An Assessment of the Mechanophysical and Hormonal Impact on Human Endometrial Epithelium Mechanics and Receptivity.

The endometrial epithelium and underlying stroma undergo profound changes to support and limit embryo adhesion and invasion, which occur in the secretory phase of the menstrual cycle during the window of implantation. This coincides with a peak in progesterone and estradiol production. We hypothesized that the interplay between hormone-induced changes in the mechanical properties of the endometrial epithelium and stroma supports this process. To study it, we used hormone-responsive endometrial adenocarcinoma-derived Ishikawa cells growing on substrates of different stiffness. We showed that Ishikawa monolayers on soft substrates are more tightly clustered and uniform than on stiff substrates. Probing for mechanical alterations, we found accelerated stress-relaxation after apical nanoindentation in hormone-stimulated monolayers on stiff substrates. Traction force microscopy furthermore revealed an increased number of foci with high traction in the presence of estradiol and progesterone on soft substrates. The detection of single cells and small cell clusters positive for the intermediate filament protein vimentin and the progesterone receptor further underscored monolayer heterogeneity. Finally, adhesion assays with trophoblast-derived AC-1M-88 spheroids were used to examine the effects of substrate stiffness and steroid hormones on endometrial receptivity. We conclude that the extracellular matrix and hormones act together to determine mechanical properties and, ultimately, embryo implantation.

The Heterogeneity of Post-Menopausal Disease Risk: Could the Basis for Why Only Subsets of Females Are Affected Be Due to a Reversible Epigenetic Modification System Associated with Puberty, Menstrual Cycles, Pregnancy and Lactation, and, Ultimately, Menopause?

For much of human evolution, the average lifespan was <40 years, due in part to disease, infant mortality, predators, food insecurity, and, for females, complications of childbirth. Thus, for much of evolution, many females did not reach the age of menopause (45-50 years of age) and it is mainly in the past several hundred years that the lifespan has been extended to >75 years, primarily due to public health advances, medical interventions, antibiotics, and nutrition. Therefore, the underlying biological mechanisms responsible for disease risk following menopause must have evolved during the complex processes leading to Homo sapiens to serve functions in the pre-menopausal state. Furthermore, as a primary function for the survival of the species is effective reproduction, it is likely that most of the advantages of having such post-menopausal risks relate to reproduction and the ability to address environmental stresses. This opinion/perspective will be discussed in the context of how such post-menopausal risks could enhance reproduction, with improved survival of offspring, and perhaps why such risks are preserved. Not all post-menopausal females exhibit risk for this set of diseases, and those who do develop such diseases do not have all of the conditions. The diseases of the post-menopausal state do not operate as a unified complex, but as independent variables, with the potential for some overlap. The how and why there would be such heterogeneity if the risk factors serve essential functions during the reproductive years is also discussed and the concept of sets of reversible epigenetic changes associated with puberty, pregnancy, and lactation is offered to explain the observations regarding the distribution of post-menopausal conditions and their potential roles in reproduction. While the involvement of an epigenetic system with a dynamic "modification-demodification-remodification" paradigm contributing to disease risk is a hypothesis at this point, validation of it could lead to a better understanding of post-menopausal disease risk in the context of reproduction with commonalities may also lead to future improved interventions to control such risk after menopause.

Minerals and the Menstrual Cycle: Impacts on Ovulation and Endometrial Health.

The role of minerals in female fertility, particularly in relation to the menstrual cycle, presents a complex area of study that underscores the interplay between nutrition and reproductive health. This narrative review aims to elucidate the impacts of minerals on key aspects of the reproductive system: hormonal regulation, ovarian function and ovulation, endometrial health, and oxidative stress. Despite the attention given to specific micronutrients in relation to reproductive disorders, there is a noticeable absence of a comprehensive review focusing on the impact of minerals throughout the menstrual cycle on female fertility. This narrative review aims to address this gap by examining the influence of minerals on reproductive health. Each mineral's contribution is explored in detail to provide a clearer picture of its importance in supporting female fertility. This comprehensive analysis not only enhances our knowledge of reproductive health but also offers clinicians valuable insights into potential therapeutic strategies and the recommended intake of minerals to promote female reproductive well-being, considering the menstrual cycle. This review stands as the first to offer such a detailed examination of minerals in the context of the menstrual cycle, aiming to elevate the understanding of their critical role in female fertility and reproductive health.

