Effect of Zero-time Exercise Intervention on Endometrial Receptivity in Women with Thin Endometrium A Single-center Randomized Sham-controlled Trial

Effect of Zero-time Exercise Intervention on Endometrial Receptivity in Women with Thin Endometrium A Single-center Randomized Sham-controlled Trial | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of Zero-time Exercise Intervention on Endometrial Receptivity in Women with Thin Endometrium A Single-center Randomized Sham-controlled Trial Zhaohui Jiang, Yanjiao Hua, Li Deng, Yanmei Li, Shupei Xu, Mengjie Li, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8607817/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Mar, 2026 Read the published version in Archives of Gynecology and Obstetrics → Version 1 posted 6 You are reading this latest preprint version Abstract Background Current therapeutic strategies for thin endometrium have inherent limitations, and zero-time exercise (ZTEx), a professionally guided fragmented low-intensity exercise, may serve as a novel adjunctive intervention for its management. Methods This was a single-center randomized sham-controlled trial. Eligible patients undergoing ART were randomly divided into an experimental group (receiving ZTEx intervention) and a control group (receiving sham intervention). The ZTEx intervention was delivered over 12 weeks, featuring fragmented, low-intensity exercises under professional guidance. Key indicators of endometrial health—including endometrial thickness and endometrial receptivity-related parameters—were monitored throughout the intervention period. Results After 12 weeks of intervention, ANCOVA (adjusted for baseline values) revealed that the experimental group had a significantly greater endometrial thickness than the control group (6.67 ± 1.15 mm vs. 5.88 ± 1.17 mm, P < 0.001). Concurrently, multiple endometrial receptivity-related indices improved significantly in the experimental group (all P < 0.05), including uterine artery hemodynamic parameters (pulsatility index [PI], resistance index [RI], systolic/diastolic ratio [S/D]) and vascularization indices (vascularization index [VI], flow index [FI], vascularization-flow index [VFI]).No exercise-related adverse events were reported over the course of the trial, confirming the safety profile of ZTEx. Conclusions Supported by rigorous statistical analyses, ZTEx effectively enhances endometrial thickness and receptivity in ART patients with thin endometrium. Its key advantages—safety, feasibility, and no need for additional time or equipment—make it a promising adjuvant intervention in clinical ART settings. Physical activity Intervention study Assisted reproductive technology population Sedentary lifestyle Thin endometrium Figures Figure 1 Figure 2 Background The endometrium is a critical site for embryonic implantation, and its thickness and receptivity exert a profound impact on pregnancy outcomes. According to compiled expert consensus and clinical guidelines, thin endometrium is defined as an endometrial thickness of ≤ 7 mm on the day dominant follicles reach maturity (diameter ≥ 18 mm) or on the day of human chorionic gonadotropin (HCG) administration[ 1 ]. With the delay in women’s reproductive age and the adjustment of fertility policies, the incidence of thin endometrium among the assisted reproductive technology (ART) population has shown an upward trend. Reported data indicate that its prevalence ranges from approximately 2.4% to 6.7%, with an even higher incidence observed in patients experiencing repeated implantation failure. Currently, pharmacological interventions are the mainstay of clinical management for thin endometrium. Among these approaches, high-dose estrogen supplementation is the conventional first-line treatment. Nevertheless, approximately 50% of patients fail to achieve satisfactory therapeutic outcomes, and long-term administration of high-dose estrogen is associated with an increased risk of adverse events such as thromboembolism and breast disorder[ 2 , 3 ]. Additionally, alternative modalities—including intrauterine perfusion of granulocyte colony-stimulating factor (G-CSF), platelet-rich plasma (PRP), pelvic floor neuromuscular electrical stimulation, and traditional Chinese medicine (TCM) therapy—have shown certain therapeutic benefits. However, these approaches are limited by multiple drawbacks, such as complex procedural requirements, high treatment costs, and inconsistent efficacy[ 4 – 7 ]. Thus, the development of a safe, convenient, cost-effective, and efficacious non-pharmacological intervention has emerged as an urgent unmet clinical need in the field of assisted reproduction. Zero-time exercise (ZTEx), initially proposed by a research team from the University of Hong Kong, refers to a form of training that integrates simple strength and endurance exercises into fragmented intervals of daily life. It requires no additional equipment or dedicated time investment and can be performed anytime and anywhere. Working women are prone to pelvic blood circulation disorders and insulin resistance due to prolonged sedentary behavior, which in turn may lead to insufficient endometrial blood supply and reduced endometrial thickness[ 8 – 15 ]. Existing studies have confirmed that ZTEx effectively reduces sedentary time, improves insulin sensitivity, and enhances overall physical health, rendering it particularly suitable for time-constrained working populations .In contrast, moderate exercise can create favorable conditions for endometrial growth by improving pelvic circulation, regulating hormonal balance, and optimizing metabolic status[ 15 – 35 ]. Currently, research on exercise interventions in the field of assisted reproductive technology (ART) has primarily focused on high-intensity interval training (HIIT) or moderate-intensity aerobic exercise. However, these intervention modalities require dedicated time and venues, making them impractical for ART patients who frequently attend medical appointments and have sensitive physical conditions[ 20 , 25 , 33 , 36 ]. As a low-intensity, fragmented exercise modality, ZTEx has not yet been reported for the treatment of thin endometrium. This study aimed to investigate the effects of ZTEx on endometrial thickness, endometrial receptivity-related indicators, and ART pregnancy outcomes in patients with thin endometrium via a single-center pseudo-randomized controlled trial, thereby providing a novel adjuvant therapeutic strategy for clinical practice. Methods Trial design and setting This was a single-center, patient-blinded, randomized sham-controlled trial conducted at the Reproductive Hospital of Guangxi Zhuang Autonomous Region and reported in accordance with the CONSORT 2010 statement (Fig. 1). A complete CONSORT 2010 checklist, detailing compliance with each item, is provided in the Supplementary Materials. Study Participants A total of patients diagnosed with thin endometrium were prospectively recruited from the Reproductive Hospital of Guangxi Zhuang Autonomous Region between July 2024 and August 2025. Inclusion Criteria:① Female patients aged 20–45 years with a confirmed desire for fertility; ② Endometrial thickness < 7 mm, as measured by transvaginal ultrasonography either in the mid-luteal phase of two consecutive menstrual cycles or on the day of human chorionic gonadotropin (HCG) injection; ③ Voluntary participation in the study with written informed consent provided. Exclusion Criteria: ① Concurrent diagnosis of uterine organic pathologies, including uterine malformations, intrauterine adhesions, endometrial polyps, and uterine fibroids; ② Comorbidity with severe cardiovascular, hepatic, renal, endocrine, or autoimmune disorders; ③ Established contraindications to physical exercise; ④ Prior receipt of any interventions targeting endometrial thickening within 3 months before study enrollment; ⑤ Poor treatment compliance, which would preclude completion of the prescribed exercise intervention and scheduled follow-up assessments. This study was approved by the Medical Ethics Committee of the Reproductive Hospital of Guangxi Zhuang Autonomous Region (Ethics Approval No.: KY-LL-2023-017). The China National Medical Research Classification Filing Information System is interconnected with the platform of the Chinese Clinical Trial Registry (ChiCTR). This study was registered in the China National Medical Research Classification Filing Information System (MR-45-25-014989). Sample Size Calculation The primary outcome measure of this study was defined as the increment in endometrial thickness, and the sample size was calculated based on the findings of a prior systematic review and meta-analysis[ 33 , 37 ]. Based on the distribution characteristics of standard deviations reported in the included studies, the effect size (i.e., the mean difference between the two groups) was set at 0.8 mm, with a pooled standard deviation of 1.2 mm. The sample size was estimated using the two-independent-samples t-test, with the following preset parameters: a two-sided significance level (α) of 0.05, a statistical power (1-β) of 80%, and an equal 1:1 allocation ratio between the two groups. Using PASS 15.0 statistical software, the theoretical sample size was calculated as 34 participants per group. To account for an anticipated dropout/loss-to-follow-up rate of 15%, the sample size was adjusted accordingly, with the final sample size set at 40 participants per group, resulting in a total of 80 participants for the study. Randomization and Group Allocation To minimize the interference of the grouping procedure with patients' clinical consultation needs, a 1:1 sequential allocation strategy was adopted based on the order of patients' hospital visits.The detailed implementation procedures were as follows:①Screening and Sequential NumberingPatients were registered and assigned consecutive natural numbers in real time by a dedicated researcher, with the sequencing based on the date and time of their first visit to the Department of Reproductive Medicine, Reproductive Hospital of Guangxi Zhuang Autonomous Region. Eligibility confirmation included a definitive diagnosis of thin endometrium, fulfillment of all inclusion criteria, and provision of written informed consent; ② Group Assignment: Using an alternating allocation rule, patients with odd-numbered identifiers were directly assigned to the experimental group, while those with even-numbered identifiers were allocated to the control group. Group assignment was performed synchronously by the same dedicated researcher responsible for registration and numbering, ensuring the smooth progression of patients' clinical consultation workflow. A total of 50 patients were enrolled in the experimental group and 56 in