Infertility: a marker of future health risk in women?

Assessing preconception exposure to environmental chemicals and fecundity: Strategies, challenges, and research priorities

In 2022, approximately one out of six people globally experienced infertility at some point in their life. Environmental chemicals, particularly those with endocrine disrupting activity, may contribute to impaired fecundity and infertility. We review existing prospective cohort studies of environmental chemicals and fecundity, identify methodological challenges and biases, and outline future research priorities. Studies of preconception environmental chemical exposures and fecundity have occurred in US, Singapore, China and Denmark with recruitment as early as 1982-1986, as recent as 2015-2017 and sample sizes ranging from 99 to 936. Higher exposure to certain chemicals (e.g. heavy metals, perfluoroalkyl substances) was associated with longer time to pregnancy; yet the literature is scarce or nonexistent for many chemicals. Furthermore, prospective studies face challenges and potential biases related to recruiting participants prior to conception, measuring environmental chemicals during critical windows of exposure, and ascertaining when pregnancy occurred. Research priorities include expanding the scope of biomonitoring data collected during the preconception period, continuing to develop and validate analytic methods for self-sampled biospecimens in traditional and novel matrices, collecting data in male partners and investigating etiologic associations according to indicators of marginalization.

Vascular Health of Females with History of Assisted Reproductive Technology

The use of assisted reproductive technologies (ART) for the treatment of infertility is gaining popularity. Limited data on the overall vascular health of females with history of ART are available. This pilot study aimed to investigate the overall vascular health of females with history of ART compared to individuals who conceived spontaneously. The assessment of overall vascular health included the measurement of brachial blood pressure, central blood pressure, and pulse wave velocity, as well as the evaluation of the arterial stiffness and carotid intima-media thickness (cIMT) of the common carotid arteries. Conventional blood lipids including lipoprotein a (Lp(a)) were also determined. In total, 45 females with history of ART and 52 females who conceived spontaneously were included (mean age: 47.72 ± 5.96 years vs. 46.84 ± 7.43 years, p = 0.525). An initial comparison revealed a significantly higher prevalence of elevated Lp(a) in ART females (p = 0.011). However, after multiple comparison correction, the significant result disappeared (p = 0.132). Within the cohort of ART females, no significantly higher cardiovascular risk was detected regarding vascular function. The potentially higher prevalence of elevated Lp(a) in ART females must be further investigated in future studies, as it might contribute to the impaired reproductive process in this cohort.

Increased Prevalence of Adverse Health Outcomes Across the Lifespan in Those Affected by Polycystic Ovary Syndrome: A Canadian Population Cohort

Background

Polycystic ovary syndrome (PCOS) is the most common metabolic-endocrine disorder impacting the health and quality of life of women over the lifespan. Evidence-based data on the scope of adverse health outcomes in those affected by PCOS is critical to improve healthcare and quality of life in this population. The aim of this study was to determine the prevalence of adverse health outcomes in those with PCOS compared to age-matched controls.

Methods

We conducted a retrospective observational case-control study in those diagnosed with PCOS and age-matched controls using the Alberta Health Services Health Analytics database and the International Classification of Diseases, for the period from 2002-2018 in Alberta, Canada.

Results

The cohort consisted of n = 16,531 exposed PCOS cases and n = 49,335 age-matched un-exposed controls. The prevalences of hypertension, renal disease, gastrointestinal disease, eating disorders, mental illness, depression-anxiety, rheumatoid arthritis, respiratory infections, and all malignancies were 20%-40% (P < 0.0001) higher in those with PCOS, compared to controls. The prevalence of obesity, dyslipidemia, nonalcoholic fatty liver disease, and type 2 diabetes was 2-3 fold higher in those with PCOS (P < 0.001). Cardiovascular, cerebrovascular, and peripheral vascular disease were 30%-50% higher, and they occurred 3-4 years earlier in those with PCOS (P < 0.0001); a 2-fold higher prevalence of dementia occurred in those with PCOS, compared to controls.

Conclusion

These findings provide evidence that PCOS is associated with a higher prevalence of morbidities over the lifespan, and the potential scope of the healthcare burden in women affected by PCOS.

