MicroRNA array and microarray evaluation of endometrial receptivity in patients with high serum progesterone levels on the day of hCG administration

Altered microRNA composition in the uterine lumen fluid in cattle (Bos taurus) pregnancies initiated by artificial insemination or transfer of an in vitro produced embryo

BACKGROUND

MicroRNAs (miRNAs) are presented in the uterine lumen of many mammals, and in vitro experiments have determined that several miRNAs are important for the regulation of endometrial and trophoblast functions. Our aim was to identify and contrast the miRNAs present in extracellular vesicles (EVs) in the uterine lumen fluid (ULF) at the onset of attachment in cattle pregnancies (gestation d 18) initiated by artificial insemination (AI) or by the transfer of an in vitro-produced blastocyst (IVP-ET). A third group had no conceptus after the transfer of an IVP embryo.

RESULTS

The abundance of 263 annotated miRNAs was quantified in the EVs collected from ULF. There was an increase in the transcript abundance of 20 miRNAs in the ULF EVs from the AI pregnant group, while 4 miRNAs had a lower abundance relative to the group not containing a conceptus. Additionally, 4 miRNAs were more abundant in ULF EVs in the AI pregnant group relative to IVP-ET group (bta-mir-17, bta-mir-7-3, MIR7-1, MIR18A). Specific miRNAs in the ULF EVs were co-expressed with messenger RNAs expressed in extra-embryonic tissues and endometrium, including genes that are known to be their targets.

CONCLUSIONS

The results provide biological insights into the participation of miRNAs in the regulation of trophoblast proliferation and differentiation, as well as in endometrium receptivity. The knowledge that in vitro cultured embryos can contribute to the altered abundance of specific miRNAs in the uterine lumen can lead to the development of corrective approaches to reduce conceptus losses during the first month of pregnancy in cattle.

A modified flexible GnRH antagonist protocol using antagonist early cessation and a gonadotropin step-down approach improves live birth rates in fresh cycles: a randomized controlled trial

STUDY QUESTION

Can pregnancy outcomes following fresh elective single embryo transfer (eSET) in gonadotropin-releasing hormone (GnRH) antagonist protocols increase using a gonadotropin (Gn) step-down approach with cessation of GnRH antagonist on the day of hCG administration (hCG day) in patients with normal ovarian response?

SUMMARY ANSWER

The modified GnRH antagonist protocol using the Gn step-down approach and cessation of GnRH antagonist on the hCG day is effective in improving live birth rates (LBRs) per fresh eSET cycle.

WHAT IS KNOWN ALREADY

Currently, there is no consensus on optimal GnRH antagonist regimens. Studies have shown that fresh GnRH antagonist cycles result in poorer pregnancy outcomes than the long GnRH agonist (GnRHa) protocol. Endometrial receptivity is a key factor that contributes to this phenomenon.

STUDY DESIGN, SIZE, DURATION

An open label randomized controlled trial (RCT) was performed between November 2021 and August 2022. There were 546 patients allocated to either the modified GnRH antagonist or the conventional antagonist protocol at a 1:1 ratio.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Both IVF and ICSI cycles were included, and the sperm samples used were either fresh or frozen from the partner, or from frozen donor ejaculates. The primary outcome was the LBRs per fresh SET cycle. Secondary outcomes included rates of implantation, clinical and ongoing pregnancy, miscarriage, and ovarian hyperstimulation syndrome (OHSS), as well as clinical outcomes of ovarian stimulation.

MAIN RESULTS AND THE ROLE OF CHANCE

Baseline demographic features were not significantly different between the two ovarian stimulation groups. However, in the intention-to-treat (ITT) population, the LBRs in the modified antagonist group were significantly higher than in the conventional group (38.1% [104/273] vs. 27.5% [75/273], relative risk 1.39 [95% CI, 1.09-1.77], P = 0.008). Using a per-protocol (PP) analysis which included all the patients who received an embryo transfer, the LBRs in the modified antagonist group were also significantly higher than in the conventional group (48.6% [103/212] vs. 36.8% [74/201], relative risk 1.32 [95% CI, 1.05-1.66], P = 0.016). The modified antagonist group achieved significantly higher implantation rates, and clinical and ongoing pregnancy rates than the conventional group in both the ITT and PP analyses (P < 0.05). The two groups did not show significant differences between the number of oocytes retrieved or mature oocytes, two-pronuclear zygote (2PN) rates, the number of embryos obtained, blastocyst progression and good-quality embryo rates, early miscarriage rates, or OHSS incidence rates (P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

A limitation of our study was that the subjects were not blinded to the treatment allocation in the RCT trial. Only women under 40 years of age who had a good prognosis were included in the analysis. Therefore, use of the modified antagonist protocol in older patients with a low ovarian reserve remains to be investigated. In addition, the sample size for Day 5 elective SET was small, so larger trials will be required to strengthen these findings.

WIDER IMPLICATIONS OF THE FINDINGS

The modified GnRH antagonist protocol using the Gn step-down approach and cessation of GnRH antagonist on hCG day improved the LBRs per fresh eSET cycle in normal responders.

STUDY FUNDING/COMPETING INTEREST(S)

This project was funded by grant 2022YFC2702503 from the National Key Research & Development Program of China and grant 2021140 from the Beijing Health Promotion Association. The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

The RCT was registered in the Chinese Clinical Trial Registry; Study Number: ChiCTR2100053453.

TRIAL REGISTRATION DATE

21 November 2021.

DATE OF FIRST PATIENT’S ENROLLMENT

23 November 2021.

Uterine fluid microRNAs in repeated implantation failure

Recurrent implantation failure (RIF) is a significant obstacle in assisted reproductive procedures, primarily because of compromised receptivity. As such, there is a need for a dependable and accurate clinical test to evaluate endometrial receptiveness, particularly during embryo transfer. MicroRNAs (miRNAs) have diverse functions in the processes of implantation and pregnancy. Dysregulation of miRNAs results in reproductive diseases such as recurrent implantation failure (RIF). The endometrium secretes several microRNAs (miRNAs) during the implantation period, which could potentially indicate whether the endometrium is suitable for in vitro fertilization (IVF). The goal of this review is to examine endometrial miRNAs as noninvasive biomarkers that successfully predict endometrium receptivity in RIF.

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.

hMG addition affects the change in progesterone level during IVF stimulation and LBR: a retrospective cohort study

BACKGROUND

Premature progesterone (P) rise during IVF stimulation reduces endometrial receptivity and is associated with lower pregnancy rates following embryo transfer (ET), which can influence provider recommendation for fresh or frozen ET. This study aimed to determine whether change in P level between in IVF baseline and trigger (𝚫P) is predictive of pregnancy outcome following fresh ET, and whether the ratio of gonadotropins influences P rise and, as a result, clinical pregnancy outcomes: clinical pregnancy rate (CPR) and live birth rates (LBR).

