Effect Of Menstrual Cycle Phase Research Articles

Hormone-based models for comparing menstrual cycle and hormonal contraceptive effects on human resting-state functional connectivity

Oral contraceptives (OCs) are widely used yet understudied given their potential for public health consequences. Emerging investigations scaling from single-subject, dense-sampling neuroimaging studies to population-level metrics have linked OCs to altered brain structure and function. Modeling the hypogonadal, hypergonadal, or mixed state effects of OCs in terms of their impact on hormone action in the brain is a valuable approach to synthesizing results across neuroimaging studies and comparing OC effects to companion findings from research on menstrual cycle phase effects on brain anatomy and function. Resting-state functional connectivity studies provide a powerful tool to evaluate the role of OCs on the intrinsic network connectivity that underlies multiple behavioral domains. The preponderance (but not consensus) of the current literature indicates that (1) as the menstrual cycle proceeds from a low to high progesterone state, prefrontal connectivity increases and parietal connectivity decreases; (2) OCs tend to mimic this connectivity pattern; therefore (3) OCs may produce a hyperprogestogenic state in the brain, in spite of overall reductions in endogenous steroid hormone levels. Alternative models are also considered.

0109 Working Memory across Sleep and the Menstrual Cycle in Young and Midlife Women

Abstract Introduction The menses phase of a woman’s menstrual cycle, compared to other phases, is more likely to be associated with poorer sleep quality and alterations in cognitive performance, specifically impaired working memory. However, the relationship among these factors has been poorly investigated, and how age impacts these relationships is currently unknown. The present study examines the effect of menstrual cycle phase and sleep on working memory performance in young and midlife women. Methods Fifty-five young and midlife women (n = 29, 18 – 35 years; n = 26, 45 – 56 years) completed four remote assessments at different phases of their menstrual cycle: menses, late-follicular, mid-luteal, and late-luteal, defined based on days of menses and ovulation. On each visit, participants completed the operation span (OSPAN) working memory task in the evening and were re-tested for sleep-related performance change in the morning. In addition, participants wore an Oura ring, a multi-sensor wearable sleep tracker, throughout the night. Mixed linear regression, correlation models, and paired t-tests were used to determine the relationship between menstrual phase, sleep, and OSPAN outcomes in both groups. Results In midlife women only, OSPAN performance improvement significantly changed across menstrual cycle phases (p < .05). The greatest post-sleep improvement in OSPAN performance was detected during the mid-luteal and late-follicular phases of the cycle, while lower performance gains were detected during menses and late-luteal phases. Post-hoc paired t-tests confirmed that post-sleep performance was significantly worst during menses compared to each of the other phases (p < .05). Additionally, during the mid-luteal phase, time spent in deep sleep positively correlated with post-sleep performance in midlife women (r = .55, p < .05). No significant effects were detected in young women. Conclusion These findings suggest a complex interaction between sleep, menstrual cycle phase, and cognitive performance in midlife women. Our data suggest that deep sleep may mediate post-sleep performance during specific cycle phases. Reasons why these results are not evident in younger women are yet to be determined. Support (If Any) Supported by: RF1AG061355 (Baker/Mednick)

Effect of the Menstrual Cycle on Electroencephalogram Alpha and Beta Bands During Motor Imagery and Action Observation.

