Embryo Transfer Strategies for Women with Recurrent Implantation Failure During the Frozen-thawed Embryo Transfer Cycles:Sequential Embryo Transfer or Double-blastocyst Transfer?

Objective Both sequential embryo transfer(SeET)and double-blastocyst transfer(DBT)can serve as embryo transfer strategies for women with recurrent implantation failure(RIF).This study aims to compare the effects of SeET and DBT on pregnancy outcomes.Methods Totally,261 frozen-thawed embryo transfer cycles of 243 RIF women were included in this multicenter retrospective analysis.According to different embryo quality and transfer strategies,they were divided into four groups:group A,good-quality SeET(GQ-SeET,n=38 cycles);group B,poor-quality or mixed-quality SeET(PQ/MQ-SeET,n=31 cycles);group C,good-quality DBT(GQ-DBT,n=121 cycles);and group D,poor-quality or mixed-quality DBT(PQ/MQ-DBT,n=71 cycles).The main outcome,clinical pregnancy rate,was compared,and the generalized estimating equation(GEE)model was used to correct potential confounders that might impact pregnancy outcomes.Results GQ-DBT achieved a significantly higher clinical pregnancy rate(aOR 2.588,95%CI 1.267–5.284,P=0.009)and live birth rate(aOR 3.082,95%CI 1.482–6.412,P=0.003)than PQ/MQ-DBT.Similarly,the clinical pregnancy rate was significantly higher in GQ-SeET than in PQ/MQ-SeET(aOR 4.047,95%CI 1.218–13.450,P=0.023).The pregnancy outcomes of GQ-SeET were not significantly different from those of GQ-DBT,and the same results were found between PQ/MQ-SeET and PQ/MQ-DBT.Conclusion SeET relative to DBT did not seem to improve pregnancy outcomes for RIF patients if the embryo quality was comparable between the two groups.Better clinical pregnancy outcomes could be obtained by transferring good-quality embryos,no matter whether in SeET or DBT.Embryo quality plays a more important role in pregnancy outcomes for RIF patients.

Pituitary Suppression before Frozen Embryo Transfer Is Beneficial for Patients Suffering from Idiopathic Repeated Implantation Failure

Long-term gonadotropin-releasing hormone agonist（Gn RHa） administration before in vitro fertilization（IVF）/intracytoplasmic sperm injection（ICSI） in infertile women with endometriosis or adenomyosis significantly enhanced the chances of pregnancy in both fresh and frozen embryo transfer cycles. We hypothesized that long-term Gn RHa treatment might also be beneficial for the idiopathic repeated implantation failure（RIF） patients. In the 21 patients receiving Gn RHa and hormone replacement therapy（G-HRT） protocols for frozen embryo transfer, their data were compared with those of the 56 of frozen/fresh cycles they had previously undergone（previous protocols）. Comparison showed that the finial results were significantly better with G-HRT protocols than with their previous protocols, with pregnancy rate, clinical pregnancy rate, implantation rate and on-going pregnancy rate being 70%, 60%, 40% and 38% respectively with G-HRT protocols, against 17%, 11%, 6.3% and 5% with previous protocols. The results showed that hormonally controlled endometrial preparation with prior Gn RHa suppression could be used for patients who had experienced repeated failures of IVF treatment despite having morphologically optimal embryos, and the treatment may help increase the receptivity of the endometrium in these patients.

Effect of Acupuncture on CXCL8 Receptors in Rats Suffering from Embryo Implantation Failure

To observe the effect of acupuncture on CXCL8 receptors（CXCR1 and CXCR2） in rat endometrium experiencing embryo implantation failure, 72 pregnant rats were randomly divided into four groups： normal group（N）, embryo implantation failure group（M）, acupuncture treatment group（A）, and progestin treatment group（W）. Then the rats in each group were equally randomized into a day-6（D6） group, a day-8（D8） group, and a day-10（D10） group. The rats in group M, group A, and group W were treated with mifepristone-sesame oil solution on day 1, while the rats in group N were injected with the same amount of sesame oil. Meanwhile, ＂Housanli＂ and ＂Sanyinjiao＂ were selected for acupuncture. From day 1 to the time of death, the rats in group A were fastened up and then acupuncture was administered while the rats in group N and group M were only fixed, and the rats in group W were given progestin. The number of implanted embryos was calculated. The expression of CXCR1 and CXCR2 in rat endometrium was detected by immunohistochemistry, Western blotting and real-time PCR. Compared to group N, the average number of implanted embryos, the protein and mRNA expression of CXCR1（D6, D8 and D10）, and the protein and mRNA expression of CXCR2（D8 and D10） in rat endometrium were significantly decreased in group M. Compared to group M, there was significant elevation in the average number of implanted embryos, the protein expression（D6, D8 and D10） and mRNA expression（D8） of CXCR1 in rat endometrium of group A, and the protein expression（D8 and D10） and mRNA expression（D8） of CXCR2 in rat endometrium of group W. These findings indicated that acupuncture can increase the number of implanted embryos in rats of embryo implantation failure, which may be relevant with up-regulation the expression of CXCR1 and CXCR2 at maternal-fetal interface of rats with embryo implantation failure.