METHODS

Retrospective cohort study at a single fertility center at an academic institution. The peak P level and 𝚫P were modeled in relation to prediction of CPR and LBR, and the ratios of hMG:rFSH were also modeled in relation to prediction of peak P level on day of trigger, 𝚫P, and CPR/LBR in a total of 291 patients undergoing fresh embryo transfer after controlled ovarian hyperstimulation-IVF (COH-IVF).

RESULTS

𝚫P correlates with CPR, with the most predictive range for success as 𝚫P 0.7-0.85 ng/mL (p = 0.005, 95% CI 0.635, 3.636; predicting CPR of 88.9%). The optimal range for peak P in regard to pregnancy outcome was 0.15-1.349 ng/mL (p = 0.01; 95% CI for coefficient in model 0.48-3.570). A multivariable logistic model for prediction of CPR and LBR using either peak or 𝚫P supported a stronger association between 𝚫P and CPR/LBR as compared to peak P. Furthermore, an hMG:rFSH ratio of > 0.6 was predictive of lowest peak P (p = 0.010, 95% CI 0.035, 0.256) and smallest 𝚫P (p = 0.012, 95% CI 0.030, 0.243) during COH-IVF cycles. Highest CPRs were observed within hMG:rFSH ratios of 0.3-0.4 [75.6% vs. 62.5% within and outside of the range, respectively, (p = 0.023, 95% CI 0.119, 1.618)]. Highest LBRs were seen within the range of 0.3-0.6 hMG:rFSH, [LBR of 55.4% vs. 41.4% (p = 0.010, 95% CI 0.176, 1.311)].

CONCLUSIONS

Our data supports use of 𝚫P to best predict pregnancy rates and therefore can improve clinical decision making as to when fresh ET is most appropriate. Furthermore, we found optimal gonadotropin ratios can be considered to minimize P rise and to optimize CPR/LBR, emphasizing the importance of luteinizing hormone (LH) activity in COH-IVF cycles.

Effect of Chinese patent medicine Kunling Pill on endometrial receptivity: A clinical trial, network pharmacology, and animal-based study

Although pregnancy success rates are raised with assisted reproductive technology, it still cannot meet clinical demands. Kunling Pill (KLP), a traditional Chinese medicine, is widely used in various gynecological disorders, particularly in improving fertility and pregnancy rates. However, the underlying mechanism of how KLP affects pregnancy outcomes remains unclear. This study aimed to explore the effects and mechanisms of KLP on endometrial receptivity. Firstly, a retrospective trial was conducted to validate the efficacy of KLP on repeated implantation failure (RIF) patients. The result indicated a significant increase in the proportion of live birth in KLP group (30.56%) compared to the control group (16.89%). Secondly, network pharmacology methods predicted the active components and network targets of KLP. Endometrial receptivity is closely associated with the activation of inflammatory factors, predicting the function of KLP on the immune system. The estrogen and apoptotic signaling pathways were also highlighted in the gene ontology enrichment analysis. Thirdly, a decreased endometrial receptivity model was established by controlled ovarian hyperstimulation (COH) in female C57BL/6 mice, divided into the COH and KLP groups. Normal female mice are as control group. In vivo, KLP administration could increase endometrial thickness and the number of endometrial glands and pinopodes. In the endometrium, KLP supplementation upregulated the expressions of estrogen receptor α, progesterone receptor, endothelial nitric oxide synthase, and integrin αVβ3 in the murine uterus and reduced serum levels of estrogen and progesterone. KLP regulated the uterine immune cells and inhibited cell apoptosis in the ovary via Bcl-2/Bax/caspase-3 pathway. In conclusion, KLP administration raised the live birth rate in RIF patients to optimize medication regimens, mainly because KLP ameliorated impaired endometrial receptivity.

MicroRNAs, small regulatory elements with significant effects on human implantation: a review

Embryo implantation is a critical process for achieving a successful pregnancy and live birth. The proper implantation must have a synchronized interaction between blastocyst and a receptive endometrium. Many genes are involved in the modulation of precise molecular events during implantation. MicroRNAs (miRNAs) have been extensively reported as gene regulatory molecules on post-transcriptional levels involved in various biological processes such as gametogenesis, embryogenesis, and the quality of sperm, oocyte, and embryos. A plethora of evidence has demonstrated critical roles for miRNAs in regulating genes involved in the implantation process; hence, dysregulation of miRNAs could be associated with significant impairments in implantation, such as recurrent implantation failure. In addition to the indispensable role of miRNAs in the intracellular control of gene expression, they can also be secreted into extracellular fluid and circulation. Therefore, miRNAs in body fluids and blood may be exploited as non-invasive diagnostic biomarkers for different pathological and physiological conditions. Recently, several studies have focused on the discovery of miRNAs function in the implantation process by appraising miRNAs and their target genes in human embryos, endometrial tissue, and cell culture models. Moreover, it was revealed that there could be a significant association between endometrial receptivity or implantation status and the expression of miRNAs in human body fluids, reinforcing their role as non-invasive biomarkers. In the current work, we reviewed the studies concerning the role of intracellular and extracellular miRNAs in human implantation and the influence of their dysregulation on implantation disorders.

The effect of the ratio of serum progesterone level to oocyte count on the day of IVF-ICSI injection on pregnancy outcomes in HCG cycles

BACKGROUND

There has been several discussion and debates regarding the possible setremental influence of elevated serum progesterone (SP) on the day of human chorionic gonadotropin (hCG) administration. Our study aims to assess progestron to oocyte rates for assessing CPR and live birth rate (LBR) in IVF cycles and review previous articles.

METHODS

In this prospective cohort study, women under ovulation induction through IVF-ICSI using the GnRH-antagonist protocol were studied. Five specific indicators were considered to assess pregnancy outcome. The statistical analysis was done using SPSS software.

RESULTS

In the present research, 78 patients underwent IVF. The cut-off points for each of the three parameters were 1.2 (with a sensitivity of 65.4% and a specificity of 54%), 6.5 (with a sensitivity of 73.1% and a specificity of 56%), and 0.16 (with a sensitivity of 65.4% and a specificity of 60%, respectively). Only the number of oocytes (area below the curve of 0.64) was able to predict clinical pregnancy. The cut-off point for this parameter was 6.5 (with a sensitivity of 74.1% and a specificity of 66%). On the other hand, none of the parameters were able to predict live birth.

CONCLUSIONS

The findings of this study should assist in the clinical management of patients with high SP on the day of HCG administration. We recommend, that the ratio of SP to oocyte is a useful parameter for refining the criteria of patients who have had embryo freezing of all embryos (by selective freezing) and subsequent transfer of frozen embryos.