Change of HeART: Cardiovascular Implications of Assisted Reproductive Technology

Cardiovascular (CV) disease is the leading cause of death in women, and it may manifest differently than in men, in part related to sex-specific CV risk factors. In females, assisted reproductive technologies (ARTs) are commonly used to treat infertility, and they utilize controlled ovarian stimulation involving the administration of exogenous sex hormones. ARTs, and especially controlled ovarian stimulation, have been associated with an increased pregnancy and short-term CV risk, although the long-term CV implications of these treatments in individuals treated with ARTs and their offspring remain unclear. This review endeavors to provide a comprehensive examination of what is known about the relationship between ART and CV outcomes for females treated with ARTs, as well as their offspring, and recommendations for future research. Novel insights into female-specific CV risk factors are critical to reduce the disproportionate burden of CV disease in Canadian women. ART has revolutionized reproductive medicine, offering hope to millions of individuals with infertility worldwide, and a further understanding of the CV implications of this important sex-specific CV risk factor is warranted urgently.

Bisphenol a downregulates GLUT4 expression by activating aryl hydrocarbon receptor to exacerbate polycystic ovary syndrome

BACKGROUND

Bisphenol A (BPA) levels are high in women with polycystic ovary syndrome (PCOS). The mechanism by which BPA induces abnormal glucose metabolism in PCOS patients is largely unknown.

METHODS

Serum and urine samples were collected from women with and without PCOS (control) at the reproductive medicine center with informed consent. Non-PCOS patients who received in vitro fertilization were recruited for collection of ovarian follicular fluid and granular cells. Wild-type C57BL/6 and AhR -/- mice were used to verify the effects of BPA on PCOS. Real-time PCR, western blotting, and ELISA were conducted to analyze the function of BPA. Chip-qPCR verified the role of AhR in GLUT4 transcription. Flow cytometry was performed to determine glucose uptake.

RESULTS

A positive correlation was observed between BPA concentration and serum BPA levels in PCOS patients. BPA aggravated the changes in PCOS with abnormal glucose metabolism, impaired fertility, and increased body fat. Mechanistically, we showed that BPA activated AhR and led to decreased glucose transport via GLUT4 downregulation in ovarian granular cells. Therefore, the use of inhibitors or knockout of AhR could effectively rescue BPA-induced metabolic disorders in PCOS mice.

CONCLUSIONS

Our results revealed that BPA suppressed GLUT4 expression and induced abnormal glucose metabolism by activating AhR, causing insulin resistance, and is thus a potential contributor to the development of PCOS. Therefore, AhR could be a potential new therapeutic target for PCOS. Video Abstract.

Reproduction as a window to future health in women

Cultivating awareness for reproduction as a window to future health presents an opportunity for early identification and modification of risk factors that can affect both individual and population-level morbidity and mortality. Infertility could serve as both a window into future health as well as a pathway to future pathology. The underlying mechanisms of infertility may share common pathways with long-term risk for health and well-being. Making this identification early in the disease process may improve opportunities for intervention, and deepen our understanding of long-term risk. Additionally, fertility treatments may increase individual risk. Only by making these associations and designing studies to understand how disease and treatment risk impact health can we truly fulfill our goal of building healthy families. The aim of this review is to discuss the short-term impact of fertility challenges and treatment, long-term associations of infertility with morbidity and mortality, and the role of parity in modifying these risk associations.

Hypothalamic-Pituitary-Gonadal Axis Disorders Impacting Fertility in Both Sexes and the Potential of Kisspeptin-Based Therapies to Treat Them

Impaired function of the hypothalamic-pituitary-gonadal (HPG) axis can lead to a vast array of reproductive disorders some of which are inherited or acquired, but many are of unknown etiology. Among the clinical consequences of HPG impairment, infertility is quite common. According to the latest report from the World Health Organization, the global prevalence of infertility during a person's lifetime is a staggering 17.5% which translate into 1 out of every 6 people experiencing it. In both sexes, infertility is associated with adverse health events, and if unresolved, infertility can cause substantial psychological stress, social stigmatization, and economic strain. Even though significant advances have been made in the management and treatment of infertility, low or variable efficacy of treatments and medication adverse effects still pose a significant problem. However, the discovery that in humans inactivating mutations in the gene encoding the kisspeptin receptor (Kiss1R) results in pubertal failure and infertility has expanded our understanding of the mechanisms underlying the neuroendocrine control of reproduction, opening up potential new therapies for the treatment of infertility disorders. In this chapter we provide an overview of common infertility disorders affecting men and women, their recommended treatments, and the potential of kisspeptin-based pharmacotherapies to treat them.