Female sex steroids (FSS) can affect the motor system, modulating motor cortex excitability as well as performance in dexterity and coordination tasks. However, it has not yet been explored whether FSS affects the cognitive components of motor behavior. Mu is a sensorimotor rhythm observed by electroencephalography (EEG) in alpha (8–12 Hz) and beta (15–30 Hz) frequency bands in practices such as motor imagery (MI) and action observation (AO). This rhythm represents a window for studying the activity of neural circuits involved in motor cognition. Herein we investigated whether the alpha-mu and beta-mu power in the sensorimotor region (C3 and C4, hypothesis-driven approach) and the alpha and beta power over frontal, parietal, and occipital regions (data-driven approach) are modulated differently in the menstrual, follicular, and luteal phases of menstrual cycles in right-handed dominant women. To do so, these women underwent MI and AO in the three menstrual cycle phases. The spectral activity of the cortical regions for the alpha and beta bands were compared between phases of the menstrual cycle and a correlation analysis was also performed in relation to estrogen and progesterone levels. For the hypothesis-based approach, beta-mu event-related desynchronization (ERD) was significantly stronger in the C3 channel in the follicular phase than in the menstrual and luteal phases. For the data-driven approach, beta ERD during MI was higher in the follicular phase than in the menstrual and luteal phases in the frontal region. These findings suggest the effect of FSS on executive movement control. No effect of menstrual cycle phases was observed in cortical areas investigated during OA, but alpha and beta bands correlated positively with the follicular phase plasma estradiol level. Thus, the attenuation of alpha and beta bands referring to mirror neuron activities appears to be associated with inhibition of cortical activity when estradiol levels are lower, improving cognitive processing of motor action.

The Effect of Menstrual Cycle Phase on Neural Recruitment Patterns during Acute Chemoreflex Stress

We have shown previously that muscle sympathetic nerve activity (MSNA) responses to acute chemoreflex stress are augmented during the early follicular (EF) phase of the menstrual cycle relative to the midluteal (ML) phase in young healthy women. Interestingly, these differences were most pronounced in terms of MSNA burst amplitude, which may imply that neural recruitment strategies are affected by menstrual cycle phase. Therefore, the purpose of this retrospective analysis was to test the hypothesis that the recruitment of large action potential (AP) clusters occurs to a greater extent during the EF phase of the menstrual cycle compared with the ML phase. MSNA data (microneurography) from 7 young healthy women (aged 23±3 years; body mass index 23±3 kg/m2) were examined at rest and during a voluntary end‐inspiratory apnea which followed a rebreathing protocol to an end‐tidal PO2 of 65 Torr. These data were collected during the EF and ML phases. APs were identified from the filtered MSNA signal using a custom wavelet deconstruction approach which quantified AP firing frequencies (overall AP frequency and AP content per integrated burst). The identified APs were also binned in accordance to peak to peak amplitude to determine individual AP clusters (Scott’s rule). Resting AP frequency and AP content per MSNA burst were not different between menstrual cycle phases (APs/min: P=0.23; APs/burst: P=0.26). Similarly, the number of identified AP clusters at rest did not differ between the EF and ML phases (8±4 vs10±4 clusters; P=0.16). During apnea, changes in AP frequency and AP content per MSNA burst (i.e. expressed relative to baseline) were greater during the EF phase than the ML phase (ΔAPs/min: P=0.02; ΔAPs/burst: P=0.02). Similarly, apnea‐induced recruitment of new AP clusters (i.e. clusters which were not activated at baseline) was greater during the EF phase compared to the ML phase (ΔAP clusters: +6±8 vs+2±6 clusters; P=0.009). Taken together, these findings confirm that augmented integrated MSNA reactivity to chemoreflex stress during the EF phase of the menstrual cycle is mediated by a greater recruitment of latent subpopulations of larger sympathetic neurons relative to the ML phase. We speculate that the change in the gonadal hormone profile between EF (i.e. low estradiol, progesterone) and ML (i.e. elevated estradiol and progesterone) may be associated with centrally‐mediated alterations to neural outflow during chemoreflex stress, although further research is certainly required to address this hypothesis.