Role of endometrial microRNAs in repeated implantation failure (mini-review)

MicroRNAs (miRNAs) play various roles in the implantation and pregnancy process. Abnormal regulation of miRNAs leads to reproductive disorders such as repeated implantation failure (RIF). During the window of implantation, different miRNAs are released from the endometrium, which can potentially reflect the status of the endometrium for in vitro fertilization (IVF). The focus of this review is to determine whether endometrial miRNAs may be utilized as noninvasive biomarkers to predict the ability of endometrium to implant and provide live birth during IVF cycles. The levels of certain miRNAs in the endometrium have been linked to implantation potential and pregnancy outcomes in previous studies. Endometrial miRNAs could be employed as non-invasive biomarkers in the assisted reproductive technology (ART) cycle to determine the optimal time for implantation. Few human studies have evaluated the association between ART outcomes and endometrial miRNAs in RIF patients. This review may pave the way for more miRNA transcriptomic studies on human endometrium and introduce a specific miRNA profile as a multivariable prediction model for choosing the optimal time in the IVF cycle.

Genome-wide analysis of cervical secretions obtained during embryo transfer reveals the association between deoxyribonucleic acid methylation and pregnancy outcomes

OBJECTIVE

To study whether the methylation status of cervical secretions can reflect the ability of the endometrium to allow embryo implantation.

DESIGN

Case-control study.

SETTING

In vitro fertilization centers.

PATIENT(S)

Women undergoing embryo transfer cycles, in which at least 1 good-quality embryo was transferred.

INTERVENTION(S)

Collection of cervical secretions during the procedure of embryo transfer.

MAIN OUTCOME MEASURE(S)

Methylation profiles of cervical secretions in relation to pregnancy outcomes.

RESULT(S)

Genome-wide methylation profiles differ between cervical secretions from pregnancy and nonpregnancy cycles. Clustering analysis on the basis of the top 2,000 differentially methylated probes of cervical secretions from 28 pregnancy and 29 nonpregnancy cycles correctly categorized 86.0% of the samples in terms of conceptional status, which was verified in selected genes by quantitative methylation-specific polymerase chain reaction and validated in another independent sample set. The combination of selected genes was estimated to predict pregnancy outcomes with a maximal area under the receiver operating characteristic curve of 0.83.

CONCLUSION(S)

The methylation profiles of cervical secretions were associated with pregnancy outcomes in embryo transfer cycles. Although not clinically useful at present, deoxyribonucleic acid methylation in cervical secretions may shed new light on the less invasive assessment of endometrial receptivity.

Placenta-Specific miR-125b Overexpression Leads to Increased Rates of Pregnancy Loss in Mice

Pregnancy loss (PL) is one of the common complications that women can experience during pregnancy, with an occurrence rate of 1 to 5%. The potential causes of pregnancy loss are unclear, with no effective treatment modalities being available. It has been previously reported that the level of miR-125b was significantly increased in placentas of PL patients. However, the role of miR-125b in the development of PL still remains unknown. In the current study, an miR-125b placenta-specific over-expression model was constructed by lentiviral transfecting zona-free mouse embryos followed by embryo transfer. On gestation day 15, it was observed that the placenta was significantly smaller in the miR-125b placenta-specific overexpression group than the control group. Additionally, the abortion rate of the miR-125b placenta-specific overexpression group was markedly higher than in the control group. The blood vessel diameter was larger in the miR-125b-overexpressing specific placenta. In addition, miR-125b-overexpressing HTR8 and JEG3 cell lines were also generated to analyze the migration and invasion ability of trophoblasts. The results showed that miR-125b overexpression significantly suppressed the migration and invasion ability of HTR8 and JEG3 cells. Overall, our results demonstrated that miR-125b can affect embryo implantation through modulating placenta angiogenesis and trophoblast cell invasion capacity that can lead to PL.

A review of the pathophysiology of recurrent implantation failure

Implantation is a critical step in human reproduction. The success of this step is dependent on a competent blastocyst, receptive endometrium, and successful cross talk between the embryonic and maternal interfaces. Recurrent implantation failure is the lack of implantation after the transfer of several embryo transfers. As the success of in vitro fertilization has increased and failures have become more unacceptable for patients and providers, the literature on recurrent implantation failure has increased. While this clinical phenomenon is often encountered, there is not a universally agreed-on definition-something addressed in an earlier portion of this Views and Reviews. Implantation failure can result from several different factors. In this review, we discuss factors including the maternal immune system, genetics of the embryo and parents, anatomic factors, hematologic factors, reproductive tract microbiome, and endocrine milieu, which factors into embryo and endometrial synchrony. These potential causes are at various stages of research and not all have clear implications or immediately apparent treatment.

Ulipristal Acetate Modifies miRNA Expression in Both Superficial and Basal Layers of the Human Endometrium

(1) Background: Ulipristal acetate (UPA) is a selective progesterone receptor modulator (SPRM) widely used for emergency contraception and mid- to long-term leiomyoma treatment. The aim of this study was to identify modifications of miRNA expression in superficial and basal layers of the human endometrium at the end of the UPA treatment for at least 3 months. (2) Methods: Microarray miRNA analysis of formalin-fixed, paraffin-embedded hysterectomy tissue samples was conducted, followed by an Ingenuity Pathway Analysis. Samples were divided into three groups: women having had 3 months of UPA treatment (n = 7); and two control groups of UPA-naïve women in the proliferative (n = 8) or secretory (n = 6) phase. (3) Results: The UPA modified the expression of 59 miRNAs involved in the processes of cell cycle, carcinogenesis, and inflammation. Their expression profiles were different in the basal and superficial layers. Most of the processes influenced by the UPA in the basal layer were connected to the cell cycle and immune regulation. (4) Conclusion: Specific changes were observed in both layers of the endometrium in the UPA group. However, the miRNA expression in the basal layer was not consistent with that in the superficial layer. Other large studies analysing the long-term impact of SPRM on endometrial miRNA expression are necessary.

Role of miRNAs in Normal Endometrium and in Endometrial Disorders: Comprehensive Review

The molecular responses to hormonal stimuli in the endometrium are modulated at the transcriptional and post-transcriptional stages. Any imbalance in cellular and molecular endometrial homeostasis may lead to gynecological disorders. MicroRNAs (miRNAs) are involved in a wide variety of physiological mechanisms and their expression patterns in the endometrium are currently attracting a lot of interest. miRNA regulation could be hormone dependent. Conversely, miRNAs could regulate the action of sexual hormones. Modifications to miRNA expression in pathological situations could either be a cause or a result of the existing pathology. The complexity of miRNA actions and the diversity of signaling pathways controlled by numerous miRNAs require rigorous analysis and findings need to be interpreted with caution. Alteration of miRNA expression in women with endometriosis has been reported. Thus, a potential diagnostic test supported by a specific miRNA signature could contribute to early diagnosis and a change in the therapeutic paradigm. Similarly, specific miRNA profile signatures are expected for RIF and endometrial cancer, with direct implications for associated therapies for RIF and adjuvant therapies for endometrial cancer. Advances in targeted therapies based on the regulation of miRNA expression are under evaluation.

Elevation of progesterone on the trigger day exerts no carryover effect on live birth in freeze-all cycles

AIM

To evaluate the effect of trigger day progesterone (P) levels on live birth in freeze-all cycles.

