Per- and polyfluoroalkyl substances exposure is associated with polycystic ovary syndrome risk among women attending a fertility clinic.

Previous studies reported that exposures to per- and polyfluoroalkyl substances (PFAS), largely in higher exposed populations, were associated with elevated risk of polycystic ovary syndrome (PCOS). However, studies evaluating PCOS risk in populations with lower background exposures to PFAS are limited. This study aimed to examine the associations between serum PFAS concentrations and PCOS risk among women attending a U.S. academic fertility clinic during 2005-2019. A total of 502 females who sought fertility evaluation and assisted reproduction treatments were included. Nine PFAS were quantified in non-fasting serum samples collected at study entry. Diagnosis of PCOS was based on the Rotterdam criteria. We used logistic regression to examine the odds ratio (OR) of PCOS in relation to individual PFAS concentrations (continuous and by tertiles) and quantile g-computation (QGC) and Bayesian Kernel Machine Regression (BKMR) to examine the joint associations of PFAS mixture with PCOS. Most participants were White and had a graduate degree or higher. Per doubling of serum perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) concentrations were associated with higher odds of PCOS [OR (95%CI): 1.70 (1.06, 2.81) and 1.45 (1.02, 2.08) for PFOS and PFHxS respectively]. There was a dose-response relationship of PFOS with PCOS risk (p of trend by PFOS tertiles = 0.07). Both QGC and BKMR identified PFOS as the most important contributor among the mixture to PCOS risk. No clear joint effects were found for other PFAS or PFAS mixtures on PCOS risk. Our findings are consistent with existing evidence in populations with higher background PFAS concentrations and highlight the adverse effects of PFAS exposure on reproductive health. Findings can inform public health measures and clinical care to protect populations vulnerable to PCOS, in part, due to environmental exposures.

Gestational exposure to environmental chemicals and epigenetic alterations in the placenta and cord blood mononuclear cells.

Background: Exposure to environmental chemicals such as phthalates, phenols, and polycyclic aromatic hydrocarbons (PAHs) during pregnancy can increase the risk of adverse newborn outcomes. We explored the associations between maternal exposure to select environmental chemicals and DNA methylation in cord blood mononuclear cells (CBMC) and placental tissue (maternal and fetal sides) to identify potential mechanisms underlying these associations. Method: This study included 75 pregnant individuals who planned to give birth at the University of Cincinnati Hospital between 2014 and 2017. Maternal urine samples during the delivery visit were collected and analyzed for 37 biomarkers of phenols (12), phthalates (13), phthalate replacements (4), and PAHs (8). Cord blood and placenta tissue (maternal and fetal sides) were also collected to measure the DNA methylation intensities using the Infinium HumanMethylation450K BeadChip. We used linear regression, adjusting for potential confounders, to assess CpG-specific methylation changes in CBMC (n = 54) and placenta [fetal (n = 67) and maternal (n = 68) sides] associated with gestational chemical exposures (29 of 37 biomarkers measured in this study). To account for multiple testing, we used a false discovery rate q-values < 0.05 and presented results by limiting results with a genomic inflation factor of 1±0.5. Additionally, gene set enrichment analysis was conducted using the Kyoto Encyclopedia of Genes and Genomics pathways. Results: Among the 29 chemical biomarkers assessed for differential methylation, maternal concentrations of PAH metabolites (1-hydroxynaphthalene, 2-hydroxyfluorene, 4-hydroxyphenanthrene, 1-hydroxypyrene), monocarboxyisononyl phthalate, mono-3-carboxypropyl phthalate, and bisphenol A were associated with altered methylation in placenta (maternal or fetal side). Among exposure biomarkers associated with epigenetic changes, 1-hydroxynaphthalene, and mono-3-carboxypropyl phthalate were consistently associated with differential CpG methylation in the placenta. Gene enrichment analysis indicated that maternal 1-hydroxynaphthalene was associated with lipid metabolism and cellular processes of the placenta. Additionally, mono-3-carboxypropyl phthalate was associated with organismal systems and genetic information processing of the placenta. Conclusion: Among the 29 chemical biomarkers assessed during delivery, 1-hydroxynaphthalene and mono-3-carboxypropyl phthalate were associated with DNA methylation in the placenta. Supplementary Information: The online version contains supplementary material available at 10.1186/s43682-024-00027-7.

Predictors of Serum Per- and Polyfluoroalkyl Substances Concentrations among U.S. Couples Attending a Fertility Clinic.

Previous studies have examined the predictors of PFAS concentrations among pregnant women and children. However, no study has explored the predictors of preconception PFAS concentrations among couples in the United States. This study included 572 females and 279 males (249 couples) who attended a U.S. fertility clinic between 2005 and 2019. Questionnaire information on demographics, reproductive history, and lifestyles and serum samples quantified for PFAS concentrations were collected at study enrollment. We examined the PFAS distribution and correlation within couples. We used Ridge regressions to predict the serum concentration of each PFAS in females and males using data of (1) socio-demographic and reproductive history, (2) diet, (3) behavioral factors, and (4) all factors included in (1) to (3) after accounting for temporal exposure trends. We used general linear models for univariate association of each factor with the PFAS concentration. We found moderate to high correlations for PFAS concentrations within couples. Among all examined factors, diet explained more of the variation in PFAS concentrations (1-48%), while behavioral factors explained the least (0-4%). Individuals reporting White race, with a higher body mass index, and nulliparous women had higher PFAS concentrations than others. Fish and shellfish consumption was positively associated with PFAS concentrations among both females and males, while intake of beans (females), peas (male), kale (females), and tortilla (both) was inversely associated with PFAS concentrations. Our findings provide important data for identifying sources of couples' PFAS exposure and informing interventions to reduce PFAS exposure in the preconception period.

Association between per- and polyfluoroalkyl substances exposure and thyroid function biomarkers among females attending a fertility clinic.

Per- and polyfluoroalkyl substances (PFAS) exposure was associated with changes in thyroid function in pregnant mothers and the general population. Limited such evidence exists in other susceptible populations such as females with fertility problems. This cross-sectional study included 287 females seeking medically assisted reproduction at a fertility clinic in Massachusetts, United States, between 2005 and 2019. Six long-alkyl chain PFAS, thyroid hormones, and autoimmune antibodies were quantified in baseline serum samples. We used generalized linear models and quantile g-computation to evaluate associations of individual PFAS and their total mixture with thyroid biomarkers. Most females were White individuals (82.7%), had graduate degrees (57.8%), and nearly half had unexplained subfertility (45.9%). Serum concentrations of all examined PFAS and their mixture were significantly associated with 2.6%-5.6% lower total triiodothyronine (TT3) concentrations. Serum concentrations of perfluorononanoate (PFNA), perfluorodecanoate (PFDA), and perfluoroundecanoate (PFUnDA), and of the total mixture were associated with higher ratios of free thyroxine (FT4) to free triiodothyronine (FT3). No associations were found for PFAS and TSH or autoimmune antibodies. Our findings support the thyroid-disrupting effect of long alkyl-chain PFAS among a vulnerable population of subfertile females.

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.