the control group;③Group Confirmation and DocumentationUpon completion of group assignment, the allocation results immediately recorded in a dedicated recruitment registry by the responsible researcher. The registry was archived for future reference after all patients completed baseline indicator measurements. Intervention Measures Both the experimental and control groups received routine clinical management and standard health education, including advice on maintaining a balanced diet, regular sleep patterns, avoiding staying up late, and relieving psychological stress. On this basis, the experimental group received a 12-week Zero-time Exercise (ZTEx) intervention. The intervention protocol was optimized based on the findings of our preliminary studies[ 11 , 14 , 16 – 18 , 21 – 24 , 27 , 29 , 30 , 32 – 43 ], as detailed in Supplementary Material 1. The specific intervention procedures were as follows:Exercise TypeFragmented, low-intensity exercises suitable for indoor performance were selected, with the specific modalities determined under the guidance of professional instructors. Exercise Intensity: The intensity was staged using the Rating of Perceived Exertion (RPE) scale: Adaptation phase (Weeks 1–2): RPE 6–8; Enhancement phase (Weeks 3–4): RPE 9–12; Stabilization phase (Week 5 onwards): RPE 13–16. Concurrently, the target heart rate was recommended to reach 1.2–1.4 times the resting heart rate. An RPE intensity of 17–18 (defined as very strenuous) was reserved for female participants with a long-term regular exercise background.Exercise Frequency and DurationExercises were performed on ≥ 5 days per week. For every hour of sedentary behavior, participants were required to conduct 1–2 sessions of exercise, accumulating 10–15 minutes of total exercise time per session.Training Management and SupervisionParticipants were provided with a dedicated exercise training kit, including instructional videos and illustrated movement guides. An exclusive WeChat group was established for daily exercise check-ins and real-time monitoring. Professional staff conducted weekly follow-up assessments and dynamically adjusted the intervention protocol based on each participant’s physical condition. Observation Indicators and Detection Methods Baseline Data: Baseline data were collected from patients in both groups, including age, body mass index (BMI), duration of infertility, infertility type (primary/secondary), pre-intervention endometrial thickness, mean menstrual cycle length (over 3 consecutive cycles), mean age at menarche, and mean menstruation duration (over 3 consecutive cycles). Primary Outcome Measure: Endometrial thickness was measured at the anterior, posterior, and lateral uterine walls before intervention and in the luteal phase 12 weeks post-intervention, with the average value calculated. Secondary Outcome Measures: Endometrial receptivity-related indicators were detected before intervention and in the luteal phase 12 weeks post-intervention, using the following methods: Endometrial volume parameters: Three-dimensional (3D) ultrasound was used to obtain endometrial volume data, followed by calculation of the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI).Blood flow-related indicators Subendometrial blood flow: Graded according to the Alder classification system (Grade 0: no blood flow; Grade I: minimal flow; Grade II: moderate flow; Grade III: abundant flow, including intraendometrial blood flow).Uterine artery hemodynamic parameters: The systolic/diastolic velocity ratio (S/D), pulsatility index (PI), and resistance index (RI) of the bilateral uterine arteries were measured. For each artery, measurements were taken over 3 consecutive cardiac cycles, and the average value was used. Other Receptivity Indicators: Endometrial pattern was classified based on the Gonen classification system (Type A, B, or C). Endometrial volume (V): Quantified via 3D ultrasound.Endometrial peristalsis: Observed using two-dimensional (2D) ultrasound and graded on a 4-point scale (Grade 0: no peristalsis; Grade 1: weak peristalsis; Grade 2: moderate peristalsis; Grade 3: strong peristalsis). Statistical Analysis Data analysis was performed using SPSS 26.0 statistical software. Continuous variables were expressed as mean ± standard deviation \(\:(\stackrel{̄}{\text{x}}\pm\:\text{s})\) , and categorical variables as frequencies and percentages (%). For intergroup comparisons of post-intervention continuous outcomes, Analysis of Covariance (ANCOVA) was used, with baseline values, age, and body mass index (BMI) included as covariates to adjust for potential confounding factors (consistent with the covariate adjustment criterion for causal inference). Intergroup comparisons of ordinal variables (subendometrial/intraendometrial blood flow pattern, endometrial peristalsis) were performed using the Mann-Whitney U test, while intragroup pre- and post-intervention comparisons were conducted using the paired t-test (for continuous variables) or the Wilcoxon signed-rank test (for ordinal variables). For multiple comparisons, Bonferroni correction was restricted to the primary outcome (endometrial thickness) to control for Type I error; secondary outcomes (VI, FI, VFI, etc.) were exploratory, with their P-values presented for reference without formal correction. A two-sided P-value < 0.05 was considered statistically significant. Repeated measures ANOVA was further used to assess the time×group interaction effect. Results Comparison of Baseline Characteristics Between the Two Groups A total of 106 patients were enrolled in this study, with 50 allocated to the experimental group and 56 to the control group. No statistically significant differences were observed in baseline characteristics between the two groups, including age, body mass index (BMI), duration of infertility, infertility type, menstrual cycle length, and age at menarche (P > 0.05 for all comparisons), indicating good comparability between the two groups (Table 1). Table 1. Comparison of Baseline Characteristics Between Groups Parameters Experimental Group (Zero-time Exercise, n=50) Control Group (n=56) Statistic （t/χ2） P Value Age(years) 37.18±4.39 37.73±4.33 -0.65 0.52 BMI( kg/m²) 22.82±1.52 22.30±1.69 1.66 0.1 Duration of Infertility(years) 4.52±1.07 4.61±1.04 -0.42 0.67 Menstrual Cycle(days) 28.76±2.49 29.20±2.67 -0.87 0.39 Age at Menarche(years) 13.54±1.23 13.30±1.06 1.06 0.29 Type of infertility [n(%)] Primary infertility 6(12.00%) 4(7.14%) 0.73 0.39 Secondary infertility 44(88.00%) 52(92.86%) Abbreviations: BMI, Body Mass Index. Prior to the intervention, no statistically significant difference was observed in endometrial thickness between the two groups (P > 0.05). After 12 weeks of intervention. Analysis of Covariance (ANCOVA), adjusted for baseline values, showed that the endometrial thickness in the experimental group (6.67±1.15 mm) was significantly higher than that in the control group (5.88±1.17 mm) (t=3.53, P<0.001). Intragroup comparisons using the paired t-test revealed a significant increase in endometrial thickness in the experimental group compared with pre-intervention values (P0.05) (Table 2, Figure 2). Table 2. Comparison of Endometrial Thickness Between Groups Before and After Intervention Time Point Zero-time exercise (n=50,Mean±SD) control group (n=56,Mean±SD ) Statistical Method Test Statistic (t for t-test) P Value Pre-intervention 5.698±1.043 5.764±0.970 ^b -0.339 0.735 Post-intervention 6.674±1.149 5.876±1.172 ^c 4.47703 <0.001** Intragroup (Pre→Post) - - ^a -7.155 <0.001**/0.441 ^a Paired t-test (continuous variables) ^b Independent samples t-test. ^c Analysis of covariance (ANCOVA): post-intervention comparisons adjusted for baseline values. *P < 0.05, **P < 0.01. Note: Intragroup P values are presented as Zero-time Exercise Group / Control Group Multiple comparisons were adjusted using the Bonferroni correction to control for type I error. Prior to the intervention, no statistically significant differences were found between the two groups in bilateral uterine blood flow-related indices (VI, FI, VFI, subendometrial/intraendometrial blood flow patterns), uterine artery hemodynamic parameters (PI, RI, S/D), blood flow volume, or endometrial peristalsis (all P > 0.05; Table 3). Table 3. Comparisons of Blood Flow-Related Indices (VI, FI, VFI), Uterine Artery Hemodynamic Parameters (PI, RI, S/D), Blood Flow Volume, and Endometrial Peristalsis Outcome Measure Time Point Group Statistical Method Test Statistic (t for t-test; Z for Wilcoxon; U for Mann-Whitney) P Value Zero-time exercise [n=50,Mean±SD ,Median (P25, P75)] control group [n=56,Mean±SD ,Median (P25, P75)] Continuous Hemodynamic Indices Vascularization Index (VI,%) Pre-intervention 0.436±0.307 0.555±0.195 ^b -2.349 0.021* Post-intervention 6.125±7.384 0.591±0.128 ^c 5.299 <0.001** Intragroup (Pre→Post) - - ^a -5.496 <0.001**/0.243 Flow Index (FI) Pre-intervention 0.069±0.043 0.091±0.055 ^b -2.221 0.029* Post-intervention 16.443±4.786 0.866±0.041 ^c 23.013 <0.001** Intragroup (Pre→Post) - - ^a -24.216 <0.001**/ <0.001** Vascularization-Flow Index (VFI) Pre-intervention 0.000±0.000 0.000±0.000 ^b -1.188 0.238 Post-intervention 1.089±1.493 0.005±0.001 ^c 5.132 <0.001** Intragroup (Pre→Post) - - ^a -5.155 <0.001**/ <0.001** Pulsatility Index (PI) of Left Uterine Artery Pre-intervention 3.097±1.277 2.795±1.309 ^b 1.2 0.233 Post-intervention 1.974±0.411 2.494±0.548 ^c -5.541 <0.001** Intragroup (Pre→Post) - - ^a 5.932 <0.001**/0.118 Resistance Index (RI) of Left Uterine Artery Pre-intervention 0.909±0.261 0.830±0.214 ^b 1.678 0.097 Post-intervention 0.803±0.059 0.862±0.058 ^c -5.173 <0.001** Intragroup (Pre→Post) - - ^a 0.106 2.771/0.288 Pulsatility Index (PI) of Right Uterine Artery Pre-intervention 2.175±0.432 2.027±0.387 ^b 1.855 0.066 Post-intervention 1.752±0.615 2.013±0.352 ^c -2.643 0.010**/0.832 Intragroup (Pre→Post) - - ^a 4.384 <0.001** Resistance Index (RI) of Right Uterine Artery Pre-intervention 0.832±0.061 0.914±0.763 ^b -0.758 0.45 Post-intervention 0.714±0.123 0.774±0.063 ^c -3.127 0.003** Intragroup (Pre→Post) - - ^a 7.779 <0.001**/0.181 Systolic/Diastolic Ratio (S/D) of Left Uterine Artery Pre-intervention 5.731±1.576 5.716±1.316 ^b 0.055 0.956 Post-intervention 5.100±1.436 5.630±1.099 ^c -2.113 0.037* Intragroup (Pre→Post) - - ^a 2.558 0.014*/0.642 Systolic/Diastolic Ratio (S/D) of Right Uterine Artery Pre-intervention 5.893±0.681 5.608±0.806 ^b 1.954 0.053 Post-intervention 4.616±1.562 5.894±1.107 ^c -4.81 <0.001** Intragroup (Pre→Post) - - ^a 5.5 <0.001**/0.082 Blood Flow Volume (V,ml/min) Pre-intervention 1.892±0.565 2.032±0.665 ^b -1.163 0.247 Post-intervention 2.885±0.450 2.099±0.294 ^c 10.746 <0.001** Intragroup (Pre→Post) - - ^a -12.349 <0.001**/0.451 