MATERIAL AND METHODS

Retrospective analysis of 1034 freeze-all female patients aged <38 years with single blastocyst transfers. Patients with (n = 268) or without (n = 766) preimplantation genetic test for aneuploidy (PGT-A) arm were further categorized into three subgroups based on trigger day P levels; low (<0.80 ng/ml), medium (0.8-1.49 ng/ml), and high (≥1.50 ng/ml).

RESULTS

Estradiol (E2) levels on trigger day, the number of oocytes retrieved and the number of mature oocytes increased significantly with increasing serum p values in cycles without and with PGT-A arms. Significant correlation was found between E2 levels on trigger day and serum P levels and between the number of total oocytes retrieved and serum P levels Live birth rates were similar in the three subgroups in without PGT-A arm (51%, 52.6%, and 51.5%, respectively; p = .922) and with PGT-A arm (55.1%, 55.1%, and 62.5%, respectively; p = .730). Multivariate regression analysis revealed that trigger day P levels were not significant for live birth.

CONCLUSION

The proposal that trigger day progesterone elevation (PE) exerts a detrimental effect on oocyte and embryo competence has no clinical validity.

Secreted MicroRNA to Predict Embryo Implantation Outcome: From Research to Clinical Diagnostic Application

Embryo implantation failure is considered a leading cause of infertility and a significant bottleneck for in vitro fertilization (IVF) treatment. Confirmed factors that lead to implantation failure involve unhealthy embryos, unreceptive endometrium, and asynchronous development and communication between the two. The quality of embryos is further dependent on sperm parameters, oocyte quality, and early embryo development after fertilization. The extensive involvement of such different factors contributes to the variability of implantation potential across different menstrual cycles. An ideal approach to predict the implantation outcome should not compromise embryo implantation. The use of clinical material, including follicular fluid, cumulus cells, sperm, seminal exosomes, spent blastocyst culture medium, blood, and uterine fluid, that can be collected relatively non-invasively without compromising embryo implantation in a transfer cycle opens new perspectives for the diagnosis of embryo implantation potential. Compositional comparison of these samples between fertile women and women or couples with implantation failure has identified both quantitative and qualitative differences in the expression of microRNAs (miRs) that hold diagnostic potential for implantation failure. Here, we review current findings of secreted miRs that have been identified to potentially be useful in predicting implantation outcome using material that can be collected relatively non-invasively. Developing non-invasive biomarkers of implantation potential would have a major impact on implantation failure and infertility.

Ovarian stimulation and exogenous progesterone affect the endometrial miR-16-5p, VEGF protein expression, and angiogenesis

Angiogenesis, where vascular endothelial growth factor (VEGF) is critically involved, is an important factor in endometrial receptivity. Angio-miRNAs form a special class of microRNAs (miRNAs) that target angiogenic genes and regulate angiogenesis. Various studies have shown that ovarian stimulation and exogenous progesterone affect endometrial vascular density. The present research aimed to assess the impact of HMG/HCG and progesterone on miR-16-5p, VEGF protein expression, and angiogenesis in the mouse endometrium during the preimplantation period. Forty adult female mice were divided into four groups: 1) control, 2) ovarian stimulation (HMG and 48 h after HCG IP), 3) progesterone (progesterone IP for 3 days), 4) ovarian stimulation + progesterone (HMG and 48 h after HCG IP) + (progesterone IP for 3 days) groups.The mice were sacrificed 96 h following HCG administration. miR-16-5p, VEGF protein expression, and CD31-positive cell (Endothelial cell) density were specified.The results showed that endothelial cell density,VEGF protein, and miR-16-5p expression increased in all treatment groups, with the maximum increase belonging to the ovarian stimulation + progesterone group. This study provides evidence that ovarian stimulation and progesterone administration enhance endometrial angiogenesis through VEGF protein upregulation. Furthermore, except for miR-16-5p, other miRNAs and molecules appear to be involved in angiogenic pathways, thereby requiring further studies.

Novel predictive and therapeutic options for better pregnancy outcome in frozen embryo transfer cycles

Since 1978, in the first decades of in vitro fertilization (IVF), the use of ovarian hyperstimulation allowed for the development and transfer of multiple embryos. As IVF technology improved, the number of multiple pregnancies increased, which led to gradual reduction in the number of embryos that were transferred. Embryo freezing (vitrification) was recommended to allow subsequent transfer if the fresh cycle was unsuccessful. However, experimentation has continued to improve pregnancy outcomes. We discuss here the significance of frozen embryo transfer cycle and the impact of uterine and peripheral immunity dominated by NK cells and regulatory T cells and human chorionic gonadotropin on pregnancy outcome in this innovative mode of IVF therapy.

Frozen IVF Cycles to Circumvent the Hormonal Storm on Endometrium

Controlled ovarian hyperstimulation (COH) determines an anticipation of endometrial maturation and a premature occurrence of the implantation window, as shown by histological, histochemical, and molecular studies and indirectly by clinical trials. There is growing agreement that in patients hyper-responding to COH and in those undergoing transfer at the blastocyst stage, deferring the transfer in a subsequent frozen cycle could increase pregnancy outcomes. For blastocysts, implantation after a fresh transfer may be limited as the implantation window is already closed while, in hyper-responders to COH, the anticipation magnitude could be more marked thus hampering implantation also for cleavage-stage embryos. Research should focus in depth on pregnancy outcomes and on the most suitable modality to prepare the endometrium for frozen transfers.

Endometrial Liquid Biopsy Provides a miRNA Roadmap of the Secretory Phase of the Human Endometrium

CONTEXT

Endometrial liquid biopsy (ELB) is a minimally invasive alternative for research and diagnosis in endometrial biology.

OBJECTIVE

We sought to establish an endometrial micro ribonucleic acid (miRNA) roadmap based on ELB during the secretory phase of the menstrual cycle in both natural and hormonal replacement therapy (HRT) cycles.

DESIGN

Human ELB samples (n = 58) were obtained from healthy ovum donors undergoing a natural and an HRT cycle consecutively. miRNA profiles were identified using next-generation sequencing (NGS). For functional analysis, messenger ribonucleic acid targets were chosen among those reported in the endometrial receptivity analysis.

RESULTS

The human endometrial secretory phase is characterized by a dynamic miRNA secretion pattern that varies from the prereceptive to the receptive stages. No differences in miRNA profiles were found among natural versus HRT cycles in the same women, reinforcing the similarities in functional and clinical outcomes in natural versus medicated cycles. Bioinformatic analysis revealed 62 validated interactions and 81 predicted interactions of miRNAs differentially expressed in the HRT cycle. Annotation of these genes linked them to 51 different pathways involved in endometrial receptivity.

