Environmental pollutants, a possible etiology for premature ovarian insufficiency: a narrative review of animal and human data

Associations of Essential and Non-Essential Trace Elements' Levels in the Blood, Serum, and Urine in Women with Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is poorly understood, with causes identified in only 25% of cases. Emerging evidence suggests links between trace elements (TEs) and POI. This study is the first to compare concentrations of manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) across urine, serum, and whole blood in women with POI compared to healthy controls (HC), aiming to explore their distribution and potential associations with POI. This cross-sectional-case-control study enrolled 81 participants (40 POI patients and 41 healthy controls) at the University Medical Centre Ljubljana, Slovenia. Blood and urine samples were collected to quantify basic biochemical parameters using standard clinical chemistry methods and concentrations of Mn, Cu, Zn, Se, Mo, As, Cd, Hg, and Pb using inductively coupled plasma-mass spectrometry (ICP-MS). Participants also completed questionnaires on socio-demographics, medical history, lifestyle, and nutrition. Data was analyzed using the Mann-Whitney U test, Student's t-tests, Fisher exact test, logistic regression models adjusted on body mass index (BMI), age, hematocrit, and Kendall's tau correlation. Women with POI had significantly higher BMI and red blood cell (RBC) indices, including hemoglobin, hematocrit, and red cell distribution width (RDW), compared to controls. A larger proportion of POI patients resided in rural agricultural areas. Liver and kidney function assessments showed no significant differences between the groups. Adjusted models revealed that POI patients had significantly lower urinary levels of Cu, Zn, Se, Mo, Cd, Hg, and Pb than controls, while whole blood Mn levels were higher. Serum Cu levels were significantly elevated in POI patients, whereas Pb, Cd, and Hg were lower. No significant differences were observed for As. Correlation analysis showed several strong to moderate associations among TEs across biofluids, but only weak correlations were found between TEs and demographic or biochemical factors. This study suggests potential associations between TEs and POI in women. Notably, most TEs (Zn, Se, Cu, Mo, Cd, Hg, Pb) were significantly lower in the urine of the POI group, while Cu, Cd, Hg, and Pb showed significant differences in both urine and serum.

PFAS and menopause onset: Is it just a matter of reverse causation? Cross-sectional and longitudinal analyses in highly exposed women in the Veneto Region

INTRODUCTION

Several cross-sectional studies have linked perfluoroalkyl substances (PFAS) to prevalence of menopause. These findings might be influenced by reverse causation mechanism, making longitudinal studies more suitable. However, existing longitudinal studies are limited and present conflicting results.

AIM

This study investigates the association between PFAS and both prevalence and incidence of menopause, using longitudinal designs to limit the impact of reverse causation.

METHODS

A surveillance program on a PFAS highly exposed population in the Veneto region started in 2017 with two rounds of screening, on average 3.8 years apart. Women who participated in the first screening (n = 11,046) were included in the cross-sectional analysis. Multivariate logistic regression models were used to estimate the Odds Ratios (ORs) of menopause associated with exposure to different PFAS. For incidence analysis a retrospective-prospective design used PFOA concentrations reconstructed to 2013 (n = 8536), and a prospective design involved women participating in both screenings (n = 1709), evaluating their baseline concentrations of PFOA, PFOS, and PFHxS. Cox proportional hazards models with age as the timescale were used to estimate Hazard Ratios (HRs), adjusting for sociodemographic and lifestyle factors.

RESULTS

Increased menopause prevalence was associated with higher ln-concentrations of PFOA, PFOS, and PFHxS, with ORs of 1.31 (CI: 1.25-1.38), 1.51 (CI: 1.38-1.66), and 1.42 (CI: 1.34-1.51), respectively. The retrospective-prospective study showed increased risk of menopause in higher PFOA reconstructed quartiles, with HRs of 1.01 (CI: 0.87-1.18), 1.17 (CI: 1.02-1.37), and 1.07 (CI: 0.93-1.23) for the second, third and fourth quartiles. The prospective longitudinal study found no association between PFAS and menopause onset.

CONCLUSIONS

Our results showed a strong cross-sectional association between PFAS exposure and menopause, a weak positive association in the retrospective-prospective study, and no association in the prospective study. This suggests that cross-sectional associations may largely result from reverse causality due to early menopause on reducing PFAS excretion.

Prenatal exposure to diethylstilbestrol has multigenerational effects on folliculogenesis

Diethylstilbestrol (DES) is an estrogenic endocrine disrupting chemical (EDC) that was prescribed to millions of pregnant women worldwide, leading to increased rates of infertility in the exposed offspring. We have previously demonstrated that this reduced fertility persists for multiple generations in the mouse. However, how altered ovarian function contributes to this infertility is unknown. Therefore, this study sought to determine if DES exposure promotes two common ovarian disorders, primary ovarian insufficiency (POI) and polycystic ovary syndrome, contributing to the reduced fertility in DES offspring. Moreover, we investigated if these impacts are transgenerational. Gestating mice were exposed to 100 µg/kg DES, and ovarian morphology was observed in F1-F3 female descendants. F1 females trended towards fewer primordial and more secondary follicles and similarly, F2 females had fewer primordial and significantly more secondary follicles compared to controls. No differences in follicle proportions were observed in the F3. Moreover, DES exposure did not increase follicular cysts. These results show that DES accelerates folliculogenesis, indicative of a POI phenotype and that this is likely contributing to the reduced fertility observed in DES descendants. Moreover, this study highlights the ability of estrogenic EDCs to disrupt folliculogenesis, which may exacerbate the onset of POI in women already at risk.

Endocrine disruptor chemicals exposure and female fertility declining: from pathophysiology to epigenetic risks

Over the last decades, human infertility has become a major concern in public health, with severe societal and health consequences. Growing evidence shows that endocrine disruptors chemicals (EDCs) have been considered as risk factors of infertility. Their presence in our everyday life has become ubiquitous because of their universal use in food and beverage containers, personal care products, cosmetics, phytosanitary products. Exposure to these products has an impact on human reproductive health. Recent studies suggest that women are more exposed to EDCs than men due to higher chemical products use. The aim of this review is to understand the possible link between reproductive disorders and EDCs such as phthalates, bisphenol, dioxins, and pesticides. In women, the loss of endocrine balance leads to altered oocyte maturation, competency, anovulation and uterine disorders, endometriosis, premature ovarian insufficiency (POI) or embryonic defect and decreases the in vitro fertilization outcomes. In this review, we consider EDCs effects on the women's reproductive system, embryogenesis, with a focus on associated reproductive pathologies.

Primary ovarian insufficiency consequence of autoimmune diseases: a bidirectional two-sample Mendelian randomization study

Background

Observational studies suggest the risk of primary ovarian insufficiency (POI) is increased in autoimmune disorders (AIDs), but it is unclear whether there is a causal relationship. Therefore, we aimed to investigate the bidirectional causality between 20 AIDs and POI using Mendelian randomization (MR) analysis.

Methods

A bidirectional two-sample MR investigation was designed by using publicly accessible summary-level data from genome-wide association studies (GWAS). The inverse variance weighted (IVW) method was performed as the main analysis, supplemented by several sensitivity analyses. Cochran Q test was used to evaluate SNP estimate heterogeneity. MR-Egger and MR-PRESSO methods were utilized to detect horizontal pleiotropy.

Results

The MR analyses revealed that genetically determined coeliac disease (CeD) (OR = 1.124, 95% CI 1.033-1.224, P = 0.007), vitiligo (OR = 1.092, 95% CI 1.003-1.188; P = 0.042), systemic lupus erythematosus (SLE) (OR = 1.122, 95% CI 1.030-1.223, P = 0.008), and selective immunoglobulin A deficiency (SIgAD) (OR = 0.866, 95% CI: 0.776-0.967, P = 0.011) exhibited significant causal relationships with POI. We also found suggestive evidence of positive effect of Addison's disease (AD) towards POI (OR5e-6 = 1.076, 95% CI 1.002-1.154, P = 0.043).

Conclusion

This comprehensive MR analysis indicated that SLE, CeD, vitiligo, and AD caused an increased risk of POI, SIgAD was associated with a decreased risk of POI. These insights carry profound clinical implications, particularly emphasizing the early intervention for women with AIDs/POI who wish to preserve their reproductive potential or plan for future pregnancies.

Gestational exposure to arsenic reduces female offspring fertility by impairing the repair of DNA double-strand breaks and synapsis formation in oocytes

Arsenic is a pollutant that can cross the placenta; however, research on the effects of arsenic exposure during pregnancy on the fertility of female offspring is limited. To address this gap, we developed a mouse model to investigate the relationship between arsenic exposure during pregnancy and fertility in female offspring. Our fertility assessment revealed that gestational exposure to 1 mg/kg arsenic or higher (10 mg/kg) resulted in reduction in litter size, ovarian volume, and multistage-follicle number in female offspring. By assessing the in vitro developmental capacity of oocytes and zygotes, we confirmed that the reduced fertility was due not to impaired oocyte quality but rather to a reduction in oocyte quantity. Arsenic exposure impedes synapsis formation in MPI and compromises homologous recombination-mediated repair of double-strand breaks, resulting in fewer crossovers. This disruption activates the pachytene-checkpoint, hindering the progression of the MPI and resulting in the elimination of defective oocytes through p-Chk2 activation. Our study reveals for the first time the detrimental effects of arsenic exposure during pregnancy on the fertility of female offspring, underscoring the urgent need to prevent such exposure to safeguard reproductive health.