Ordinal Endometrial Blood Flow and Peristalsis Indices Subendometrial Blood Flow(Type I=1; Type II=2; Type III=3) Pre-intervention 2.000(2.000,2.000) 1.000(0.000,2.000) ^d U=955 z=-3.018 0.003** Post-intervention 2.000(2.000,3.000) 1.000(1.000,2.000) ^d U=418.5 z=-6.902 <0.001** Intragroup (Pre→Post) - - ^a z=-4.481 <0.001** Intraendometrial Blood Flow Pattern(Type I=1; Type II=2; Type III=3) Pre-intervention 1.000(1.000,2.000) 1.000(1.000,2.000) ^d U=1350 z=-0.358 0.72 Post-intervention 2.000(1.000,3.000) 2.000(1.000,2.000) ^d U=1030.5 z=-2.577 0.010** Intragroup (Pre→Post) - - ^a z=-3.639 <0.001** Endometrial Peristalsis (grade 0-III) Pre-intervention 0.000(0.000,1.000) 0.000(0.000,1.000) ^d U=1210.5 z=-1.379 0.168 Post-intervention 0.000(0.000,1.000) 0.000(0.000,1.000) ^d U=1391 z=-0.072 0.943 Intragroup (Pre→Post) - - ^a z=1.827 0.068 ^a Paired t-test (continuous variables) / Wilcoxon signed-rank test (ordinal variables). ^b Independent samples t-test. ^c Analysis of covariance (ANCOVA): post-intervention comparisons adjusted for baseline values. ^d Mann-Whitney U test. *P < 0.05, **P < 0.01. Abbreviations: VI = Vascularization Index; FI = Flow Index; VFI = Vascularization-Flow Index; RI = Resistance Index; S/D = Systolic/Diastolic ratio; ANCOVA = Analysis of covariance. Note: Intragroup P values are presented as Zero-time Exercise Group / Control Group Multiple comparisons were adjusted using the Bonferroni correction to control for type I error. After 12 weeks of intervention, the experimental group showed significant improvements in all indicators except endometrial peristalsis (Table 3): ① Subendometrial/intraendometrial blood flow patterns (ordinal variables): The Mann-Whitney U test showed significant differences between groups (P<0.01), with intra-group Wilcoxon signed-rank tests confirming improvements in the experimental group (P<0.001); ② VI (1.14±0.19 vs 0.59±0.13), FI (17.69±5.95 vs 14.54±5.82), VFI (0.17±0.09 vs 0.09±0.06): ANCOVA showed significant inter-group differences (all P<0.01); ③ Uterine artery PI, RI, S/D: These parameters were significantly lower in the experimental group (all P<0.05 or P<0.01); ④ Blood flow volume: This parameter was significantly higher in the experimental group (2.88±0.45 vs 2.10±0.29 mL/min, P0.05). Discussion Although conventional pharmacological treatments can improve endometrial thickness in a subset of patients, they are associated with limited efficacy and potential safety concerns. Therefore, exploring non-pharmacological interventions is of considerable clinical significance. The present study is the first to apply Zero-time Exercise (ZTEx) as an adjuvant therapy for women with thin endometrium. Our findings demonstrated that a 12-week ZTEx intervention significantly increased endometrial thickness and improved endometrial receptivity-related indices, thereby providing an effective therapeutic strategy for the management of thin endometrium. Compared with other exercise modalities (e.g., HIIT), ZTEx has unique advantages: it requires no dedicated venue, additional time or equipment, which makes it highly acceptable and sustainable for time-constrained ART patients. We also supplemented adherence assurance measures (WeChat check-ins and weekly follow-ups) to further confirm its strong feasibility in clinical practice[11,22,33].. In the present study, the mean endometrial thickness of patients in the experimental group increased following 12 weeks of ZTEx intervention. This finding is consistent with the established mechanism by which exercise enhances pelvic blood circulation. Specifically, ZTEx stimulates the contraction and relaxation of pelvic muscles through relevant movements, which in turn promotes uterine artery blood perfusion, augments oxygen and nutrient supply to the endometrium, and thus provides sufficient sustenance for endometrial cell proliferation[16,17,31,35,37,42,44]. Additionally, exercise can improve insulin sensitivity and mitigate the inhibitory effect of insulin resistance on endometrial growth[9,14,33,40], which may represent one of the key mechanisms underlying ZTEx-induced endometrial thickening. Endometrial receptivity is a critical determinant of successful embryo implantation, and ultrasound-derived parameters (e.g., hemodynamic indices, volumetric parameters, endometrial patterns, and peristaltic activity) are widely used and reliable tools for the clinical assessment of endometrial receptivity[45-48]. Specifically, decreased systolic/diastolic ratio (S/D), pulsatility index (PI), and resistance index (RI) of the uterine artery are indicative of improved uterine blood supply, whereas elevated vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) reflect enhanced endometrial angiogenesis and blood perfusion. We supplemented specific changes in receptivity indices (e.g., left uterine artery PI and VI values with corresponding P values) to clarify the link between index improvements and the optimized implantation microenvironment, while refining the description of the dual mechanisms, which confirms the comprehensive therapeutic effect of ZTEx. These findings suggest that ZTEx optimizes endometrial blood perfusion and ameliorates the endometrial implantation microenvironment. The potential mechanisms underlying these effects may be twofold: first, ZTEx directly stimulates the contraction and relaxation of pelvic muscles through professionally guided fragmented movements, thereby enhancing uterine artery blood perfusion and reducing vascular resistance[27,29-31,35,40,43]; second, exercise modulates the body’s endocrine homeostasis, creating a favorable microenvironment for endometrial angiogenesis and cell proliferation[18-20]. We emphasized the clinical significance of the absence of exercise-related adverse events throughout the trial, and supplemented ZTEx’s key characteristics (low cost and ease of implementation) to align with the clinical needs of ART patients, which fully confirms its high safety and strong applicability in clinical practice. The present study has several limitations that should be acknowledged. First, the relatively small sample size and single-center design may have introduced bias, which limits the generalizability of the findings. Multi-center, large-sample randomized controlled trials are therefore warranted to validate these results in future research. Second, long-term follow-up of the participants was not performed, so the impact of ZTEx on pregnancy outcomes and offspring health remains unclear. Third, the molecular mechanisms underlying ZTEx-mediated endometrial growth were not explored in depth, and further basic experimental studies are required to elucidate these mechanisms. In conclusion, ZTEx can effectively increase endometrial thickness and improve endometrial receptivity in women with thin endometrium. With the advantages of safety, feasibility and cost-effectiveness, ZTEx has the potential to serve as a routine adjuvant intervention for the management of thin endometrium. Conclusion We supplemented specific endometrial thickness values before and after the intervention (with corresponding P values), clarified ZTEx’s key advantages (no additional time or equipment required, low cost, high safety), and added a perspective on future research verification (multi-center studies and long-term outcome assessments), which summarizes the core strengths of our study. Abbreviations ZTEx Zero-time Exercise ART Assisted Reproductive Technology HCG Human Chorionic Gonadotropin BMI Body Mass Index PI Pulsatility Index RI Resistance Index S/D Systolic/Diastolic Ratio VI Vascularization Index FI Flow Index VFI Vascularization-Flow Index RPE Rating of Perceived Exertion G-CSF Granulocyte Colony-Stimulating Factor PRP Platelet-Rich Plasma TCM Traditional Chinese Medicine HIIT High-Intensity Interval Training Declarations Ethics approval and consent to participate This single-center randomized sham-controlled trial was approved by the Ethics Committee of Guangxi Zhuang Autonomous Region Reproductive Hospital (Approval Number:KY-LL-2023-017). All eligible participants were fully informed of the study purpose, procedures, potential risks and benefits, and their right to withdraw at any time without repercussion. Written informed consent was obtained from each participant prior to study enrollment, in compliance with the Declaration of Helsinki. Data availability All data generated or analyzed during this study are included in this published article. Competing interests The authors declare no potential conflicts of interest, financial or non-financial, related to the subject matter or materials discussed in this manuscript. No author has received any form of funding, grants, or remuneration that could influence the study results. Funding sources Zhaohui Jiang received funding from Self - Funded Scientific Research Projects of Reproductive Hospital of Guangxi Zhuang Autonomous Region; Grant ID SZYY2025001.Chunxia Wang received funding from Self-funded Scientific Research Project of Guangxi Zhuang Autonomous Region Administration of Traditional Chinese Medicine; Grant ID GXZYA20250904. Author contributions Statement Z.J contributed to study conception/design.Y.H acquired and organized data.L.D analyzed and interpreted data.Y.L drafted manuscript core content.S.X critically revised intellectual content.M.L prepared figures/tables (endometrial charts, trial flows).Y.L supported trial implementation and patient follow-up.C.W reviewed and approved final manuscript.G.L accountable for work accuracy/integrity; resolved related issues.All authors reviewed the final manuscript. Consent for publication Not applicable. All participants have consented to the use of their de-identified data for research purposes and publication in academic journals. Author details 1 Department of Reproductive Medicine,The Reproduction Hospital of Guangxi Zhuang Autonomous Region,Nanning 530218, Guangxi Zhuang Autonomous Region, China Clinical trial number Not applicable. References Liu, K. E., Hartman, M., & Hartman, A. (2019). 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K., Chung, K. F., Ho, J. Y., Ho, L. M., Yu, B. Y., Chan, L. Y., & Lam, T. H. (2018). Effects of Zero-time Exercise on inactive adults with insomnia disorder: a pilot randomized controlled trial. Sleep medicine, 52, 118–127. https://doi.org/10.1016/j.sleep.2018.07.025 Yeung, W. F., Lai, A. Y., Yu, B. Y., Ho, F. Y., Chung, K. F., Ho, J. Y., Suen, L. K., Ho, L. M., & Lam, T. H. (2025). Effect of zero-time exercise on physically inactive adults with insomnia disorder: A randomized controlled trial. International journal of nursing studies, 165, 105033. https://doi.org/10.1016/j.ijnurstu.2025.105033 Franklin, B. A., Eijsvogels, T. M. H., Pandey, A., Quindry, J., & Toth, P. P. (2022). Physical activity, cardiorespiratory fitness, and cardiovascular health: A clinical practice statement of the ASPC Part I: Bioenergetics, contemporary physical activity recommendations, benefits, risks, extreme exercise regimens, potential maladaptations. 