Obesity and its impact on female reproductive health: unraveling the connections

When Weight Matters: How Obesity Impacts Reproductive Health and Pregnancy-A Systematic Review

PURPOSE OF REVIEW

This systematic review evaluates the impact of obesity on both male and female reproductive health, assisted reproductive technology (ART) outcomes, and pregnancy-related complications, providing a comprehensive synthesis of the evidence.

RECENT FINDINGS

Obesity is a critical factor adversely affecting reproductive health, ART success rates, and pregnancy outcomes. Recent studies indicate hormonal disruptions, metabolic syndrome, and epigenetic modifications as central mechanisms linking obesity to infertility and adverse pregnancy results. A systematic search adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines included 35 studies, focusing on obesity-related reproductive outcomes. The review highlights that obesity disrupts hormonal balance, including reductions in sex hormone-binding globulin (SHBG) and testosterone levels, alongside increased insulin resistance and chronic inflammation. These mechanisms impair ovarian function, endometrial receptivity, and sperm quality, resulting in prolonged time-to-pregnancy (TTP), reduced ART success rates, and increased miscarriage risk. During pregnancy, maternal obesity elevates risks of gestational diabetes mellitus (GDM), preeclampsia, and cesarean delivery while contributing to neonatal complications, such as macrosomia and neonatal intensive care unit (NICU) admissions. The findings emphasize the dual impact of maternal and paternal obesity on offspring health, particularly through epigenetic modifications leading to intergenerational metabolic dysfunction. This review underscores the necessity of preconception weight management, individualized ART protocols, and tailored antenatal care to mitigate obesity's adverse effects on reproductive outcomes. Future research should focus on understanding male infertility mechanisms, optimizing ART interventions for individuals with obesity, and conducting longitudinal studies on the intergenerational impacts of obesity on reproductive health. This synthesis provides actionable insights to guide clinical practices and future investigations.

Optimal waist circumference cut-off points for predicting metabolic syndrome among females of reproductive age in Wakiso district, central Uganda

Metabolic syndrome (MetS) poses a significant challenge to global public health, due to its strong association with Type 2 diabetes and cardiovascular disease. Waist circumference (WC) is a convenient metric for diagnosing MetS. Our study sought to establish waist circumference cut-off points that predict MetS among females of reproductive age in Wakiso district, central Uganda.The data collected were from a cross-sectional study conducted in Wakiso district, central Uganda, involving 697 randomly selected females aged 15 to 49, between 9th June 2021 and 17th August 2021. Data included MetS components: WC, High-Density Lipoprotein (HDL) Cholesterol, triglycerides, blood pressure, and fasting blood glucose. MetS status was identified based on two or more MetS components excluding WC. ROC analysis established the average optimal WC. The accuracy and performance of the cut-off points were evaluated through sensitivity, specificity, positive likelihood ratio, and the Youden Index. Of the 634 participants who were aged 18-49 years, 51.4% had two or more MetS risk factors. Their average optimal WC threshold was 80.3 cm. Variations in optimal WC thresholds were observed across different age groups: 80.4 cm (18-24 years), 79.9 cm (25-34 years), 85.6 cm (35-44 years), and 91.1 cm (45-49 years) respectively. The area under the ROC curve at the cut point for these age groups ranged from 0.78 to 0.86, indicating good discriminatory capability. The sensitivity ranged from 85% to 97%, specificity from 58% to 88%, and the Youden Index from 0.557 to 0.729. A waist circumference of 80.3 cm was the optimal threshold for identifying metabolic syndrome in females between the ages of 18 and 49 years in the setting. This finding concurs with the guidance set forth by the International Diabetes Federation. Additionally, study participants' WC cut-offs varied, ranging from 79.9 cm to 91.1 cm, depending on their age.

Exposure to circadian disrupting environment and high-fat diet during pregnancy and lactation alter reproductive competence and lipid profiles of liver, mammary, plasma and milk of ICR mice