MicroRNAs as Biomarkers and Therapeutic Targets in Female Infertility

The study of microRNAs (miRNAs) has emerged in recent decades as a key approach to understanding the pathophysiology of many diseases, exploring their potential role as biomarkers, and testing their use as future treatments. Not only have neurological, cardiovascular diseases, or cancer benefited from this research but also infertility. Female infertility, as a disease, involves alterations at multiple levels, such as ovarian and uterine alterations. This review compiles the latest studies published in humans that link female disorders that affect fertility with altered miRNA profiles. Studies on ovarian alterations, including diminished ovarian reserve (DOR), poor ovarian response to stimulation (POR), premature ovarian insufficiency (POI), and polycystic ovary syndrome (PCOS), are summarized and classified based on the expression and type of sample analyzed. Regarding uterine disorders, this review highlights upregulated and downregulated miRNAs primarily identified as biomarkers for endometriosis, adenomyosis, decreased endometrial receptivity, and implantation failure. However, despite the large number of studies in this field, the same limitations that reduce reproducibility are often observed. Therefore, at the end of this review, the main limitations of this type of study are described, as well as specific precautions or safety measures that should be considered when handling miRNAs.

Environmental Exposure to Per- and Polyfluorylalkyl Substances (PFASs) and Reproductive Outcomes in the General Population: A Systematic Review of Epidemiological Studies

This Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) systematic review synthesized effects of background levels of per- and polyfluorylalkyl substance (PFAS) levels on reproductive health outcomes in the general public: fertility, preterm birth, miscarriage, ovarian health, menstruation, menopause, sperm health, and in utero fetal growth. The inclusion criteria included original research (or primary) studies, human subjects, and investigation of outcomes of interest following non-occupational exposures. It drew from four databases (Web of Science, PubMed, Embase and Health and Environmental Research Online (HERO)) using a standardized search string for all studies published between 1 January 2017 and 13 April 2022. Risk of bias was assessed by two independent reviewers. Data were extracted and reviewed by multiple reviewers. Each study was summarized under its outcome in terms of methodology and results and placed in context, with recommendations for future research. Of 1712 records identified, 30 were eligible, with a total of 27,901 participants (33 datasets, as three studies included multiple outcomes). There was no effect of background levels of PFAS on fertility. There were weakly to moderately increased odds of preterm birth with higher perfluorooctane sulfonic acid (PFOS) levels; the same for miscarriage with perfluorooctanoic acid (PFOA) levels. There was limited yet suggestive evidence for a link between PFAS and early menopause and primary ovarian insufficiency; menstrual cycle characteristics were inconsistent. PFAS moderately increased odds of PCOS- and endometriosis-related infertility, respectively. Sperm motility and DNA health were moderately impaired by multiple PFAS. Fetal growth findings were inconsistent. This review may be used to inform forthcoming drinking water standards and policy initiatives regarding PFAS compounds and drinking water. Future reviews would benefit from more recent studies. Larger studies in these areas are warranted. Future studies should plan large cohorts and open access data availability to capture small effects and serve the public. Funding: Great Lakes Water Authority (Detroit, MI), the Erb Family Foundation through Healthy Urban Waters at Wayne State University (Detroit, MI), and Wayne State University CLEAR Superfund Research (NIH P42ES030991).

Oestrogens, adipose tissues and environmental exposures influence obesity and diabetes across the lifecycle

Endogenous oestrogens regulate essential functions to include menstrual cycles, energy balance, adipose tissue distribution, pancreatic β-cell function, insulin sensitivity and lipid homeostasis. Oestrogens are a family of hormones which include oestradiol (E2), oestrone (E1) and oestriol (E3). Oestrogens function by binding and activating oestrogen receptors (ERs). Phytoestrogens are plant-derived compounds which exhibit oestrogenic-like activity and can bind to ERs. Phytoestrogens exert potential oestrogenic-like benefits; however, their effects are context-dependent and require cautious consideration regarding generalised health benefits. Xenoestrogens are synthetic compounds which have been determined to disrupt endocrine function through binding to ERs. Xenoestrogens enter the body through various routes and given their chemical structure they can accumulate, posing long-term health risks. Xenoestrogens interfere with endogenous oestrogens and their functions contributing to conditions like cancer, infertility, and metabolic disorders. Understanding the interplay between endogenous and exogenous oestrogens is critical in order to determine their potential health consequences and requires further investigation. This manuscript provides a summary of the role endogenous oestrogens have in regulating metabolic functions. Additionally, we discuss the impact phytoestrogens and synthetic xenoestrogens have on biological systems across various life stages. We highlight their mechanisms of action, potential benefits, risks and discuss the need for further research to bridge gaps in understanding and mitigate exposure-related health risks.

Exposure to organophosphate esters and early menopause: A population-based cross-sectional study

Organophosphate esters (OPEs), increasingly used as new flame retardants and plasticizers in various products, have been found to have reproductive toxicity with overt endocrine disruption potential, yet the relationship between OPEs and early menopause remains unexplored. In the present study, we included 2429 women who participated in the U.S. National Health and Nutrition Examination Survey data (2011-2020) and had data of five urinary OPE metabolite levels and information of menopause characteristics, to investigate the associations of OPEs exposure with premature ovarian insufficiency (POI) and age of menopause. Multivariable adjusted linear and logistic regression were used to assess the associations of urinary OPE metabolites with age of menopause and POI, respectively. Quantile g computation (QGC) models were used to assess the relative contribution of individual metabolites to associations of OPE metabolites mixture. After adjusting for covariates, urinary bis(2-chloroethyl) phosphate (BCEP) concentration was inversely associated with menopause age (β = - 0.21; 95% confidence interval (CI): 0.41, - 0.002). Higher urinary BCEP level (>median) was associated with earlier age at menopause (β = -1.14, 95% CI: 1.83, - 0.46), and elevated odds of having POI (OR = 1.93; 95% CI: 1.02, 3.66). These associations were robust to the further adjustment of cardiometabolic diseases and related traits (e.g., body mass index). Further QGC analyses confirmed that BCEP was the dominant metabolite contributing most to the associations of OPEs mixture with age of menopause (weight = 49.5%) and POI (weight = 75.1%). No significant associations were found for the other four OPE metabolites. In this cross-sectional study, urinary BCEP level was associated with earlier menopause and increased odds of POI, highlighting the potential negative impacts of this chemical and its parent compound tris(2-chloroethyl) phosphate on ovarian function. Further studies are required to validate our findings and reveal potential underlying mechanisms.

Primary ovarian insufficiency: update on clinical and genetic findings

Primary ovarian insufficiency (POI) is a disorder of insufficient ovarian follicle function before the age of 40 years with an estimated prevalence of 3.7% worldwide. Its relevance is emerging due to the increasing number of women desiring conception late or beyond the third decade of their lives. POI clinical presentation is extremely heterogeneous with a possible exordium as primary amenorrhea due to ovarian dysgenesis or with a secondary amenorrhea due to different congenital or acquired abnormalities. POI significantly impacts non only on the fertility prospect of the affected women but also on their general, psychological, sexual quality of life, and, furthermore, on their long-term bone, cardiovascular, and cognitive health. In several cases the underlying cause of POI remains unknown and, thus, these forms are still classified as idiopathic. However, we now know the age of menopause is an inheritable trait and POI has a strong genetic background. This is confirmed by the existence of several candidate genes, experimental and natural models. The most common genetic contributors to POI are the X chromosome-linked defects. Moreover, the variable expressivity of POI defect suggests it can be considered as a multifactorial or oligogenic defect. Here, we present an updated review on clinical findings and on the principal X-linked and autosomal genes involved in syndromic and non-syndromic forms of POI. We also provide current information on the management of the premature hypoestrogenic state as well as on fertility preservation in subjects at risk of POI.

Clusterin-carrying extracellular vesicles derived from human umbilical cord mesenchymal stem cells restore the ovarian function of premature ovarian failure mice through activating the PI3K/AKT pathway

BACKGROUND

Emerging evidence has highlighted the therapeutic potential of human umbilical cord mesenchymal stem cells (UC-MSCs) in chemotherapy-induced premature ovarian failure (POF). This study was designed to investigate the appropriate timing and molecular mechanism of UC-MSCs treatment for chemotherapy-induced POF.

METHODS

Ovarian structure and function of mice were assessed every 3 days after injections with cyclophosphamide (CTX) and busulfan (BUS). UC-MSCs and UC-MSCs-derived extracellular vesicles (EVs) were infused into mice via the tail vein, respectively. Ovarian function was analyzed by follicle counts, the serum levels of hormones and ovarian morphology. The apoptosis and proliferation of ovarian granulosa cells were analyzed in vitro and in vivo. Label-free quantitative proteomics was used to detect the differentially expressed proteins in UC-MSC-derived EVs.

RESULTS

After CTX/BUS injection, we observed that the ovarian function of POF mice was significantly deteriorated on day 9 after CTX/BUS infusion. TUNEL assay indicated that the number of apoptotic cells in the ovaries of POF mice was significantly higher than that in normal mice on day 3 after CTX/BUS injection. Transplantation of UC-MSCs on day 6 after CTX/BUS injection significantly improved ovarian function, enhanced proliferation and inhibited apoptosis of ovarian granulosa cells, whereas the therapeutic effect of UC-MSCs transplantation decreased on day 9, or day 12 after CTX/BUS injection. Moreover, EVs derived from UC-MSCs exerted similar therapeutic effects on POF. UC-MSCs-derived EVs could activate the PI3K/AKT signaling pathway and reduce ovarian granulosa cell apoptosis. Quantitative proteomics analysis revealed that clusterin (CLU) was highly expressed in the EVs of UC-MSCs. The supplementation of CLU proteins prevented ovarian granulosa cells from chemotherapy-induced apoptosis. Further mechanistic analysis showed that CLU-knockdown blocked the PI3K/AKT signaling and reversed the protective effects of UC-MSCs-derived EVs.