CONCLUSION

This NGS-based study describes the miRNA signature in human ELB during the secretory phase of natural and HRT cycles. A consistent endometrial miRNA signature was observed in the acquisition of endometrial receptivity. Interestingly, no significant differences in miRNA expression were found in natural versus HRT cycles reinforcing the functional clinical similarities between both approaches.

mir-320b rs755613466 T>C and mir-27a rs780199251 G>A polymorphisms and the risk of IVF failure in Kurdish women

In vitro fertilization failure is not only the cause of despair among couples and individuals undergoing the treatment, it has also been contributing to the impediment of assistive reproductive technologies' development. MicroRNAs (miRNAs) have been linked to significant events in the reproduction course. The identification of miRNA polymorphisms may provide a good lead for the potential of diagnosis and treatment of unidentified in vitro fertilization (IVF) failure causes. The aim of our study is to explore the association between miRNA polymorphisms (mir-320b T>C and mir-27a G >A) and IVF failure. Our case-control study consisted of 200 Kurdish women in total, 100 with IVF failure and the other 100 control who have had at least two successful pregnancies and no history of pregnancy loss, we used tetra amplification refractory mutation system PCR to identify the polymorphisms within the groups. The TT genotype of mir-320b was found more frequently in IVF failure patients when compared to the healthy women (OR 8.07, CI 2.18-29.78, P = 0.001) and T allele was more present in the case group (OR 1.83, CI 91.04-2.12, P = 0.034), however mir-27a seemed to show no association with IVF failure in regards to genotype and allele frequencies. The difference in genotype and allele frequencies of mir-320b of the two groups may indicate that it has an effect on the target mRNAs and alter the implantation of embryo during IVF cycles.

Mir-let-7a/g Enhances Uterine Receptivity via Suppressing Wnt/β-Catenin Under the Modulation of Ovarian Hormones

Microarray has indicated a huge number of miRNAs exist in reproductive tissues and cells. Moreover, the expression of miRNA in the reproductive system varies under the strict monitoring of different regulations. To understand the role of miRNA-mediated post-transcriptional gene regulation in female reproduction, we investigated the level and function of a mir-let-7 family member in both mice and human uterine receptivity. As we observed, mir-let-7 a/g had a higher expression in mouse and human receptive uterine epithelium; the level of mir-let-7a was under the inverse regulation of estrogen and progesterone; upregulated mir-let-7a/g in mouse and human uterine epithelium increased uterine receptivity, thus improved implantation-related embryo attachment and outgrowth ability; the let-7a/g enhanced uterine receptivity through suppressing canonical Wnt signaling. In summary, our findings suggest that mir-let-7 a/g increases uterine receptivity via inhibiting Wnt signaling and under the modulation of ovarian hormones.

Effects of progesterone variation on IVF Progesterone variation during controlled ovarian stimulation: effects on in vitro results

The objective of this study was to investigate the impact of the progesterone variation (PV) between early progesterone and preovulatory progesterone on pregnancy rate (PR), number of oocytes, and embryo quality. Three hundred and thirty-eight cycles of in vitro fertilisation were included and progesterone was measured on 5th day of stimulation GnRH as well as on the day of induction of ovulation. Fresh embryo transfer (ET) on the second-third day after follicular puncture was made in 152/338 cycles, with positive pregnancies in 61/152 (40%). In the cycles in which ET was cancelled (186/338) higher levels of estradiol and P2 were detected, as well as greater PV and number of oocytes obtained than those made in with fresh transfer. A greater PV was not associated with a worse clinical PR but with a minor embryo quality in the group of 35-37 years old patients.Impact StatementWhat is already known on this subject? Preovulatory progesterone (P2) elevation has been linked to worse results in IVF cycles. It has also been described been reported that there is a lower pregnancy rate (PR) in patients with high progesterone in the early follicular phase (P1). In our study, we measured P1 and P2 to evaluate the possible repercussion of progesterone variation (PV) (ratio of P2 to P1) on PR, a variable that has not previously been analysed.What do the results of this study add? Negative correlation between preovulatory progesterone and embryo quality was found, according to the literature. In the present study, a negative significant correlation between PV and embryo quality was also found, however, only in the group of 35-37 years old women.What are the implications of these findings for clinical practice and/or further research? This could indicate that a rapid increase in progesterone levels after the early follicular phase is related to a lower quality of the obtained embryos, although further studies are required to achieve greater statistical significance.

Effects of high progesterone in in-vitro fertilization cycle on DNA methylation and gene expression of adhesion molecules on endometrium during implantation window

PURPOSE

High progesterone is associated with low implantation rate. Our previous study demonstrated that DNA methylation in endometrium was increased in women with high progesterone in IVF cycles. However, the DNA methylation status is still not yet confirmed, and how it affects endometrial receptivity in high progesterone is still unknown. Current study investigated the effects of high progesterone on DNA methylation and gene expression of adhesion molecules on endometrium during implantation window.

METHODS

A cohort study included 20 women with high progesterone (HP) and 20 with normal progesterone (NP) on the day of human chorionic gonadotropin (hCG) administration after controlled ovarian hyperstimulation in IVF cycle. Endometrial tissues were collected on the 7th day after hCG administration. Immunohistochemical staining of DNA methyltransferases (DNMT1 and DNMT3B) and adhesion molecules (MUC1, CDH1 and CTNNB1) were performed. Methylation of MUC1, CDH1, and CTNNB1 promoter regions was detected by Sequenom MassARRAY or bisulfite sequencing PCR. RT-qPCR was used to quantify mRNA expression levels, and correlation of methylation and gene expression level of the adhesion molecules were determined.

RESULTS

DNMT3B, but not DNMT1, in nucleus of luminal and glandular epithelial cells in HP group was significantly higher than that in NP group. Promoter regions of CDH1 and CTNNB1, but not MUC1, in endometrium of HP group were hypermethylated. Protein and mRNA expression of MUC1, CDH1, and CTNNB1 in endometrium of HP group was significantly lower than that in NP group. Level of DNA methylation was negatively correlated with the gene expression of CDH1 and CTNNB1, but not MUC1.

CONCLUSIONS

DNA hypermethylation and low expression of adhesion molecules on endometrium were associated with high progesterone during implantation window, which may contribute to the underlying epigenetic mechanism in the failure of IVF treatment.

Lipid Profiling of Peri-implantation Endometrium in Patients With Premature Progesterone Rise in the Late Follicular Phase

CONTEXT

Late follicular phase elevation in serum progesterone (P) during controlled ovarian hyperstimulation negatively affects the outcome of assisted reproductive technology by contributing to endometrial-embryo asynchrony. There are still no data on lipid metabolite alterations during this process.

OBJECTIVES

To investigate alterations in the lipid profile during the window of implantation in patients with premature P rise.

DESIGN

Lipidomic variations in the endometrium were evaluated by ultrahigh-performance liquid chromatography coupled with electrospray ionization high-resolution mass spectrometry.

SETTING

University assisted reproductive medicine unit.