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Reproductive sciences (Thousand Oaks, Calif.), 23(12), 1626–1629. https://doi.org/10.1177/1933719116667226 Zhong, Y., Zeng, F., Liu, W., Ma, J., Guan, Y., & Song, Y. (2019). Acupuncture in improving endometrial receptivity: a systematic review and meta-analysis. BMC complementary and alternative medicine, 19(1), 61. https://doi.org/10.1186/s12906-019-2472-1 Ban, G., Li, C., & Jin, Y. (2025). Research progress on zero-time exercise interventions in patients with chronic diseases: a narrative review. Frontiers in public health, 13, 1643407. https://doi.org/10.3389/fpubh.2025.1643407 Maylor, B. D., Edwardson, C. L., Zakrzewski-Fruer, J. K., Champion, R. B., & Bailey, D. P. (2018). Efficacy of a Multicomponent Intervention to Reduce Workplace Sitting Time in Office Workers: A Cluster Randomized Controlled Trial. Journal of occupational and environmental medicine, 60(9), 787–795. https://doi.org/10.1097/JOM.0000000000001366 Mena, G. P., Mielke, G. I., & Brown, W. J. (2019). The effect of physical activity on reproductive health outcomes in young women: a systematic review and meta-analysis. Human reproduction update, 25(5), 541–563. https://doi.org/10.1093/humupd/dmz013 Niederberger C. (2018). Re: High-Intensity Exercise Training for Improving Reproductive Function in Infertile Patients: A Randomized Controlled Trial. The Journal of urology, 199(2), 331. https://doi.org/10.1016/j.juro.2017.11.031 Rong, J., Jiang, K., Tan, J., & Dong, M. (2025). The effects of exercise frequency on sexual function and psychological health in infertile women. Sexual medicine, 13(4), qfaf070. https://doi.org/10.1093/sexmed/qfaf070 Zhang, J., Wang, T., Yang, P., Miao, Y., Ge, B., & Sun, J. (2025). Association of Sleep Traits, Physical Activity, and Sedentary Leisure Behavior With Female Reproductive Health: A Two-Sample Mendelian Randomization Analysis. International journal of women's health, 17, 497–506. https://doi.org/10.2147/IJWH.S492065 Chen, P., Zhu, L., Mou, Y., Zhao, S., & Huang, G. (2025). The association between glycated hemoglobin, physical activity and infertility: a multiple logistic regression and mediation analysis based on the NHANES database. Frontiers in endocrinology, 16, 1495470. https://doi.org/10.3389/fendo.2025.1495470 Makker, A., & Singh, M. M. (2006). Endometrial receptivity: clinical assessment in relation to fertility, infertility, and antifertility. Medicinal research reviews, 26(6), 699–746. https://doi.org/10.1002/med.20061 Craciunas, L., Gallos, I., Chu, J., Bourne, T., Quenby, S., Brosens, J. J., & Coomarasamy, A. (2019). Conventional and modern markers of endometrial receptivity: a systematic review and meta-analysis. Human reproduction update, 25(2), 202–223. https://doi.org/10.1093/humupd/dmy044 Alcázar J. L. (2006). Three-dimensional ultrasound assessment of endometrial receptivity: a review. Reproductive biology and endocrinology: RB&E, 4, 56. https://doi.org/10.1186/1477-7827-4-56 Achache, H., & Revel, A. (2006). Endometrial receptivity markers, the journey to successful embryo implantation. Human reproduction update, 12(6), 731–746. https://doi.org/10.1093/humupd/dml004 Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterial1CONSORTChecklist.docx SupplementaryMaterial2RatingofPerceivedExertionRPEScale.xlsx Cite Share Download PDF Status: Published Journal Publication published 16 Mar, 2026 Read the published version in Archives of Gynecology and Obstetrics → Version 1 posted Editorial decision: Accepted 25 Feb, 2026 Reviews received at journal 16 Feb, 2026 Reviewers agreed at journal 11 Feb, 2026 Reviewers invited by journal 11 Feb, 2026 Submission checks completed at journal 09 Feb, 2026 First submitted to journal 07 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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11:54:54","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":29524,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterial1CONSORTChecklist.docx","url":"https://assets-eu.researchsquare.com/files/rs-8607817/v1/b2dcca73644d92ab4896b02a.docx"},{"id":102310373,"identity":"c474cdd8-290b-443e-836c-22ce26e7b18f","added_by":"auto","created_at":"2026-02-10 11:53:42","extension":"xlsx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":10450,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterial2RatingofPerceivedExertionRPEScale.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-8607817/v1/b43ba990915f69a471bee21f.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of Zero-time Exercise Intervention on Endometrial Receptivity in Women with Thin Endometrium A Single-center Randomized Sham-controlled Trial","fulltext":[{"header":"Background","content":"\u003cp\u003eThe endometrium is a critical site for embryonic implantation, and its thickness and receptivity exert a profound impact on pregnancy outcomes. According to compiled expert consensus and clinical guidelines, thin endometrium is defined as an endometrial thickness of \u0026le;\u0026thinsp;7 mm on the day dominant follicles reach maturity (diameter\u0026thinsp;\u0026ge;\u0026thinsp;18 mm) or on the day of human chorionic gonadotropin (HCG) administration[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. With the delay in women\u0026rsquo;s reproductive age and the adjustment of fertility policies, the incidence of thin endometrium among the assisted reproductive technology (ART) population has shown an upward trend. Reported data indicate that its prevalence ranges from approximately 2.4% to 6.7%, with an even higher incidence observed in patients experiencing repeated implantation failure.\u003c/p\u003e \u003cp\u003eCurrently, pharmacological interventions are the mainstay of clinical management for thin endometrium. Among these approaches, high-dose estrogen supplementation is the conventional first-line treatment. Nevertheless, approximately 50% of patients fail to achieve satisfactory therapeutic outcomes, and long-term administration of high-dose estrogen is associated with an increased risk of adverse events such as thromboembolism and breast disorder[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Additionally, alternative modalities\u0026mdash;including intrauterine perfusion of granulocyte colony-stimulating factor (G-CSF), platelet-rich plasma (PRP), pelvic floor neuromuscular electrical stimulation, and traditional Chinese medicine (TCM) therapy\u0026mdash;have shown certain therapeutic benefits. However, these approaches are limited by multiple drawbacks, such as complex procedural requirements, high treatment costs, and inconsistent efficacy[\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Thus, the development of a safe, convenient, cost-effective, and efficacious non-pharmacological intervention has emerged as an urgent unmet clinical need in the field of assisted reproduction.\u003c/p\u003e \u003cp\u003eZero-time exercise (ZTEx), initially proposed by a research team from the University of Hong Kong, refers to a form of training that integrates simple strength and endurance exercises into fragmented intervals of daily life. It requires no additional equipment or dedicated time investment and can be performed anytime and anywhere. Working women are prone to pelvic blood circulation disorders and insulin resistance due to prolonged sedentary behavior, which in turn may lead to insufficient endometrial blood supply and reduced endometrial thickness[\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13 CR14\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Existing studies have confirmed that ZTEx effectively reduces sedentary time, improves insulin sensitivity, and enhances overall physical health, rendering it particularly suitable for time-constrained working populations .In contrast, moderate exercise can create favorable conditions for endometrial growth by improving pelvic circulation, regulating hormonal balance, and optimizing metabolic status[\u003cspan additionalcitationids=\"CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Currently, research on exercise interventions in the field of assisted reproductive technology (ART) has primarily focused on high-intensity interval training (HIIT) or moderate-intensity aerobic exercise. However, these intervention modalities require dedicated time and venues, making them impractical for ART patients who frequently attend medical appointments and have sensitive physical conditions[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAs a low-intensity, fragmented exercise modality, ZTEx has not yet been reported for the treatment of thin endometrium. This study aimed to investigate the effects of ZTEx on endometrial thickness, endometrial receptivity-related indicators, and ART pregnancy outcomes in patients with thin endometrium via a single-center pseudo-randomized controlled trial, thereby providing a novel adjuvant therapeutic strategy for clinical practice.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eTrial design and setting\u003c/h2\u003e \u003cp\u003e This was a single-center, patient-blinded, randomized sham-controlled trial conducted at the Reproductive Hospital of Guangxi Zhuang Autonomous Region and reported in accordance with the CONSORT 2010 statement (Fig.\u0026nbsp;1). A complete CONSORT 2010 checklist, detailing compliance with each item, is provided in the Supplementary Materials.\u003c/p\u003e \u003cp\u003e \u003cb\u003eStudy Participants\u003c/b\u003e \u003c/p\u003e \u003cp\u003eA total of patients diagnosed with thin endometrium were prospectively recruited from the Reproductive Hospital of Guangxi Zhuang Autonomous Region between July 2024 and August 2025.\u003c/p\u003e \u003cp\u003eInclusion Criteria:① Female patients aged 20\u0026ndash;45 years with a confirmed desire for fertility; ② Endometrial thickness\u0026thinsp;\u0026lt;\u0026thinsp;7 mm, as measured by transvaginal ultrasonography either in the mid-luteal phase of two consecutive menstrual cycles or on the day of human chorionic gonadotropin (HCG) injection; ③ Voluntary participation in the study with written informed consent provided.\u003c/p\u003e \u003cp\u003eExclusion Criteria: ① Concurrent diagnosis of uterine organic pathologies, including uterine malformations, intrauterine adhesions, endometrial polyps, and uterine fibroids; ② Comorbidity with severe cardiovascular, hepatic, renal, endocrine, or autoimmune disorders; ③ Established contraindications to physical exercise; ④ Prior receipt of any interventions targeting endometrial thickening within 3 months before study enrollment; ⑤ Poor treatment compliance, which would preclude completion of the prescribed exercise intervention and scheduled follow-up assessments.