CONCLUSIONS

Administration of UC-MSCs and UC-MSCs-derived EVs on day 6 of CTX/BUS injection could effectively improve the ovarian function of POF mice. UC-MSCs-derived EVs carrying CLU promoted proliferation and inhibited apoptosis of ovarian granulosa cells through activating the PI3K/AKT pathway. This study identifies a previously unrecognized molecular mechanism of UC-MSCs-mediated protective effects on POF, which pave the way for the use of cell-free therapeutic approach for POF.

Roundup® induces premature senescence of mouse granulosa cells via mitochondrial ROS-triggered NLRP3 inflammasome activation

Roundup, a glyphosate-based herbicide widely used in agriculture, has raised concerns regarding its potential impact on human health due to the detection of its residues in human urine and serum. Granulosa cells are essential for oocyte growth and follicle development. Previous research has shown that Roundup could affect steroid synthesis, increases oxidative stress, and induces apoptosis in granulosa cells. However, little is known about the effects of Roundup on NLRP3 (nucleotide binding oligomerization domain-like receptor family pyrin-containing domain protein 3) inflammasome activation and cellular senescence in granulosa cells. Here, we provided evidence that exposure to Roundup induced premature senescence in mouse granulosa cells through the activation of NLRP3 inflammasome triggered by mitochondrial ROS. Our findings demonstrated that Roundup significantly reduced the viability of granulosa cells under in vitro culture conditions. It also disrupted mitochondrial function and induced oxidative stress in these cells. Subsequent investigations showed that NLRP3 inflammasome was activated in treated granulosa cells, as evidenced by the upregulation of inflammasome-related genes and the processing of inflammatory cytokines IL-1β and IL-1α into their mature forms. Consequently, premature cellular senescence occurred in response to the challenge posed by Roundup. Notably, direct inhibition of NLRP3 inflammasome with MCC950 does not alleviate mitochondrial damage and oxidative stress. However, supplementation of resveratrol, which has been known to attenuate mitochondrial damage and oxidative stress, effectively mitigated the inflammatory response and the expression of senescence-related markers, and prevented the senescence in granulosa cells. These results suggested that mitochondrial function and oxidative homeostasis might play pivotal roles as upstream regulators of NLRP3 inflammasome. In summary, our findings indicated that the premature senescence of granulosa cells caused by mitochondrial ROS-triggered NLRP3 inflammasome activation might contribute to the ovarian toxicity of Roundup, in addition to its known effects on steroidogenesis and apoptosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-024-00229-0.

The impact of follicular fluid phthalate metabolites on the ovarian reserve and ovarian function in Indian women undergoing intracytoplasmic sperm injection

OBJECTIVE

To investigate the adverse effects of phthalate-induced ovarian toxicity on the ovarian reserve and ovarian function. To assess whether the accumulation of higher levels of selected phthalate metabolites in the follicular fluid (FF) of Indian women undergoing intracytoplasmic sperm injection (ICSI) was associated with a decline in their antral follicle count (AFC) and/or serum antimüllerian hormone (AMH) levels, suggesting a negative impact on the ovarian reserve. To evaluate the effects of follicular phthalate metabolites on peak serum estradiol (E2) levels and the total number of oocytes and mature metaphase II (MII) stage oocytes retrieved to assess the impact of phthalate toxicity on ovarian function.

DESIGN

A subanalysis of an ongoing prospective cohort study was conducted to examine the association between the levels of six phthalate metabolites, namely, mono-n-butyl phthalate (MBP), mono-ethyl phthalate (MEP), mono-isononyl phthalate (MiNP), mono-isodecyl phthalate (MiDP), mono(2-ethyl-5-oxohexyl) phthalate, and mono(2-ethyl-5-hydroxyhexyl) phthalate, in the FF of Indian women undergoing ICSI and their ovarian reserve markers (AFC and serum AMH levels). To investigate the association of these follicular phthalate metabolite levels with the peak E2 levels and the total number of oocytes and number of MII stage oocytes retrieved.

SETTING

In vitro fertilization center in a referral hospital in India.

PATIENT(S)

A total of 245 consenting Indian women who had undergone oocyte retrieval between April 2017 and mid-March 2020 were included. Each woman contributed one FF sample to the study. This was screened for six phthalate metabolites. The samples were collected before the coronavirus disease 2019 pandemic.

INTERVENTION(S)

Using liquid chromatography-tandem mass spectrometry, the total levels of six phthalate metabolites were quantified in the FF of 245 women. Using linear regression models that were unadjusted and adjusted for maternal age and body mass index (BMI), we evaluated the association between the follicular metabolites in these women and their AFC, serum AMH levels, peak E2 levels, total number of oocytes, and MII stage oocytes.

MAIN OUTCOME MEASURE(S)

To evaluate the impact of phthalate-induced ovarian toxicity on the ovarian reserve and ovarian function in Indian women undergoing ICSI by studying their accumulated levels in their FF.

RESULT(S)

For MiNP (a metabolite of di-isononyl phthalate), in linear regression models adjusted for age and BMI, we found that with increasing quartiles of follicular MiNP, there was a significant trend in the decrease in mean AFC (P-trend = 0.023) and a suggestive trend in the decrease in mean serum AMH levels (P-trend = 0.077). For MiDP (a metabolite of di-isodecyl phthalate), in the unadjusted regression model, we found that with increasing quartiles of follicular MiDP, there was a significant trend in the decrease in mean serum AMH levels (P-trend = 0.045). For MBP (a metabolite of dibutyl phthalate), in linear regression models adjusted for age and BMI, we found that with increasing quartiles of follicular MBP, there were significant trends in the decrease in the mean number of total oocytes retrieved (P-trend = 0.003), a decrease in the mean number of MII stage oocytes retrieved, (P-trend = 0.003) and a decrease in the mean peak E2 levels (P-trend = 0.016). Although we found that with increasing quartiles of follicular mono(2-ethyl-5-oxohexyl) phthalate there was a decrease in the mean number of total and MII stage oocytes retrieved and higher follicular MEP levels were negatively associated with the mean AFC and serum AMH levels, neither trend was statistically significant. We also found that although follicular MEP levels did not show an adverse impact on ovarian function, follicular mono(2-ethyl-5-hydroxyhexyl) phthalate levels did not show an adverse impact on both the ovarian reserve and function.

CONCLUSION

In this study of 245 Indian women, higher accumulated FF levels of MiNP and MiDP were negatively associated with AFC and serum AMH levels, suggesting an adverse effect on the ovarian reserve. Higher accumulated FF levels of MBP were negatively associated with the total number of oocytes, MII stage oocytes, and peak E2 values, suggesting a negative impact on ovarian function. Although we found that phthalate-induced ovarian toxicity was statistically significant for selected phthalate metabolites, the role of the cumulative effect of multiple phthalates in the ovarian microenvironment cannot be ruled out and needs to be investigated further.

Association between neighborhood poverty and ovarian reserve: the ovarian aging study

OBJECTIVE

This study aimed to examine the association between neighborhood poverty and ovarian reserve.

METHODS

Among 1,019 healthy premenopausal women in the Ovarian Aging Study, aggregate exposure to neighborhood poverty was examined in relation to biomarkers of ovarian reserve, antimüllerian hormone (AMH) and antral follicle count (AFC). Specifically, the interaction of age-x-neighborhood poverty was assessed cross-sectionally to determine whether AMH and AFC declines across women may be greater in women exposed to more neighborhood poverty. Neighborhood poverty was assessed by geocoding and linking women's residential addresses in adulthood to US Census data.

RESULTS

Independent of covariates, a significant interaction term showed the association between age and AMH varied by degree of exposure to neighborhood poverty in adulthood ( b = -0.001, P < 0.05). AMH declines increased progressively across women exposed to low, medium, and high levels of neighborhood poverty. In addition, main effects showed that higher neighborhood poverty was related to higher AMH in the younger women only ( b = 0.022, P < 0.01). Results related to AFC were all nonsignificant ( P > 0.05).

CONCLUSIONS

Across women, greater aggregate exposure to neighborhood poverty in adulthood was related to lower ovarian reserve, indexed by AMH. In addition, there was a positive association between neighborhood poverty and AMH in younger women that attenuated in the older women. Together, results suggest that neighborhood disadvantage may have detrimental impacts that manifest as initially higher AMH, resulting in greater ovarian follicle loss over time. However, it remains unclear whether these results examining differences across women may replicate when AMH declines by neighborhood poverty are examined longitudinally.

Spontaneous pregnancy after thread-embedding therapy treatment with premature ovarian insufficiency after unilateral oophorectomy: a case report

Premature ovarian insufficiency (POI) is a condition characterized by menstrual disturbance, subfertility, and estrogen deficiency symptoms. Women with POI have a small chance of natural conception, which may be even smaller when complicated with unilateral ovarian due to reduction of the ovarian follicular reserve. In China, acupuncture has been widely used to treat POI and POI-induced infertility, and studies have shown that acupuncture is helpful for improving ovarian function. Thread-embedding therapy is a method of acupuncture treatment development and extension, which can make the acupuncture effect last. In this article, we report a patient diagnosed with POI after unilateral oophorectomy (UO) who spontaneously conceived after thread-embedding therapy. Thread-embedding therapy may improve ovarian function in patients with POI, thereby providing a treatment strategy for infertility in patients with POI. This case report was written in accordance with the CARE guidelines.