Impact of aerobic fitness status, menstrual cycle phase, and oral contraceptive use on exercise metabolic flexibility

Metabolic flexibility is the ability to appropriately store or utilize substrates. Exercise such as high‐intensity interval exercise (HIIE) is also a robust test of one’s ability to shift between substrates to support metabolic demand. Menstrual cycle or oral contraceptive use may impact metabolic responses to exercise. Fitness status also plays an important role in metabolism. We assessed the impact of hormonal fluctuation and fitness status on exercise metabolism in women during HIIE. 25, healthy, active women (24.4±3.6yrs; 165.5±6.9 cm; 65.1±10.5 kg; 38.8±6.6mL/kg/min) experiencing a regular menstrual cycle (n=15) or using oral contraceptives (n=11) completed the study. Participants were split by aerobic fitness status (High: 43.7±4.7mL/kg/min; Low: 33.6±3.9mL/kg/min). Participants completed a baseline and counterbalanced HIIE sessions in the follicular (FOL) and luteal phase (LUT). FOL sessions took place 2‐7d after onset of menstruation or non‐active OC days. LUT sessions took place ~6‐8d following urine ovulation or third week of active OC pills. Exercise was performed on an electrically braked cycle ergometer. High intervals (H1‐H4) were 4x4 min intervals at the power output corresponding to 50% of the difference between the ventilatory threshold and VO2peak, separated with 3min of unloaded cycling (0W; low intervals). RPE and blood lactate assessed via finger stick were taken after each interval. There was no effect of menstrual cycle phase or oral contraceptive use on fat oxidation, carbohydrate oxidation or blood lactate. There was an effect of fitness status on fat oxidation in LUT and FOL (p=0.002). High fit women oxidized more fat during the full session (FOL: p=0.050, LUT: p=0.001), high intervals (FOL: p=0.048, LUT: p=0.001), and low intervals (FOL: p=0.032, LUT: p=0.024) during FOL and LUT, and recovery during LUT (p=0.033). Carbohydrate oxidation (g/kg; p=0.049) and AUC (p=0.024) were greater in high women during FOL, but not LUT. Blood lactate was significantly greater in low fit women during exercise interval H2 through recovery during FOL, but not LUT (p≤0.050). Total change in rate of fat oxidation (Δ g/kg/min) during HIIE intervals was greater in high vs low fitness during FOL (H2: p= 0.018, H3: p=0.004), and LUT (H1: p=0.041, H2: p=0.001, H3: p=0.001, H4: p=0.006). There was a correlation between exercise fat oxidation (g/kg) and lactate AUC (H1‐L4) during FOL (r=‐0.440, p=0.030; n=25) but not LUT (‐30 minute) (r=0.215, p=0.143; n=25). Our results reflect fitness status plays an important role in exercise fat oxidation, carbohydrate oxidation and blood lactate during HIIE in young women. High fitness women benefit from greater exercise metabolic flexibility than their low fit counterparts. These these differences may be unique to the menstrual cycle phase, with low fitness women having poorer exercise metabolic flexibility in the follicular phase.

Menstrual Cycle Related Fluctuations in Circulating Markers of Bone Metabolism at Rest and in Response to Running in Eumenorrheic Females