Fertility Health Knowledge in U.S. Adults: Men Narrowing the Knowledge Gap

Much of young people's fertility health knowledge has been limited to avoiding sexually transmitted infections and preventing pregnancy thus lacking what is necessary to support future overall health as well as reproductive goals. This study assesses university students' knowledge related to fertility health factors to verify consistencies and discrepancies in fertility health knowledge, with a sub-assessment focusing on men's knowledge. The Fertility Health Knowledge survey was delivered to 17,189 students at three American universities. Twenty percent or 546 of the 2,692 participants were male. The 30-question survey addresses knowledge of modifiable and non-modifiable risk factors on fertility health in men and women, and four questions regarding fertility intentions. Across all 30 questions, 63% of female responses were correct and 61% of male responses were correct. For 10 questions, less than 70% of males and females answered correctly, with men answering correctly more often than females for six of the questions. Males exhibited more knowledge regarding male fertility. Knowledge of fertility health was consistently limited, regardless of site or demographics. Men demonstrated improved overall fertility health knowledge and more knowledge regarding male factors. There are still considerable gaps in knowledge of modifiable risk factors that may impact fertility health and future overall health. Fertility health promotion through education should be comprehensive and widely available in secondary schools, colleges, and universities. As well, increased education regarding fertility health in primary care settings should become the norm-with male inclusion as a standard of their care.

Healthcare Use in the Five Years Before a First Infertility Diagnosis: A Danish Register-Based Case–Control Study in the CROSS-TRACKS Cohort

Purpose

Infertility may affect somatic and mental health later in life. Nevertheless, health status before diagnosed infertility is sparsely studied in women. We aimed to describe healthcare use in primary and secondary care before a first infertility diagnosis and compare use between cases and controls.

Materials and Methods

The case–control study was based on register data and used incidence density sampling. From the CROSS-TRACKS Cohort, we included women residing in the Horsens area in Denmark in 2012–2018 (n = 54,175). Eligible women were aged 18–40 years, nulliparous, and living in heterosexual relationships. Cases were women with a first infertility diagnosis in the Danish National Patient Registry (index date). Five controls were matched on age, birth year, and calendar time. Through linkage to Danish national health registries, we identified general practitioner (GP) attendance, paraclinical examinations, hospital contacts, diagnoses, and redeemed prescriptions. Healthcare use from one year to five years before index date was compared with conditional logistic regression.

Results

We identified 711 cases and 3555 controls. At one year before index date, cases consulted their GP (odds ratio (OR) = 5.2, 95% confidence interval (CI): 3.2, 8.3) and visited hospital (OR = 1.2, 95% CI: 1.0, 1.4) and redeemed prescriptions (OR = 2.3 95% CI: 1.9, 2.7) more often compared to controls. Cases more often had blood and hemoglobin tests performed, redeemed more drugs related to genitourinary and hormonal diseases, and were more often diagnosed with endocrine and genitourinary diseases in the year before a first infertility diagnosis compared to controls. Cases and controls had comparable healthcare use from five years to one year before a first infertility diagnosis.

Conclusion

Cases and controls had similar healthcare use from five years to one year before a first infertility diagnosis. However, cases had a higher healthcare use in the year preceding a first infertility diagnosis compared to controls.

Berberine alleviates LPS-induced apoptosis, oxidation, and skewed lineages during mouse preimplantation development†

Female infertility is a heterogeneous disorder with a variety of complex causes, including inflammation and oxidative stress, which are also closely associated with the pathogenesis of polycystic ovary syndrome (PCOS). As a new treatment for PCOS, berberine (BER), a natural compound from Berberis, has been clinically applied recently. However, the mechanisms underlying the association between BER and embryogenesis are still largely unknown. In this study, effects of BER on preimplantation development were evaluated under both normal and inflammatory culture conditions induced by lipopolysaccharide (LPS) in mice. Our data first suggest that BER itself (25 nM) does not affect embryo quality or future developmental potency; however, it can effectively alleviate LPS-induced embryo damage by mitigating apoptosis via reactive oxygen species (ROS)-/caspase-3-dependent pathways and by suppressing proinflammatory cytokines via inhibition of the NF-κB signaling pathway during preimplantation embryonic development. In addition, skewed cell lineage specification in the inner cell mass (ICM) and primitive endoderm (PE) caused by LPS can also be successfully rescued with BER. In summary, these findings for the first time demonstrate the nontoxicity of low doses of BER and its antiapoptotic and antioxidative properties on embryonic cells during mammalian preimplantation development.