L-carnitine fails to rescue chemotherapy injured ovaries by epigenetic changes of transcription factors

Cyclophosphamide (CP), as an anti-cancer drug, is frequently used to treat various types of cancer. A decreased number of ovarian follicles impaired normal ovarian function, and subsequent premature ovarian failure (POF) presented as a side effect of cyclophosphamide usage. These events may eventually affect the fertility rate of individuals. The present study showed the effect of cyclophosphamide on ovarian reserves and the protective effect of L-carnitine (LC) as an antioxidant to prevent POF. To design the study, six to eight-week-old NMRI female mice were divided into three groups: control, cyclophosphamide (CP), and cyclophosphamide + L-carnitine (CP + LC). Mice received drugs intraperitoneally (IP) for 21 days. In the following 24 h after the last injection, both ovaries were used to evaluate the expression of Sohlh1 and Lhx8 genes by Real-time PCR. Furthermore, the alteration of Lhx8 promoter methylation was examined by Methylation-sensitive high-resolution melting analysis (MS-HRM). The present data showed the negative effect of CP on regulator genes of oogenesis including Sohlh1 and Lhx8. In addition, an examination of the epigenetic status of the Lhx8 gene showed a change in promoter methylation of this gene following cyclophosphamide injection. Although, L-carnitine is an effective antioxidant in relieving oxidative stress caused by cyclophosphamide and its damage, in the present study, however, the use of L-carnitine failed to protect the ovaries from changes caused by CP injection. So, using cyclophosphamide can alter the expression of folliculogenesis genes through its effects on epigenetic changes and may cause POF. The results of the present study showed that L-carnitine consumption can't protect the ovaries against the adverse effects of CP.

Pressures of the urban environment on the endocrine system: Adverse effects and adaptation

With an increasing collective awareness of the rapid environmental changes, questions and theories regarding the adaptability of organisms are emerging. Global warming as well as chemical and non-chemical pollution have been identified as triggers of these adaptative changes, but can we link different kinds of stressors to certain phenotypic traits? The physiological adaptation, and particularly endocrine system adaptation, of living beings to urban environments is a fascinating way of studying urban endocrinology, which has emerged as a research field in 2007. In this paper, we stress how endocrine disruption in humans and environment can be studied in the urban environment by measuring the levels of pollution, endocrine activities or adversity. We broaden the focus to include not only exposure to the chemicals that have invaded our private spheres and their effects on wild and domestic species but also non-chemical effectors such as light, noise and climate change. We argue that taking into account the various urban stress factors and their effects on the endocrine system would enable the adoption of new approaches to protect living organisms.

Protective role of stem cells in POI: Current status and mechanism of action, a review article

Premature ovarian insufficiency (POI) has far-reaching consequences on women's life quality. Due to the lack of full recognition of the etiology and complexity of this disease, there is no appropriate treatment for infected patients. Recently, stem cell therapy has attracted the attention of regenerative medicine scholars and offered promising outcomes for POI patients. Several kinds of stem cells, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) have been used for the treatment of ovarian diseases. However, their potential protective mechanisms are still unknown. Undoubtedly, a better understanding of the therapeutic molecular and cellular mechanisms of stem cells will address uncover strategies to increase their clinical application for multiple disorders such as POI. This paper describes a detailed account of the potential properties of different types of stem cells and provides a comprehensive review of their protective mechanisms, particularly MSC, in POI disorder. In addition, ongoing challenges and several strategies to improve the efficacy of MSC in clinical use are addressed. Therefore, this review will provide proof-of-concept for further clinical application of stem cells in POI.

Exposure to air pollution and ovarian reserve parameters

Exposure to air pollution is associated with many different health effects, especially cardiovascular and respiratory diseases. Additionally, highly significant links between exposure to air pollution and fertility, particularly male fertility was observed, however the studies regarding exposure to selected air pollutants and female fertility assessed by ovarian reserve are rare. Hence, the main aim of the study was to analyze relationship between exposure to ambient air pollution and ovarian reserve parameters among Polish women. The study population consisted of 511 women, who attended to infertility clinic because of diagnostic purposes. Participants filled in the questionnaire about social-demographic, lifestyle and health factors. Infertility specialists assessed ovarian parameters such as: antral follicle count (AFC) and concentration of hormones: Anti-Müllerian hormone (AMH), follicle stimulating hormone (FSH) and estradiol (E2). The air pollutants level (sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone, particulate matters) were obtained via National Environmental Protection Inspectorate database. Significant negative association between PM2,5 and AHM (p = 0.032) as well as AFC (p = 0.044) was observed. Moreover, SO2 concentrations decrease AFC (p = 0.038). The results also suggest that PM10, PM2.5, SO2 exposure on antral follicle count may be more pronounced among women with a female factor infertility diagnosis. Additionally, exposure to PM2.5 and NOx on AFC and AMH was stronger among older women (> 35 years of age). To conclude, the present study found that air pollution could lead to decrease in follicle antral count and Anti-Müllerian hormone level, especially exposure to PM2,5 and SO2 thus the evidence suggest negative impact to ovarian reserve.

Mechanism Exploration of Environmental Pollutants on Premature Ovarian Insufficiency: a Systematic Review and Meta-analysis

As a public health problem, premature ovarian insufficiency leads to infertility or sub-fertility. In addition to premature ovarian insufficiency (POI) increases the lifetime risk of bone fragility, cardiovascular disease, and cognitive impairment. To investigate the effects of environmental pollutants on the occurrence of POI and explore its mechanism, we conducted a computer search for articles published in electronic databases by December 13, 2022. Three reviewers independently examined all included studies and scored the qualities of included studies using the Newcastle-Ottawa Scale criteria. In this meta-analysis, eight clinical studies as well as ten preclinical findings showed a pooled OR of 2.331 and 95% CI of 1.968-2.760. This confirms that environmental pollutants, including POPs, heavy metals, PAEs, PAHs, cosmetic and pharmaceutical products, and cigarette smoke, are indeed significant risk factors for POI. In addition, it is demonstrated from the results of this study that signaling pathway of calcium and PI3K Akt and Xpnpep2, Col1, Col3, Col4, Cx43, Egr3, Tff1, and Ptgs2 genes may all be involved in the process. Environmental pollutants, including POPs, heavy metals, PAEs, PAHs, cosmetic and pharmaceutical products, and cigarette smoke, are indeed significant risk factors for POI.

The influence of environmental factors on premature ovarian insufficiency and ovarian aging

Premature ovarian insufficiency and ovarian aging are complex conditions that affect women's reproductive health and overall well-being. They are both characterized by hypergonadotropic hypogonadism and infertility, and together affect about 1 in 100 women by the age of 40. This review explores the influence of environmental factors on the development and progression of premature ovarian insufficiency and ovarian aging. When referring to environmental factors, we include a wide range of external agents and conditions, including chemicals, socioeconomic factors and lifestyle choices. Through a review of the literature, we attempt to highlight the link between environmental factors and ovarian health. We examine the impact of endocrine-disrupting chemicals, such as bisphenol A and phthalates, on ovarian function and investigate the mechanisms by which these chemicals can disrupt hormone signaling pathways, leading to alterations in ovarian reserve, oocyte quality, and folliculogenesis. Moreover, we explore lifestyle factors like obesity, stress, smoking and alcohol in relation to their effects on ovarian aging. Epigenetic changes may play a crucial role in the prevalence of premature ovarian insufficiency. Understanding the impact of environmental factors on premature ovarian insufficiency and ovarian aging is very important in public and clinical health contexts. By identifying risk factors, healthcare providers can develop targeted and strategic prevention and intervention plans. Furthermore, this knowledge can promote reproductive health and minimize exposure to harmful environmental agents.

Intergenerational effects on fertility in male and female mice after chronic exposure to environmental doses of NSAIDs and 17α-ethinylestradiol mixtures

Non-steroidal anti-inflammatory drugs (NSAIDs) and 17α-ethinylestradiol (EE2) are extensively used in human and veterinary medicine. Due to their partial removal by wastewater treatment plants, they are frequent environmental contaminants, particularly in drinking water. Here, we investigated the adverse outcomes of chronic exposure to mixtures of NSAIDs (ibuprofen, 2hydroxy-ibuprofen, diclofenac) and EE2 at two environmentally relevant doses in drinking water, on the reproductive organ development and fertility in F1-exposed male and female mice and in their F2 offspring. In male and female F1 mice, which were exposed to these mixtures, reproductive organ maturation, estrous cyclicity, and spermiogenesis were altered. These defects were observed also in F2 animals, in addition to some specific sperm parameter alterations in F2 males. Transcriptomic analysis revealed significant changes in gene expression patterns and associated pathways implicated in testis and ovarian physiology. Chronic exposure of mice to NSAID and EE2 mixtures at environmental doses intergenerationally affected male and female fertility (i.e. total number of pups and time between litters). Our study provides new insights into the adverse effects of these pharmaceuticals on the reproductive health and will facilitate the implementation of a future regulatory environmental risk assessment of NSAIDs and EE2 for human health.

COVID-19-related premature ovarian insufficiency: case report and literature review

OBJECTIVE

The aim of this study is to present the case report of a 36-year-old woman developing premature ovarian insufficiency (POI) after COVID-19 and review the literature referring to the possible impact of SARS-CoV-2 infection on female reproduction.

