Reproductive and transcriptome characteristics of endometrium at the window of im-plantation in patients after fertility-sparing treatment of endometrial intraepithelial neoplasm or cancer.

Background: Progestin therapy is an option for patients with endometrial carcinoma (EC) or endometrial intraepithelial neoplasm (EIN) who fit specific criteria of fertility-sparing treatment. However, the implantation rate remains low among females receiving in vitro fertilization (IVF) even after the complete reversal of endometrial lesions. Methods: Here, ten patients with EC/EIN achieved complete regression (CR) in histology. Their relevant metabolic and IVF parameters were collected. An endometrial sampling at the window of implantation (WOI) and transcriptome analysis were conducted among them, and four healthy controls were analyzed to analyze endometrial receptivity. Results: On average, it took ten patients five months to achieve CR after four curettage procedures. The interquartile range of endometrium thickness on trigger day was between 8.8 and 10.0 mm, while the range was 15.2-18.5 mm for controls. Five patients got pregnant after a frozen-embryo transfer. According to ERA analysis, the endometrial sampling at WOI showed pre-receptive status in four cases. In total, 1458 differential expression genes were identified, and 70 belonged to the ERA genes. ImmuneScore indicated decreased NK cells in the endometrium, affecting endometrial receptivity. Conclusions: Even after EC/EIN reversal in histology, endometrial receptivity has already been compromised regarding altered WOI and immune microenvironment, leading to a low pregnancy rate.

Personalized embryo transfer guided by rsERT with hourly precision improves pregnancy outcomes in patients with a receptive window of implantation: a pilot study.

PURPOSE: To investigate whether personalized embryo transfer (pET) predicted by a modified RNA-sequencing-based endometrial receptivity test (rsERT) model can improve intrauterine pregnancy rate (IPR) in patients with a receptive window of implantation (WOI). DESIGN: A retrospective pilot study was conducted in the Center for Reproductive Medicine, Central South University, from January 2018 to December 2023. A total of 524 patients with receptive WOI results from rsERT were assigned into two groups based on whether they underwent conventional embryo transfer (conventional ET) or pET. Patients in the conventional ET were matched with those in the pET group at a 1:1 ratio using propensity score matching (PSM). RESULTS: Before PSM, the IPR (55.73% vs. 46.19%, P = 0.032) and implantation rate (IR) (47.51% vs. 34.03%, P = 0.000) in the pET group were significantly higher than that in the conventional ET group. However, the number and types of transferred embryos differed significantly between the two groups. After adjusting for confounding factors, IPR (57.38% vs. 44.81, P = 0.016) and IR (46.81% vs. 33.10%, P = 0.001) remained significantly higher in the pET group compared to the conventional ET group. The implantation failure rate was significantly lower in the pET group compared to controls (42.62% vs. 55.19%, P = 0.016). Additionally, the multiple-pregnancy rate was significantly higher in the pET group compared to the conventional ET group (10.29% vs. 1.68%, P = 0.001). CONCLUSIONS: Women with receptive WOI results could benefit from the receptivity-timed pET predicted by the newly refined rsERT. These findings provide a basis for future research in precision medicine for embryo transfer.

Expression of Endometrial Receptivity Markers throughout the Menstrual Cycle in Women with and without Uterine Adenomyosis.

Background/Objectives: While it is known that adenomyosis is associated with poor reproductive outcomes, the underlying mechanisms are unclear, and to date, there is no standard treatment protocol for these patients. Endometrium from adenomyosis patients is characterized by several abnormalities, potentially resulting in impaired receptivity and subsequent implantation failure. Methods: Endometrial biopsies were collected from 26 women with adenomyosis and 26 control subjects. Immunohistochemistry was performed to evaluate the expression of markers of endometrial receptivity, namely the progesterone receptor (PR), glycodelin, leukemia inhibitory factor (LIF), homeobox A10 (HOXA10), integrin beta chain beta 3 (integrin ß3) and osteopontin. Scanning electron microscopy was used to observe pinopodes on the surface of mid-secretory endometrial epithelium. Results: PR, LIF and osteopontin expression were all found to be weaker in secretory-phase stroma from adenomyosis patients than in healthy controls. HOXA10 expression was decreased in adenomyosis during the secretory phase, and also the proliferative phase, where it reached statistical significance in both epithelial and stromal compartments. Glycodelin and integrin ß3 levels did not differ between diseased and healthy tissues in any of the cycle phases. Pinopodes were fewer and at later developmental stages in adenomyosis compared to those on the surface of healthy endometrium from the same time period of the menstrual cycle. Conclusions: Endometrium from adenomyosis patients is characterized by abnormal expression of various receptivity markers. The stromal compartment appears to be affected most, showing reduced expression of PR, LIF and osteopontin in the secretory phase and lower levels of HOXA10 during both proliferative and secretory phases. Decreased receptivity due to impaired stromal decidualization may contribute to poor reproductive outcomes in adenomyosis patients.