This study's objective was to determine the effects of pre-pregnancy obesity induced by a high-fat diet and exposure to circadian-disrupting light-dark phase shifts on birth littler size, pup survival to 24h and growth to lactation day 12, and their relationship to maternal feeding patterns, fecal corticosterone levels, milk composition, and lipid profiles of liver, plasma, mammary gland, and milk. A 2 by 2 factorial designed experiment of female ICR mice assigned to control (CON; 10% fat) or high-fat (HF; 60% fat) and either a 12-hour light-dark (LD) cycle or a chronic jet lag model of 6-hour phase-shifts (PS) in light-dark cycle every 3 days throughout pregnancy and lactation, resulted in 4 treatment groups: CON-LD, CON-PS, HF-LD and HF-PS. HF diet increased maternal pre-pregnancy body weight and elevated milk lactose. Whereas PS reduced milk lactose within the CON diet group, and increased maternal feed intake and fecal corticosterone levels. PS exposure also affected the time of day of birth. Neither PS nor HF affected birth litter size or pup survival. Only diet impacted final litter weight, with HF greater than CON. Among the 1204 lipids detected by multiple reaction monitoring (MRM)-profiling, diet altered 67.1% in milk, 58.1% in mammary gland, 27.2% in the liver, and 10.9% in plasma, with HF increasing the carbon length of diacylglycerols in the liver and milk, and carbon length of triacylglycerols in plasma, mammary gland and milk. Although exposure to PS had no overall impact on maternal lipid profiles, interactions (P < 0.05) were found between PS and diets in the phosphatidylcholine and phosphatidylethanolanine class of lipids. Findings support that high fat diet and exposure to circadian disrupting environments impact maternal feeding behavior and stress responses as well as lipid profiles, which may relate to their negative association with maternal health and offspring development.

Impact of maternal body mass index on pregnancy outcomes following frozen embryo transfer: A systematic review and meta-analysis

OBJECTIVE

There is still a significant gap in understanding how maternal body mass index (BMI) impacts outcomes of pregnancy after frozen embryo transfer (FET). This review aims to evaluate the effects of various BMI categories on clinical pregnancy and live birth rates in women undergoing FET.

METHODS

PubMed, Scopus, Embase, and Web of Science databases were searched for studies, published up to March, 2024, using the keywords "obesity", "overweight", "obese", "maternal body mass index," "pregnancy outcomes," "frozen embryo transfer,". Eligible studies were selected based on predefined inclusion criteria, statistical analysis was performed using a random-effects model, and ther results were presented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

A total of 17 studies were included in the meta-analysis. Pooled findings indicate significantly reduced live birth rate in underweight (OR 0.93; 95% CI: 0.89, 0.98) and obese (OR 0.85; 95% CI: 0.77, 0.93) women but not in those who were overweight (OR 0.96; 95% CI: 0.92, 1.00), compared to those with normal BMI. Further, only those women who were underweight (OR 0.91; 95% CI: 0.85, 0.97) had reduced odds of clinical pregnancy rate but not those who were overweight (OR 0.99; 95% CI: 0.94, 1.05) or obese (OR 0.92; 95% CI: 0.82, 1.03).

CONCLUSION

Maternal BMI impacts pregnancy outcomes after frozen embryo transfer, with underweight and obese women having lower live birth rates and only underweight women showing reduced clinical pregnancy rates compared to those with normal BMI. These findings underscore the importance of addressing BMI in women undergoing FET to improve pregnancy outcomes.

Association between female waist-hip ratio and live birth in patients undergoing in vitro fertilization: a retrospective cohort study

Background

Maternal obesity is associated with adverse pregnancy outcomes. It negatively affects IVF/ICSI outcomes and offspring health. However, it is unclear whether waist-hip ratio (WHR) has an impact on outcomes of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles.

Methods

A retrospective cohort study screened 943 patients who underwent IVF/ICSI treatment between February and June 2020 in Shanghai, China, and 828 patients were finally included in the analyses. The body weight, height, waist circumference and hip circumference were measured before ovarian stimulation, and their IVF/ICSI outcomes were followed up. The cut-off point of WHR was determined by the area under the receiver operating characteristic (ROC) curve. Live birth rate from the first embryo transfer cycle was the primary outcome. The secondary outcomes included cumulative live birth, miscarriage rate and birthweight.

Results

Women with relatively high WHR (≥0.783) showed lower live birth rate (adjusted odds ratio (aOR): 0.657, 95%CI: 0.466-0.926), lower cumulative live birth rate (aOR: 0.580, 95%CI: 0.413-0.814), and higher miscarriage rate (aOR=2.865, 95%CI: 1.300-6.316) as compared with those with low WHR (<0.783), independently of BMI. Joint WHR and BMI analyses showed that, compared with the reference group (those with low WHR and normal weight), those with high WHR and normal BMI had lower live birth rate (aOR=0.653, 95%CI: 0.447-0.954) and cumulative live birth rate (aOR=0.600, 95%CI: 0.413-0.872), and higher miscarriage rate (aOR=2.865, 95%CI: 1.229-6.676), Whereas the patients with both high WHR and high BMI only showed a significant lower cumulative live birth rate (aOR=0.612, 95%CI: 0.404-0.926). Moreover, there was no significant association between BMI and pregnancy outcomes, or between maternal WHR and birth weights.

Conclusions

Our results demonstrated that higher WHR was associated with lower fecundability in women undergoing IVF/ICSI cycles, independently of BMI. Interestingly, the adverse effects of central obesity were more evident in patients with lower BMI. Thus WHR appears to be a better predictor of female fertility treatment outcomes as compared with BMI.