METHODS

A 36-year-old nulligravida with normal menstrual cycles, non-smoker, with a normal body mass index and no pelvic surgery or oncological treatment in her medical history presented to the Infertility Center of the Institute of Mother and Child in Warsaw after a year of unsuccessful attempts to get pregnant. During diagnostic process she was affected by COVID-19 with a mild manifestation and thereafter she presented amenorrhea with intense hot flushes. Further diagnostic confirmed the diagnosis of POI.

RESULTS

There is a strong molecular basis for a possible effect of SARS-CoV-2 infection on the female reproductive system; however, the results of available research are conflicting. All of these aspects are discussed in detail.

CONCLUSIONS

SARS-CoV-2 infection may cause serious complications that cast a long shadow on a patient's future life and health. Further research is needed to assess the real impact of SARS-CoV-2 infection on female reproductive health, as well as potential preventive and therapeutic strategies for women affected with COVID-19.

Impact of climate and environmental change on the menopause

The huge impact of climate change on humankind is multidimensional, and includes direct and indirect challenges to the physical, psychological and socio-cultural wellbeing. Women may be more vulnerable to climate-sensitive diseases, but little attention has been paid to specific needs and challenges associated with the menopause transition. The increase in average and extreme temperatures may modulate the manifestation of vasomotor symptoms; in particular, environmental temperature and seasonality may affect hot flushes and night sweats. However, more research is needed to define the impact of climate-related factors among the determinants influencing the individual experience of menopause. In addition, increased exposure to environmental pollution and toxins may also have a role in the modulation of ovarian aging mechanisms, possibly influencing timing of menopause. Finally, both air pollution and menopause transition are associated with unfavorable modifications of cardio-metabolic, bone and cognitive health, and account should be taken of these in the evaluation of the individual woman's health vulnerabilities. Overall, the evidence reported in this narrative review supports the need for specific strategies aimed at reducing the burden of climate and environmental change on menopausal women. Healthcare providers should promote behavioral measures that reduce anthropogenic climate change and at the same time have a beneficial role on several domains of physical and psychological wellbeing. From this perspective, menopause represents a golden moment to implement virtuous behaviors that will benefit at the same time women's longevity and the planet.

[Disruptors of thyroid hormones: Which consequences for human health and environment?]

Endocrine disruptors (EDs) of chemical origin are the subject of numerous studies, some of which have led to measures aimed at limiting their use and their impact on the environment and human health. Dozens of hormones have been described and are common to all vertebrates (some chemically related messengers have also been identified in invertebrates), with variable roles that are not always known. The effects of endocrine disruptors therefore potentially concern all animal species via all endocrine axes. These effects are added to the other parameters of the exposome, leading to strong, multiple and complex adaptive pressures. The effects of EDs on reproductive and thyroid pathways have been among the most extensively studied over the last 30 years, in a large number of species. The study of the effects of EDs on thyroid pathways and brain development goes hand in hand with increasing knowledge of 1) the different roles of thyroid hormones at cellular or tissue level (particularly developing brain tissue) in many species, 2) other hormonal pathways and 3) epigenetic interactions. If we want to understand how EDs affect living organisms, we need to integrate results from complementary scientific fields within an integrated, multi-model approach (the so-called translational approach). In the present review article, we aim at reporting recent discoveries and discuss prospects for action in the fields of medicine and research. We also want to highlight the need for an integrated, multi-disciplinary approach to studying impacts and taking appropriate action.

[Male infertility, environment and lifestyle]

BACKGROUND

Since the 1970s, there has been a quantitative and qualitative decline in sperm parameters. The main hypothesis to explain such a rapid evolution is the involvement of environmental and behavioral phenomena.

METHODS

A bibliographic search limited to English and French literature in men published before 7/2023 was carried out on the links between fertility and pollution, xenobiotics, tobacco, narcotics, cannabis, alcohol, weight, sport, sedentary lifestyle, sleep and anabolics.

RESULTS

Profound changes in lifestyle have occurred over the past 50 years: reduced sleep time, sedentary lifestyle, dietary changes, tobacco consumption, use of narcotics and anabolics. These changes have a proven impact on spermogram parameters, and should be corrected in an effort to optimize reproductive health. Other environmental parameters: pollution, exposure to heavy metals, exposure to xenobiotics, phthalates and pesticides… will be more difficult to exclude from patients' daily lives, but deserve to be taken more into account.

CONCLUSION

This review should help the urologist to assess and counsel patients in order to improve their reproductive health. These factors should be routinely investigated in infertile men.

Potential factors result in diminished ovarian reserve: a comprehensive review

The ovarian reserve is defined as the quantity of oocytes stored in the ovary or the number of oocytes that can be recruited. Ovarian reserve can be affected by many factors, including hormones, metabolites, initial ovarian reserve, environmental problems, diseases, and medications, among others. With the trend of postponing of pregnancy in modern society, diminished ovarian reserve (DOR) has become one of the most common challenges in current clinical reproductive medicine. Attributed to its unclear mechanism and complex clinical features, it is difficult for physicians to administer targeted treatment. This review focuses on the factors associated with ovarian reserve and discusses the potential influences and pathogenic factors that may explain the possible mechanisms of DOR, which can be improved or built upon by subsequent researchers to verify, replicate, and establish further study findings, as well as for scientists to find new treatments.

Exosomes derived from menstrual blood stromal cells ameliorated premature ovarian insufficiency and granulosa cell apoptosis by regulating SMAD3/AKT/MDM2/P53 pathway via delivery of thrombospondin-1

Premature ovarian insufficiency (POI) is clinically irreversible and seriously damages female fertility. We previously demonstrated that menstrual blood stromal cells (MenSCs)-derived exosomes (EXOs) effectively improved ovarian functions in the POI rat model. In this study, we investigated whether TSP1 is the key component in EXOs to ameliorate ovarian functions and further explored the molecular mechanism of EXOs in improving granulosa cell (GCs) activities. Our results demonstrated that knockdown TSP1 significantly debilitated the therapeutic effect of EXOs on estrous cyclicity, ovarian morphology, follicle numbers and pregnancy outcomes in 4-vinylcyclohexene diepoxide (VCD) induced POI rat model. In addition, EXOs treatment significantly promoted the activities and inhibited the apoptosis of VCD induced granulosa cells in vitro. Moreover, EXOs stimulation markedly activated the phosphorylation of SMAD3(Ser425) and AKT(Ser473), up-regulated the expressions of BCL2 and MDM2 as well as down-regulated the expressions of CASPASE3, CASPASE8, P53 and BAX. All these effects were supressed by SIS3, a inhibitor of TGF1/SMAD3. Our study revealed the key role of TSP1 in EXOs in improving POI pathology, restoring ovarian functions and GCs activities, andprovided a promising basis for EXOs in the treatment of ovarian dysfunction.

Biological therapies for premature ovarian insufficiency: what is the evidence?

Premature Ovarian Insufficiency (POI) is a multi-factorial disorder that affects women of reproductive age. The condition is characterized by the loss of ovarian function before the age of 40 years and several factors have been identified to be implicated in its pathogenesis. Remarkably though, at least 50% of women have remaining follicles in their ovaries after the development of ovarian insufficiency. Population data show that approximately up to 3.7% of women worldwide suffer from POI and subsequent infertility. Currently, the treatment of POI-related infertility involves oocyte donation. However, many women with POI desire to conceive with their own ova. Therefore, experimental biological therapies, such as Platelet-Rich Plasma (PRP), Exosomes (exos) therapy, In vitro Activation (IVA), Stem Cell therapy, MicroRNAs and Mitochondrial Targeting Therapies are experimental treatment strategies that focus on activating oogenesis and folliculogenesis, by upregulating natural biochemical pathways (neo-folliculogenesis) and improving ovarian microenvironment. This mini-review aims at identifying the main advantages of these approaches and exploring whether they can underpin existing assisted reproductive technologies.

Phthalate exposure and risk of ovarian dysfunction in endometriosis: human and animal data

Objective: We aimed to explore the correlations between and possible mechanisms of common environmental endocrine disruptors, phthalates, and ovarian dysfunction in endometriosis. Methods: Subjects were included in the case group (n = 107) who were diagnosed with endometriosis by postoperative pathology in Fujian Maternal and Child Hospital from February 2018 to February 2021, and the women who were excluded from endometriosis by surgery were as the control group (n = 70). The demographic information of the subjects were evaluated by questionnaire, and the clinical characteristics were evaluated by medical records and 3-year follow-up results. Gas chromatography‒mass spectrometry was used to quantify 10 metabolites of phthalates, including dimethyl ortho-phthalate (DMP), mono-n-methyl phthalate (MMP), dioctyl ortho-phthalate (DEP), mono-ethyl phthalate (MEP), di-n-butyl ortho-phthalate (DBP), mono-butyl phthalate (MBP), benzylbutyl phthalate (BBzP), mono-benzyl; phthalate (MBzP), diethylhexyl phthalate (DEHP) and mono-ethylhexyl phthalate (MEHP), in the urine samples of the subjects. Furthermore, a total of 54 SD rats were exposed to DEHP 0, 5, 50, 100, 250, 500, 1,000, 2000, and 3,000 mg/kg/day for 2 weeks. The SD rats' body weight, oestrus cycle changes, and serum anti-mullerian hormone (AMH) levels were evaluated. After sacrifice, the mass index of the rat uterus and bilateral ovaries were calculated. Finally, bioinformatics analysis of rat ovarian tissues was performed to explore the possible mechanism. SPSS 24.0 (IBM, United States) was used for data analysis. p-value <0.05 was considered statistically significant. Results: The human urinary levels of DMP (p < 0.001), MMP (p = 0.001), DEP (p = 0.003), MEP (p = 0.002), DBP (p = 0.041), MBP (p < 0.001), BBzP (p = 0.009), DEHP (p < 0.001), and MEHP (p < 0.001) were significantly higher in women with endometriosis than in controls. Notably, DEHP was a significant risk factor for endometriosis (OR: 11.0, 95% CI: 5.4-22.6). The area under the ROC curve increased when multiple phthalates were diagnosed jointly, reaching 0.974 as the highest value, which was helpful for the diagnosis of endometriosis. In vivo experiments showed that after DEHP exposure in rats, the mass index of the ovary and uterus decreased in a dose-dependent manner; the oestrus cycle of SD rats was irregularly prolonged and disordered; and the serum AMH level was negatively correlated with the DEHP exposure dose (Rho = -0.8, p < 0.001). Bioinformatics analysis of rat ovarian tissues showed that seven genes involved in the steroid biosynthesis pathway were upregulated and may play a negative role in ovarian function. Conclusion: Exposure to phthalates, especially DEHP, is associated with the occurrence of endometriosis and affects women's reproductive prognosis and ovarian function. The steroid biosynthesis pathway may be related to ovarian dysfunction. The detection of phthalate in urine may become a new biological target for the diagnosis of endometriosis.