PI3K/AKT signaling alters glucose metabolism in uterine microenvironment of women with idiopathic recurrent spontaneous miscarriage.

BACKGROUND: This study aims to identify metabolomic signatures in uterine fluid of women with idiopathic recurrent spontaneous miscarriage (IRSM) during window of implantation (WOI). Also, glucose transporters GLUT3 and GLUT4 and proteins of PI3K-Akt signaling pathway in endometrial tissue are assessed. METHODS: Paired uterine fluid and endometrial biopsies were collected during WOI from women with IRSM (n = 24) and healthy women with azoospermic male partners as controls (n = 15). NMR metabolomics was used to identify the dysregulated metabolites in uterine fluid of IRSM women. Additionally, proteins and glucose transporters were investigated in the endometrial tissue using immunohistochemistry (IHC) and western blotting. RESULTS: Uterine fluid metabolomics indicated eleven metabolites to be significantly downregulated in IRSM. While expression levels of PI3K (p85), PI3K (p110), p-Akt (Thr308), p-Akt (Ser473), GLUT3 and GLUT4 were significantly downregulated in endometrial tissue of these women, p-IKK α/ß (Ser176/180) and p-NFkBp65 (Ser536) were significantly increased. CONCLUSION: Our findings suggest that dysregulation of PI3K/Akt pathway in the uterine microenvironment could be a likely cause of endometrial dysfunction, thereby affecting implantation. Further studies on the downstream effects of the Akt signaling pathway in-vitro for improved understanding of the Akt-mediated cellular responses in IRSM is, therefore, warranted.

Effects of Variable Embryo Transfer on the Variable Window of Implantation and Analysis of Pregnancy Outcomes.

Background A descriptive analysis of patients who underwent various embryo transfer methods to address the root cause of their infertility at a tertiary infertility care complex in Wardha, India, is presented herein. This analysis aims to evaluate the management of infertility and assess pregnancy outcomes. Methodology We conducted a retrospective cohort study on patients who underwent various embryo transfer methods to address the cause of their infertility, specifically focusing on a variable window of implantation (WOI) at a tertiary infertility clinic over a one-year period. The medical records of 11 patients in both the variable embryo transfer (VET) and control groups were reviewed and analyzed for this article. Results The examination of medical records revealed a significant improvement in the rate of implantation (p-value = 0.04) and clinical pregnancy outcomes (p-value = 0.03) among patients who underwent VET. Comparable statistical outcomes were observed for other variables of pregnancy outcome, including miscarriage rate, multiple pregnancy rate, and biochemical pregnancy rate. Conclusion This retrospective cohort study suggests that the utilization of VET could be a viable option for women experiencing recurrent implantation failure cycles, particularly when an adequate number of embryos are available. This is owing to the challenges in clinically diagnosing a variable WOI. Further studies with a significantly larger sample population are recommended to validate the results and integrate this approach into the standard operating procedures, aiming to enhance the likelihood of pregnancy in these populations.

Oil-soluble contrast medium bathing attenuated endometrial inflammation and improved endometrial receptivity in women with recurrent implantation failure: a descriptive study.