The hidden impact of GLP-1 receptor agonists on endometrial receptivity and implantation

Increasing infertility rates represent a growing medical challenge in modern societies resulting from a complex interplay of sociocultural trends, lifestyle factors, exposure to environmental toxins, and underlying health problems. Women's fertility is particularly vulnerable to these shifts. The obesogenic lifestyle not only accelerates weight gain, but also disrupts ovulation driving the rise in infertility. Among several medications used for treating obesity and type 2 diabetes, glucagon-like peptide-1 receptor agonists (GLP-1RAs) show promising improvement in female fertility most likely by stimulating ovulation. However, the effects of GLP-1RAs on the endometrium remain unclear. Further studies are needed to investigate the impact of GLP-1RAs on endometrial receptivity and embryo implantation and early development. The aim of this study is to address the knowledge gap regarding the effects of GLP-1RAs on human reproduction, with special focus on the endometrium. Understanding these mechanisms may help to develop new strategies for improving fertility treatment, reduce implantation failure and address potential safety concerns regarding teratogenicity and adverse developmental outcomes for children born to women conceiving during or soon after GLP-1RA treatment.

Association between the body roundness index and female infertility: a cross-sectional study from NHANES

Background

Infertility is strongly associated with obesity. The body roundness index (BRI) is a more accurate assessment of visceral fat content than the body mass index (BMI). However, current evidence on the association between visceral fat accumulation and infertility remains insufficient and controversial. Therefore, we utilized the 2017-2020 National Health and Nutrition Examination Survey (NHANES) database to explore the correlation between BRI and infertility.

Methods

We used multiple logistic regression, smoothed curve fitting, subgroup analyses, and interaction tests to investigate the potential association between BRI and infertility. Additionally, we assessed the ability of BRI and BMI to predict infertility risk using receiver operating curve (ROC) analysis and calculate the area under the curve (AUC),sensitivity, and specificity.

Results

In the study, 1463 women aged 20 to 45 participated, and 172 of them were found to be infertile. After adjusting for all factors except body measurements, the findings indicated that for each one-unit increase in BRI, there was a 19% increase in the risk of infertility (OR = 1.19, 95% CI 1.05, 1.34). The analysis also revealed a positive nonlinear relationship between BRI and infertility. Furthermore, based on the ROC curves, it was observed that BRI was a more reliable predictor of infertility risk compared to BMI (BRI AUC = 0.5773, BMI AUC = 0.5681).

Conclusion

This study demonstrated a positive association between higher BRI values and infertility among adult women in the United States and showed a stronger association than BMI.

The Contribution of Precision Nutrition Intervention in Subfertile Couples

BACKGROUND/AIM

Subfertility is characterized by a decrease in reproductive efficiency, which can result in delayed pregnancy, and affects one in six individuals during their lifetime. The present narrative review aims to evaluate the contribution of precision nutrition to changes in fertility in subfertile couples.

METHODS

The literature review was carried out through bibliographic research in the PubMed, Scopus, SciELO and Google Scholar databases. The following search criteria were applied: (1) original articles and narrative, systematic or meta-analytic reviews, and (2) the individual or combined use of the following keywords: "genetic variation", "nutrigenetics", "precision nutrition", "couple's subfertility", and "couple's infertility". A preliminary reading of all the articles was carried out, and only those that best fit the themes and subthemes of the narrative review were selected.

RESULTS

Scientific evidence suggests that adherence to a healthy diet that follows the Mediterranean pattern is associated with increased fertility in women and improved semen quality in men, better metabolic health and reduced levels of inflammation and oxidative stress, as well as maintaining a healthy body weight. The integration of different tools, such as nutrigenetics, predictive biochemical analyses, intestinal microbiota tests and clinical nutrition software, used in precision nutrition interventions can contribute to providing information on how diet and genetics interact and how they can influence fertility.

CONCLUSIONS

The adoption of a multidisciplinary and precision approach allows the design of dietary and lifestyle recommendations adapted to the specific characteristics and needs of couples with subfertility, thus optimizing reproductive health outcomes and achieving successful conception.