Research progress on the role and mechanism of DNA damage repair in germ cell development

In the complex and dynamic processes of replication, transcription, and translation of DNA molecules, a large number of replication errors or damage can occur which lead to obstacles in the development process of germ cells and result in a decreased reproductive rate. DNA damage repair has attracted widespread attention due to its important role in the maintenance and regulation of germ cells. This study reports on a systematic review of the role and mechanism of DNA damage repair in germline development. First, the causes, detection methods, and repair methods of DNA damage, and the mechanism of DNA damage repair are summarized. Second, a summary of the causes of abnormal DNA damage repair in germ cells is introduced along with common examples, and the relevant effects of germ cell damage. Third, we introduce the application of drugs related to DNA damage repair in the treatment of reproductive diseases and related surgical treatment of abnormal DNA damage, and summarize various applications of DNA damage repair in germ cells. Finally, a summary and discussion is given of the current deficiencies in DNA damage repair during germ cell development and future research development. The purpose of this paper is to provide researchers engaged in relevant fields with a further systematic understanding of the relevant applications of DNA damage repair in germ cells and to gain inspiration from it to provide new research ideas for related fields.

Multigenerational Effects of a Complex Human-Relevant Exposure during Folliculogenesis and Preimplantation Embryo Development: The FEDEXPO Study

Animal toxicological studies often fail to mimic the complexity of the human exposome, associating low doses, combined molecules and long-term exposure. Since the reproductive potential of a woman begins in the fetal ovary, the literature regarding the disruption of its reproductive health by environmental toxicants remains limited. Studies draw attention to follicle development, a major determinant for the quality of the oocyte, and the preimplantation embryo, as both of them are targets for epigenetic reprogramming. The "Folliculogenesis and Embryo Development EXPOsure to a mixture of toxicants: evaluation in the rabbit model" (FEDEXPO) project emerged from consideration of these limitations and aims to evaluate in the rabbit model the impacts of an exposure to a mixture of known and suspected endocrine disrupting chemicals (EDCs) during two specific windows, including folliculogenesis and preimplantation embryo development. The mixture combines eight environmental toxicants, namely perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), 2,2'4,4'-tetrabromodiphenyl ether (BDE-47), di(2-ethylhexyl) phthalate (DEHP) and bisphenol S (BPS), at relevant exposure levels for reproductive-aged women based on biomonitoring data. The project will be organized in order to assess the consequences of this exposure on the ovarian function of the directly exposed F0 females and monitor the development and health of the F1 offspring from the preimplantation stage. Emphasis will be made on the reproductive health of the offspring. Lastly, this multigenerational study will also tackle potential mechanisms for the inheritance of health disruption via the oocyte or the preimplantation embryo.

Cocktails of NSAIDs and 17α Ethinylestradiol at Environmentally Relevant Doses in Drinking Water Alter Puberty Onset in Mice Intergenerationally

Non-steroidal anti-inflammatory drugs (NSAIDs) and 17α-ethinyl-estradiol (EE2) are among the most relevant endocrine-disrupting pharmaceuticals found in the environment, particularly in surface and drinking water due to their incomplete removal via wastewater treatment plants. Exposure of pregnant mice to NSAID therapeutic doses during the sex determination period has a negative impact on gonadal development and fertility in adults; however, the effects of their chronic exposure at lower doses are unknown. In this study, we investigated the impact of chronic exposure to a mixture containing ibuprofen, 2hydroxy-ibuprofen, diclofenac, and EE2 at two environmentally relevant doses (added to the drinking water from fetal life until puberty) on the reproductive tract in F1 exposed mice and their F2 offspring. In F1 animals, exposure delayed male puberty and accelerated female puberty. In post-pubertal F1 testes and ovaries, differentiation/maturation of the different gonad cell types was altered, and some of these modifications were observed also in the non-exposed F2 generation. Transcriptomic analysis of post-pubertal testes and ovaries of F1 (exposed) and F2 animals revealed significant changes in gene expression profiles and enriched pathways, particularly the inflammasome, metabolism and extracellular matrix pathways, compared with controls (non-exposed). This suggested that exposure to these drug cocktails has an intergenerational impact. The identified Adverse Outcome Pathway (AOP) networks for NSAIDs and EE2, at doses that are relevant to everyday human exposure, will improve the AOP network of the human reproductive system development concerning endocrine disruptor chemicals. It may serve to identify other putative endocrine disruptors for mammalian species based on the expression of biomarkers.

Polychlorinated biphenyls and the risk of endometriosis: Systematic review and meta-analysis

OBJECTIVE

We aimed to collect recent findings for a deeper understanding of the association between human exposure to polychlorinated biphenyls (PCBs) and endometriosis development.

METHODS

Web of Science, PubMed, Scopus, Google Scholar, and Embase were searched based on inclusion criteria from 2000 to the end of 2020. No filter was exerted to limit the language of publications and geographical restriction. Odds ratios (OR) using the random-effects model and the corresponding 95% confidence interval (CI) were calculated for each included study.

RESULTS

Fourteen studies were included in our analyses. The pooled OR and 95% CI for PCB was 1.96 (1.31 to 2.93). Despite being statistically significant, there was evidence of moderate heterogeneity (I² = 63%, P = 0.001, τ² = 0.32). Findings from our subgroup analyses showed a significant association between PCB exposure and endometriosis among European population (OR = 3.66, 95% CI: 2.08-6.44). Also a positive association was detected between PCB exposure and an increased odds of endometriosis in studies with laparoscopy (OR = 2.32, 95% CI: 1.16-4.63) or surgery confirm of controls (OR = 1.39, 95% CI: 1.02-1.89). Moreover, according to matched-pairs design, a significant association between PCB exposure and endometriosis development was detected (OR = 1.51, 95% CI: 1.04-2.18), also heterogeneity decreased in studies with matched-pairs design (I² = 30.4%).

CONCLUSIONS

Findings of this study confirm an association between endometriosis and exposure to PCB. However, more primary studies using proper methodology are needed to confirm this association.

Microcystin-LR accelerates follicular atresia in mice via JNK-mediated adherent junction damage of ovarian granulosa cells

Microcystin-LR (MC-LR), one of aquatic environmental contaminants with reproductive toxicity produced by cyanobacterial blooms, but its toxic effects and mechanisms on the ovary are not fully understood. Here, proteomic techniques and molecular biology experiments were performed to study the potential mechanism of MC-LR-caused ovarian toxicity. Results showed that protein expression profile of ovarian granulosa cells (KK-1) was changed by 17 μg/mL MC-LR exposure. Comparing with the control group, 118 upregulated proteins as well as 97 downregulated proteins were identified in MC-LR group. Function of differentially expressed proteins was found to be enriched in pathways related to adherent junction, such as cadherin binding, cell-cell junction, cell adhesion and focal adherens. Furthermore, in vitro experiments, MC-LR significantly downregulated the expression levels of proteins associated with adherent junction (β-catenin, N-cadherin, and α-catenin) as well as caused cytoskeletal disruption in KK-1 cells (P < 0.05), indicating that the adherent junction was damaged. Results of in vivo experiments have shown that after 14 days of acute MC-LR exposure (40 μg/kg), damaged adherent junction and an increased number of atretic follicles were observed in mouse ovaries. Moreover, MC-LR activated JNK, an upstream regulator of adherent junction proteins, in KK-1 cells and mouse ovarian tissues. In contrast, JNK inhibition alleviated MC-LR-induced adherent junction damage in vivo and in vitro, as well as the number of atretic follicles. Taken together, findings from the present study indicated that JNK is involved in MC-LR-induced granulosa cell adherent junction damage, which accelerated follicular atresia. Our study clarified a novel mechanism of MC-LR-caused ovarian toxicity, providing a theoretical foundation for protecting female reproductive health from environmental pollutants.