Effect of heparin on recurrent IVF-ET failure patients

Objective:To elucidate the possible role of unfractionated heparin in patients with failed repeated in in vitro fertilization and embryo transfer(IVF-ET)and thrombophilia.Methods:This case control study evaluated the efficacy of the unfractionated heparin in increasing the pregnancy and implantation ratio in women with recurrent IVF-ET failures.Eighty-six women received in vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)with a record of three or more previous IVF-ET failures.Participants were randomly distributed into two groups.Group A(n=43)received unfractionated heparin 5000 IU twice daily,and group B(n=43)did not take any antithrombotic drugs.Coagulation abnormalities such as factor桋Leiden(FVL)mutation,methylene tetra hydro folate reductase(MTHFR)mutation and prothrombin mutation(F栻)were evaluated.Age,body mass index,basal follicular stimulating hormone,basal estradiol,duration of infertility,and number of IVF-ET failures were compared between two groups.Results:45.0%and 17.4%of women were pregnant with and without MTHFR and prothrombin mutation,respectively,when they received unfractionated heparin treatment.The implantation rate was more in group A(12.5%)than group B(4.3%)and differences in the fertilization rate of the two groups were observed(27.7%vs.35.9%).The clinical pregnancy rate per cycle was remarkably more in group A(30.2%)than group B(14.0%).Conclusions:Heparin is a safe and valuable treatment for patients with repeated IVF-ET failures.The clinical pregnancy and implantation rates are higher in the heparin-treated group in contrast with the control group.

VAD implantation in cardiac failure patients with prosthetic valves

Objective An increasing number of patients requiring ventricular assist devices (VAD) have had previous valvular corrections,including valve repair,and valve replacement with mechanical or bioprosthetic valves. The operative and peri-operative management of these patients are various. Methods A retrospective study of VADs between Jan 1994 and June 2008 revealed 10 patients

Immediate Effect of Electro-acupuncture on Endometrial Blood Flow in Patients with Recurrent Implantation Failure:A Randomized Controlled Trial

Objective To investigate the immediate effects of electro-acupuncture(EA)on endometrial blood flow among recurrent implantation failure(RIF)patients.Methods Eighty RIF patients,enrolled from March 2022 to December 2022,were randomly allocated into either the EA group(40 cases)or the waiting-list(WL)group(40 cases)by using a random number table.The EA group underwent acupuncture at points of Shenting(GV 24),Baihui(GV 4),Benshen(GB 13),bilateral Zigong(EX-CA 1),Huangshu(KI 16),Sanyinjiao(SP 6)and Xuehai(SP10),and electric acupuncture apparatus was connected to EX-CA 1,KI 16,SP 6,and SP 10 with disperse-dense waves at 4/20 Hz frequencies for 30 min after transvaginal ultrasound,while the WL group received no intervention.The primary outcome measured was the endometrial volume blood flow.The secondary outcomes included the bilateral uterine artery index,endometrial volume,endometrial blood flow type,vascular distribution index(VI^(MV))for endometrial and ovary,clinical pregnancy rate,and embryo implantation rate.Results In the EA group,there was a notable decrease in the bilateral pulsatility index and a significant improvement in the endometrial blood flow type post-EA(P<0.05).Both the endometrial blood flow type and VI^(MV) for the endometrium and right ovary were markedly higher in the EA group compared to the WL group post-treatment(P<0.05).Conversely,no significant disparities were observed in vascular index,flow index,vascular blood flow index,uterine arterial blood flow indices,endometrial volume,clinical pregnancy rate and embryo implantation rate between the two groups after treatment(P>0.05).Besides,no adverse events related to EA were observed.Conclusions EA can promptly ameliorate VI^(MV) for the endometrial and right ovary,and endometrial blood flow type.Future randomized controlled trials are warranted to investigate the long-term effects of EA on blood flow of RIF patients and its implications for pregnancy outcomes.(Trial registration No.ChiCTR2200057377).

Macrophage polarization disorder in the endometrial immune microenvironment may contribute to recurrent implantation failure

Objective:To investigate the role and mechanisms by which macrophages(MΦ)contribute to the immune environment of the endometrium in cases of recurrent implantation failure(RIF).Methods:Endometrial transcriptome data from women with and without RIF(control group)were collected.The CIBERSORT software was used to determine the abundance of immune cells within the endometrial tissue based on expression profiles.Weighted gene co-expression network analysis was used to identify crucial regulatory genes and pathways.Results:Application of CIBERSORT confirmed significant infiltration of macrophages in the RIF group.SOX6,TTC21A,KLHL31,NFIA,TNNT1,TPM1,CPVL,FUS,PEX5,and SLC43A3 were all closely correlated with M2 and M0 macrophages.Metascape and DisNor analyses revealed that these genes contribute to the regulation of macrophage polarization via the Wnt signaling pathway.Conclusion:This study identified dysregulation of macrophage polarization within the immune microenvironment of the endometrium in patients with RIF.A comprehensive analysis was conducted to investigate the potential mechanisms underlying this disorder.Dysregulation of macrophage polarization in the endometrium of patients with RIF is strongly associated with the Wnt signaling pathway.