This study examined potential fluctuations in bone metabolic markers across the menstrual cycle both at rest and after a 30-min bout of continuous running at 80% of V̇O2max. Resting and post-exercise (0, 30, 90min) sclerostin, parathyroid hormone (PTH), carboxy-terminal cross-linking telopeptide of type I collagen (β-CTXI), and procollagen type 1N propeptide (PINP) were assessed in 10 eumenorrheic women (age: 21 ± 3 y, BMI: 23.2 ± 3.0kg.m2) during the mid- to late-follicular (FP: day 8.0 ± 1.4) and mid-luteal (LP: day 22.0 ± 2.5) phases of the menstrual cycle. Ovulation was determined using ovulation kits and daily measurement of oral body temperature upon awakening. Menstrual cycle phase was subsequently confirmed by measurement of plasma estradiol and progesterone. On average, resting estradiol concentrations increased from 46.3 ± 8.9pg·mL-1 in the FP to 67.3 ± 23.4pg·mL-1 in the LP (p = 0.015), and resting progesterone increased from 4.12 ± 2.36ng·mL-1 in the FP to 11.86 ± 4.49ng·mL-1 in the LP (p < 0.001). At rest, there were no differences between menstrual cycle phases in sclerostin (FP: 260.1 ± 135.0pg·mL-1; LP: 303.5 ± 99.9pg·mL-1; p = 0.765), PTH (FP: 0.96 ± 0.64pmol·L-1; LP: 0.79 ± 0.44pmol·L-1; p = 0.568), β-CTXI (FP: 243.1 ± 158.0ng·L-1; LP: 202.4 ± 92.3ng·L-1; p = 0.198), and PINP (FP: 53.6 ± 8.9μg·L-1; LP: 66.2 ± 20.2μg·L-1; p = 0.093). Main effects for time (p < 0.05) were shown in sclerostin, PTH, β-CTXI and PINP, without phase or interaction effects. Sclerostin increased from pre- to immediately post-exercise (45%; p = 0.007), and so did PTH (43%; p = 0.011), both returning to resting concentrations 30min post-exercise. β-CTXI decreased from pre- to post-exercise (20%; p = 0.027) and was stillbelow its pre-exercise concentrations at 90min post-exercise (17%; p = 0.013). PINP increased immediately post-exercise (29%; p < 0.001), returning to resting concentrations at 30min post-exercise. These results demonstrate no effect of menstrual cycle phase on resting bone marker concentrations or on the bone metabolic marker response to intense exercise.

FMUP - Nov 2021 (summary and comments of paper)

Summary of: The Effects of Menstrual Cycle Phase on Elite Athlete Performance: A Critical and Systematic Review

A Pilot Study on the Impact of Menstrual Cycle Phase on Elite Australian Football Athletes.

The effect of the menstrual cycle on athlete performance, wellbeing and perceived exertion and fatigue is not well understood. Furthermore, it has not been investigated specifically in Australian Football athletes. This pilot study aimed to explore how naturally menstruating Australian Football athletes may be affected by menstrual cycle phase. The data collected from the routine monitoring of five naturally menstruating athletes (average menstrual cycle length of 28 ± 3 [SD] days) in one team (athlete age range 18–35 years) competing in the Women’s Australian Football League during the 2019 season were retrospectively analysed to compare performance (countermovement jump parameters and adductor squeeze pressure), perceived exertion, perceived fatigue and wellbeing (perceived sleep quality, stress and soreness) outcomes between the follicular and luteal phases. Performance, perceived exertion, stress and soreness did not appear to be affected by menstrual cycle phase (p > 0.17). However, perceived fatigue appeared to be significantly greater (p = 0.042) and sleep quality worse (p = 0.005) in the luteal phase. This pilot study suggests further research focusing on the effect of menstrual cycle phase on subjective fatigue and wellbeing is warranted.

The Effects of Menstrual Cycle Phase on Elite Athlete Performance: A Critical and Systematic Review.

Background: In elite athletes, training individualization is widely recommended to optimize competitive performance. Previous studies have evidenced the impact of hormonal fluctuations on different performance parameters among female athletes. While consideration of menstrual cycle (MC) phases as a parameter in training individualization strategies is necessary, systematic evidence identifying such impacts in elite athletes should be evaluated.Objective: Systematically review publications that have investigated the link between MC phases and performance in elite female athletes. The overarching aim is to identify whether a consensus across studies exists enabling evidence-based recommendations for training individualization depending on menstrual cycle phases.Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three major scientific publication databases were searched from inception until November 3, 2020. Studies included focused on the influence of physiological or psychological parameters throughout at least one phase of the menstrual cycle of elite athletes.Results: A total of 780 search results were yielded and 26 references from a past bibliography were added manually. About 662 papers were reviewed of which 218 studies were assessed for eligibility. Of these, only seven (1%) precisely investigated the influence of a performance or physical parameter during at least one menstrual cycle phase. These seven studies included a total of 314 elite female participants (20.58 ± 1.91 years). Three used interviews, questionnaires or prospective analyses of reports. Four conducted several performance tests or included physical measures although only two performed tests during training or before/during competition. Among the seven studies, five performed hormonal testing through sampling of blood, saliva, or urine. The remaining relied on athletes’ menstruation diaries. The current evidence suggests a variable association between menstrual cycle and a few performance-related outcomes, such as endurance or power resistance, ligament stiffness, decision making skills, psychology, or competitiveness.Conclusion: Different sports performance-related parameters are affected during the menstrual cycle among elite athletes, but the parameters themselves and the magnitude and the direction of the effects are inconclusive. Additional longitudinal and prospective studies to systematically monitor on-field performance parameters are urgently required in order to enable recommendations and training individualization in female elite athletes.