Heavy Metal(loid) Accumulation in the Ovarian Tissue of Free-Ranging Queens and Bitches Inhabiting Highly Polluted Urban Environments

There is strong scientific evidence that exposure to environmental contaminants, such as heavy metal(loid)s (HMs), can impair female reproductive function. Pets, such as cats and dogs, who share the same habitat as humans, may be particularly useful sentinel models for detecting HMs in the ovary. In the present study, we compared the concentration of essential (Ems; Cu, Fe, Mn, Se, and Zn) and non-essential metal(loid)s (NEMs; Al, As, Cd, and Pb) in the ovarian tissues of free-ranging queens and bitches of different ages living in industrialized/highly polluted (south group) and non-polluted (north group) urban areas of the island of Sardinia, Italy. The results showed that both EMs and NEMs were present at detectable concentrations in feline and canine ovaries and their levels varied according to geographical areas and animal age. Among the EMs, Cu was found elevated in older queens and bitches inhabiting the southern area. Cadmium and lead were higher in feline and canine ovaries of older animals from the south compared to those living in the north. In addition, Cd and Pb concentrations increased in individuals of both species living in the south. These findings showed new perspectives for the use of pets as early warning sentinels of environmental pollution by HMs and for the risk of human exposure within a "One Health" approach. Pets may help to study the link between exposure to metals and female reproductive disturbances in mammals.

Epigenetic regulation in premature ovarian failure: A literature review

Premature ovarian failure (POF), or premature ovarian insufficiency (POI), is a multifactorial and heterogeneous disease characterized by amenorrhea, decreased estrogen levels and increased female gonadotropin levels. The incidence of POF is increasing annually, and POF has become one of the main causes of infertility in women of childbearing age. The etiology and pathogenesis of POF are complex and have not yet been clearly elucidated. In addition to genetic factors, an increasing number of studies have revealed that epigenetic changes play an important role in the occurrence and development of POF. However, we found that very few papers have summarized epigenetic variations in POF, and a systematic analysis of this topic is therefore necessary. In this article, by reviewing and analyzing the most relevant literature in this research field, we expound on the relationship between DNA methylation, histone modification and non-coding RNA expression and the development of POF. We also analyzed how environmental factors affect POF through epigenetic modulation. Additionally, we discuss potential epigenetic biomarkers and epigenetic treatment targets for POF. We anticipate that our paper may provide new therapeutic clues for improving ovarian function and maintaining fertility in POF patients.

Urinary phthalate metabolite concentrations and hot flash outcomes: Longitudinal associations in the Midlife Women's Health Study

Midlife in women is an understudied time for environmental chemical exposures and menopausal outcomes. Recent cross-sectional research links phthalates with hot flashes, but little is known regarding such associations over time. Our objective was to estimate longitudinal associations between repeated measures of urinary phthalate metabolite concentrations and hot flash outcomes in midlife women. Using data from the Midlife Women's Health Study (MWHS), a prospective longitudinal study, we fit generalized linear mixed-effects models (GLMMs) and Cox proportional hazards regression models to repeated measures over a 4-year period. Recruitment occurred in Baltimore and surrounding counties, Maryland, USA between 2006 and 2015. Participants were premenopausal/perimenopausal women (n = 744) aged 45-54 years, who were not pregnant, not taking menopausal symptom medication or oral contraceptives, did not have hysterectomy/oophorectomy, and irrespective of hot flash experience. Baseline mean (SD) age was 48.4 (2.45), and 65% were premenopausal. Main outcome measures included adjusted odds ratios (ORs) for 4 self-reported hot flash outcomes (ever experienced, past 30 days experience, weekly/daily, and moderate/severe), and hazard ratios (HRs) for incident hot flashes. We observed mostly increased odds of certain hot flash outcomes with higher concentrations of metabolites of di (2-ethylhexyl) phthalate (DEHP), monoisobutyl phthalate (MiBP), and a molar summary measure of plasticizer phthalate metabolites (DEHP metabolites, mono-(3-carboxypropyl) phthalate (MCPP), monobenzyl phthalate (MBzP)). Some associations between exposures and outcomes indicated decreased odds. In conclusion, phthalate metabolites were associated with certain hot flash outcomes in midlife women. Midlife may be a sensitive period for higher phthalate metabolite concentrations with respect to menopausal symptoms.

Mixtures of persistent organic pollutants and ovarian function in women undergoing IVF

RESEARCH QUESTION

Do internal levels of persistent organic pollutants (POP) in serum and follicular fluid affect ovarian function of women attending IVF?

DESIGN

This cohort study included 136 women undergoing IVF in the assisted reproductive technology (ART) service of University Hospital from Nantes (France). Representative POP were measured using gas and liquid chromatography coupled with tandem mass spectrometry. Polyfluoroalkylated and perfluoroalkylated substances were measured in serum and polychlorinated biphenyls and organochlorinated pesticides in follicular fluid. Statistical associations between POP and ovarian reserve markers (anti-Müllerian Hormone [AMH] and antral follicle count [AFC], and ovarian responsiveness markers (Ovarian Sensitivity Index [OSI] and Follicular Output RaTe [FORT]), were explored in single and multipollutant regression models.

RESULTS

Twenty-seven out of 53 POP congeners were frequently detected in almost all women attending IVF. Adjusted models did not show statistically significant associations between POP and ovarian reserve markers. Positive associations were found between some POP, i.e. hexachlorobenzene with FORT (β 0.42, 95% CI 0.13 to 0.71, P = 0.005) or PCB52 with Ovarian Sensitivity Index (β 0.22; 95% CI, 0.07 to 0.38, P = 0.005). Negative associations between some polyfluoroalkylated and perfluoroalkylated substances, PCB189 and trans-nonachlor with AFC and AMH were found among current smokers.

CONCLUSIONS

Globally, associations between POP and the markers of ovarian function or responsiveness were lacking. Nonetheless, the stratification analysis suggested that current smoking could be a risk modifier, and extension of the study to a larger population sample size is needed.

Research Progress on the Etiology and Treatment of Premature Ovarian Insufficiency

Background

Menopause in women marks the knot of reproductive life, and menopause is defined as the last menstrual period in a woman, but this is caused by the failure of the ovarian reserve. The average age of natural menopause in the general population of women has remained around 50-52 years. Premature ovarian insufficiency (POI) is a debilitating clinical syndrome that manifests as a decline in ovarian function in women under 40. This condition is a prominent cause of female infertility.

Summary

POI is a debilitating condition that not only wreaks havoc on patients' physical and mental well-being but also imposes substantial mental, psychological, and economic burdens, particularly on women. In addition to diminished fertility, individuals afflicted with POI face an elevated risk of developing debilitating conditions such as osteoporosis and cardiovascular disease. The etiologies of POI are highly heterogeneous, and it can be caused by spontaneous genetic defects or induced by autoimmune diseases, infections, and iatrogenic or environmental factors. Alarmingly, idiopathic POI, a subtype characterized by an unknown etiology, accounts for more than half of all POI cases. Currently, clinical interventions for POI primarily consist of hormone replacement therapy. Fertility preservation methods are cryopreservation of embryos, oocytes, and ovarian tissue. Immunological interventions, gene editing techniques, and stem cell-based therapies are being explored to unravel the diverse etiologies and underlying mechanisms of POI, thereby enabling the identification of optimal therapeutic interventions. These innovative approaches offer unprecedented opportunities to advance the field of reproductive medicine.

Key Messages

The main aim of this paper was to offer a succinct summary of the latest research breakthroughs concerning the elucidation of the mechanisms governing the origin and management of POI.

Ovarian Reserve Disorders, Can We Prevent Them? A Review

The ovarian reserve is finite and begins declining from its peak at mid-gestation until only residual follicles remain as women approach menopause. Reduced ovarian reserve, or its extreme form, premature ovarian insufficiency, stems from multiple factors, including developmental, genetic, environmental exposures, autoimmune disease, or medical/surgical treatment. In many cases, the cause remains unknown and resulting infertility is not ultimately addressed by assisted reproductive technologies. Deciphering the mechanisms that underlie disorders of ovarian reserve could improve the outcomes for patients struggling with infertility, but these disorders are diverse and can be categorized in multiple ways. In this review, we will explore the topic from a perspective that emphasizes the prevention or mitigation of ovarian damage. The most desirable mode of fertoprotection is primary prevention (intervening before ablative influence occurs), as identifying toxic influences and deciphering the mechanisms by which they exert their effect can reduce or eliminate exposure and damage. Secondary prevention in the form of screening is not recommended broadly. Nevertheless, in some instances where a known genetic background exists in discrete families, screening is advised. As part of prenatal care, screening panels include some genetic diseases that can lead to infertility or subfertility. In these patients, early diagnosis could enable fertility preservation or changes in family-building plans. Finally, Tertiary Prevention (managing disease post-diagnosis) is critical. Reduced ovarian reserve has a major influence on physiology beyond fertility, including delayed/absent puberty or premature menopause. In these instances, proper diagnosis and medical therapy can reduce adverse effects. Here, we elaborate on these modes of prevention as well as proposed mechanisms that underlie ovarian reserve disorders.

Association of Coenzyme Q10 with Premature Ovarian Insufficiency

The aim of the study was to analyze the relationship between levels of coenzyme Q10 (CoQ10) and the risk of premature ovarian insufficiency (POI). In this cross-sectional case–control study, 32 women with POI and 58 women with normal menstrual cycles were recruited. The serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-Müllerian hormone (AMH), CoQ10 and total cholesterol were measured. The association of CoQ10 with POI was assessed using binary logistic regression analysis. The CoQ10/total cholesterol ratio was significantly lower in the women with POI than in the women with normal menstrual cycles (120.94 ± 25.35 nmol/mmol vs 138.97 ± 39.19 nmol/mmol, P = 0.021). The serum CoQ10/total cholesterol ratio was inversely associated with POI (the unadjusted odds ratio (OR) = 0.984, 95% CI: 0.970–0.998, P = 0.027). The same trend was found after adjusting for confounding factors (such as age, body mass index, annual household income and education) (OR = 0.976, 95% CI: 0.956–0.996, P = 0.020). The serum CoQ10/total cholesterol ratio was inversely associated with POI, indicating that antioxidant deficiency may be a risk associated with the development of POI. CoQ10 may be a protective factor for ovarian tissue.