Association of infertility with atherosclerotic cardiovascular disease among postmenopausal participants in the Women’s Health Initiative

OBJECTIVE

To investigate the association of infertility with atherosclerotic cardiovascular disease (ASCVD) among postmenopausal participants in the Women's Health Initiative (WHI). We hypothesized that nulliparity and pregnancy loss may reveal more extreme phenotypes of infertility, enabling further understanding of the association of infertility with ASCVD.

DESIGN

Prospective cohort study.

SETTING

Forty clinical centers in the United States.

PATIENT(S)

A total of 158,787 postmenopausal participants in the Women's Health Initiative cohort.

INTERVENTION(S)

Infertility, parity, and pregnancy loss.

MAIN OUTCOME MEASURE(S)

The primary outcome was risk of ASCVD among women with and without a history of infertility, stratified by history of live birth and pregnancy loss. Cox proportional-hazards models were adjusted for demographics and risk factors for ASCVD.

RESULT(S)

Among 158,787 women, 25,933 (16.3%) reported a history of infertility; 20,427 (80%) had at least 1 live birth; and 9,062 (35%) had at least 1 pregnancy loss. There was a moderate overall association between infertility and ASCVD (adjusted hazard ratio, 1.02; 95% confidence interval [CI], 0.99-1.06) over 19 years of follow-up. Among nulliparous women, infertility was associated with a 13% higher risk of ASCVD (95% CI, 1.04-1.23). Among nulliparous women who had a pregnancy loss, infertility was associated with a 36% higher risk of ASCVD (95% CI, 1.09-1.71).

CONCLUSION(S)

Women with a history of infertility overall had a moderately higher risk of ASCVD compared with women without a history of infertility. Atherosclerotic cardiovascular disease risk was much higher among nulliparous infertile women and among nulliparous infertile women who also had a pregnancy loss, suggesting that in these more extreme phenotypes, infertility may be associated with ASCVD risk.

Mouse Cre drivers: tools for studying disorders of the human female neuroendocrine-reproductive axis†

Benign disorders of the human female reproductive system, such primary ovarian insufficiency and polycystic ovary syndrome are associated with infertility and recurrent miscarriage, as well as increased risk of adverse health outcomes, including cardiovascular disease and type 2 diabetes. For many of these conditions, the contributing molecular and cellular processes are poorly understood. The overarching similarities between mice and humans have rendered mouse models irreplaceable in understanding normal physiology and elucidating pathological processes that underlie disorders of the female reproductive system. The utilization of Cre-LoxP recombination technology, which allows for spatial and temporal control of gene expression, has identified the role of numerous genes in development of the female reproductive system and in processes, such as ovulation and endometrial decidualization, that are required for the establishment and maintenance of pregnancy in mammals. In this comprehensive review, we provide a detailed overview of Cre drivers with activity in the neuroendocrine-reproductive axis that have been used to study disruptions in key intracellular signaling pathways. We first summarize normal development of the hypothalamus, pituitary, ovary, and uterus, highlighting similarities and differences between mice and humans. We then describe human conditions resulting from abnormal development and/or function of the organ. Finally, we describe loss-of-function models for each Cre driver that elegantly recapitulate some key features of the human condition and are associated with impaired fertility. The examples we provide illustrate use of each Cre driver as a tool for elucidating genetic and molecular underpinnings of reproductive dysfunction.

Psychosocial Aspects of Gestational Grief in Women Undergoing Infertility Treatment: A Systematic Review of Qualitative and Quantitative Evidence

