeneous, and the mechanisms underlying the action of PFASs to target THs have not been fully characterized. We examined the relation between first-trimester maternal PFAS and TH levels and the role played by polymorphisms in the iodothyronine deiodinase 1 (DIO1) and 2 (DIO2) genes in this association. Our sample comprised 919 pregnant Spanish women (recruitment = 2003-2008) with measurements of perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), thyroid-stimulating hormone (TSH), total triiodothyronine (TT3), and free thyroxine (FT4), and we genotyped for single-nucleotide polymorphisms in the DIO1 (rs2235544) and DIO2 (rs12885300) genes. We performed multivariate regression analyses between PFASs and THs and included the interaction term PFAS-genotypes in the models. PFHxS was associated with an increase in TSH (% change in outcome [95% CI] per 2-fold PFAS increase = 6.09 [-0.71, 13.4]), and PFOA and PFNA were associated with a decrease in TT3 (-7.17 [-13.5, -0.39] and -6.28 [-12.3, 0.12], respectively). We found stronger associations between PFOA, PFNA, and TT3 for DIO1-CC and DIO2-CT genotypes, although interaction p-values were not significant. In conclusion, this study found evidence of an inverse association between PFOA and TT3 levels. No clear effect modification by DIO enzyme genes was observed.

Serum levels of perfluorooctanoic acid and perfluorooctane sulfonic acid in pregnant women: Maternal predictors and associations with birth outcomes in the PIPA Project

AIM

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent pollutants associated with adverse birth outcomes. This study aimed to identify predictors of blood PFOA and PFOS concentrations in pregnant women and to estimate their associations with birth outcomes in Brazil.

METHODS

We conducted a cross-sectional study with 139 pregnant women enrolled in the pilot study of the Rio Birth Cohort Study on Environmental Exposure and Childhood Development (PIPA Project). Multiple linear regression was used to estimate associations between PFOA and PFOS with maternal predictors and birth outcomes.

RESULTS

Higher levels of PFOA were observed in women aged 16-19 and 20-39 years, while fish consumption from 0.6 to 2.0 times per week was associated with lower levels of the substance. PFOS levels were higher in women living in houses with up to four rooms but lower in those who reported passive exposure to smoking. Increased newborn length and head circumference were also associated with higher maternal levels of PFOA.

CONCLUSIONS

In our study, age, fish consumption, passive smoking, and the number of rooms in the house were predictors of maternal PFAS levels. However, we did not observe significant associations between maternal plasma PFAS concentrations and birth outcomes.

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.

Exposure to toxic metals and per- and polyfluoroalkyl substances and the risk of preeclampsia and preterm birth in the United States: a review

Preeclampsia and preterm birth are among the most common pregnancy complications and are the leading causes of maternal and fetal morbidity and mortality in the United States. Adverse pregnancy outcomes are multifactorial in nature and increasing evidence suggests that the pathophysiology behind preterm birth and preeclampsia may be similar-specifically, both of these disorders may involve abnormalities in placental vasculature. A growing body of literature supports that exposure to environmental contaminants in the air, water, soil, and consumer and household products serves as a key factor influencing the development of adverse pregnancy outcomes. In pregnant women, toxic metals have been detected in urine, peripheral blood, nail clippings, and amniotic fluid. The placenta serves as a "gatekeeper" between maternal and fetal exposures, because it can reduce or enhance fetal exposure to various toxicants. Proposed mechanisms underlying toxicant-mediated damage include disrupted placental vasculogenesis, an up-regulated proinflammatory state, oxidative stressors contributing to prostaglandin production and consequent cervical ripening, uterine contractions, and ruptured membranes and epigenetic changes that contribute to disrupted regulation of endocrine and immune system signaling. The objective of this review is to provide an overview of studies examining the relationships between environmental contaminants in the US setting, specifically inorganic (eg, cadmium, arsenic, lead, and mercury) and organic (eg, per- and polyfluoroalkyl substances) toxicants, and the development of preeclampsia and preterm birth among women in the United States.