Association between environmental pollutants and the FSH/AMH ratio as a marker of ovarian reserve

The ovarian function decreases with age, and various markers, such as follicle stimulating hormone, inhibin B, antral follicle count, and anti-Müllerian hormone, are used for its evaluation. Recently, exposure to various environmental pollutants in daily life has been reported as an important cause of ovarian function decline. Therefore, the present study aimed to confirm the effect of environmental pollutants on the relationship between age and decline in ovarian function. The exposure levels of 16 environmental pollutants were evaluated in women aged 26-40 years, and the AMH levels and FSH/AMH ratios were used as markers for the decline of ovarian function. The participants were divided into two groups: low-level or high-level for each environmental pollutant if their exposure level was below or above the median respectively. The slope of the decrease or increase in the AMH level and FSH/AMH ratio of each group with age was evaluated. The FSH/AMH ratio better presented the difference in the rate of change with age in each group than did AMH alone. In particular, the rate of change in the FSH/AMH ratio increased 5.2 and 3.7 times (p<0.05) in the group exposed to high levels of the volatile organic compound metabolite, trans, trans-muconic acid and the polycyclic aromatic hydrocarbons metabolite, 2-hydroxynaphthalene, respectively, than in the low-level exposure groups for those metabolites. This study confirmed that environmental pollutants influenced the rate of change in the FSH/AMH ratio with age. Further studies on larger populations are necessary in the future.

The effects of environmental prenatal program on environmental health perception and behavior using internet-based intervention in South Korea: A non-randomized controlled study

PURPOSE

This study aimed to develop and examine the effects of an internet-based intervention program on environmental perception and behavior among Korean pregnant women based on revised protection motivation theory.

METHOD

This study was a non-equivalent control group pre-post-test design. The experimental program consisted of prenatal education, reduction of fine dust, birth education, environmental health promotion, and postnatal management education using zoom video conferences. The face-to-face interventions were provided through regular prenatal classes at public health services for the control group. The total participant was 49 pregnant women: 25 in the experimental group and 24 in the control group. The program adaptation was conducted between April 2021 and November 2021 in Korea. The data were analyzed by ANCOVA and t-test to examine the effects using SPSS 26.0 program.

RESULTS

After intervention of the program, environmental severity (F = 17.96, p < .001), response efficacy (F = 15.69, p < .001), and total environmental perception (F = 7.80, p = .008) were higher in the experimental group than in the control group. There were no significant differences in feasibility, accessibility, satisfaction, susceptibility, self-efficacy, barrier, personal environmental behavior, and community environmental behavior between the two groups.

CONCLUSION

The internet-based educational program can be the alternative for the face-to-face prenatal class to promote environmental health perceptions during pregnancy in the pandemic situations.

Efficacy of Acupoint Application on In Vitro Fertilization Outcome in Patients with Polycystic Ovary Syndrome: A UHPLC-MS-Based Metabolomic Study

Objective

To explore the clinical effect of acupoint application on the outcome of in vitro fertilization-embryo transfer (IVF-ET) in patients with polycystic ovary syndrome (PCOS) of the phlegm-dampness type and elucidate its possible mechanism of action from the perspective of follicular fluid metabolomics.

Methods

A total of 90 patients undergoing IVF-ET due to infertility were selected and divided into three groups: the treatment group (PCOS with acupoint application, n = 30), the control group (PCOS without acupoint application, n = 30), and the normal group (non-PCOS, n = 30). All patients received a gonadotropin-releasing hormone agonist (GnRH-a) long protocol for controlled ovarian hyperstimulation (COH). Among them, the treatment group was also given the acupoint application from the day of pituitary downregulation to the day of the human chorionic gonadotrophin (hCG) trigger. Ultrahigh-performance liquid chromatography connected with quadrupole time-of-flight mass spectrometry (UHPLC-MS) was adopted for untargeted metabolomic analysis of follicular fluid collected from the three groups of patients on the day of oocyte pick-up (OPU). The significantly differential metabolites were screened using univariate and multivariate statistical analysis, and the related metabolic pathways were identified by the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

Results

Metabolomic analysis showed that the treatment group's follicular fluid samples were aggregated with the normal group and separated from the control group. A total of 34 significantly differential metabolites were found in the follicular fluid of patients with phlegm-dampness PCOS and normal people. With the intervention of acupoint application, seven metabolites (pseudouridine, phenol, 2-oxoadipic acid, 9R,10S-EpOME, DL-lactate, nicotinamide, and DL-indole-3-lactic acid) were all downregulated, mainly involving the pathways of pyruvate metabolism, nicotinate and nicotinamide metabolism, protein digestion and absorption, biosynthesis of amino acids, and pyrimidine metabolism.

Conclusions

Acupoint application can effectively improve the clinical symptoms and the outcome of IVF-ET treatment in patients with PCOS of the phlegm-dampness type, and its mechanism of action may be related to the regulation of the pathways of pyruvate metabolism, nicotinate and nicotinamide metabolism, protein digestion and absorption, biosynthesis of amino acids, and pyrimidine metabolism.

Significant changes in follicular fluid phthalate metabolite levels reflect the lifestyle changes brought about by the strict COVID-19 lockdown in India

OBJECTIVE

To assess if the unprecedented changes in lifestyle because of the lockdown initiated by the COVID-19 pandemic, which altered human behavior, and influenced purchase and consumption patterns, may have had an impact on the exposure to phthalates in Indian women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). To evaluate if the effects of the strict and lengthy lockdown in India, which promoted the new norms of stay-at-home and work-from-home, closure of beauty parlors, and restriction on public gatherings, may have contributed to a decrease in the exposure to phthalates like dibutyl phthalate and diethyl phthalate. These chemicals are found in many personal care products (PCPs) which include cosmetics and fragrances. To investigate if the extensive use of flexible single-use plastic in personal protective equipment like face masks/gloves and in plastic packaging used for online purchases, food takeaways, and home deliveries of essentials and groceries during the COVID-19 pandemic, in an attempt to provide a contact-free delivery system may have inadvertently led to an increase in exposure to phthalates like di(2-ethylhexyl) phthalate, di-isononyl phthalate, and di-isodecyl phthalate which are plasticizers used in manufacturing flexible plastic.

DESIGN

A comparative study of the levels of six phthalate metabolites detected in follicular fluid (FF) of Indian women undergoing IVF/ICSI 1 year before and immediately after the lockdown initiated by the COVID-19 pandemic.

SETTING

In vitro fertilization center in a large referral hospital in India.

PATIENT(S)

A total of 176 Indian women seeking treatment for infertility and undergoing oocyte retrieval were included after obtaining consent. Each woman contributed one FF sample to the study. Group A (n = 96) women (mean age, 34.0 [±3.9] years, and mean BMI, 25.4 [±4.8]) had their FF samples collected and screened between January 2019 and mid-March 2020, 1 year before the lockdown. Group B (n = 80) women (mean age, 33.9 [±4.1] years, and mean BMI, 25.0 [±4.4]) had their FF collected and screened post the lockdown between October 2020 and June 2021. Both groups were matched by age and BMI.

INTERVENTION(S)

The cryopreserved FF samples of 176 women were processed using enzymatic deconjugation as well as the solid-phase extraction technique, and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect the total levels of six phthalate metabolites.

MAIN OUTCOME MEASURE(S)

To evaluate the impact of the COVID-19 lockdown on the change in the phthalate metabolite levels in the FF of Indian women undergoing IVF/ICSI pre and post the lockdown.

RESULT(S)

The median levels of mono-n-butyl phthalate (1.64 ng/ml in group A vs. 0.93 ng/ml in group B; P<.001) and mono-ethyl phthalate (5.25 ng/ml in group A vs. 3.24 ng/ml in group B; P<.001) metabolites of dibutyl phthalate and diethyl phthalate found in PCPs including cosmetics and fragrances were significantly higher in the FF of 96 women (group A) compared with the levels seen in the FF of 80 women (group B). However, the median levels of mono-isononyl phthalate (0.11ng/ml in group A vs. 0.13 ng/ml in group B; P<.001), mono-isodecyl phthalate (0.11 ng/ml in group A vs. 0.14 ng/ml in group B; P<.001), and mono(2-ethyl-5-oxohexyl) phthalate (0.13 ng/ml in group A vs. 0.14 ng/ml in group B; P=.023) metabolites of di-isononyl phthalate, di-isodecyl phthalate, and di(2-ethylhexyl) phthalate used as plasticizers were significantly higher in the FF of women in group B compared with women in group A.

CONCLUSION(S)

The significant drop in mono-n-butyl phthalate and mono-ethyl phthalate levels, accumulated in the FF of 80 Indian women in group B reflects a decrease or absence of usage patterns of PCPs, including cosmetics and fragrances, thereby suggesting that these women may have deprioritized their use during the COVID-19 pandemic giving preference to personal hygiene and safety. Whereas the unprecedented increase in the use of flexible single-use plastic that became our first line of defense against the coronavirus during the COVID-19 pandemic might be responsible for the accumulation of significantly higher levels of mono-isononyl phthalate, mono-isodecyl phthalate, and mono(2-ethyl-5-oxohexyl) phthalate in FF of the same group.