Women undergoing assisted reproduction treatment without being able to become pregnant, and experiencing pregnancy loss after assisted reproduction, are triggering factors for prolonged grief and mourning. This review aims to investigate the psychosocial aspects of gestational grief among women who have undergone infertility treatment. We searched the databases of MEDLINE/PubMed, EMBASE, CINAHL, Scopus, ScienceDirect, and Lilacs for works published up to 5 March 2021. The outcomes analyzed were negative and positive psychosocial responses to gestational grief among women suffering from infertility and undergoing assisted human reproduction treatment. Eleven studies were included, which yielded 316 women experiencing infertility who were undergoing treatment. The most frequently reported negative psychosocial manifestations of grief response were depression (6/11, 54.5%), despair or loss of hope/guilt/anger (5/11, 45.5%), anxiety (4/11, 36.4%), frustration (3/11, 27.3%), and anguish/shock/suicidal thoughts/isolation (2/11, 18.2%). Positive psychosocial manifestations included the hope of becoming pregnant (4/6, 66.6%) and acceptance of infertility after attempting infertility treatment (2/6, 33.3%). We identified several negative and positive psychosocial responses to gestational grief in women experiencing infertility. Psychological support before, during, and after assisted human reproduction treatment is crucial for the management of psychosocial aspects that characterize the grief process of women experiencing infertility who become pregnant and who lose their pregnancy. Our results may help raise awareness of the area of grief among infertile women and promote policy development for the mental health of bereaved women.

Anti-Müllerian hormone concentration as an indicator of female general health status: a cross-sectional study

RESEARCH QUESTION

To evaluate the correlation between clinical and hormonal parameters and comorbidity burden in Caucasian women presenting for fertility treatment.

DESIGN

Monocentric cross-sectional study including a cohort of 3163 Caucasian women seeking medical care for fertility treatment. All patients underwent centralized laboratory testing for hormonal assessment. Complete clinical and laboratory data from the entire cohort were retrospectively analysed. Comorbidity burden score was assessed by the Charlson Comorbidity Index (CCI; categorized as 0 versus 1 versus ≥2).

RESULTS

Descriptive statistics and regression models tested the associations between clinical and laboratory parameters and CCI. Among the entire cohort of patients, a CCI = 0 was found in 2977 women (94.1%), and CCI = 1 and CCI ≥2 were found in 113 (3.6%) and 73 (2.3%) patients, respectively. Age (P = 0.009), gravidity (P = 0.001), anti-Müllerian hormone (AMH, P < 0.001) and TSH (P = 0.003) values were significantly different among CCI groups. In regression models, age at presentation and AMH emerged as independent indicators of CCI ≥ 1. Age at presentation <36 years (odds ratio [OR] 1.742, 95% confidence interval [CI] 1.284-2.364) and an AMH concentration ≤2.3 ng/ml (OR 1.864, 95% CI 1.29-2.69) were the most informative cut-off values for CCI ≥ 1 in the study population.

CONCLUSIONS

A younger age at presentation and lower AMH concentrations are significant independent indicators of decreased general health in women requiring clinical evaluation for fertility treatment. As observed for sperm parameters in men, AMH might serve as a proxy of women's general health status.

Infertility and the Risk of Cardiovascular Disease: Findings From the tudy of omen's Health cross the ation (SWAN)

Background

Cardiovascular disease (CVD) is the leading cause of death in women globally. In recent years, attention has turned to infertility and pregnancy-related events as potential markers for early mortality and future CVD.

Methods

The Study of Women’s Health Across the Nation (SWAN) is an ongoing longitudinal cohort study of women’s health. Women aged 42-52 years with a uterus and ≤ 1 intact ovary, a menstrual period, and no hormone medications within 3 months before enrollment were eligible. Infertility was self-reported and defined as the inability to achieve pregnancy after 12 months of trying to conceive, or use of fertility medications for > 1 month. Outcomes included development of metabolic syndrome over a 7-year follow-up, and any atherosclerotic CVD event (ie, stroke, angina, myocardial infarction) over a 10-year follow-up. Cox proportional hazards models were used to calculate hazard ratios (HRs) for metabolic syndrome and CVD events in participants with infertility, with adjustment for relevant covariates. Participants without infertility were used as the comparison group.

Results

We included 2370 participants in the analysis of metabolic syndrome risk, and 2809 participants were included in the analysis of CVD event risk. Participants with self-reported infertility did not have a higher risk of developing metabolic syndrome (HR, 0.91; 95% confidence interval, 0.71-1.15) or experiencing CVD events (HR, 0.79; 95% confidence interval, 0.52-1.21) after adjusting for relevant covariates.

Conclusions

Infertility was not associated with development of metabolic syndrome or CVD events in women; further research is required to investigate the effects of specific causes of infertility and fertility treatments on CVD outcomes.

Female Infertility and Cardiovascular Risk - A Hype or an Underestimated Reality?