BACKGROUND: The oil-soluble contrast medium used in hysterosalpingography has been shown to have a fertility-enhancing effect, but the underlying mechanism is unclear, especially regarding the role of window of implantation (WOI). This study aimed to assess the endometrial immunological impact of the WOI before and after bathing with the oil-soluble contrast medium in women with recurrent implantation failure (RIF). METHODS: This descriptive study involved two medical centers between December 18, 2019, and December 30, 2020. We included infertile women who underwent three or more transfer cycles, cumulative transplantation of at least four high-quality cleavage-stage embryos or three high-quality blastocysts without clinical pregnancy, and high-quality frozen embryos that were still available for implantation. Patients received 5 ml of ethiodized poppyseed oil bathing, endometrial biopsy around bathing, and frozen-thawed embryo transfer (FET) within four menstrual cycles after bathing. Patients were excluded if failure to complete anyone. Data on the baseline characteristics and clinical data of the FET cycles were collected, and endometrial biopsy specimens were collected in the luteal phase before and after bathing and subjected to immunohistochemistry. The number of CD56 and CD138 positive cells and H-score of expression of ανß-3 and HOXA10 in endometrium were collected. RESULTS: Thirty-four patients were initially enrolled in the study; ultimately, twelve patients with a median age of 32.5 years (range 27-40 years) completed the research. The median number of embryo transfer cycles was three (range 3-8). A total of 4 of 12 women (33.33%) were diagnosed with chronic endometritis before oil-soluble contrast bathing. After bathing, the median numbers of CD138-positive cells in endometrium decreased from 0.75 (range 0-13.5) to 0.65 (range 0-6), P = 0.035; additionally, the H-score of expression of ανß-3 in endometrium increased from 148.50 ± 31.63 to 175.58 ± 31.83, P < 0.001. The thickness of the endometrium also significantly increased (8.90 ± 1.45 mm vs.10.11 ± 1.98 mm, P = 0.005). However, no consistent changes were found in the expression of CD56 and HOXA10 in the endometrium. Five patients experienced biochemical pregnancies (41.67%), four had clinical pregnancies (33.33%), and three achieved live births following oil-soluble contrast bathing (25%). CONCLUSIONS: These results suggest that oil-soluble contrast medium bathing decreased CD138-positive cells and upregulated expression of ανß-3 during WOI in patients with RIF. This histological impact of endometrium may result in enhanced fertility during FET cycles. Investigating the ability of intrauterine bathing with lower-dosage oil-soluble contrast to improve pregnancy in the RIF population is warranted.

APOE-E4 allele as a potential marker for implantation failure: A comparison between fertile women, ART success and RIF patients.

OBJECTIVE: Apolipoprotein E (APOE) is the most important precursor for the production of steroid hormones and is also involved in regulating the function of steroid hormones, hence playing a significant role in reproductive processes. So, APOE gene expression may be correlated with the implantation process. This study tries to make a better clarification of the correlation between APOE gene polymorphisms and recurrent implantation failure (RIF), where we compared the frequency of APOE polymorphisms in RIF patients, assisted reproductive treatment (ART) success cases and fertile women. METHOD: In all, 100 women with successful ART who got pregnant (fetal heart rate positive) in their first or second cycle of in vitro fertilization or intracytoplasmic sperm injection, 100 infertile RIF cases, and 100 normal fertile control cases with at least one live birth were included in present study. Following DNA extraction, genotypes were determined through polymerase chain reaction-restriction fragment length polymorphism method using HhaI restriction enzyme. Finally, statistical analysis was performed by chi-squared (χ2) test in SPSS software (P < 0.05). RESULTS: The RIF group showed significantly higher frequency for E3/E4 genotype (29%) compared with the other two control groups (fertile = 15%, ART success [ART+] = 13%) (P = 0.007). There was also a significantly higher frequency of the E4 allele in the RIF group (14.5%) compared with both of the control groups (fertile = 7.5%, ART+ = 6.5%) (P = 0.018). CONCLUSION: APOE4 is correlated with recurrent failure in the process of embryo implantation and, accordingly, it may potentially be considered a possible risk factor to the implantation process. The presence of E4 can be proposed as a predictive indicator in determining the results of assisted reproductive techniques.

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

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

Meta-analysis of endometrial transcriptome data reveals novel molecular targets for recurrent implantation failure.

PURPOSE: Gene expression analysis of the endometrium has been shown to be a useful approach for identifying the molecular signatures and pathways involved in recurrent implantation failure (RIF). Nevertheless, individual studies have limitations in terms of study design, methodology and analysis to detect minor changes in expression levels or identify novel gene signatures associated with RIF. METHOD: To overcome this, we conducted an in silico meta-analysis of nine studies, the systematic collection and integration of gene expression data, utilizing rigorous selection criteria and statistical techniques to ensure the robustness of our findings. RESULTS: Our meta-analysis successfully unveiled a meta-signature of 49 genes closely associated with RIF. Of these genes, 38 were upregulated and 11 downregulated in RIF patients' endometrium and believed to participate in key processes like cell differentiation, communication, and adhesion. GADD45A, IGF2, and LIF, known for their roles in implantation, were identified, along with lesser-studied genes like OPRK1, PSIP1, SMCHD1, and SOD2 related to female infertility. Many of these genes are involved in MAPK and PI3K-Akt pathways, indicating their role in inflammation. We also investigated to look for key miRNAs regulating these 49 dysregulated mRNAs as potential diagnostic biomarkers. Along with this, we went to associate protein-protein interactions of 49 genes, and we could recognize one cluster consisting of 11 genes (consisted of 22 nodes and 11 edges) with the highest score (p = 0.001). Finally, we validated some of the genes by qRT-PCR in our samples. CONCLUSION: In summary, the meta-signature genes hold promise for improving RIF patient identification and facilitating the development of personalized treatment strategies, illuminating the multifaceted nature of this complex condition.