Nitrate-Nitrite-Nitric Oxide Pathway, Oxidative Stress, and Fertility Outcomes in Morbidly Obese Women Following Bariatric Surgery: A Systematic Review

Obesity reduces nitric oxide (NO) production due to endothelial nitric oxide synthase (eNOS) dysfunction, resulting in oxidative stress, mitochondrial dysfunction, and chronic inflammation. These factors have a negative impact on reproductive health, including oocyte quality, endometrial receptivity, and embryo implantation. When oxidative stress affects eNOS function, the nitrate-nitrite-nitric oxide (NO3-NO2-NO) pathway provides an alternate route for NO production. Bariatric surgery has been found to restore NO production, reduce oxidative stress, and improve fertility in morbidly obese women. This review investigates the molecular mechanisms by which bariatric surgery affects eNOS activity, the NO3-NO2-NO pathway, and oxidative stress reduction, with an emphasis on intracellular activities including mitochondrial biogenesis and NO production. A systematic review employing PRISMA criteria included articles published between 2000 and 2024 from PubMed, Scopus, and Embase that investigated NO3-NO2 pathways, oxidative stress markers, hormonal alterations, and reproductive outcomes in morbidly obese women following bariatric surgery. After evaluating 1542 studies, 11 were selected for the final analysis. Results showed a 45% increase in NO3-NO2 levels (p < 0.001), a 35% reduction in oxidative stress indicators (p < 0.01), a 60% increase in pregnancy rates, and a 50% increase in spontaneous ovulation rates following surgery. These benefits were connected to improved mitochondrial function and endometrial receptivity as a result of reduced oxidative stress and inflammation. The NO3-NO2-NO route is critical in compensating for lower NO generation under oxidative stress and hypoxia, and bariatric surgery significantly improves this pathway to optimize blood flow, mitochondrial function, and reproductive results.

Efficacy and safety of dietary polyphenol administration as assessed by hormonal, glycolipid metabolism, inflammation and oxidative stress parameters in patients with PCOS: a meta-analysis and systematic review

BACKGROUND

The current knowledge about the efficacy and safety of dietary polyphenol administration in patients with polycystic ovarian syndrome (PCOS) is divergent.

OBJECTIVE

To evaluate the pooled efficacy and safety of dietary polyphenol administration in the treatment of patients with PCOS.

METHODS

The pubmed, Embase, Scopus, Cochrane Library, and Web of Science databases were searched for randomized controlled trials (RCTs) of dietary polyphenol administration for the treatment of PCOS. English-language RCTs involving adults with PCOS were thoroughly searched in electronic databases from the time of their establishment to May 2024. Random-effects models were used because heterogeneity was derived from differences in intervention materials and study duration, among other confounding factors. The effect sizes of the outcomes in the pooled analysis are expressed as weighted mean differences (WMDs) and 95% confidence intervals (CIs).

RESULTS

A total of 15 RCTs involving 934 patients were finally included. Compared with control treatments, dietary polyphenol administration significantly reduced luteinizing hormone (LH) (WMD: -0.85, 95% CI [-1.32 to -0.38], p = 0.00), and prolactin levels (WMD: -3.73, 95% CI [-6.73 to -0.74], p = 0.01). Dietary polyphenol administration significantly reduced insulin levels (WMD: -0.85, 95% CI [-1.32 to -0.38], p = 0.00). Regarding lipid metabolism, dietary polyphenol administration only reduced triglyceride levels (WMD: -8.96, 95% CI [-16.44 to -1.49], p = 0.02). Malondialdehyde (MDA) (WMD: -0.65, 95% CI [-0.68 to -0.62], p = 0.00), tumor necrosis factor (TNF-α) (WMD: -1.39, 95% CI [-2.41 to -0.37], p = 0.01) concentrations were significantly reduced by dietary polyphenol administration. None of the interventions significantly affected weight, body mass index (BMI), waist circumference (WC), homeostatic model-insulin resistance (HOMA-IR), fasting blood sugar (FBS), glycated hemoglobin (HBA1c), follicle-stimulating hormone (FSH), testosterone (T), dehydroepiandrosterone (DHEA), estradiol (E2), anti-Müllerian hormone (AMH), quantitative insulin-sensitivity check index (QUICKI), sex hormone-binding globulin (SHBG), total antioxidant capacity (TAC), C-peptide, C-reactive protein (CRP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), cholesterol, cholesterol/HDL, acne score, thyroid-stimulating hormone (TSH), aspartate aminotransferase (AST), alanine aminotransferase (ALT) or alkaline phosphatase (ALP).

CONCLUSION

Dietary polyphenol administration was efficacious in patients with PCOS in our study. This review might provide new insight into the treatment of patients with PCOS and the potential of daily polyphenol supplementation in patients with PCOS. Nevertheless, these results must be interpreted carefully as a result of the heterogeneity and risk of bias among the studies and we expect that more high-quality RCTs evaluating the efficacy and safety of dietary polyphenol adnimistration in patients with PCOS will be conducted in the future.

SYSTEMATIC REVIEW REGISTRATION

CRD42024498494.

Association between visceral adipose surrogates and infertility among reproductive-aged females: a cross-sectional study

Background

Visceral adipose tissue (VAT) exerts a substantial influence on female infertility. Nevertheless, the relationship between VAT surrogates and female infertility remains ambiguous.