Effects of epidural steroid injections on menstrual cycle in women: An observational study.

OBJECTIVES: The aim of this study was to investigate the effect of epidural steroid injections on the menstrual cycle of women and to identify risk factors in those with changes. METHODS: A total of 78 women who had epidural steroid injections between the ages of 18 and 55 years were retrospectively analyzed. The patients were called by phone and asked whether there was any change in their menstrual cycles after the epidural injections. Data including demographic and clinical characteristics, body height and weight, education status, alcohol and smoking habits, comorbidities, number of children, birth control method, history of cesarean section, miscarriage, and abortion were recorded. RESULTS: Changes in the menstrual cycle were seen in five of 12 patients who underwent cervical interlaminar epidural steroid injection, in 27 of 56 patients who underwent lumbar transforaminal epidural steroid injection, in one of two patients who underwent lumbar interlaminar epidural steroid injection, and in three of eight patients who underwent caudal epidural steroid injection. The number of patients with obesity was higher in the patients with changes than those without, indicating a statistically significant difference (41.7% vs. 14.3%, respectively; p=0.007). CONCLUSION: Our study suggests that epidural steroid injections are associated with changes in the menstrual cycle. Obesity is a risk factor for menstrual cycle changes after epidural steroid injections.

Evidence that the woman's ovarian cycle is driven by an internal circamonthly timing system.

The ovarian cycle has a well-established circa-monthly rhythm, but the mechanisms involved in its regularity are unknown. Is the rhythmicity driven by an endogenous clock-like timer or by other internal or external processes? Here, using two large epidemiological datasets (26,912 cycles from 2303 European women and 4786 cycles from 721 North American women), analyzed with time series and circular statistics, we find evidence that the rhythmic characteristics of the menstrual cycle are more likely to be explained by an endogenous clock-like driving mechanism than by any other internal or external process. We also show that the menstrual cycle is weakly but significantly influenced by the 29.5-day lunar cycle and that the phase alignment between the two cycles differs between the European and the North American populations. Given the need to find efficient treatments of subfertility in women, our results should be confirmed in larger populations, and chronobiological approaches to optimize the ovulatory cycle should be evaluated.

Higher number of steps is related to lower endogenous progesterone but not estradiol levels in women.

OBJECTIVES: Sex steroid hormones are important not only for reproduction but also for many aspects of women's health, including the risk of breast cancer. Physical activity has been shown to influence sex hormone levels in women. This study aimed to investigate a relationship between the average daily number of steps and the sex hormone (estradiol and progesterone) levels in premenopausal women. MATERIALS AND METHODS: Data were collected from 85 healthy, urban women of reproductive age who performed at least 180 minutes/week of moderate physical activity for two complete menstrual cycles. Physical activity was measured using wrist bands. Estradiol and progesterone concentrations were measured in daily-collected saliva samples in the second menstrual cycle. RESULTS: There was a significant negative association between the average number of steps taken daily and salivary progesterone levels after adjusting for potential confounding factors (age, BMI). Women who took more than 10,000 steps a day had significantly lower progesterone levels compared to women who took less than 10,000 steps. The association between physical activity and estradiol levels was statistically insignificant. DISCUSSION: Our results indicate that taking at least 10,000 steps a day reduces progesterone levels, but this intensity of physical activity may not be high enough to affect estradiol levels. Daily step tracking is a valuable element of health promotion, but currently recommended levels of physical activity may not be high enough for healthy premenopausal women to significantly reduce both sex hormone levels and thus their risk of postmenopausal breast cancer.