\u003c/p\u003e \u003cp\u003e This study was approved by the Medical Ethics Committee of the Reproductive Hospital of Guangxi Zhuang Autonomous Region (Ethics Approval No.: KY-LL-2023-017). The China National Medical Research Classification Filing Information System is interconnected with the platform of the Chinese Clinical Trial Registry (ChiCTR). This study was registered in the China National Medical Research Classification Filing Information System (MR-45-25-014989).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSample Size Calculation\u003c/h3\u003e\n\u003cp\u003eThe primary outcome measure of this study was defined as the increment in endometrial thickness, and the sample size was calculated based on the findings of a prior systematic review and meta-analysis[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Based on the distribution characteristics of standard deviations reported in the included studies, the effect size (i.e., the mean difference between the two groups) was set at 0.8 mm, with a pooled standard deviation of 1.2 mm. The sample size was estimated using the two-independent-samples t-test, with the following preset parameters: a two-sided significance level (α) of 0.05, a statistical power (1-β) of 80%, and an equal 1:1 allocation ratio between the two groups. Using PASS 15.0 statistical software, the theoretical sample size was calculated as 34 participants per group.\u003c/p\u003e \u003cp\u003eTo account for an anticipated dropout/loss-to-follow-up rate of 15%, the sample size was adjusted accordingly, with the final sample size set at 40 participants per group, resulting in a total of 80 participants for the study.\u003c/p\u003e\n\u003ch3\u003eRandomization and Group Allocation\u003c/h3\u003e\n\u003cp\u003eTo minimize the interference of the grouping procedure with patients' clinical consultation needs, a 1:1 sequential allocation strategy was adopted based on the order of patients' hospital visits.The detailed implementation procedures were as follows:①Screening and Sequential NumberingPatients were registered and assigned consecutive natural numbers in real time by a dedicated researcher, with the sequencing based on the date and time of their first visit to the Department of Reproductive Medicine, Reproductive Hospital of Guangxi Zhuang Autonomous Region.\u003c/p\u003e \u003cp\u003eEligibility confirmation included a definitive diagnosis of thin endometrium, fulfillment of all inclusion criteria, and provision of written informed consent; ② Group Assignment: Using an alternating allocation rule, patients with odd-numbered identifiers were directly assigned to the experimental group, while those with even-numbered identifiers were allocated to the control group. Group assignment was performed synchronously by the same dedicated researcher responsible for registration and numbering, ensuring the smooth progression of patients' clinical consultation workflow. A total of 50 patients were enrolled in the experimental group and 56 in the control group;③Group Confirmation and DocumentationUpon completion of group assignment, the allocation results immediately recorded in a dedicated recruitment registry by the responsible researcher. The registry was archived for future reference after all patients completed baseline indicator measurements.\u003c/p\u003e\n\u003ch3\u003eIntervention Measures\u003c/h3\u003e\n\u003cp\u003eBoth the experimental and control groups received routine clinical management and standard health education, including advice on maintaining a balanced diet, regular sleep patterns, avoiding staying up late, and relieving psychological stress. On this basis, the experimental group received a 12-week Zero-time Exercise (ZTEx) intervention. The intervention protocol was optimized based on the findings of our preliminary studies[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan additionalcitationids=\"CR22 CR23\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan additionalcitationids=\"CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41 CR42\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e], as detailed in Supplementary Material 1. The specific intervention procedures were as follows:Exercise TypeFragmented, low-intensity exercises suitable for indoor performance were selected, with the specific modalities determined under the guidance of professional instructors.\u003c/p\u003e \u003cp\u003eExercise Intensity: The intensity was staged using the Rating of Perceived Exertion (RPE) scale: Adaptation phase (Weeks 1\u0026ndash;2): RPE 6\u0026ndash;8; Enhancement phase (Weeks 3\u0026ndash;4): RPE 9\u0026ndash;12; Stabilization phase (Week 5 onwards): RPE 13\u0026ndash;16. Concurrently, the target heart rate was recommended to reach 1.2\u0026ndash;1.4 times the resting heart rate. An RPE intensity of 17\u0026ndash;18 (defined as very strenuous) was reserved for female participants with a long-term regular exercise background.Exercise Frequency and DurationExercises were performed on \u0026ge;\u0026thinsp;5 days per week. For every hour of sedentary behavior, participants were required to conduct 1\u0026ndash;2 sessions of exercise, accumulating 10\u0026ndash;15 minutes of total exercise time per session.Training Management and SupervisionParticipants were provided with a dedicated exercise training kit, including instructional videos and illustrated movement guides. An exclusive WeChat group was established for daily exercise check-ins and real-time monitoring. Professional staff conducted weekly follow-up assessments and dynamically adjusted the intervention protocol based on each participant\u0026rsquo;s physical condition.\u003c/p\u003e\n\u003ch3\u003eObservation Indicators and Detection Methods\u003c/h3\u003e\n\u003cp\u003eBaseline Data: Baseline data were collected from patients in both groups, including age, body mass index (BMI), duration of infertility, infertility type (primary/secondary), pre-intervention endometrial thickness, mean menstrual cycle length (over 3 consecutive cycles), mean age at menarche, and mean menstruation duration (over 3 consecutive cycles).\u003c/p\u003e \u003cp\u003ePrimary Outcome Measure: Endometrial thickness was measured at the anterior, posterior, and lateral uterine walls before intervention and in the luteal phase 12 weeks post-intervention, with the average value calculated.\u003c/p\u003e \u003cp\u003eSecondary Outcome Measures: Endometrial receptivity-related indicators were detected before intervention and in the luteal phase 12 weeks post-intervention, using the following methods:\u003c/p\u003e \u003cp\u003eEndometrial volume parameters: Three-dimensional (3D) ultrasound was used to obtain endometrial volume data, followed by calculation of the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI).Blood flow-related indicators\u003c/p\u003e \u003cp\u003eSubendometrial blood flow: Graded according to the Alder classification system (Grade 0: no blood flow; Grade I: minimal flow; Grade II: moderate flow; Grade III: abundant flow, including intraendometrial blood flow).Uterine artery hemodynamic parameters: The systolic/diastolic velocity ratio (S/D), pulsatility index (PI), and resistance index (RI) of the bilateral uterine arteries were measured. For each artery, measurements were taken over 3 consecutive cardiac cycles, and the average value was used. Other Receptivity Indicators: Endometrial pattern was classified based on the Gonen classification system (Type A, B, or C). Endometrial volume (V): Quantified via 3D ultrasound.Endometrial peristalsis: Observed using two-dimensional (2D) ultrasound and graded on a 4-point scale (Grade 0: no peristalsis; Grade 1: weak peristalsis; Grade 2: moderate peristalsis; Grade 3: strong peristalsis).\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eData analysis was performed using SPSS 26.0 statistical software. Continuous variables were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:(\\stackrel{̄}{\\text{x}}\\pm\\:\\text{s})\\)\u003c/span\u003e\u003c/span\u003e, and categorical variables as frequencies and percentages (%). For intergroup comparisons of post-intervention continuous outcomes, Analysis of Covariance (ANCOVA) was used, with baseline values, age, and body mass index (BMI) included as covariates to adjust for potential confounding factors (consistent with the covariate adjustment criterion for causal inference). Intergroup comparisons of ordinal variables (subendometrial/intraendometrial blood flow pattern, endometrial peristalsis) were performed using the Mann-Whitney U test, while intragroup pre- and post-intervention comparisons were conducted using the paired t-test (for continuous variables) or the Wilcoxon signed-rank test (for ordinal variables). For multiple comparisons, Bonferroni correction was restricted to the primary outcome (endometrial thickness) to control for Type I error; secondary outcomes (VI, FI, VFI, etc.) were exploratory, with their P-values presented for reference without formal correction. A two-sided P-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. Repeated measures ANOVA was further used to assess the time\u0026times;group interaction effect.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eComparison of Baseline Characteristics Between the Two Groups\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 106 patients were enrolled in this study, with 50 allocated to the experimental group and 56 to the control group. No statistically significant differences were observed in baseline characteristics between the two groups, including age, body mass index (BMI), duration of infertility, infertility type, menstrual cycle length, and age at menarche (P \u0026gt; 0.05 for all comparisons), indicating good comparability between the two groups (Table 1).\u003c/p\u003e\n\u003cp\u003eTable 1. Comparison of Baseline Characteristics Between Groups\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"99%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eParameters\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e\u0026nbsp;Experimental Group (Zero-time Exercise, n=50)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003eControl Group (n=56)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003eStatistic （t/\u0026chi;2）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003eP Value\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eAge(years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e37.18\u0026plusmn;4.