The Vascular Response to Sympathetic Activation is Attenuated in Young Women Following Acute Intermittent Hypoxia

INTRODUCTION : Acute intermittent hypoxia (AIH) elicits an increase in sympathetic nervous activity (SNA) that persists following return to room air. This AIH-mediated sympathetic activation is associated with an increase in blood pressure in men, but not women. These data suggest the vascular responsiveness to SNA is attenuated in young women, although mechanisms are unclear. We sought to examine the vascular responsiveness to sympathetic activation before and after AIH in heathy young men and women. We hypothesized the vascular response to sympathetic activation would be preserved following AIH in men. We further hypothesized the vascular response to sympathetic activation would be attenuated in women following AIH, with the greatest effect observed when endogenous estradiol was high. METHODS : Twelve men (25±1 yrs) and nine women (24±1 yrs) participated. Women were studied twice, during the early follicular (EF, Estradiol 28±4 pg/mL) and late follicular (LF, Estradiol 185±51 pg/mL) phases of the menstrual cycle. Before and after 30-min AIH, a 2-min cold pressor test (CPT) was conducted to increase SNA. Forearm blood flow (FBF, venous occlusion plethysmography) and blood pressure (finger photoplethysmography) were measured continuously. FBF was normalized for mean blood pressure (forearm vascular conductance, FVC) and a change in response to CPT was calculated (ΔFVC = Baseline - CPT). RESULTS : Mean blood pressure increased following AIH in men (p=0.03) with no effect in women (p>0.05). In men, the vascular response to sympathetic activation was preserved following AIH in men (ΔFVC -0.5±0.4 vs -0.4±0.6 mL/min/dL/100 mmHg, p=0.85). In contrast, the vascular response to sympathetic activation was attenuated in women following AIH (ΔFVC: EF -1.0±0.3 vs -0.4±0.2 mL/min/dL/100 mmHg; LF -0.8±0.4 vs -0.1±0.2 mL/min/dL/100 mmHg, p<0.01) with no effect of menstrual cycle phase (p=0.99). CONCLUSION : The vascular response to sympathetic activation is preserved in men following AIH, but is attenuated in women and is independent of menstrual cycle phase. Present data highlight sex-related differences in the neurovascular response to AIH and indicate sex differences in the blood pressure response to AIH may be due, in part, to an attenuated vascular response to SNA in women.

Does Premedıcatıon wıth Mıdazolam Reduce Preoperatıve Anxıety Through Menstrular Cycle Phases?

Aim: In this study, it was aimed to investigate and compare the effects of menstrual cycle phases on preoperative anxiety and postoperative pain scores in patients given midazolam for premedication before anesthesia. Methods: Septorhinoplasty, goiter surgery and laparoscopic cholecystectomy 126 female patients, aged 21-45, with American Society of Anesthesiologists (ASA) score I-II and with regular menstrual cycles, were included. Of the cases; The phase of the menstrual cycle was recorded according to the last menstrual period (SAT) and accordingly the patients were divided into 3 groups as Follicular phase, the Ovulatory phase, and the Luteal phase. Anxiety assessment was performed using the State-Trait Anxiety Inventory (STAI FORM TX-1) test. Anxiety scores were evaluated by performing a preoperative test 3 minutes before and 1 hour after intravenous (IV) administration of 0.02 mg/kg midazolam. Visual analog scale (VAS) was used for postoperative pain assessment. Results: Midazolam was found to decrease STAI FORM TX-1 scores the most during the ovulatory phase of the menstrual cycle, but there was no significant difference between the groups in terms of VAS scores. Conclusion: It has been observed that premedication with midazolam reduces preoperative anxiety in all phases of the menstrual cycle in women of reproductive age, but is most effective in the ovulatory phase. The effect of premedication with midazolam on postoperative pain does not change according to the phases of the menstrual cycle.