PATIENTS OR OTHER PARTICIPANTS

Forty-three patients undergoing in vitro fertilization/intracytoplasmic sperm injection because of a tubal factor or male factor infertility were included in this study. The patients were divided into a high P group (P ≥ 1.5 ng/mL, 15 patients) and a normal P group (P < 1.5 ng/mL, 28 patients) on the day of human chorionic gonadotropin administration.

INTERVENTIONS

The endometrial tissues were obtained by Pipelle biopsy 7 days after human chorionic gonadotropin administration.

MAIN OUTCOME MEASURES

Alterations in lipid metabolites.

RESULTS

A total of 1026 ions were identified, and 25 lipids were significantly upregulated. The endometrial lipid profile was characterized by substantial increases in the concentrations of phosphatidylcholine, phosphatidylethanolamine, lysophosphatidylcholine, diacylglycerol, ceramide, phosphatidylinositol, and phosphatidylserine in patients with a premature P rise at the end of the follicular phase. The correlation analysis between P levels and lipids showed a stronger negative correlation between phosphatidylethanolamine or phosphatidylserine and P levels.

CONCLUSIONS

Premature P elevation disrupts the lipid homeostasis of the endometrium during the peri-implantation period. The altered lipid levels may impair endometrial receptivity and early embryo implantation.

The recipient's Day after ovulation and the number of corpora lutea influence the likelihood of pregnancy in mares following transfer of ICSI frozen embryos

Asynchronous embryo transfer is an excellent tool to investigate how subtle differences in the uterine environment affect embryo development and survival. Progesterone secreted from the corpus luteum following ovulation is one of the main factors responsible for establishing endometrial receptivity for the pre-implantation embryo via complex alterations in the expression of genes involved in the secretion of the histotroph. The objective of this retrospective study was to determine whether the recipient's Day after ovulation and the number of CL at ET influence the pregnancy rates of IVP horse embryos. The study included 650 heterologous frozen ICSI horse embryo transfer cycles and evaluated the pregnancy and ongoing pregnancy rate. The ongoing pregnancy was significantly lower in recipient mares with ET performed 5 and 6 days after ovulation (47.4% and 37.5%, respectively) than in recipients with ET 4 days after ovulation (67.3%). Furthermore, Day 5 recipient mares (Day 0 = Day of ovulation) with 2 corpora lutea (CL) at the time of ET had lower ongoing pregnancy rate (36.1%) than Day 5 recipient mares with 1 CL (51.9%). In contrast, the presence of 2 CL was associated with a higher ongoing pregnancy rate (75.8%) in recipient mares with a less advanced uterine stage at the time of ET (Day 3 and 4 after ovulation), compared to recipients with only 1 CL at ET (62.7%). In conclusion, both the number of days after ovulation and the number of CL recorded in the recipient mare at ET influenced the ongoing clinical pregnancy rate. This study highlights the importance of establishing exactly when progesterone rises above a threshold (relative to the Day of ovulation) when trying to determine the optimal window for transferring an IVF/IVP embryo.

Serum Antimüllerian hormone does not predict elevated progesterone levels among women who undergo controlled ovarian hyperstimulation for in vitro fertilization

Serum Antimüllerian hormone (AMH) has been shown to predict various in vitro fertilization (IVF) outcomes. AMH and progesterone (P) are products of granulosa cells of the ovary. Since overall granulosa cell number directly correlates with oocyte number and AMH production, the aim of this study is to evaluate whether or not serum AMH is associated with elevated P during controlled ovarian hyperstimulation (COH) for IVF. For this retrospective study, data were abstracted from charts of first IVF cycles of women (n = 201) who had undergone COH between May 2014 and May 2017. Groups were as follows: (A) AMH < 1 ng/mL (n = 32), (B) AMH 1-3.99 ng/mL (n = 109), (C), AMH ≥ 4 ng/mL (n = 60). The primary outcome measure was serum P level at trigger prior to oocyte retrieval. Mean serum P levels among groups A, B, and C were 0.92 ng/mL, 0.96 ng/mL, and 0.84 ng/mL, respectively. One-way ANOVA showed that there was no difference in mean serum P level among groups A, B, and C (p-value = 0.28). Multivariable linear regression with P as the dependent variable showed that total gonadotropin dose and peak estradiol level on day of trigger each had a significant positive relationship with P, and clinical pregnancy had a significant negative relationship. Although AMH is a predictor of certain IVF outcomes, AMH is not a predictor of elevated serum P level at trigger among women who undergo COH for IVF.

Live birth rates with a freeze-only strategy versus fresh embryo transfer: secondary analysis of a randomized clinical trial

RESEARCH QUESTION

What are the roles of serum progesterone and endometrial thickness as biomarkers in the decision between a freeze-only and fresh embryo transfer in IVF for women without polycystic ovary syndrome (PCOS)?

DESIGN

This was a secondary analysis of a randomized controlled trial including 782 couples who were followed up until the end of the first completed cycle. Couples scheduled for their first or second IVF cycle with a FSH/gonadotrophin-releasing hormone antagonist protocol were randomized to a freeze-only (n = 391) or fresh embryo transfer (n = 391) strategy. The endpoint for this analysis was live birth rate (LBR) after the first embryo transfer.

RESULTS

There was no significant difference in LBR after the first cycle between a freeze-only and fresh transfer strategy. When serum progesterone levels at trigger were in the third quartile (Q3, 1.14-1.53 ng/ml), LBR was significantly higher in the freeze-only versus fresh transfer group (P = 0.01); when serum progesterone was ≥1.14 ng/ml, LBR was significantly better in the freeze-only group (37.4% versus 23.8% in the fresh transfer group; P = 0.004). LBRs in the freeze-only and fresh embryo transfer groups were similar across all quartiles of endometrial thickness, although a small advantage for freeze-only in women with a very thin endometrium could not be excluded.

CONCLUSIONS

Serum progesterone level on the day of trigger may have potential as a biomarker on which to base a prospective decision about whether to use a freeze-only or fresh embryo transfer strategy in women undergoing IVF.

A Two-Cohort RNA-seq Study Reveals Changes in Endometrial and Blood miRNome in Fertile and Infertile Women

The endometrium undergoes extensive changes to prepare for embryo implantation and microRNAs (miRNAs) have been described as playing a significant role in the regulation of endometrial receptivity. However, there is no consensus about the miRNAs involved in mid-secretory endometrial functions. We analysed the complete endometrial miRNome from early secretory (pre-receptive) and mid-secretory (receptive) phases from fertile women and from patients with recurrent implantation failure (RIF) to reveal differentially expressed (DE) miRNAs in the mid-secretory endometrium. Furthermore, we investigated whether the overall changes during early to mid-secretory phase transition and with RIF condition could be reflected in blood miRNA profiles. In total, 116 endometrial and 114 matched blood samples collected from two different population cohorts were subjected to small RNA sequencing. Among fertile women, 91 DE miRNAs were identified in the mid-secretory vs. early secretory endometrium, while no differences were found in the corresponding blood samples. The comparison of mid-secretory phase samples between fertile and infertile women revealed 21 DE miRNAs from the endometrium and one from blood samples. Among discovered novel miRNAs, chr2_4401 was validated and showed up-regulation in the mid-secretory endometrium. Besides novel findings, we confirmed the involvement of miR-30 and miR-200 family members in mid-secretory endometrial functions.