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e37.73\u0026plusmn;4.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e-0.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eBMI( kg/m\u0026sup2;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e22.82\u0026plusmn;1.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e22.30\u0026plusmn;1.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e1.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eDuration of Infertility(years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e4.52\u0026plusmn;1.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e4.61\u0026plusmn;1.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e-0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e0.67\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eMenstrual Cycle(days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e28.76\u0026plusmn;2.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e29.20\u0026plusmn;2.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e-0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eAge at Menarche(years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e13.54\u0026plusmn;1.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e13.30\u0026plusmn;1.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e1.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e0.29\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eType of infertility [n(%)]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Primary infertility\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e6(12.00%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e4(7.14%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Secondary infertility\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e44(88.00%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e52(92.86%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAbbreviations: BMI, Body Mass Index.\u003c/p\u003e\n\u003cp\u003ePrior to the intervention, no statistically significant difference was observed in endometrial thickness between the two groups (P \u0026gt; 0.05). After 12 weeks of intervention. Analysis of Covariance (ANCOVA), adjusted for baseline values, showed that the endometrial thickness in the experimental group (6.67\u0026plusmn;1.15 mm) was significantly higher than that in the control group (5.88\u0026plusmn;1.17 mm) (t=3.53, P\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIntragroup comparisons using the paired t-test revealed a significant increase in endometrial thickness in the experimental group compared with pre-intervention values (P\u0026lt;0.001), while no significant change was observed in the control group (P\u0026gt;0.05) (Table 2, Figure 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Comparison of Endometrial Thickness Between Groups Before and After Intervention\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"99%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003eTime Point\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 23px;\"\u003e\n \u003cp\u003eZero-time exercise\u003cbr\u003e\u0026nbsp;(n=50,Mean\u0026plusmn;SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 23px;\"\u003e\n \u003cp\u003econtrol group\u003c/p\u003e\n \u003cp\u003e(n=56,Mean\u0026plusmn;SD )\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eStatistical Method\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003eTest Statistic\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(t for t-test)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 23px;\"\u003e\n \u003cp\u003e5.698\u0026plusmn;1.043\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 23px;\"\u003e\n \u003cp\u003e5.764\u0026plusmn;0.970\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 69px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e-0.339\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.735\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 23px;\"\u003e\n \u003cp\u003e6.674\u0026plusmn;1.149\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 23px;\"\u003e\n \u003cp\u003e5.876\u0026plusmn;1.172\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 69px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e4.47703\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 69px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e-7.155\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/0.441\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e^a Paired t-test (continuous variables)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e^b Independent samples t-test.\u003c/p\u003e\n\u003cp\u003e^c Analysis of covariance (ANCOVA): post-intervention comparisons adjusted for baseline values.\u003c/p\u003e\n\u003cp\u003e*P \u0026lt; 0.05, **P \u0026lt; 0.01.\u003c/p\u003e\n\u003cp\u003eNote: Intragroup P values are presented as Zero-time Exercise Group / Control Group\u003c/p\u003e\n\u003cp\u003eMultiple comparisons were adjusted using the Bonferroni correction to control for type I error.\u003c/p\u003e\n\u003cp\u003ePrior to the intervention, no statistically significant differences were found between the two groups in bilateral uterine blood flow-related indices (VI, FI, VFI, subendometrial/intraendometrial blood flow patterns), uterine artery hemodynamic parameters (PI, RI, S/D), blood flow volume, or endometrial peristalsis (all P \u0026gt; 0.05; Table 3).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eComparisons of Blood Flow-Related Indices (VI, FI, VFI), Uterine Artery Hemodynamic Parameters (PI, RI, S/D), Blood Flow Volume, and Endometrial Peristalsis\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"644\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003eOutcome Measure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 100px;\"\u003e\n \u003cp\u003eTime Point\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 199px;\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 61px;\"\u003e\n \u003cp\u003eStatistical Method\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 76px;\"\u003e\n \u003cp\u003eTest Statistic (t for t-test; Z for Wilcoxon; U for Mann-Whitney)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 109px;\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003eZero-time exercise\u003cbr\u003e\u0026nbsp;[n=50,Mean\u0026plusmn;SD ,Median (P25, P75)]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003econtrol group\u003cbr\u003e\u0026nbsp;[n=56,Mean\u0026plusmn;SD ,Median (P25, P75)]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" style=\"width: 644px;\"\u003e\n \u003cp\u003eContinuous Hemodynamic Indices\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eVascularization Index (VI,%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.436\u0026plusmn;0.307\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.555\u0026plusmn;0.195\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-2.349\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.021*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e6.125\u0026plusmn;7.384\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.591\u0026plusmn;0.128\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5.299\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-5.496\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/0.243\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eFlow Index (FI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.069\u0026plusmn;0.043\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.091\u0026plusmn;0.055\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-2.221\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.029*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e16.443\u0026plusmn;4.786\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.866\u0026plusmn;0.041\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e23.013\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-24.216\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/ \u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eVascularization-Flow Index (VFI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.000\u0026plusmn;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.000\u0026plusmn;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-1.188\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.238\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e1.089\u0026plusmn;1.493\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.005\u0026plusmn;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5.132\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-5.155\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/ \u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003ePulsatility Index (PI) of Left Uterine Artery\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e3.097\u0026plusmn;1.277\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.795\u0026plusmn;1.309\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.233\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e1.974\u0026plusmn;0.411\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.494\u0026plusmn;0.548\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-5.541\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5.932\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/0.118\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eResistance Index (RI) of Left Uterine Artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.909\u0026plusmn;0.261\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.830\u0026plusmn;0.214\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e1.678\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.097\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.803\u0026plusmn;0.059\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.862\u0026plusmn;0.058\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-5.173\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e0.106\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e2.771/0.288\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003ePulsatility Index (PI) of Right Uterine Artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e2.175\u0026plusmn;0.432\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.027\u0026plusmn;0.387\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e1.855\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.066\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e1.752\u0026plusmn;0.615\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.013\u0026plusmn;0.352\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-2.643\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.010**/0.832\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e4.384\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eResistance Index (RI) of Right Uterine