MiR-135a-5p regulates window of implantation by suppressing pinopodes development and decidualization of endometrial stromal cells.

PURPOSE: The window of implantation (WOI) is a brief period during which the endometrium is receptive to embryo implantation. This study investigated the relationship between miR-135a-5p and endometrial receptivity. METHODS: Peripheral blood was collected on the day of ovulation and the 5th day after ovulation for high-throughput sequencing from women who achieved clinical pregnancy through natural cycle frozen embryo transfer. RT-qPCR assessed miR-135a-5p expression in the endometrium tissue or cells during the mouse implantation window or decidualization. Scanning electron microscopy was utilized to observe pinopode morphology and quantity in mice overexpressing miR-135a-5p during the WOI. Human endometrial stromal cells (HESC) and artificial induction of mouse uterine decidualization were used to explore whether miR-135a-5p overexpression inhibits decidualization by regulating HOXA10 and BMPR2. Furthermore, the impact of miR-135a-5p on HESC proliferation and HTR8/SVneo invasion was explored. RESULTS: A total of 54 women were enrolled in the study. bioinformatics analysis and animal models demonstrated that miR-135a-5p was significantly downregulated during the WOI, and its high expression can lead to abnormal pregnancy outcomes. Overexpression of miR-135a-5p resulted in the absence of pinopode in mouse endometrial tissue during the WOI. High miR-135a-5p levels were found to potentially inhibit endometrial tissue decidualization by downregulating HOXA10 and BMPR2 expression. Finally, CEBPD was identified as a potential regulator of miR-135a-5p, which would explain the decreased miR-135a-5p expression during the WOI. CONCLUSION: MiR-135a-5p expression is significantly downregulated during the WOI. High miR-135a-5p levels suppress pinopode development and endometrial tissue decidualization through HOXA10 and BMPR2, contributing to inadequate endometrial receptivity.

Unlocking Infertility: Enhancing Pregnancy Rates With Personalized Embryo Transfers Using Optimal Time for Endometrial Receptivity Analysis in Recurrent Implantation Failure Patients Undergoing In Vitro Fertilization.

Background Infertility remains a significant global challenge, and recurrent implantation failure (RIF) poses a considerable concern in assisted reproductive technology. Understanding the factors contributing to implantation failure is essential for developing accurate diagnostic tools and treatment strategies. Endometrial receptivity (ER) during the window of implantation is crucial for successful embryo implantation in in vitro fertilization (IVF) procedures. Molecular-based endometrial receptivity analysis and next-generation sequencing provide insights into ER, but there is a lack of research on these in the Indian population, particularly in patients with RIF. This retrospective cohort study evaluates the effectiveness of Optimal Timing for Endometrial Receptivity Analysis (OpERA)-guided personalized embryo transfer (pET) in Indian patients with a history of RIF. Methodology The study includes 158 female patients with a history of failed embryo transfers who underwent OpERA testing before frozen embryo transfer. Patients were categorized based on the number of previous failed transfers. OpERA outcomes were assessed, and clinical outcomes were compared between groups undergoing preimplantation genetic testing for aneuploidy (PGT-A) with and without OpERA. Endometrial preparation involved hormone replacement therapy, and OpERA testing was performed at the Neuberg Centre for Genomic Medicine using RNA extraction, cDNA conversion, and sequencing. Results OpERA outcomes showed no significant differences in receptive rates among patient groups. Group 3, with three or more failed transfers, exhibited significantly higher biochemical pregnancy rates (BPRs), clinical pregnancy rates (CPRs), and abortion rates (ARs) compared to Groups 1 and 2. OpERA with PGT-A showed significantly higher BPR, implantation rate, CPR, and lower AR compared to OpERA without PGT-A. Conclusions OpERA-guided pET, especially with PGT-A, demonstrated improved pregnancy outcomes, particularly in patients with a history of RIF. The study emphasizes the importance of OpERA in determining optimal transfer timing, moving beyond the traditional reliance on embryo quality alone. OpERA presents promise in predicting pregnancy outcomes for Indian patients with previous IVF failures. The integration of OpERA and PGT-A represents a significant advancement in personalized reproductive medicine, offering new hope for individuals grappling with infertility complexities.