Unmet clinical needs in women with polycystic ovary syndrome in regard to mental health: a cross-sectional study.

PURPOSE: Polycystic ovary syndrome (PCOS) management has hardly been standardized until recent years. Despite the existence of a detailed, evidence-based guideline published by the European Society of Human Reproduction and Embryology (ESHRE), it remains unclear to what extent healthcare providers adhere to this guideline. Our aim is to evaluate the gynaecological medical care provided in women with PCOS, particularly in terms of mental health, from the patients' perspective. METHODS: For this cross-sectional online cohort study in women with PCOS, we designed a standardized, non-validated questionnaire covering aesthetic aspects, metabolism, menstrual cycle, reproduction, mental health, and prevention of chronic non-communicable diseases. RESULTS: Among 1879 participants, various mental health aspects were reported: body image (n = 1879), eating patterns/habits (n = 1878), and emotional well-being (n = 1874). Although nearly all women (99.7%) reported complaints on at least one session of mental health, consultation rates were low (body image 9.7%, eating patterns/habits 16.6%, emotional well-being 4.4%). Mean satisfaction with counselling on the different domains varied from moderate to fairly satisfying, with scores of 56.0 points (SD 31.7), 53.5 points (SD 32.0), and 63.7 points (SD 30.2), respectively. More complaints were associated with lower satisfaction. The overall satisfaction with the management provided by the healthcare practitioner (HCP) was low, averaging 36.5 points (SD 29.7). Consequently, most women wished for more counselling (58.9%). CONCLUSION: Women affected by PCOS are not properly managed according to ESHRE guideline in regard to mental health issues. Overall consultation rates and corresponding satisfaction with management were poor, highlighting the need for significant improvements in healthcare provision.

Translation and validation of the Chinese version of the menstrual distress questionnaire.

BACKGROUND: The Menstrual Distress Questionnaire (MDQ) is a commonly used questionnaire that assesses various symptoms and distress associated with the menstrual cycle in women. However, the questionnaire has not been completely translated into Chinese with rigorous reliability and validity testing. METHODS: This study translated the Menstrual Distress Questionnaire Form Cycle (MDQC) from English into Chinese: MDQCC in two stages. First, it was translated forward and backward using Jones' model; second, to test the validity and reliability, 210 Chinese-speaking women were recruited through online announcements and posters posted between June 2019 and May 2020. Expert validity, construct validity, convergent validity, and factorial validity were determined using content validity index (CVI), intraclass correlation coefficient (ICC), composite reliability (CR), and exploratory factor analysis, respectively. For concurrent criterion validity, MDQCC score was compared with three existing pain scales. Reliability was evaluated using internal consistency across items and two-week test-retest reliability over time. RESULTS: The CVI for content validity was .92. Item-CVI for expert validities among the 46 items ranged from .50 - 1; scale-CVI for the eight subscales, from .87 - 1; ICC, from .650 - .897; and CRs, from .303 - .881. Pearson correlation coefficients between MDQCC and short-form McGill pain questionnaire, present pain intensity, and visual analog scale scores were .640, .519, and .575, respectively. Cronbach's α for internal consistency was satisfactory (.932). ICC for test-retest reliability was .852 for the entire MDQCC. CONCLUSION: MDQCC was valid and reliable for Mandarin Chinese-speaking women. It can be used to evaluate female psychiatric symptoms related to the menstrual cycle in future work.

The Menstrual Distress Questionnaire has been used to evaluate menstrual distress, including dysmenorrhoea and premenstrual syndrome. This questionnaire has been translated into Persian, Korean, Japanese, and Cantonese, rendering it to be used more and more widely all over the world. The study translated all 46 items of the Menstrual Distress Questionnaire from English to Mandarin Chinese using a two-stage strategy. The Chinese version of this questionnaire developed by the present study was found to be a valid and reliable tool in Chinese Mandarin-speaking female populations. It could be used to evaluate women's physical and psychiatric symptoms related to the menstrual cycle in future works.