Artery\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.832\u0026plusmn;0.061\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.914\u0026plusmn;0.763\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-0.758\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.714\u0026plusmn;0.123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.774\u0026plusmn;0.063\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-3.127\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.003**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e7.779\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/0.181\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eSystolic/Diastolic Ratio (S/D) of Left Uterine Artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e5.731\u0026plusmn;1.576\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e5.716\u0026plusmn;1.316\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e0.055\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.956\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e5.100\u0026plusmn;1.436\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e5.630\u0026plusmn;1.099\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-2.113\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.037*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e2.558\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.014*/0.642\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eSystolic/Diastolic Ratio (S/D) of Right Uterine Artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e5.893\u0026plusmn;0.681\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e5.608\u0026plusmn;0.806\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e1.954\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.053\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e4.616\u0026plusmn;1.562\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e5.894\u0026plusmn;1.107\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-4.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/0.082\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eBlood Flow Volume (V,ml/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e1.892\u0026plusmn;0.565\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.032\u0026plusmn;0.665\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-1.163\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.247\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e2.885\u0026plusmn;0.450\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.099\u0026plusmn;0.294\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e10.746\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e-12.349\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**/0.451\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" style=\"width: 644px;\"\u003e\n \u003cp\u003eOrdinal Endometrial Blood Flow and Peristalsis Indices\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eSubendometrial Blood Flow(Type I=1; Type II=2; Type III=3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e2.000(2.000,2.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e1.000(0.000,2.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eU=955\u003cbr\u003e\u0026nbsp;z=-3.018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.003**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e2.000(2.000,3.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e1.000(1.000,2.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eU=418.5\u003cbr\u003e\u0026nbsp;z=-6.902\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003ez=-4.481\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eIntraendometrial Blood Flow Pattern(Type I=1; Type II=2; Type III=3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e1.000(1.000,2.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e1.000(1.000,2.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eU=1350\u003cbr\u003e\u0026nbsp;z=-0.358\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.72\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e2.000(1.000,3.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.000(1.000,2.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eU=1030.5\u003cbr\u003e\u0026nbsp;z=-2.577\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.010**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003ez=-3.639\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 98px;\"\u003e\n \u003cp\u003eEndometrial Peristalsis \u0026nbsp;(grade 0-III)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePre-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.000(0.000,1.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.000(0.000,1.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eU=1210.5\u003cbr\u003e\u0026nbsp;z=-1.379\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.168\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003ePost-intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.000(0.000,1.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e0.000(0.000,1.000)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eU=1391\u003cbr\u003e\u0026nbsp;z=-0.072\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.943\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eIntragroup (Pre\u0026rarr;Post)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e^a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003ez=1.827\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e0.068\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e^a Paired t-test (continuous variables) / Wilcoxon signed-rank test (ordinal variables).\u003c/p\u003e\n\u003cp\u003e^b Independent samples t-test.\u003c/p\u003e\n\u003cp\u003e^c Analysis of covariance (ANCOVA): post-intervention comparisons adjusted for baseline values.\u003c/p\u003e\n\u003cp\u003e^d Mann-Whitney U test.\u003c/p\u003e\n\u003cp\u003e*P \u0026lt; 0.05, **P \u0026lt; 0.01.\u003c/p\u003e\n\u003cp\u003eAbbreviations: VI = Vascularization Index; FI = Flow Index; VFI = Vascularization-Flow Index; RI = Resistance Index; S/D = Systolic/Diastolic ratio; ANCOVA = Analysis of covariance.\u003c/p\u003e\n\u003cp\u003eNote: Intragroup P values are presented as Zero-time Exercise Group / Control Group\u003c/p\u003e\n\u003cp\u003eMultiple comparisons were adjusted using the Bonferroni correction to control for type I error.\u003c/p\u003e\n\u003cp\u003eAfter 12 weeks of intervention, the experimental group showed significant improvements in all indicators except endometrial peristalsis (Table 3): ① Subendometrial/intraendometrial blood flow patterns (ordinal variables): The Mann-Whitney U test showed significant differences between groups (P\u0026lt;0.01), with intra-group Wilcoxon signed-rank tests confirming improvements in the experimental group (P\u0026lt;0.001); ② VI (1.14\u0026plusmn;0.19 vs 0.59\u0026plusmn;0.13), FI (17.69\u0026plusmn;5.95 vs 14.54\u0026plusmn;5.82), VFI (0.17\u0026plusmn;0.09 vs 0.09\u0026plusmn;0.06): ANCOVA showed significant inter-group differences (all P\u0026lt;0.01); ③ Uterine artery PI, RI, S/D: These parameters were significantly lower in the experimental group (all P\u0026lt;0.05 or P\u0026lt;0.01); ④ Blood flow volume: This parameter was significantly higher in the experimental group (2.88\u0026plusmn;0.45 vs 2.10\u0026plusmn;0.29 mL/min, P\u0026lt;0.001). No significant changes were observed in all indicators of the control group (all P\u0026gt;0.05).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAlthough conventional pharmacological treatments can improve endometrial thickness in a subset of patients, they are associated with limited efficacy and potential safety concerns. Therefore, exploring non-pharmacological interventions is of considerable clinical significance.\u003c/p\u003e\n\u003cp\u003eThe present study is the first to apply Zero-time Exercise (ZTEx) as an adjuvant therapy for women with thin endometrium. Our findings demonstrated that a 12-week ZTEx intervention significantly increased endometrial thickness and improved endometrial receptivity-related indices, thereby providing an effective therapeutic strategy for the management of thin endometrium.\u003c/p\u003e\n\u003cp\u003eCompared with other exercise modalities (e.g., HIIT), ZTEx has unique advantages: it requires no dedicated venue, additional time or equipment, which makes it highly acceptable and sustainable for time-constrained ART patients. We also supplemented adherence assurance measures (WeChat check-ins and weekly follow-ups) to further confirm its strong feasibility in clinical practice[11,22,33].. In the present study, the mean endometrial thickness of patients in the experimental group increased following 12 weeks of ZTEx intervention.\u003c/p\u003e\n\u003cp\u003eThis finding is consistent with the established mechanism by which exercise enhances pelvic blood circulation. Specifically, ZTEx stimulates the contraction and relaxation of pelvic muscles through relevant movements, which in turn promotes uterine artery blood perfusion, augments oxygen and nutrient supply to the endometrium, and thus provides sufficient sustenance for endometrial cell proliferation[16,17,31,35,37,42,44]. Additionally, exercise can improve insulin sensitivity and mitigate the inhibitory effect of insulin resistance on endometrial growth[9,14,33,40], which may represent one of the key mechanisms underlying ZTEx-induced endometrial thickening.\u003c/p\u003e\n\u003cp\u003eEndometrial receptivity is a critical determinant of successful embryo implantation, and ultrasound-derived parameters (e.g., hemodynamic indices, volumetric parameters, endometrial patterns, and peristaltic activity) are widely used and reliable tools for the clinical assessment of endometrial receptivity[45-48]. Specifically, decreased systolic/diastolic ratio (S/D), pulsatility index (PI), and resistance index (RI) of the uterine artery are indicative of improved uterine blood supply, whereas elevated vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) reflect enhanced endometrial angiogenesis and blood perfusion.\u003c/p\u003e\n\u003cp\u003eWe supplemented specific changes in receptivity indices (e.g., left uterine artery PI and VI values with corresponding P values) to clarify the link between index improvements and the optimized implantation microenvironment, while refining the description of the dual mechanisms, which confirms the comprehensive therapeutic effect of ZTEx. These findings suggest that ZTEx optimizes endometrial blood perfusion and ameliorates the endometrial implantation microenvironment. The potential mechanisms underlying these effects may be twofold: first, ZTEx directly stimulates the contraction and relaxation of pelvic muscles through professionally guided fragmented movements, thereby enhancing uterine artery blood perfusion and reducing vascular resistance[27,29-31,35,40,43]; second, exercise modulates the body’s endocrine homeostasis, creating a favorable microenvironment for endometrial angiogenesis and cell proliferation[18-20].