A Case Report on Endometrial Receptivity Array Test for Infertile Patient to Enhance Reproductive Outcomes.

The issue of infertility affects couples all over the world. Recurrent implantation failure (RIF) is caused by immunology, thrombophilias, endometrial receptivity, microbiota, anatomical anomalies, male factors, and embryo aneuploidy. An accurate evaluation of endometrial receptivity (ER) in cases of RIF during in-vitro fertilization (IVF) treatments is crucial to improve reproductive outcomes. To find her accurate window of implantation (WOI), a 34-year-old woman with unexplained RIF underwent an endometrial receptivity array (ERA) test. This case study examines her inexplicable RIF and reproductive results. The ERA test examined gene expression patterns in endometrial tissue to determine the receptive phase for proper embryo transfer. Primary infertility, ineffective intrauterine insemination (IUI), and several unsuccessful IVF rounds were all part of the patient's medical history. Her WOI determined the embryo transfer timing after getting the ERA test results. The patient's clinical pregnancy was successful. This particular case focuses on the potential of the ERA test to improve reproductive outcomes. However, when using this strategy, it is essential to consider difficulties, including invasiveness and related expenses. In this case, the positive results urge future research to apply customized WOI determination using the ERA test to improve the effectiveness of IVF therapies in patients with recurrent implantation failure. More extensive investigations and controlled trials are required to confirm these results and the broader applicability of this strategy. The ERA test is promising, but to provide a holistic approach to infertility care, it should be taken into account together with endometrial changes and elements of embryo-endometrial interaction that impact the success of implantation.

Closer to the Reality-Proteome Changes Evoked by Endometrial Scratching in Fertile Females.

Endometrial scratching (ES) has been widely used in assisted reproductive technology to possibly improve pregnancy rates, but its exact mechanism is still not understood or investigated, and its benefits are controversially discussed. Hypothetically, ES may trigger a local immune response, leading to an improved endometrial receptivity. So far, it has been shown that ES affects the gene expression of cytokines, growth factors, and adhesive proteins, potentially modulating inflammatory pathways and adhesion molecule expression. Our pilot study applying proteomic analysis reveals that ES probably has an impact on the proteins involved in immune response pathways and cytoskeleton formation, which could potentially increase endometrial receptivity. Specifically, proteins that are involved in the immune response and cytoskeleton regulation showed a trend toward higher abundance after the first ES. On the other hand, proteins with a decreasing abundance after the first ES play roles in the regulation of the actin cytoskeleton and cellular processes such as intracellular transport, apoptosis, and autophagy. These trends in protein changes suggest that ES may affect endometrial tissue stiffness and extracellular matrix remodeling, potentially enhancing the embryos' implantation. To our knowledge, this pilot study provides, for the first time, data investigating potential changes in the endometrium due to the scratching procedure that might explain its possible benefit for patients in infertility treatment. Furthermore, the proteome of a group of patients suffering from repeated implantation failure was compared to that of the fertile group in order to transfer the basic science to clinical routine and application.

Endometrial receptivity tests in reproduction: a SWOT analysis.

Endometrial receptivity and its management in assisted reproduction is now a significant focus of research interest. Endometrial receptivity tests, which analyze different panels of gene expression, are usually offered in fertility clinics to determine the women's individual 'window of implantation', providing a personalized timing for embryo transfer. However, there are still no definite indications on whether its inclusion in the study of the infertile couple or the study of patients with repeated implantation failure is essential.

An interplay of Progesterone, Leukemia Inhibitor Factor and Interleukin-6 in the window of implantation; Impact on fertility.