Methods

This study employed a cross-sectional design and analyzed data from the National Health and Nutrition Examination Survey (NHANES, 2012-2016). Weighted logistic regression models were utilized to examine the association between VAT surrogates and infertility. Furthermore, Receiver Operating Characteristic (ROC) curve analysis was conducted to assess the diagnostic efficacy of these surrogates for infertility.

Results

Individuals experiencing infertility exhibited markedly elevated levels of the Chinese Visceral Adiposity Index (CVAI) (108.30 vs. 69.86, P<0.001) and Visceral Adiposity Index (VAI) (1.68 vs. 1.35, P<0.001). When considered as a continuous variable, CVAI (odds ratio [OR]: 1.06, 95% confidence interval [CI]: 1.03-1.09, P<0.001), rather than VAI (OR:1.02, 95%CI: 0.98-1.06, P=0.259), demonstrated a significant association with the risk of female infertility. Consistent findings were also evident after dividing participants into 4 subgroups based on CVAI quartiles. Additionally, ROC curves indicated that CVAI exhibited the most robust diagnostic value for female infertility compared to other indices. Subgroup analyses revealed a robust association between CVAI and infertility across different populations.

Conclusion

Females with elevated CVAI levels faced a significantly heightened risk of infertility in the United States. CVAI holds promise as a valuable tool for stratifying the risk of infertility.

The Impact of Parental Preconception Nutrition, Body Weight, and Exercise Habits on Offspring Health Outcomes: A Narrative Review

An increasing number of studies highlight the critical role of both maternal and paternal nutrition and body weight before conception in shaping offspring health. Traditionally, research has focused on maternal factors, particularly in utero exposures, as key determinants of chronic disease development. However, emerging evidence underscores the significant influence of paternal preconception health on offspring metabolic outcomes. While maternal health remains vital, with preconception nutrition playing a pivotal role in fetal development, paternal obesity and poor nutrition are linked to increased risks of metabolic disorders, including type 2 diabetes and cardiovascular disease in children. This narrative review aims to synthesize recent findings on the effects of both maternal and paternal preconception health, emphasizing the need for integrated early interventions. The literature search utilized PubMed, UNF One Search, and Google Scholar, focusing on RCTs; cohort, retrospective, and animal studies; and systematic reviews, excluding non-English and non-peer-reviewed articles. The findings of this review indicate that paternal effects are mediated by epigenetic changes in sperm, such as DNA methylation and non-coding RNA, which influence gene expression in offspring. Nutrient imbalances during preconception in both parents can lead to low birth weight and increased metabolic disease risk, while deficiencies in folic acid, iron, iodine, and vitamin D are linked to developmental disorders. Additionally, maternal obesity elevates the risk of chronic diseases in children. Future research should prioritize human studies to explore the influence of parental nutrition, body weight, and lifestyle on offspring health, ensuring findings are applicable across diverse populations. By addressing both maternal and paternal factors, healthcare providers can better reduce the prevalence of metabolic syndrome and its associated risks in future generations.

The Interplay of Uterine Health and Obesity: A Comprehensive Review

Uterine physiology encompasses the intricate processes governing the structure, function, and regulation of the uterus, a pivotal organ within the female reproductive system. The escalating prevalence of obesity has emerged as a significant global health issue, profoundly impacting various facets of well-being, including female reproductive health. These effects extend to uterine structure and function, influencing reproductive health outcomes in women. They encompass alterations in uterine morphology, disruptions in hormonal signaling, and inflammatory processes. Insulin and leptin, pivotal hormones regulating metabolism, energy balance, and reproductive function, play crucial roles in this context. Insulin chiefly governs glucose metabolism and storage, while leptin regulates appetite and energy expenditure. However, in obesity, resistance to both insulin and leptin can develop, impacting uterine function. Inflammation and oxidative stress further exacerbate the development of uterine dysfunction in obesity. Chronic low-grade inflammation and heightened oxidative stress, characteristic of obesity, contribute to metabolic disruptions and tissue damage, including within the uterus. Obesity significantly disrupts menstrual cycles, fertility, and pregnancy outcomes in women. The accumulation of excess adipose tissue disrupts hormonal equilibrium, disturbs ovarian function, and fosters metabolic irregularities, all of which detrimentally impact reproductive health.

Association between cardiometabolic index and female infertility: A population-based study

BACKGROUND

One of the risk indicators of infertility is obesity. The cardiometabolic index (CMI) comprises obesity and blood lipids and is regarded as a novel indicator for evaluating obesity. Nevertheless, it is unclear whether it has any connection to infertility. This study set out to investigate the association between infertility and CMI.

METHODS

Based on cross-sectional data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES), infertility and CMI statistics with complete information were selected. This study investigated the correlation between CMI and infertility using multivariate logistic regression analyses and subgroups. Use fitted smooth curves and threshold effect analysis to describe the nonlinear association between CMI and infertility.