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances and birth outcomes: A longitudinal cohort with repeated measurements

BACKGROUND

Previous studies on perfluoroalkyl and polyfluoroalkyl substances (PFAS) showed inconsistent results when biological samples were collected in different time of pregnancy.

OBJECTIVES

To describe the change of PFAS concentration during pregnancy and to identify a sensitive window for adverse effects of PFAS on the fetus.

METHODS

A total of 255 pregnant women were selected from the Shanghai Birth Cohort (SBC). We quantified 10 PFAS with high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) in maternal plasma at three trimesters and cord blood at delivery. Multiple linear regression analyses were used to analyze the association between PFAS and birth outcomes, including birth weight, birth length, and head circumference.

RESULTS

The concentrations of most PFAS declined substantially during pregnancy. PFOS, PFNA, PFDA, PFUA and PFDoA were negatively related to birth length only in the first trimester. The coefficients and 95% confidence intervals (CI) of birth length change with a log-unit increase in PFOS, PFNA, PFDA, PFUS and PFDoA concentrations were -0.27 cm (-0.51, -0.02), -0.34 cm (-0.65, -0.03), -0.27 cm (-0.53, -0.01), -0.29 cm (-0.58, -0.01), and -0.54 cm (-1.00, -0.08), respectively. The effects were only observed for female fetuses. No association between PFAS and birth weight or head circumference was observed.

CONCLUSION

The concentrations of most PFAS in the maternal circulation declined during pregnancy. There were negative associations between several PFAS and birth length. The sensitive window of exposure appeared to be the first trimester. The association was stronger for female fetuses.

Concentrations of persistent organic pollutants in blood of the Spanish population: Temporal trend

The present article reviews the human biomonitoring studies conducted in Spain to assess exposure to persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), polybrominated diphenyl ethers (PBDEs), and per- and poly-fluoroalkyl substances (PFAS). In general terms, important variations in POPs concentrations between Spanish regions and specific populations were observed, while no associations between exposure to POPs and adverse health outcomes were found. Moreover, occupational exposure seems not to be a risk factor with regards to POPs exposure in the Spanish population. The present review highlights the importance of conducting human biomonitoring studies to find possible associations between POPs and adverse health effects.

PFAS concentration during pregnancy in relation to cardiometabolic health and birth outcomes

INTRODUCTION

Poly- and perfluoroalkyl substances (PFAS) are persistent organic pollutants with pervasive exposure and suspected associations with metabolic abnormalities and adverse pregnancy outcomes. The goal of the present study was to examine the relationship between serum-PFAS concentrations measured in late pregnancy with relevant outcomes.

METHODS

The study sample included 433 pregnant women enrolled in the Vanguard Pilot Study of the National Children's Study. Six PFAS were measured in primarily third trimester serum, as well as fasting insulin, total cholesterol, and triglycerides. The PFAS were examined in quartiles in relation to serum biomarkers, gestational age at birth and birth weight standardized for gestational age using multivariable-adjusted regression models.

RESULTS

Over 98% of the study population had detectable concentrations of four of the PFAS, and concentrations varied by race/ethnicity. Total cholesterol was positively associated with PFDA, PFNA, and PFOS, and triglycerides with PFDA, PFNA, PFOS, and PFOA, but PFAS were not associated with fasting insulin in adjusted models. Only PFNA was associated with an increased odds of birth at <37 weeks gestation. PFAS were generally not associated with birth weight, though PFHxS was associated with the first quartile of birth weight among males only.

CONCLUSIONS

This study of pregnant U.S. women supports the ubiquitous exposure to PFAS and positive associations between PFAS exposure with serum-lipid concentrations. PFAS were largely unassociated with gestational age at birth and birth weight, though PFNA was associated with preterm birth. The results support the vulnerability to PFAS exposure of pregnancy.