BACKGROUND: The process of implantation is crucial for the initiation of conception and hence fertility. In addition to a number of factors, it is regulated by a cross talk of gonadotrophins [Luteinizing Hormone (LH), Follicle Stimulatory Hormone (FSH)], ovarian steroids [Estrogen (Et), Progesterone (Pt)] and cytokines [Leukemia inhibitory factor (LIF) and Interleukin 6 (IL6)]. These biomarkers are chief players of implantation. OBJECTIVE: We aimed to explore the role of gonadotrophins (LH, FSH, LH/FSH ratio), ovarian steroids (Et, Pt) and cytokines (LIF, IL6) in the implantation process. This aim was achieved by comparing these hormones and cytokines in the fertile and infertile groups [Polycystic ovaries (PCOs), endometriosis, unexplained infertility (Uex-IF)] and finding their association in all study groups. METHODS: A case control study conducted from October 2020-March 2023. A total of 135 infertile women (with PCOs, Uex-IF, and endometriosis) and 177 fertile women (matched for age and BMI) were selected. Levels of 'Et', 'Pt', 'LIF' and, 'IL6' were estimated using Enzyme Linked Immunosorbent Assay (ELISA). LH and FSH values were obtained from hospital desk records. The Independent Student'st-test was used to compare fertile and infertile groups. One-way ANOVA test was used to compare more than two groups, and Pearson's chi-square (χ2) test was employed to compare percentages of variables. Pearson correlation analysis was performed to assess the associations and correlations. A p value < 0.05 was considered statistically significant. RESULTS: Significantly higher levels of LIF and IL6 were observed in fertile women compared to infertile women. Pt levels were significantly greater in the fertile group than in the infertile group. The FSH/LH ratio was significantly higher in the fertile group. Among infertile women, PCOs (71%) and Uex-IF (91%) exhibited lower Pt levels than the fertile controls (p < 0.01), but these levels remained within the reference range (RR). Among the fertile group (81%), levels of LIF within the RR were significantly higher compared to those with Uex-IF (49%) and females with endometriosis (37%). Moreover, the highest number of participants (57%) with Uex-IF exhibited IL6 levels significantly below the RR in comparison to the fertile group and infertile groups (PCOS and endometriosis). However, lower levels of IL6 were observed in women with Uex-IF. In the control group, LIF exhibited a significant positive correlation with IL6 (r = 0.370), Pt (r = 0.496), Et (r = 0.403), and LH (r = 0.428). Among women with PCOs, LIF showed a significant positive correlation with IL6 (r = 0.443), Pt (r = 0.607), and LH (r = 0.472). In cases of Uex-IF, LIF demonstrated a significant positive correlation with IL6 (r = 0.727). Females with endometriosis displayed a significant positive correlation between LIF and IL6 (r = 0.535) as well as Pt (r = 0.605). In fertile women, a positive correlation was observed between LH and IL6 (r = 0.197, p = 0.009), LIF (r = 0.428, p = 0.000), Pt (r = 0.238, p = 0.001), and Et (r = 0.356, p = 0.000). Furthermore, a positive correlation was found between LH and LIF (r = 0.472, p = 0.000) in women with PCOs. CONCLUSION: Elevated levels of Pt were found to increase the production of LIF in fertile females. However, infertile females with PCOs and Uex-IF exhibited deficient levels of Pt, supporting its role as a biomarker for successful implantation in infertile women. These females showed decreased levels of gonadotropins as well as reduced LH/FSH ratio and diminished secretion of receptivity marker LIF, in addition to reduced Pt secretion. This suggests that reduced gonadotropin levels contribute to a lower LH/FSH ratio, resulting in decreased Pt secretion and ultimately leading to low levels of LIF, thereby causing impaired implantation in women with PCOs and Uex-IF. The exploration of low levels of LIF in patients with endometriosis requires further investigation. The significantly low levels of IL6 in the Uex-IF group elucidate the role of this cytokine in association with decreased Pt and LIF synthesis within this group.

Association between duration of progesterone supplementation and clinical outcomes in artificial frozen-thawed embryo transfer cycles.