RESULTS

202 (13.31%) among the 1720 participants that got involved in the investigation were female infertile. Among the three models, the outcomes confirmed a positive correlation between CMI levels and the incidence of infertility (OR = 1.12, 95% CI: 1.01-1.24). Additionally, significant relationships were maintained in subgroup analysis (p > 0.05). Smooth curve fitting indicated a nonlinear positive connection between CMI and infertility, and an inflection point of 0.93 (log-likelihood ratio P < 0.05) was shown by threshold effect analysis.

CONCLUSION

Our findings suggest a significant relationship between CMI and infertility in American females. This helps identify high-risk groups for infertility, informing clinical practice and public health policy to improve metabolic and reproductive health.

Exposure to Environmental Chemicals and Infertility Among US Reproductive-Aged Women

Environmental chemical exposure has been rising over the past few decades but its impact on fertility remains uncertain. We assessed exposures to 23 common chemicals across a range of sociodemographic characteristics and their relationship with self-reported infertility. The analytic sample was non-pregnant women aged 18-49 years without a history of hysterectomy or oophorectomy (n = 2579) from the National Health and Nutrition Examination Survey (2013-2016). Environmental chemical exposure was assessed with biospecimens and dichotomized as high and low levels of exposure based on the median. Logistic regression models estimated the adjusted odds ratio (aOR) and 95% confidence intervals (CIs) for the association between high levels of exposure and infertility, adjusted for age, race, education level, family income, and smoking status. We observed associations between infertility and cadmium [aOR: 1.88; 95% CI: 1.02-3.47] and arsenic [aOR: 1.88 (1.05-3.36)]. Two pesticides hexachlorobenzene [OR: 2.04 (1.05-3.98)] and oxychlordane [OR: 2.04 (1.12-3.69)] were also associated with infertility in unadjusted analyses. There were negative associations with two Per- and polyfluoroalkyl substances with n-perfluorooctanoic acid [aOR: 0.51: (0.30-0.86)] and n-perfluorooctane sulfonic acid [aOR: 0.51: (0.26-0.97). Specific chemicals may contribute to infertility risk, highlighting the need for targeted public health strategies to mitigate exposure.

Relationship between Cardiometabolic index and endometriosis in a US nationally representative sample: results from NHANES 1999-2006

Background

Endometriosis is an estrogen-dependent gynecological endocrine condition and a systemic inflammatory disease associated to improper lipid metabolism and increased cardiovascular risk. The Cardiometabolic Index (CMI) is a novel indicator representing visceral adipose tissue distribution and metabolic dysfunction, integrating lipid metabolism indicators and the waist-to-height ratio. While anomalies in lipid metabolism are often associated with (BMI) Body Mass Index, literature consistently shows a negative link between endometriosis and female BMI, and some studies have found that endometriosis is one of the few reproductive diseases not persistently positively correlated with obesity. Given the limitations of BMI, a comprehensive index like CMI is crucial for exploring the incidence of endometriosis. Currently, research on the correlation between CMI and endometriosis is lacking, prompting this study to investigate this association.

Objective

To investigate the association between the CMI and the risk of having endometriosis in a sample representing the entire U.S. population.

Study design

A cross-sectional analysis was conducted using data from four cycles of the National Health and Nutrition Examination Survey (NHANES) spanning the years 1999 to 2006. The study included individuals aged 20 to 54 with a documented history of endometriosis and complete CMI data. Logistic regression analysis, subgroup and interaction analyses, smooth curve fitting, and restricted cubic splines (RCS) were utilized to examine the association between CMI and endometriosis.

Results

The study found that individuals with higher CMI had an increased probability of developing endometriosis. This relationship remained significant after adjusting for potential confounders such as age, ethnicity, Poverty Income Ratio (PIR), drinking, smoking, education level, and marital status. The fully adjusted model revealed a positive correlation between CMI and endometriosis (OR = 1.21; 95% CI, 1.04-1.40, p < 0.05). Subgroup and interaction analyses showed no significant effect modification by age, BMI, PIR, hypertension, drinking, smoking, or menarche age (all p-values for interaction > 0.05).

Conclusion

Our study shows a link between CMI and the chance of getting endometriosis.Due to the common occurrence of endometriosis and the lack of clarity surrounding their cause, more study is needed to confirm our results and find out if CMI could be used as a warning sign for endometriosis.