Infertility may be an early indicator of later-life health risk development, such as cardiovascular disease (CVD), the leading cause of death globally. Various infertility-associated factors such as female age, polycystic ovarian syndrome, endometriosis and metabolic syndrome are also risk factors for CVD. Whether there is a real association between female infertility and CVD, given that common pathways lead to both entities, or since both female infertility and CVD share a common basis, needs to be further investigated. If such an association is confirmed, infertile women might benefit from the initiation of preventive strategies aiming to control CVD risk factors. Thus, female infertility may represent an early indicator of future CVD and concomitantly a unique opportunity to identify women at increased risk for developing CVD. It is therefore imperative that large population- based studies are performed to elucidate this issue further and promote public awareness, if necessary.

Persistent organic pollutants and couple fecundability: a systematic review

BACKGROUND

Despite increasing regulation, exposure to persistent organic pollutants (POPs) remains a serious public health concern due to their accumulation in the environment and ability to biomagnify up the food chain. POPs are associated with endocrine-disrupting effects including adverse reproductive outcomes that could affect fecundability, i.e. the capacity to conceive a pregnancy, quantified as time to pregnancy (TTP).

OBJECTIVE AND RATIONALE

Results of epidemiologic studies that examine the impact of various chemical classes of POPs on TTP have not been synthesised. We undertook a systematic review to summarise the strength of evidence for associations of four common groups of POPs with couple fecundability and to identify gaps and limitations in the literature in order to inform policy decisions and future research.

SEARCH METHODS

We performed an electronic search of literature published between 1 January 2007 and 6 August 2019 in MEDLINE, EMBASE.com, Global Health, DART/TOXLINE and POPLINE. We included empirical research papers that examined human exposure to organochlorine (OC) pesticides, brominated flame retardants, polychlorinated organic compounds and/or per- and polyfluoroalkyl substances (PFAS) and considered TTP or fecundability as an outcome. Standardised forms for screening, data extraction and study quality were developed using DistillerSR software, and all reviews were completed in duplicate. We used the Newcastle-Ottawa Scale to assess risk of bias and devised additional quality metrics based on specific methodological features of fecundability studies.

OUTCOMES

The search returned 4573 articles, and 28 papers from 19 different studies met inclusion criteria. Among them, four studies measured TTP prospectively, three had data on participants' prenatal exposure, three examined associations in both male and female partners and one focused exclusively on males. Analyses varied widely in terms of exposure characterisation, precluding a meta-analytic approach. Evidence was strongest for adverse associations of female exposure to polychlorinated biphenyls with TTP, with some additional support for associations of female exposure to polybrominated diphenyl ethers and PFAS with longer TTP. Our review provided little or no support for associations between female exposure to OC pesticides or male exposure to any of the POP groups and TTP.

WIDER IMPLICATIONS

Evidence suggests that female exposure to at least some POPs may reduce fecundability. Although many of these chemicals are no longer in production, they are still detectable in human biosamples because of their persistence in the environment. Replacement chemicals that are being introduced as older ones are restricted may have similar reproductive consequences. Future studies should examine these newer POPs, assess interactions between POPs and other chemical and non-chemical exposures, investigate how POPs are distributed in and metabolised by the human body and focus on populations that may be disproportionately exposed.

Ovarian mitochondrial and oxidative stress proteins are altered by glyphosate exposure in mice

Glyphosate (GLY) usage for weed control is extensive. To investigate ovarian impacts of chronic GLY exposure, female C57BL6 mice were orally administered saline as vehicle control (CT) or GLY at 0.25 (G0.25), 0.5 (G0.5), 1.0 (G1.0), 1.5 (G1.5), or 2 (G2.0) mg/kg for five days per wk. for 20 wks. Feed intake increased (P < .05) in G1.5 and G2.0 mice and body weight increased (P < .05) in G1.0 mice. There was no impact of GLY on estrous cyclicity, nor did GLY affect circulating levels of 17β-estradiol or progesterone. Exposure to GLY did not impact heart, liver, spleen, kidney or uterus weight. Both ovarian weight and follicle number were increased (P < .05) by G2.0 but not affected at lower GLY concentrations. There were no detectable effects of GLY on ovarian protein abundance of pAKT, AKT, pAKT:AKT, γH2AX, STAR, CYP11A1, HSD3B, CYP19A, ERA or ERB. Increased (P < .05) abundance of ATM protein was observed at G0.25 but not higher GLY doses. A dose-dependent effect (P < .10) of GLY exposure on ovarian protein abundance as quantified by LC-MS/MS was observed (G0.25-4 increased, 19 decreased; G0.5-5 increased, 25 decreased; G1.0-65 increased, 7 decreased; G1.5-145 increased, 2 decreased; G2.0-159 increased, 4 decreased). Pathway analysis was performed using DAVID and identified glutathione metabolism, metabolic and proteasome pathways as GLY exposure targets. These data indicate that chronic low-level exposure to GLY alters the ovarian proteome and may ultimately impact ovarian function.