The Impact of Menstrual Cycle Phase on Athletes' Performance: A Narrative Review.

The effect of the menstrual cycle on physical performance is being increasingly recognised as a key consideration for women’s sport and a critical field for further research. This narrative review explores the findings of studies investigating the effects of menstrual cycle phase on perceived and objectively measured performance in an athletic population. Studies examining perceived performance consistently report that female athletes identify their performance to be relatively worse during the early follicular and late luteal phases. Studies examining objective performance (using anaerobic, aerobic or strength-related tests) do not report clear, consistent effects of the impact of menstrual cycle phase on physical performance. Overall sport performance can be influenced by both perceived and physical factors. Hence, to optimise performance and management of eumenorrheic female athletes, there is a need for further research to quantify the impact of menstrual cycle phase on perceived and physical performance outcomes and to identify factors affecting variability in objective performance outcomes between studies.

The Impact of the Menstrual Cycle and Underlying Hormones in Anxiety and PTSD: What Do We Know and Where Do We Go From Here?

This paper reviews the recent literature on menstrual cycle phase effects on outcomes relevant to anxiety and PTSD, discusses potential neurobiological mechanisms underlying these effects, and highlights methodological limitations impeding scientific advancement. The menstrual cycle and its underlying hormones impact symptom expression among women with anxiety and PTSD, as well as psychophysiological and biological processes relevant to anxiety and PTSD. The most consistent findings are retrospective self-report of premenstrual exacerbation of anxiety symptoms and the protective effect of estradiol on recall of extinction learning among healthy women. Lack of rigorous methodology for assessing menstrual cycle phase and inconsistent menstrual cycle phase definitions likely contribute to other conflicting results. Further investigations that address these limitations and integrate complex interactions between menstrual cycle phase-related hormones, genetics, and psychological vulnerabilities are needed to inform personalized prevention and intervention efforts for women.

The Effect of Menstrual Cycle Phase on the Prognostic Factors in Patients with Premenopausal Breast Tumors.

Background: Estrogen receptor and progesterone receptor positivity and c-erbB2 gene expression levels are important in determining breast cancer development and aggression. Although the importance of hormonal factors in tumor cell proliferation, migration and differentiation is increasing, it needs more evidence. The effect of BC surgery timing during the menstrual cycle on prognosis remains controversial. In order to clarify this hypothesis, we aimed to determine the importance of adjusting the timing of surgery according to the menstrual cycle by examining the relationship between estrogen receptor, progesterone receptor, c-erbB2 gene and the menstrual cycle phase in patients with premenopausal breast cancer. Method: Our study was designed retrospectively. 50 patients with premenopausal breast cancer who were operated were included in the study. Results: Our results showed that the patients in the luteal phase had higher ER positivity, PR positivity and c-erbB2 negativity, and the number of metastatic axillary lymph nodes was lower than the patients in follicular phase. Conclusions: BC surgery during the luteal phase in pre-menopausal women is associated with a better clinical outcome. Although larger-scale studies are needed, our results suggest that better results can be achieved by performing surgery in luteal phase in BC patients during premenopausal period.

The effects of menstrual cycle phase on physical performance in female rugby athletes: A case-study

The effects of menstrual cycle phase on physical performance in female rugby athletes: A case-study

Menstrual cycle phase, alcohol consumption, alcohol cravings, and mood among women in outpatient treatment for alcohol use disorder.