Application of Eight Machine Learning Algorithms in the Establishment of Infertility and Pregnancy Diagnostic Models: A Comprehensive Analysis of Amino Acid and Carnitine Metabolism

To explore the effects of altered amino acids (AAs) and the carnitine metabolism in non-pregnant women with infertility (NPWI), pregnant women without infertility (PWI) and infertility-treated pregnant women (ITPW) compared with non-pregnant women (NPW, control), and develop more efficient models for the diagnosis of infertility and pregnancy, 496 samples were evaluated for levels of 21 AAs and 55 carnitines using targeted high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Three methods were used to screen the biomarkers for modeling, with eight algorithms used to build and validate the model. The ROC, sensitivity, specificity, and accuracy of the infertility diagnosis training model were higher than 0.956, 82.89, 66.64, and 82.57%, respectively, whereas those of the validated model were higher than 0.896, 77.67, 69.72, and 83.38%, respectively. The ROC, sensitivity, specificity, and accuracy of the pregnancy diagnosis training model were >0.994, 96.23, 97.79, and 97.69%, respectively, whereas those of the validated model were >0.572, 96.39, 93.03, and 94.71%, respectively. Our findings indicate that pregnancy may alter the AA and carnitine metabolism in women with infertility to match the internal environment of PWI. The developed model demonstrated good performance and high sensitivity for facilitating infertility and pregnancy diagnosis.

The Impact of the Endocrine and Immunological Function of Adipose Tissue on Reproduction in Women with Obesity

Obesity, which leads to metabolic dysregulation and body function impairment, emerges as one of the pressing health challenges worldwide. Excessive body fat deposits comprise a dynamic and biologically active organ possessing its own endocrine function. One of the mechanisms underlying the pathophysiology of obesity is low-grade systemic inflammation mediated by pro-inflammatory factors such as free fatty acids, lipopolysaccharides, adipokines (including leptin, resistin and visfatin) and cytokines (TNF-α, IL-1β, Il-6), which are secreted by adipose tissue. Together with obesity-induced insulin resistance and hyperandrogenism, the exacerbated immune response has a negative impact on the hypothalamic-pituitary-gonadal axis at all levels and directly affects reproduction. In women, it results in disrupted ovarian function, irregular menstrual cycles and anovulation, contributing to infertility. This review focuses on the abnormal intracellular communication, altered gene expression and signaling pathways activated in obesity, underscoring its multifactorial character and consequences at a molecular level. Extensive presentation of the complex interplay between adipokines, cytokines, immune cells and neurons may serve as a foundation for future studies in search of potential sites for more targeted treatment of reproductive disorders related to obesity.

Pregnancy, delivery, and neonatal outcomes among women with PCOS and endometriosis: a population database cohort

PURPOSE

PCOS and endometriosis are independent risk factors for perinatal outcomes. Little research has evaluated the concomitant effects of these conditions, nor have studies been conducted on a population database. We sought to identify the pregnancy, delivery, and neonatal outcomes in women with polycystic ovary syndrome (PCOS) and endometriosis vs. PCOS without endometriosis.

METHODS

A retrospective population-based cohort study was performed extracting data using ICD-9 codes from the HCUP-NIS Database from 2004 to 2014. Endometriosis in women with PCOS represented the study group (n = 163), and the remaining PCOS, non-endometriosis patients constituted the reference group (n = 14,719). Subjects were included once per delivery. Demographics were compared using chi-squared tests. Confounding effects in pregnancy outcomes were controlled using binary logistic regression analysis.

RESULTS

Concomitant endometriosis and PCOS patients were more likely to be white (88.5% vs.71.0%, p < 0.001), with BMI < 30 kg/m2 (87.1% vs.77.8%, p < 0.004) and from lower income quartiles (27.1% vs.17.1%, p < 0.017) when compared to PCOS without endometriosis. Comparing pregnancy complication rates, placental abruption (p < 0.018, aOR 3.01, 95% CI 1.21-7.50), Cesarean section (p < 0.003, aOR 1.75, 95% CI 1.21-2.53), deep venous thromboses (p < 0.002, aOR 74.31, 95% CI 4.57-1209.21), and venous thromboembolic events (p < 0.031, aOR 10.40, 95% CI 1.24-87.37), were increased in the study group compared to the reference group.

CONCLUSION

Women with PCOS and endometriosis were more likely to be white, of lower socioeconomic status, lean, and experience abruptio-placenta, cesarean deliveries, and venous thromboembolisms. Since little was previously known about the combined outcomes of PCOS and endometriosis, it is difficult to counsel patients on risks. Our findings can help clinicians manage pregnant PCOS patients with endometriosis to minimize complications such as abruptio placenta and VTE.