Effect of the red uniform on the judgment of position or movement used in Wushu Routine, evaluated by practitioners of the modality.

In the artistic sports program, the referee' scores directly determine the final results of the athletes. Wushu is a artistic sport that has a Chinese characteristic and has the potential to become an official competition at the Summer Olympic. In this study we tested whether a red uniform color affects Wushu Routine practitioners' ratings of athletes' position or movement of Wushu Routine. We also tested whether the effect varied depending on the gender of the athlete and the practitioner, and depending on whether female practitioners were in the ovulation phase of their menstrual cycle. Male (Experiment 1: N = 72) and female (Experiment 1: N = 72; Experiment 2: N = 52) participants who major in Wushu Routine were recruited to take a referee's perspective and rate the movement quality of male and female athletes wearing red or blue uniforms. The results of Experiment 1 showed that both male and female athletes wearing red uniform (compared to blue uniform) received higher ratings (p = .002, η2 = .066; p = .014, η2 = .043), and the red effect was especially strong when male practitioners rated female athletes (p = .002, η2 = .069). The results of Experiment 2, in an all-female sample, showed that in most cases there was no difference in ratings made by women in the ovulation and non-ovulation phases of their menstrual cycle, with the exception of their ratings of male athletes wearing red; in this condition, women gave higher ratings when they were in the ovulation phase of their cycle (p = .026). The results suggest that there is a red effect in an artistic sport like Wushu Routine, in which gender and the female menstrual cycle play an important role.

Comparison of menstrual cycle irregularities among young women based on coronavirus disease 2019 infection status: a cross-sectional study.

OBJECTIVE: The coronavirus disease 2019 pandemic that has emerged recently has significantly affected and continues to affect our lives. The Severe Acute Respiratory Syndrome Coronavirus 2 virus has significant effects on women's health due to gender-related physiological differences. The aim of this study was to compare the menstrual cycle status of young women according to their status of having had coronavirus disease 2019. METHODS: This descriptive cross-sectional study was conducted with 220 young women aged between 18 and 25 years who received at least one dose of coronavirus disease 2019 vaccine. The study data were collected as a survey on the online platform. RESULTS: The descriptive characteristics of young women who had had and had not had coronavirus disease 2019 were distributed homogeneously between the groups (p>0.05). Furthermore, there was no statistical difference in terms of menstrual cycle patterns (p>0.05). The mean scores from the Premenstrual Syndrome Scale and its subscales and the mean scores from the COVID Stress Scale and its subscales were similar in both groups, and no statistically significant difference was identified (p>0.05). CONCLUSION: Although menstrual cycle irregularities due to coronavirus disease 2019 have been reported, these effects are usually observed during the pandemic. A decrease in stress and anxiety with the end of the pandemic may explain the return of the menstrual cycle to normal.

Cortical morphology variations during the menstrual cycle in individuals with and without premenstrual dysphoric disorder.

BACKGROUND: Premenstrual dysphoric disorder (PMDD) is hypothesized to stem from maladaptive neural sensitivity to ovarian steroid hormone fluctuations. Recently, we found thinner cortices in individuals with PMDD, compared to healthy controls, during the symptomatic phase. Here, we aimed at investigating whether such differences illustrate state-like characteristics specific to the symptomatic phase, or trait-like features defining PMDD. METHODS: Patients and controls were scanned using structural magnetic resonance imaging during the mid-follicular and late-luteal phase of the menstrual cycle. Group-by-phase interaction effects on cortical architecture metrics (cortical thickness, gyrification index, cortical complexity, and sulcal depth) were assessed using surface-based morphometry. RESULTS: Independently of menstrual cycle phase, a main effect of diagnostic group on surface metrics was found, primarily illustrating thinner cortices (0.3 < Cohen's d > 1.1) and lower gyrification indices (0.4 < Cohen's d > 1.0) in patients compared to controls. Furthermore, menstrual cycle-specific effects were detected across all participants, depicting a decrease in cortical thickness (0.4 < Cohen's d > 1.7) and region-dependent changes in cortical folding metrics (0.4 < Cohen's d > 2.2) from the mid-follicular to the late luteal phase. LIMITATIONS: Small effects (d = 0.3) require a larger sample size to be accurately characterized. CONCLUSIONS: These findings provide initial evidence of trait-like cortical characteristics of the brain of individuals with premenstrual dysphoric disorder, together with indications of menstrual cycle-related variations in cortical architecture in patients and controls. Further investigations exploring whether these differences constitute stable vulnerability markers or develop over the years may help understand PMDD etiology.