Invited Commentary: Women's Reproductive Life Spans and Subsequent Inflammatory Profiles-How to Best Measure Reproductive Life Span and the Need for Baseline Assessments

Inflammatory processes are known to drive the pathogenesis of several chronic diseases, including cardiovascular disease and Alzheimer disease, as well as all-cause mortality. Emerging research indicates that women who have a longer reproductive life span-roughly determined as the period from menarche to menopause or lifetime number of ovulatory cycles after accounting for anovulatory time spans-are at lower risk for these inflammation-related chronic diseases. The paradox is that ovulation is known to induce acute inflammation. Given the limited research assessing the relationship between reproductive life span and later inflammatory profiles, Huang et al. (Am J Epidemiol. 2020;189(7):660-670) set out to investigate this relationship within 2 of the most robust longitudinal cohort studies of women, the Nurses' Health studies. They found that after adjustment for other inflammation-related factors, including adiposity, exercise, and diet, lifetime ovulatory years was associated with lower C-reactive protein levels in both premenopausal and postmenopausal women. Huang et al. call attention to several challenges in research on women's reproductive life spans, including how to appropriately capture lifetime ovulatory cycles and the need for repeated measurements of inflammatory biomarkers across the life course if we wish to understand pathogenic processes linking reproductive factors to subsequent chronic disease.

Risk of hospitalization for early onset of cardiovascular disease among infertile women: a register-based cohort study

STUDY QUESTION

Is female infertility predictive of a woman’s future risk of early cardiovascular disease (CVD)?

SUMMARY ANSWER

Female infertility does not seem to be predictive of early CVD during a mean follow-up of 9 years.

WHAT IS KNOWN ALREADY

Associations between infertility and comorbidity have been found in several studies, but data on the association between female infertility and risk of CVD are scarce and inconclusive.

STUDY DESIGN, SIZE, DURATION

In this nationwide cohort study, we included 87 221 women registered in the Danish National IVF register, undergoing medically assisted reproduction (MAR) between 1st of January 1994 and 31st of December 2015. The cohort was followed for incident hospitalization due to CVD in the Danish National Patient Register from enrollment to 31 December 2015. Women with a history of CVD prior to enrollment were excluded. Cox proportional hazard models with age as the underlying time scale were used to estimate hazard ratios (HR) with 95% CI of CVD among women with an infertility diagnosis, compared to women without an infertility diagnosis. All analyses were adjusted for educational attainment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Female infertility and the reason for infertility was diagnosed and registered in the IVF register by specialists in Danish public and private fertility clinics since 1st of January 1994. In our cohort, 53 806 women (61.7%) were diagnosed with female factor infertility, while 33 415 (38.3%) did not have a female factor infertility diagnosis and made up the reference group.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 686 (1.3%) infertile women were hospitalized for CVD compared to 250 (0.7%) among women without an infertility diagnosis during a mean follow-up time of 9 years. We found no increased risk of early CVD in our analyses (adjusted HR 0.98, 95% CI: 0.85;1.14). Likewise, analyses stratified by specific infertility diagnosis, showed no risk difference.

LIMITATIONS, REASONS FOR CAUTION

We were unable to adjust for confounding parameters such as body mass index, cigarette smoking or alcohol consumption. These results may not be generalizable to infertile women who do not seek out fertility treatment, or infertile women with other lifestyle characteristics than Danish women.

WIDER IMPLICATIONS OF THE FINDINGS

Diagnosing female infertility or the time of MAR does not seem to be a window of opportunity where early screening for cardiovascular disease risk factors can have a prophylactic potential.

STUDY FUNDING/COMPETING INTEREST(S)

This study is part of the ReproUnion collaborative study, co-financed by the European Union, Interreg V ÖKS. None of the authors declare any conflict of interest.