The Molecular Link between Obesity and the Endometrial Environment: A Starting Point for Female Infertility

Female infertility constitutes a growing health problem in developing countries and could be associated with several possible causes including reproductive disorders, congenital malformations, infections and hormonal dysfunction. Nonetheless, a series of additional factors can also negatively impact female fertility and are represented by chronic exposure to environmental pollutants, stress, unhealthy lifestyle choices such as cigarette smoking and, among others, obesity. Excess weight is associated with several chronic diseases, and growing evidence demonstrates that it can compromise reproductive physiology due to its influence on endometrial gene expression and receptivity. Thus, the current review of the literature mainly focused on how obesity can impair uterine receptivity, mostly from a molecular point of view throughout the window of implantation (WOI) period at an endometrial level. It was also highlighted that an obesity-related increase in adipose tissue may lead to a modulation in the expression of multiple pathways, which could cause a hostile endometrial environment with a consequent negative impact on the uterine receptivity and the establishment of pregnancy. Thanks to the use of the endometrial receptivity assay (ERA), a specific microarray that studies the expression of a series of genes, it is now possible to evaluate the endometrial status of patients with infertility problems in a more detailed manner. Moreover, female fertility and endometrial receptivity could be affected by endometriosis, a chronic benign gynecological disease, whose cause-and-effect relationship to obesity is still uncertain. Therefore, further investigations would be required to better elucidate these mechanisms that govern embryo implantation and could be potentially useful for the generation of new strategies to overcome implantation failure and improve the pregnancy rates in obese women.

Examining the causal relationship between sex hormone-binding globulin (SHBG) and infertility: A Mendelian randomization study

BACKGROUND

The causal relationship between sex hormone-binding globulin (SHBG) and infertility has remained unclear. Thus, we used Mendelian randomization (MR) to investigate this relationship.

METHODS

Risk factors for SHBG were extracted from European individuals within the UK Biobank using single-nucleotide polymorphism (SNP) data. Summary-level data for infertility outcomes were obtained from the FinnGen dataset. The causal relationship between SHBG and infertility was examined using inverse variance weighted, weighted model, weighted median, and MR-Egger regression analyses. Additionally, Cochran's Q test and Egger intercept tests were used to confirm the heterogeneity and pleiotropy of identified instrumental variables (IVs).

RESULTS

Our findings revealed a significant negative association between sex hormone-binding globulin (SHBG) levels and infertility, particularly with anovulation, a specific form of female infertility. However, SHBG did not exert a causal impact on male infertility or on female infertility of tubal origin.

CONCLUSIONS

SHBG expression offers protection against the development of certain types of female infertility, suggesting it is a potential therapeutic target for infertility.

Mechanism of elevated LH/FSH ratio in lean PCOS revisited: a path analysis

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder affecting 5-20% of reproductive-age women. However, the treatment of PCOS is mainly based on symptoms and not on its pathophysiology. Neuroendocrine disturbance, as shown by an elevated LH/FSH ratio in PCOS patients, was thought to be the central mechanism of the syndrome, especially in lean PCOS. LH and FSH secretion are influenced by GnRH pulsatility of GnRH neurons in the hypothalamus. Kisspeptin is the main regulator of GnRH secretion, whereas neurokinin B (NKB) and dynorphin regulate kisspeptin secretion in KNDy neurons. This study aims to deepen the understanding of the neuroendocrine disorder in lean PCOS patients and its potential pathophysiology-based therapy. A cross-sectional study was performed at Dr. Cipto Mangunkusumo Kencana Hospital and the IMERI UI HRIFP cluster with 110 lean PCOS patients as subjects. LH, FSH, LH/FSH ratio, kisspeptin, NKB, dynorphin, leptin, adiponectin, AMH, fasting blood glucose, fasting insulin, HOMA-IR, testosterone, and SHBG were measured. Bivariate and path analyses were performed to determine the relationship between variables. There was a negative association between dynorphin and kisspeptin, while NKB levels were not associated with kisspeptin. There was no direct association between kisspeptin and the LH/FSH ratio; interestingly, dynorphin was positively associated with the LH/FSH ratio in both bivariate and pathway analyses. AMH was positively correlated with the LH/FSH ratio in both analyses. Path analysis showed an association between dynorphin and kisspeptin levels in lean PCOS, while NKB was not correlated with kisspeptin. Furthermore, there was a correlation between AMH and the LH/FSH ratio, but kisspeptin levels did not show a direct significant relationship with the LH/FSH ratio. HOMA-IR was negatively associated with adiponectin levels and positively associated with leptin and FAI levels. In conclusion, AMH positively correlates with FAI levels and is directly associated with the LH/FSH ratio, showing its important role in neuroendocrinology in lean PCOS. From the path analysis, AMH was also an intermediary variable between HOMA-IR and FAI with the LH/FSH ratio. Interestingly, this study found a direct positive correlation between dynorphin and the LH/FSH ratio, while no association between kisspeptin and the LH/FSH ratio was found. Further research is needed to investigate AMH and dynorphin as potential therapeutic targets in the management of lean PCOS patients.