Feasibility Study on Menstrual Cycles With Fitbit Device (FEMFIT): Prospective Observational Cohort Study.

BACKGROUND: Despite its importance to women's reproductive health and its impact on women's daily lives, the menstrual cycle, its regulation, and its impact on health remain poorly understood. As conventional clinical trials rely on infrequent in-person assessments, digital studies with wearable devices enable the collection of longitudinal subjective and objective measures. OBJECTIVE: The study aims to explore the technical feasibility of collecting combined wearable and digital questionnaire data and its potential for gaining biological insights into the menstrual cycle. METHODS: This prospective observational cohort study was conducted online over 12 weeks. A total of 42 cisgender women were recruited by their local gynecologist in Berlin, Germany, and given a Fitbit Inspire 2 device and access to a study app with digital questionnaires. Statistical analysis included descriptive statistics on user behavior and retention, as well as a comparative analysis of symptoms from the digital questionnaires with metrics from the sensor devices at different phases of the menstrual cycle. RESULTS: The average time spent in the study was 63.3 (SD 33.0) days with 9 of the 42 individuals dropping out within 2 weeks of the start of the study. We collected partial data from 114 ovulatory cycles, encompassing 33 participants, and obtained complete data from a total of 50 cycles. Participants reported a total of 2468 symptoms in the daily questionnaires administered during the luteal phase and menses. Despite difficulties with data completeness, the combined questionnaire and sensor data collection was technically feasible and provided interesting biological insights. We observed an increased heart rate in the mid and end luteal phase compared with menses and participants with severe premenstrual syndrome walked substantially fewer steps (average daily steps 10,283, SD 6277) during the luteal phase and menses compared with participants with no or low premenstrual syndrome (mean 11,694, SD 6458). CONCLUSIONS: We demonstrate the feasibility of using an app-based approach to collect combined wearable device and questionnaire data on menstrual cycles. Dropouts in the early weeks of the study indicated that engagement efforts would need to be improved for larger studies. Despite the challenges of collecting wearable data on consecutive days, the data collected provided valuable biological insights, suggesting that the use of questionnaires in conjunction with wearable data may provide a more complete understanding of the menstrual cycle and its impact on daily life. The biological findings should motivate further research into understanding the relationship between the menstrual cycle and objective physiological measurements from sensor devices.

Selective attention towards infants in nulliparous women across the menstrual cycle.

Research in women showed that testosterone is associated with decreased selective attention towards infant stimuli, which can be compensated for by oxytocin administration. In theory, caregiving behavior is thought to be mediated by oxytocin. Oxytocin binds to dopaminergic neurons and thus supposedly motivates aspects of caregiving through its influence on dopaminergic transmission. Most previous studies on caregiving behaviors were thereby performed in women under hormonal contraception to avoid hormonal fluctuations. However, recent studies repeatedly demonstrated decisive influences of the hormonal changes across the female menstrual cycle on dopamine-mediated behaviors, suggesting that estradiol acts as dopamine agonist in the follicular phase and progesterone as dopamine antagonist in the luteal phase. In the present study, we investigated selective attention towards infants as one central aspect of caregiving behavior over the natural menstrual cycle and in relation to interindividual differences of estradiol and progesterone. As expected, we found that women with higher estradiol in the follicular phase also showed higher selective attention towards infant faces among adult distractors, whereas the correlation disappeared in the luteal phase. In contrast, progesterone did not correlate with selective attention towards infants. The present findings collectively support the assumption that estradiol may act as dopamine agonist in the follicular phase, thereby supposedly promoting an important aspect of caretaking behavior.