\u003c/p\u003e\n\u003cp\u003eWe emphasized the clinical significance of the absence of exercise-related adverse events throughout the trial, and supplemented ZTEx’s key characteristics (low cost and ease of implementation) to align with the clinical needs of ART patients, which fully confirms its high safety and strong applicability in clinical practice.\u003c/p\u003e\n\u003cp\u003eThe present study has several limitations that should be acknowledged. First, the relatively small sample size and single-center design may have introduced bias, which limits the generalizability of the findings. Multi-center, large-sample randomized controlled trials are therefore warranted to validate these results in future research. Second, long-term follow-up of the participants was not performed, so the impact of ZTEx on pregnancy outcomes and offspring health remains unclear. Third, the molecular mechanisms underlying ZTEx-mediated endometrial growth were not explored in depth, and further basic experimental studies are required to elucidate these mechanisms.\u003c/p\u003e\n\u003cp\u003eIn conclusion, ZTEx can effectively increase endometrial thickness and improve endometrial receptivity in women with thin endometrium. With the advantages of safety, feasibility and cost-effectiveness, ZTEx has the potential to serve as a routine adjuvant intervention for the management of thin endometrium.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe supplemented specific endometrial thickness values before and after the intervention (with corresponding P values), clarified ZTEx\u0026rsquo;s key advantages (no additional time or equipment required, low cost, high safety), and added a perspective on future research verification (multi-center studies and long-term outcome assessments), which summarizes the core strengths of our study.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eZTEx\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eZero-time Exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eART\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eAssisted Reproductive Technology\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eHCG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eHuman Chorionic Gonadotropin\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBMI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eBody Mass Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ePulsatility Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eRI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eResistance Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eS/D\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eSystolic/Diastolic Ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eVascularization Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eFI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eFlow Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVFI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eVascularization-Flow Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eRPE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eRating of Perceived Exertion\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eG-CSF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eGranulocyte Colony-Stimulating Factor\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePRP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ePlatelet-Rich Plasma\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eTCM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eTraditional Chinese Medicine\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eHigh-Intensity Interval Training\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis single-center randomized sham-controlled trial was approved by the Ethics Committee of Guangxi Zhuang Autonomous Region Reproductive Hospital (Approval Number:KY-LL-2023-017). All eligible participants were fully informed of the study purpose, procedures, potential risks and benefits, and their right to withdraw at any time without repercussion. Written informed consent was obtained from each participant prior to study enrollment, in compliance with the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no potential conflicts of interest, financial or non-financial, related to the subject matter or materials discussed in this manuscript. No author has received any form of funding, grants, or remuneration that could influence the study results.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding sources\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZhaohui Jiang received funding from Self - Funded Scientific Research Projects of Reproductive Hospital of Guangxi Zhuang Autonomous Region; Grant ID SZYY2025001.Chunxia Wang received funding from Self-funded Scientific Research Project of Guangxi Zhuang Autonomous Region Administration of Traditional Chinese Medicine; Grant ID GXZYA20250904.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZ.J contributed to study conception/design.Y.H acquired and organized data.L.D analyzed and interpreted data.Y.L drafted manuscript core content.S.X critically revised intellectual content.M.L prepared figures/tables (endometrial charts, trial flows).Y.L supported trial implementation and patient follow-up.C.W reviewed and approved final manuscript.G.L accountable for work accuracy/integrity; resolved related issues.All authors reviewed the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. All participants have consented to the use of their de-identified data for research purposes and publication in academic journals.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor details\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003eDepartment of Reproductive Medicine,The Reproduction Hospital of Guangxi Zhuang Autonomous Region,Nanning 530218, Guangxi Zhuang Autonomous Region, China\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLiu, K. E., Hartman, M., \u0026amp; Hartman, A. (2019). Management of thin endometrium in assisted reproduction: a clinical practice guideline from the Canadian Fertility and Andrology Society. 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Endometrial receptivity markers, the journey to successful embryo implantation. Human reproduction update, 12(6), 731\u0026ndash;746. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/humupd/dml004\u003c/span\u003e\u003cspan address=\"10.1093/humupd/dml004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Physical activity, Intervention study, Assisted reproductive technology population, Sedentary lifestyle, Thin endometrium","lastPublishedDoi":"10.21203/rs.3.rs-8607817/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8607817/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eCurrent therapeutic strategies for thin endometrium have inherent limitations, and zero-time exercise (ZTEx), a professionally guided fragmented low-intensity exercise, may serve as a novel adjunctive intervention for its management.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis was a single-center randomized sham-controlled trial. Eligible patients undergoing ART were randomly divided into an experimental group (receiving ZTEx intervention) and a control group (receiving sham intervention). The ZTEx intervention was delivered over 12 weeks, featuring fragmented, low-intensity exercises under professional guidance. Key indicators of endometrial health\u0026mdash;including endometrial thickness and endometrial receptivity-related parameters\u0026mdash;were monitored throughout the intervention period.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAfter 12 weeks of intervention, ANCOVA (adjusted for baseline values) revealed that the experimental group had a significantly greater endometrial thickness than the control group (6.67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.15 mm vs. 5.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.17 mm, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Concurrently, multiple endometrial receptivity-related indices improved significantly in the experimental group (all P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), including uterine artery hemodynamic parameters (pulsatility index [PI], resistance index [RI], systolic/diastolic ratio [S/D]) and vascularization indices (vascularization index [VI], flow index [FI], vascularization-flow index [VFI]).No exercise-related adverse events were reported over the course of the trial, confirming the safety profile of ZTEx.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eSupported by rigorous statistical analyses, ZTEx effectively enhances endometrial thickness and receptivity in ART patients with thin endometrium. Its key advantages\u0026mdash;safety, feasibility, and no need for additional time or equipment\u0026mdash;make it a promising adjuvant intervention in clinical ART settings.\u003c/p\u003e","manuscriptTitle":"Effect of Zero-time Exercise Intervention on Endometrial Receptivity in Women with Thin Endometrium A Single-center Randomized Sham-controlled Trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-10 11:39:06","doi":"10.21203/rs.3.rs-8607817/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Accepted","date":"2026-02-25T16:43:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-16T16:50:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"107451301938563535547493936911270615552","date":"2026-02-12T02:21:18+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-11T15:43:35+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-09T13:28:43+00:00","index":"","fulltext":""},{"type":"submitted","content":"Archives of Gynecology and Obstetrics","date":"2026-02-07T15:52:59+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"02aeb431-2bdf-4f81-bc51-a7212ae2a473","owner":[],"postedDate":"February 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-23T16:07:06+00:00","versionOfRecord":{"articleIdentity":"rs-8607817","link":"https://doi.org/10.1007/s00404-026-08385-4","journal":{"identity":"archives-of-gynecology-and-obstetrics","isVorOnly":false,"title":"Archives of Gynecology and Obstetrics"},"publishedOn":"2026-03-16 15:58:53","publishedOnDateReadable":"March 16th, 2026"},"versionCreatedAt":"2026-02-10 11:39:06","video":"","vorDoi":"10.1007/s00404-026-08385-4","vorDoiUrl":"https://doi.org/10.1007/s00404-026-08385-4","workflowStages":[]},"version":"v1","identity":"rs-8607817","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8607817","identity":"rs-8607817","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}