High-throughput sequencing of hair follicle development-related micrornas in cashmere goat at various fetal periods

Inner Mongolia cashmere goat marks a precious gerplasm genetic resource due to its excellent cashmere traits. Therefore, it is of crucial importance to investigate the cashmere development mechanism of cashmere goat and to search for the important cashmere growth-related candidate genes. Fetal skin samples at 10 different periods of cashmere goat were collected in this research. Moreover, high-throughput sequencing was conducted on RNA samples from side skin of cashmere goat fetuses collected at three critical periods of skin hair follicle initiation, growth and development (namely, 45, 55 and 65 days) after balanced mix in line with the previous research results. Meanwhile, 3 samples at corresponding periods were used as the biological duplications. Data regarding microRNA and mRNA expression in skin and hair follicles of cashmere goats at various fetal periods were obtained using the high-throughput sequencing method. The results indicated that microRNAs in the oar-let-7 and oar-miR-200 families in 55 days and 66 days of pregnancy samples had been notably up-regulated relative to those in 45 days of pregnancy samples. This revealed that they might be the critical microRNAs in hair follicle development.

Roles of microRNAs in mammalian reproduction: from the commitment of germ cells to peri-implantation embryos

MicroRNAs (miRNAs) are active regulators of numerous biological and physiological processes including most of the events of mammalian reproduction. Understanding the biological functions of miRNAs in the context of mammalian reproduction will allow a better and comparative understanding of fertility and sterility in male and female mammals. Herein, we summarize recent progress in miRNA‐mediated regulation of mammalian reproduction and highlight the significance of miRNAs in different aspects of mammalian reproduction including the biogenesis of germ cells, the functionality of reproductive organs, and the development of early embryos. Furthermore, we focus on the gene expression regulatory feedback loops involving hormones and miRNA expression to increase our understanding of germ cell commitment and the functioning of reproductive organs. Finally, we discuss the influence of miRNAs on male and female reproductive failure, and provide perspectives for future studies on this topic.

Does progesterone to oocyte index have a predictive value for IVF outcome? A retrospective cohort and review of the literature

The potential adverse effect of Serum progesterone (SP) elevation on the day of hCG administration is a matter of continued debate. Our study aimed to evaluate the relative value of progesterone to a number of aspirated oocytes ratio (POI) to predict clinical pregnancy (CP) and live birth (LB) in fresh IVF cycles and to review the relevant literature. A retrospective analysis of GnRH Antagonist IVF-ET cycles. POI was calculated by dividing the SP on the day of hCG by the number of aspirated mature oocytes. A multivariate logistic regression analysis was performed to evaluate the predictive value of POI for CP and LB. Cycle outcome parameters included clinical pregnancy, live-birth and miscarriage. A total of 2,693 IVF/ICSI cycles were analyzed. POI was inversely associated with CP adjusted OR 0.063 (95% CI 0.016-0.249, p < .001) and with LB adjusted OR 0.036 (95% CI 0.007-0.199, p < .001). For prediction of LB, the area under the curve (AUC) was 0.68 (95% CI 0.64-0.71, p < .001) for the POI model. POI above the 90th percentile with a value of 0.36 ng/mL/oocyte results in CP and LB rates of 8.0 and 5.9%, respectively. POI is a simple index for the prediction of IVF-ET cycle outcomes, it can advocate a limit above which embryo transfer should be reconsidered.

The curious case of premature luteinization

PURPOSE

Premature luteinization (PL) affects 12.3-46.7% of fresh in vitro fertilization cycles, and there is accumulating evidence confirming its negative effect on success rates. However, despite its clinical significance, PL is poorly understood and defined. This narrative review aims to provide a fresh look at the phenomenon of PL by summarizing the existing evidence and re-evaluating fundamental issues.

METHODS

A thorough electronic search was conducted covering the period from 1978 until January 2018 in PubMed, Embase, and Medline databases, and references of relevant studies were cross-checked. Meeting proceedings of the European Society of Human Reproduction and Embryology and the American Society for Reproductive Medicine were also hand searched.

RESULTS

In the curious case of PL, one should go back to the beginning and re-consider every step of the way. The pathogenesis, definition, measurement methods, clinical implications, and management strategies are discussed in detail, highlighting controversies and offering "food for thought" for future directions.

CONCLUSIONS

Authors need to speak the same language when studying PL in order to facilitate comparisons. The terminology, progesterone cut-off, measurement methods and days of measurement should be standardized and globally accepted; otherwise, there can be no scientific dialog. Future research should focus on specific patient profiles that may require a tailored approach. Progesterone measurements throughout the follicular phase possibly depict the progesterone exposure better than an isolated measurement on the day of hCG. Adequately powered randomized controlled trials should confirm which the best prevention and management plan of PL is, before introducing any strategy into clinical practice.

Adverse effect of prematurely elevated progesterone in in vitro fertilization cycles: a literature review

Premature progesterone (P) elevation was commonly seen in IVF prior to the utilization of GnRH analogues for suppression of endogenous gonadotropin release. The cause and effect of premature P elevation has finally been better elucidated in the past decade. Although still occurring in 5-38% of all IVF cycles, the adverse effects of premature P elevation on pregnancy outcomes are now well known.

hsa-miRNA-154-5p expression in plasma of endometriosis patients is a potential diagnostic marker for the disease

RESEARCH QUESTION

As microRNA (miRNA) are stable in circulation, this study tested whether they could serve as putative non-invasive biomarkers for endometriosis, and their expression differences between endometriosis patients and controls. It also addressed whether the combination of differently expressed miRNA together with clinical parameters in a statistical model could distinguish between endometriosis patients and controls.

DESIGN

This prospective cohort study explored the possibility of using changes in extracellular miRNA spectra in plasma of 51 patients with endometriosis compared with 41 controls combined with clinical data as non-invasive biomarkers for the disease. The project was divided into three different phases for biomarker screening, discovery and validation. The differences in expression levels of plasma miRNA obtained from women with and without endometriosis were analysed with quantitative PCR-based microarrays. The diagnostic performance of the selected individual and/or combined differentially expressed miRNA candidates and clinical parameters was assessed using in silico bioinformatics modelling and receiver operating characteristic curve analysis.

RESULTS

Data showed that a specific plasma miRNA signature is associated with endometriosis and that hsa-miR-154-5p, which alone or in combination with hsa-miR-196b-5p, hsa-miR-378a-3p, and hsa-miR-33a-5p and the clinical parameters of body mass index and age, are potentially applicable for non-invasive diagnosis of the disease. Changes in the levels of expression of certain circulating plasma miRNA also occurred within the phases of the menstrual cycle.