Timing of Coronavirus Disease 2019 (COVID-19) Vaccination and Effects on Menstrual Cycle Changes.

OBJECTIVE: To assess whether menstrual cycle timing (follicular or luteal phase) of coronavirus disease 2019 (COVID-19) vaccine administration is associated with cycle length changes. METHODS: We used prospectively collected (2021-2022) menstrual cycle tracking data from 19,497 reproductive-aged users of the application "Natural Cycles." We identified whether vaccine was delivered in the follicular or luteal phase and also included an unvaccinated control group. Our primary outcome was the adjusted within-individual change in cycle length (in days) from the average of the three menstrual cycles before the first vaccination cycle (individuals in the unvaccinated control group were assigned a notional vaccine date). We also assessed cycle length changes in the second vaccination cycle and whether a clinically significant change in cycle length (8 days or more) occurred in either cycle. RESULTS: Most individuals were younger than age 35 years (80.1%) and from North America (28.6%), continental Europe (33.5%), or the United Kingdom (31.7%). In the vaccinated group, the majority received an mRNA vaccine (63.8% of the full sample). Individuals vaccinated in the follicular phase experienced an average 1-day longer adjusted cycle length with a first or second dose of COVID-19 vaccine compared with their prevaccination average (first dose: 1.00 day [98.75% CI, 0.88-1.13], second dose: 1.11 days [98.75% CI, 0.93-1.29]); those vaccinated in the luteal phase and those in the unvaccinated control group experienced no change in cycle length (respectively, first dose: -0.09 days [98.75% CI, -0.26 to 0.07], second dose: 0.06 days [98.75% CI, -0.16 to 0.29], unvaccinated notional first dose: 0.08 days [98.75% CI, -0.10 to 0.27], second dose: 0.17 days [98.75% CI, -0.04 to 0.38]). Those vaccinated during the follicular phase were also more likely to experience a clinically significant change in cycle length (8 days or more; first dose: 6.8%) than those vaccinated in the luteal phase or unvaccinated (3.3% and 5.0%, respectively; P <.001). CONCLUSION: COVID-19 vaccine-related cycle length increases are associated with receipt of vaccination in the first half of the menstrual cycle (follicular phase).

Changes in Psychotropic Drug Concentrations Across the Menstrual Cycle: A Pilot Study.

BACKGROUND: The escalating prescription of psychopharmacological medications to women of reproductive age underscores the growing significance of sex-specific variations in pharmacotherapy. Despite this, clinical trials have largely overlooked these differences. Preliminary data indicate sex-specific variations in the neurobiology of affective disorders and in the metabolism, pharmacodynamics, and kinetics of therapeutic drugs. This underscores the imperative for a more nuanced exploration of menstrual cycle-dependent fluctuations in psychotropic drugs. This pilot study aimed to investigate drug and hormone fluctuations in female patients with affective disorders, aiming to enhance comprehension of the interplay between cycle-related hormone fluctuations and pharmacokinetics. The ultimate goal is to facilitate more effective and safer pharmacological therapy in the future. METHODS: Blood samples were collected from 27 patients and 27 age-matched control participants at 3 distinct time points (early follicular phase, ovulation, and late luteal phase) during each menstrual cycle. Depressive and manic symptoms were assessed, and hormone concentrations were measured in the entire sample, while drug concentrations were assessed solely in the affective disorder sample using mass spectrometry. RESULTS: Significant variations in drug concentration were observed throughout the menstrual cycle for bupropion, with a trend toward altered concentration for venlafaxine. Moreover, notable differences in hormone concentrations were identified between patients and controls, even after accounting for the impact of contraceptive use, diagnoses, and medication. CONCLUSIONS: This pilot study reinforces previously reported data, underscoring the significance of sex-specific pharmacological therapy approaches. It provides further evidence supporting the interaction among sex hormones, drugs, and symptoms of affective disorders.