Research shows fluctuations in drinking across the menstrual cycle among women with alcohol use disorder (AUD), but little work has investigated moderators of these fluctuations. This study examined drinking and craving intensity across the menstrual cycle, and the moderating effect of baseline depression and emotional distress during the midlate luteal phase and/or menses, among women receiving AUD treatment. Fifty-nine regularly cycling women reported menstrual history and baseline depression. Over 3 months of treatment, they kept daily logs of drinks, alcohol cravings, and menstruation (yes/no). Emotional distress during the midlate luteal phase and/or menses of their most recent menstrual cycle was also assessed during treatment. Menstrual cycle phase was estimated for each within-treatment day. Mixed model analyses tested main and interactive effects of menstrual cycle phase, baseline depression, and emotional distress during the midlate luteal phase and/or menses on daily drinks and craving intensity. Women drank most during the midlate luteal phase and menses compared with other phases. Among women with lower baseline depression, those with lower distress during the midlate luteal phase and/or menses reported more intense cravings during the midlate luteal phase (ΔM = .77, p = .000) and menses (ΔM = .51, p = .012); those with higher distress reported more intense cravings during menses, compared with all other phases (p < .01). Among women with higher baseline depression, craving intensity remained consistently high. Results document more drinking during the midlate luteal phase and menses and suggest that cycle-related distress and depression moderate the alcohol-menstrual association among women in AUD treatment. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Timing of breast cancer surgery during the menstrual cycle-is there an optimal time of the month?

An intriguing relationship between menstrual cycle phase at the time of breast cancer surgery and clinical outcomes was first proposed in the late 1980s. Despite a number of clinical studies conducted to address this, as well as meta-analyses and systematic reviews, there remains significant controversy surrounding the effect of menstrual cycle phase at time of surgery on the prognosis of premenopausal breast cancer. While some studies have suggested that surgery performed during the luteal phase results in the most favourable outcome, other studies report the follicular phase is more favourable, and others show no association. Given the conflicting results, there remains insufficient evidence to determine whether there is an optimal time of the month to perform surgery. This issue has dogged breast cancer surgery for decades; knowledge of an optimal time of the month to conduct surgery would be a simple approach to improving patient outcomes. This review explores the potential biological mechanisms through which the hormonal milieu might contribute to differences in prognosis, and why clinical findings are so variable. It is concluded that a significant problem with current clinical research is the lack of insight from mechanistic studies. While there are a number of plausible biological mechanisms that could lead to altered survival, supporting evidence is limited. There are also variable approaches to defining the menstrual cycle phase and hormone receptor status of the tumour and few studies controlled for prognostic factors such as tumour size and stage, or addressed the impact of adjuvant treatments. Elucidation of the specific confounding factors, as well as biological mechanistic pathways that could explain the potential relationship between timing of surgery and survival, will greatly assist in designing robust well-controlled prospective clinical studies to evaluate this paradigm.

Content matters: Cyclic effects on women's voices depend on social context

Women's voices reportedly sound more attractive during the fertile days compared to the non-fertile days of their menstrual cycle. Here we investigated whether the speech content modulates the cyclic changes in women's voices. We asked 72 men and women to rate how interested they were in getting to know the speaker based on her voice. Forty-two naturally cycling women were recorded once during the late follicular phase (high fertility) and once during the luteal phase (low fertility) while speaking sentences of neutral and social content. Listeners were more interested in getting to know the speakers when hearing sentences with social content. Furthermore, raters were more interested in getting to know the speakers when these were recorded in the late follicular than in the luteal phase, but only in sentences with social content. Notably, levels of reproductive hormones (EP ratio) across the cycle phases did not significantly predict the preference for late follicular voices, but echoing the perceptual ratings, there was a significant EP ratio x speech content interaction. Phonetic analyses of mean fundamental frequency (F0) revealed a main effect of menstrual cycle phase and speech content but no interaction. Employing an action-oriented task, the present study extends findings of cycle-dependent voice changes by emphasising that speech content critically modulates fertility effects.