Objective: The administration of progesterone before transfer in hormone replacement treatment (HRT) is crucial for the clinical outcomes of frozen-thawed embryo transfer (FET), but the optimal duration of progesterone remains controversial. This study aimed to investigate the effect of the duration of progesterone administration on the clinical outcomes of FET cycles. Methods: This prospective cohort study included 353 artificial FET cycles conducted at a reproductive medicine center between April and October 2021. The FET cycles were stratified into four groups based on the duration of progesterone supplementation before the procedure and the embryonic development stage: group P3 (73 patients) received intramuscular progesterone for 3 days and group P4 (87 patients) for 4 days before Day 3 frozen embryo transfer, group P5 (70 patients) for 5 days and group P6 (123 patients) for 6 days before frozen blastocyst transfer. This trial was performed using one or two vitrified embryo(s) when the endometrial thickness reached 7 mm after estrogen supplementation in an artificial cycle. The primary outcome was clinical pregnancy, and secondary outcomes included biochemical pregnancy, implantation, early pregnancy loss, and live births. Results: There were no significant differences in the demographic and clinical characteristics between the groups. No significant difference was observed in the clinical pregnancy rates between groups: 23/73 (31.5%) in group P3 vs 28/87 (32.2%) in group P4 (P = 0.927). Compared to group P5 (41/70, 58.6%), the clinical pregnancy rate was not significantly different in group P6 (77/123, 62.6%, P = 0.753). There was no significant difference in the implantation rates between groups: 33/136 (24.3%) in group P3 vs 34/166 (20.5%) in group P4 (P = 0.431), and 62/133 (46.6%) in group P5 vs 107/231 (46.3%) in group P6 (P = 0.956). The duration of progesterone supplementation (mean: 3.5 ± 0.5 days; range:3-4 days) before Day 3 frozen embryo transfer did not impact clinical pregnancy (odds ratio [OR] 1.048; 95% confidence interval [CI], 0.518-2.119). The duration of progesterone administration (mean: 5.6 ± 0.5 days; range:5-6 days) before frozen blastocyst transfer may not affect clinical pregnancy (OR 1.339; 95% CI, 0.717-2.497). Conclusion: There may be no significant correlation between the duration of progesterone supplementation and pregnancy outcomes in artificial FET cycles, although the clinical pregnancy rate was higher when progesterone supplementation was extended for one day before FET.

Autoimmune thyroid disease disrupts immune homeostasis in the endometrium of unexplained infertility women-a single-cell RNA transcriptome study during the implantation window.

Objective: Autoimmune thyroid disease (AITD) is known to be associated with unexplained infertility in women. Although the presence of antithyroid antibodies have been speculated to be a marker of an immune imbalance that might lead to implantation failure, its underlying mechanism influencing the endometrial receptivity remains to be elucidated. In this study, we used single-cell RNA sequencing (scRNA-seq) to dissect immune microenvironment in endometrium of AITD patients during window of implantation (WOI). Methods: We collected CD45+ immune cell populations of endometrium samples of unexplained infertile women with AITD (n=3), as well as samples of AITD- controls (n=3). The cells were then processed with 10X Genomics Chromium for further analysis. Results: We characterized 28 distinct immune cell subtypes totally, and uncovered differences in the composition and gene expression patterns between AITD patients and controls. The proportions of T CD4+, cNK, ILC3, T CD8+ GZMK+, T CD8+ Cytotoxic and ILC3 CD3E - cells were increased, and CD366+ uNK1 was decreased in AITD+ patients. And the abnormal expression of GNLY and chemokines was observed in AITD patients. In addition, uNK and T CD8+ Cytotoxic cells showed lower cytotoxicity but activation of immune response. Genes enriched in cell adhesion of ILC3 and Tregs were downregulated, while the number of ILC3 and Tregs were increased. Conclusion: Immune imbalance exists in endometrium during WOI, which may impact embryo implantation.

One center experience with a personalized frozen-thawed embryo transfer in patients with recurrent implantation failure.

PURPOSE: Displaced endometrial receptivity has been discussed as a possible cause of recurrent implantation failure in patients undergoing assisted reproductive technology. The aim of this study was to document our experience with the endometrial receptivity analysis in patients with recurrent implantation failure. METHODS: This retrospective cohort study, conducted at the Fertility Centre of the University Hospital, Duesseldorf Germany, presents the results of the endometrial receptivity analysis in 67 patients with recurrent implantation failure and compares the clinical outcome between these 67 patients who underwent a personalized frozen-thawed embryo transfer guided by the results of the endometrial receptivity analysis and 32 patients with recurrent implantation failure who performed a standardized frozen-thawed embryo transfer. RESULTS: The data analysis revealed a displaced endometrial receptivity in 73% (49/67) of all tested patients. Out of these patients, 24% (12/49) were early receptive, 74% (36/49) were pre-receptive, and 2% (1/49) were post-receptive. Comparison of pregnancy rate, clinical pregnancy rate, and live-birth rate between personalized (49%, 39%, 27%, respectively) and standardized embryo transfer (44%, 31%, 19%, respectively) reveals no statistically significant difference. In both groups, patients had an average of four unsuccessful embryo transfers. CONCLUSION: In this cohort of patients with recurrent implantation failure, the endometrial receptivity analysis showed a high incidence of displaced endometrial receptivity. However, a personalized embryo transfer did not increase reproductive outcome. Displaced endometrial receptivity might not be the main cause for recurrent implantation failure in this cohort.