CONCLUSIONS

miRNA seem to be promising candidates for the non-invasive diagnosis of endometriosis. Further, other clinical parameters may help in distinguishing women suffering from endometriosis from healthy individuals.

Oocyte-triggering day progesterone levels and endometrial appearance in normoresponders undergoing IVF/ICSI cycles: a hypothesis and a study protocol

In this report, we propose a study protocol capable of improving IVF outcomes in subfertile women with expected normal ovarian response. This proposal derives from conflicting published data and observations in our daily practice, concerning the negative impact of progesterone (P4) elevation at the day of oocyte triggering on pregnancy outcomes. Our hypothesis points to the combination of two previous "suspects" of reduced success after assisted reproduction techniques (ART) - the endometrium ultrasonographic parameters and P4 elevation at the day of oocyte triggering on their impact on pregnancy outcomes. Up-to-the minute data show that, there is a different impact of elevated P4 in fresh, frozen and donor cycles, whereas there are plenty of reports pointing to a different endometrial gene expression on different P4 measurements. Gaps in the literature are linked with a variation of the measurements of P4, its cycle-to-cycle reproducibility, the different cut-off levels used, the impact of various protocols of ovarian stimulation and the limitations of systematic reviews originating from the initial studies. Our hypothesis states that the combination of P4 values and endometrial ultrasound parameters at the day of oocyte triggering can affect clinical pregnancy rates in normal responders undergoing ART.

Does premature elevated progesterone on the day of trigger increase spontaneous abortion rates in fresh and subsequent frozen embryo transfers?

Recent evidence has shown elevated progesterone (P) advances the endometrium in fresh ART cycles, creating asynchrony with the embryo and thus implantation failure and decreased live birth rates. If the window of implantation is closing as the embryo attempts to implant, there may be difficulty with trophoblastic invasion, leading to failure of early pregnancies. Our objective was to evaluate if P on the day of trigger was associated with spontaneous abortion (SAB) rates in fresh ART transfers. This was a retrospective cohort study involving fresh autologous and FET cycles from 2011 to 2013. The main outcome was spontaneous abortion rates. About 4123 fresh and FET transfer cycles were included which resulted in 1547 fresh and 491 FET pregnancies. The overall SAB rate was 20% among fresh cycles and 19% in FET cycles. P on the day of trigger, as a continuous variable or when > 2 ng/mL, was not associated with SAB in fresh cycles. Similar results were found after adjusting for age, embryo quality, and embryo stage. Despite elevated P likely advancing the window of implantation, once implantation occurs, pregnancies were no longer negatively impacted by progesterone.

Deferred Frozen Embryo Transfer: What Benefits can be Expected from this Strategy in Patients with and without Endometriosis?

Progress with cryopreservation techniques have enabled development of the deferred frozen-thawed embryo transfer (DET) strategy as an alternative to relying on fresh embryo transfers.

With DET, the entire embryo cohort is cryopreserved, and embryo transfer is then performed in a subsequent cycle that takes place separately from the controlled ovarian stimulation (COS).

Initially developed to limit the risk of ovarian hyperstimulation syndrome that occurs with high responders, this strategy has been applied extensively with other populations in an effort to improve implantation rates. The assumption is that COS, which is essential for in vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) procedures to obtain a multi-follicular development, could have a detrimental impact on the endometrium as a result of greatly elevated levels of steroids. It is currently not clear whether the DET strategy can be generally applied to all women requiring an IVF/ICSI procedure.

The objectives of this literature review regarding DET, were hence: (i) to present the scientific background that contributed to extensive adoption of this technique, (ii) to detail the pregnancy outcomes and potential obstetric and neonatal consequences, (iii) to report on its ability to prevent risks induced by COS, and (iv) to propose indications for the DET strategy in clinical practice.

Does elevated progesterone on day of oocyte maturation play a role in the racial disparities in IVF outcomes?

The aim of this study was to evaluate if premature progesterone elevation on the last day of assisted reproduction technique stimulation contributes to racial disparities in IVF outcome. A total of 3289 assisted reproduction technique cycles were evaluated in Latino, Asian, African American, and white women. Live birth was more likely in white women (42.6%) compared with Asian (34.8%) and African American women (36.3%), but was similar to Latino women (40.7%). In all racial groups, progesterone was negatively associated with live birth and the negative effect of progesterone persisted when adjusting for confounders. Although the effect of elevated progesterone was similar in all racial groups, the prevalence of elevated progesterone differed. Progesterone > 1.5 ng/ml occurred in only 10.6% of cycles in white women compared with 18.0% in Latino and 20.2% in Asian women. Progesterone > 2 ng/ml occurred in only 2.3% of cycles in white women compared with 6.3% in Latino, 5.9% in Asian and 4.4% in African American women. The increased prevalence of premature elevated progesterone persisted when controlling for IVF stimulation parameters. In conclusion, premature progesterone elevation had a negative effect on live birth in all racial groups studied. The prevalence of elevated progesterone was higher in racial minorities.

Circulating MicroRNAs as Potential Molecular Biomarkers in Pathophysiological Evolution of Pregnancy

MicroRNAs represent nonprotein coding small RNA molecules that are very stable to degradation and responsible for gene silencing in most eukaryotic cells. Increased evidence has been accumulating over the years about their potential value as biomarkers for several diseases. MicroRNAs were predicted to be involved in nearly all biological processes from development to oncogenesis. In this review, we address the importance of circulating microRNAs in different conditions associated with pregnancy starting with the implantation period to preeclampsia and we shortly describe the correlation between placental circulating miRNAs and pregnancy status. We also discuss the importance of microRNAs in recurrent abortion and ectopic pregnancy.

Osteopontin and Integrin αvβ3 Expression during the Implantation Window in IVF Patients with Elevated Serum Progesterone and Oestradiol Level

Background: To explore whether endometrial receptivity is determined by osteopontin (OPN) and integrin αvβ3 expression in women with elevated serum progesterone (P) and/or oestradiol (E₂) who are undergoing in vitro fertilisation (IVF). Methods: According to serum hormone levels on the day of HCG administration, 33 infertile women were divided into 3 groups: the high E₂, high P, and high E₂ and P groups. The control group included 11 fertile, healthy women. Endometrial biopsy was performed on ovulation day + 7 to + 8 for all study participants, and the mRNA and protein expression levels of OPN and integrin αvβ3 were analyzed. Result: No statistically significant differences regarding OPN and integrin αvβ3 expression were found between infertile patients in the high P, high E₂, high E₂ and P and control groups. There was no significant correlation between OPN and integrin αvβ3 staining intensity during the implantation window biopsy in any of the groups studied. Conclusion: Endometrial OPN and integrant αvβ3 expression/co-expression is not impaired during the window of implantation in patients with high P, high E₂, or high E₂ and P levels. The clinical value of assessing endometrial receptivity with OPN and integrin αvβ3 seems to be uncertain.