Physical, Biochemical, and Neuromuscular Responses to Repeated Sprint Exercise in Eumenorrheic Female Handball Players: Effect of Menstrual Cycle Phases.

Graja, A, Kacem, M, Hammouda, O, Borji, R, Bouzid, MA, Souissi, N, and Rebai, H. Physical, biochemical, and neuromuscular responses to repeated sprint exercise in eumenorrheic female handball players: effect of menstrual cycle phases. J Strength Cond Res 36(8): 2268-2276, 2022-Very few studies have been interested in the relationship between ovarian hormones and physiological function in female athletes. The aim of this study was to assess the effect of menstrual phases (MP) on physical, neuromuscular, and biochemical responses after repeated sprint exercise (RSE) in female handball players. Ten eumenorrheic athletes (22.5 ± 1.5 years, 1.70 ± 0.04 m) participated in 3 study visits (follicular phase [FP], luteal phase [LP], and premenstrual phase [PMP]). During each MP, they performed 20 × 5-second cycle sprints interspersed with 25 seconds of rest. Maximal voluntary contraction (MVC) tests of the knee extensor muscles at 90° of knee flexion were performed before and after RSE. Peak force and electromyography (EMG) signals were measured during the MVC tests. Blood samples were collected before and 3 minutes after each session. The percentage of decrement in peak power output over the 20 × 5-second cycle test (i.e., fatigue index) calculated between sprints 1 and 20 decreased significantly during PMP (-43.3% ± 5.7%) but not in LP (-39.2% ± 7.7%) compared with FP (-32.44% ± 6.3%) ( p < 0.05). Moreover, no significant difference was found between MP in all frequency components of EMG before RSE ( p > 0.05). Maximal voluntary contraction, neuromuscular efficiency, and median frequency values of vastus lateralis and rectus femoris were significantly decreased in PMP compared with FP and LP ( p < 0.05). Creatine kinase (CK) levels were significantly higher in PMP compared with FP and LP after RSE ( p < 0.05). These findings suggest that RSE induces more peripheral fatigue associated with muscle damage in PMP. This might be attributable to hormonal variation across MP. Therefore, FP seems to be the right time for intense training to improve strength performance.

Influence of the Menstrual Cycle on Blood Markers of Muscle Damage and Inflammation Following Eccentric Exercise.

The aim of this study was to evaluate whether the menstrual cycle and its underlying hormonal fluctuations affect muscle damage and inflammation in well-trained females following an eccentric exercise. Nineteen eumenorrheic women performed an eccentric squat-based exercise in the early follicular phase, late follicular phase and mid-luteal phase of their menstrual cycle. Sex hormones and blood markers of muscle damage and inflammation –creatine kinase, myoglobin, lactate dehydrogenase, interleukin-6, tumoral necrosis factor-α, and C reactive protein– were analyzed in each phase. No effect of menstrual cycle phase was observed (p > 0.05), while an interaction for interleukin-6 was shown (p = 0.047). Accordingly, a moderate effect size [0.68 (0.53)–0.84 (0.74)], indicated that interleukin-6 values 2 h post-trial (2.07 ± 1.26 pg/mL) were likely to be higher than baseline (1.59 ± 0.33 pg/mL), 24 h (1.50 ± 0.01 pg/mL) and 48 h (1.54 ± 0.13 pg/mL) in the mid-luteal phase. Blood markers of muscle damage and inflammation were not affected by the menstrual cycle in well-trained women. The eccentric exercise barely triggered muscle damage and hence, no inflammation was observed, possibly due to participants training status. The mid-luteal phase was the only phase reflecting a possible inflammatory response in terms of interleukin-6, although further factors than sex hormones seem to be responsible for this finding.