Personalized embryo transfer guided by endometrial receptivity analysis: a systematic review with meta-analysis.

STUDY QUESTION: Does a personalized embryo transfer (pET) guided by tests for endometrial receptivity (TER) increase the effectiveness of ART procedures? SUMMARY ANSWER: The use of TER-guided pET is not supported by current published evidence in women without repeated implantation failure (RIF), while in women with RIF more research is needed to assess a potential benefit. WHAT IS KNOWN ALREADY: Implantation rates are still far from ideal, especially in some patients that have RIF with good-quality embryos. As a potential solution, a wide range of diverse TER use different sets of genes to identify displacements of the window of implantation to adjust the individual length of progesterone exposure in a pET. STUDY DESIGN, SIZE, DURATION: A systematic review with meta-analysis was performed. Search terms included endometrial receptivity analysis, ERA, personalized embryo transfer. CENTRAL, PubMed, Embase, reference lists, clinical trials registers, and conference proceedings (search date October 2022) were searched, with no language restrictions. PARTICIPANTS/MATERIALS, SETTING, METHODS: Randomized controlled trials (RCTs) and cohort studies comparing a pET guided by TER vs standard embryo transfer (sET) in different subgroups that undergo ART were identified. We also investigated pET in non-receptive-TER vs sET in receptive-TER, and pET in a specific population vs sET in a general population. Risk of bias (RoB) was assessed with the Cochrane tool and ROBINS-I. Only those with low/moderate RoB underwent meta-analysis. The GRADE approach was used to evaluate the certainty of evidence (CoE). MAIN RESULTS AND THE ROLE OF CHANCE: We screened 2136 studies and included 35 (85% used ERA and 15% used other TER). Two studies were RCTs comparing endometrial receptivity analysis (ERA)-guided pET vs sET in women with no history of RIF. In women without RIF, no important differences (moderate-CoE) were found in live birth rates and clinical pregnancy rates (CPR). We also performed a meta-analysis of four cohort studies that were adjusted for confounding. In agreement with the RCTs, no benefits were found in women without RIF. However, in women with RIF, low CoE suggests that pET might improve the CPR (OR 2.50, 95% CI 1.42-4.40). LIMITATIONS, REASONS FOR CAUTION: We found few studies with low RoB. Only two RCTs in women without RIF were published, and none in women with RIF. Furthermore, the heterogeneity observed in populations, interventions, co-interventions, outcomes, comparisons, and procedures limited the pooling of many of the included studies. WIDER IMPLICATIONS OF THE FINDINGS: In the population of women without RIF, in agreement with previously published reviews, pET did not prove to be more effective than sET and, therefore, it precludes the routine use of this strategy in this population until more evidence is available. However, more research is advisable in women with RIF as low-certainty evidence from observational studies adjusted for confounders suggests that the CPR might be higher with pET guided by TER in this population. Although this review presents the best available evidence, it is still insufficient to change current policies. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was obtained for this study. There are no conflicts of interest to declare. REGISTRATION NUMBER: PROSPERO CRD42022299827.

Personalized embryo transfer reduces success rates because endometrial receptivity analysis fails to accurately identify the window of implantation.

After more than a decade of increasingly widespread clinical use, personalized embryo transfer guided by endometrial receptivity analysis (ERA) remains controversial and unproven. One key element missing from the historical literature is the recognition that potential benefits from personalized embryo transfer are entirely dependent on the accuracy and predictive value of the ERA test. Results from the first comprehensive clinical trial, designed in a way that allowed independent evaluation of both potential benefits of personalized embryo transfer and the predictive value of the ERA test upon which it is based, were recently published. However, the authors failed to conduct an appropriate analysis or recognize the significance of their results. Here, we present a simple reanalysis of data from this otherwise excellent randomized controlled trial, demonstrating for the first time that the ERA was unable to identify the window of implantation as purported and that, as a result, personalized embryo transfer based on the ERA actually reduced rather than increased the birth rates. Based on these results and the lack of any contradictory evidence, it is our opinion that all clinical use of ERA-guided personalized embryo transfer should be discontinued immediately, outside of a controlled experimental setting with appropriate informed consent of all participating patients.