A nine-month repeat-dose intravaginal ring (Ovaprene) irritation study in sheep.

OBJECTIVES: Ovaprene is a novel, investigational, intravaginal hormone-free monthly ring contraceptive designed for use in women of reproductive age to be worn over multiple weeks (one menstrual cycle). The objective of this work was to evaluate the safety of Ovaprene during a nine-month repeat-dose sheep study. STUDY DESIGN: In addition to traditional safety endpoints such as histopathological evaluation of the sheep female reproductive tract, vaginal fluids were collected and tested for released iron over time. Also, the amount of iron in the rings was assessed following removal, and serum iron levels were measured. There were four sheep in each group (Ovaprene group and sham group). RESULTS: There were no macroscopic clinical findings. There was minimal to mild, mixed or mononuclear cell infiltration present in all levels of vagina (cranial, mid, and caudal) from all animals including sham controls based on post-study necropsy. The female reproductive tract from animals treated with the Ovaprene ring was comparable to the sham controls. The concentrations of serum iron in sheep treated with Ovaprene ring were similar compared to a sham treated animal. The average amount of ferrous gluconate released from Ovaprene over the 29-day period of use was 175 mg of the approximately 512 mg nominally loaded into the rings. CONCLUSIONS: Overall, the Ovaprene devices were well-tolerated in female sheep. IMPLICATIONS: This study should support a chronic (e.g., one year) contraceptive efficacy study in women.

Food-related exploration across the menstrual cycle.

When deciding what to eat we constantly weigh different aspects of the options at hand and make trade-offs between exploiting opportunities with a known outcome (e.g., eating your usual meal) and exploring novel opportunities with a potentially better outcome (e.g., trying a new dish). Environmental factors, such as scarcity, have previously been shown to tip the balance towards either exploration or exploitation. Studies in animals have further linked female steroid hormones (including estradiol and progesterone) to exploratory behavior. Previous work in humans has suggested that food preferences and food intake also change over the menstrual cycle. However, it remains unknown whether exploratory behavior in food choices also changes across the menstrual phases in humans. In a rating phase, 112 adult women (age range 18-45 years) on or off hormonal birth control rated 40 food items on desirability. In the choice phase, participants made binary choices between food items. On some trials, a surprise box replaced one of the two food options, allowing us to examine exploratory choices. Women off hormonal birth control reported their average cycle length and time since the first day of their last menstruation. Analysis of the percentage surprise choices across the menstrual cycle indicated a small, but significant effect, with exploratory choice behavior tending to increase around the middle of/later during the cycle. This provides preliminary novel evidence that hormonal fluctuations are associated with food-related exploratory choice behavior. Importantly, these effects were observed beyond effects of other food-related factors. Future studies should investigate the nature of these effects using more direct hormonal measures.

Proteomics of appetite-regulating system influenced by menstrual cycle and intensive exercise in female athletes: a pilot study.

Female athletes who endure intense training are at risk of developing the 'female athlete triad,' making energy intake management crucial. However, the fluctuations in estradiol and progesterone levels throughout the menstrual cycle present a challenge in maintaining consistent energy intake. This study aimed to uncover the underlying factors associated with appetite regulation linked to menstrual phases and exercise using proteomic approach. Five female athletes engaged in 60 min of bicycle exercise, followed by 90 min of rest, during both the follicular and luteal phases. Serum samples were collected before, during, and after exercise, and the serum proteome was analyzed using 2D-gel electrophoresis. A total of 511 spots were detected in the subjects' serum profiles, with significant decreases observed in haptoglobin during the luteal phase and complement component 3 during bicycle training. Unsupervised learning with a generalized estimating equation analysis showed that serum peptide YY (PYY), an appetite suppressor, significantly influenced the fluctuations of serum proteins induced by exercise (p < 0.05). Regression analysis demonstrated a positive correlation between PYY and serum IgM (R = 0.87), implying that the intestinal environment and the immune response in female athletes may contribute to appetite regulation.