Clinical application of the endometrial microbiota test combined with personalized treatment in patients with repeated implantation failure

Objective:The objective of this study was to investigate the clinical value of the endometrial microbiota test(EMT)combined with personalized treatment in patients with repeated implantation failure(RIF).Methods:From March 2019 to August 2022,the clinical data of patients with RIF at the Reproductive Medicine Research Center of the Sixth Affiliated Hospital of Sun Yat-sen University were retrospectively analyzed.A total of 356 patients underwent the EMT using 16S rRNA sequencing and were included in the EMT group.The SPSS statistical software propensity score was set at 1:1 to match the age,anti-Müllerian hormone(AMH),antral follicle count(AFC),years of infertility,and body mass index(BMI)of the women who had not undergone the EMT;subsequently,354 patients were classified in the non-EMT group.We compared the clinical characteristics of the two groups and analyzed the clinical pregnancy outcomes after personalized treatment.Results:The clinical pregnancy rate(CPR)of the EMT group was significantly higher than that of the non-EMT group(47.81%vs.13.38%,P<0.05).Among 356 patients who underwent the EMT,55 patients(15.45%)in group A with normal endometrial microbiota composition did not test positive for the pathogenic bacteria causing chronic endometritis,34 patients(9.55%)in group B with abnormal endometrial microbiota composition did not test positive for the pathogenic bacteria causing chronic endometritis,35 patients(9.83%)in group C with normal endometrial microbiota composition tested positive for the pathogenic bacteria causing chronic endometritis,and 232 patients(65.17%)in group D with abnormal endometrial microbiota composition tested positive for the pathogenic bacteria causing chronic endometritis.After administration of probiotics or antibiotic plus probiotics treatment,the pregnancy rates of groups C and D were higher than those of group A(44.00%vs.20.00%and 55.03%vs.20.00%,respectively;bothP<0.05).Conclusion:The EMT combined with personalized treatment in patients with RIF has solid clinical value as a new treatment strategy.

Acupuncture improves the live birth of patients with repeated implantation failure: a retrospective cohort study

OBJECTIVE:To explore the therapeutic efficacy of acupuncture treatment on repeated implantation failure(RIF)patients with cryo-thawed embryo transfer(CET).METHODS:In a retrospective cohort study,all eligible women undergoing RIF were recruited in our center from January 1,2018 to December 31,2021.The patients were grouped by whether an acceptance of acupuncture treatment before CET,including the acupuncture group(Acu-group,55 cycles)and control group(Con-group,244 cycles).Data were analyzed by using binary logistic regression to explore the relationship of acupuncture treatment with pregnancy outcomes.RESULTS:The Acu-group had higher live-birth rate(LBR)[54.5%vs 41.0%,respectively;odds ratio(OR)=1.105,95%confidence interval(CI)(1.029,1.187),P=0.006]and ongoing pregnancy rate(OPR)[56.4%vs 43.0%,respectively;OR=1.100,95%CI(1.025,1.181),P=0.008]than the Con-group.There were no significant between-group differences in the rates of implantation[OR=1.070,95%CI(0.996,1.149),P=0.064],clinical pregnancy[OR=1.065,95%CI(0.997,1.138),P=0.061],biochemical pregnancy[OR=1.002,95%CI(0.903,1.112),P=0.967],or miscarriage[OR=0.778,95%CI(0.551,1.099),P=0.155].Perinatal outcomes did not differ significantly between the two groups.CONCLUSIONS:Acupuncture treatment could improve the LBR and OPR in RIF patients with CET cycles,suggesting a potential adjuvant therapy of acupuncture to improve the pregnancy outcomes in RIF patients.

Integrated bioinformatics analysis to identify key genes and pathways involved in the endometria of patients with recurrent implantation failure undergoing in vitro fertilization and embryo transfer

Objectives: Recurrent implantation failure (RIF) is a challenging clinical problem that occurs in approximately 10% of patients undergoingin vitro fertilization and embryo transfer. Because of the varied criteria for RIF, as well as differences in the time and methods of endometrial biopsy, previous studies have not reached an agreement regarding the key genes and pathways of RIF. In this study, bioinformatic analyses were performed in a homogeneous population with consistent biopsy conditions to explore the molecular mechanisms and identify key RIF-associated genes and pathways in the endometrium.Methods: Seven datasets from the Gene Expression Omnibus database were reviewed in detail, and GSE111974, GSE103465, and GSE26787 were included for further analysis. Common differentially expressed genes (DEGs) were identified using the GEO2R online tool. Gene Ontology and pathway enrichment analyses were performed and a protein–protein interaction (PPI) network was constructed. The RNA and protein expression files of the hub genes were obtained.Results: A total of 402 common DEGs were identified between patients with RIF and controls. The enrichment of these DEGs was mainly associated with tube morphogenesis, vasculature development, and positive regulation of cell migration. Pathway enrichment indicated that pathways involved in cancer, the vascular endothelial growth factor A-vascular endothelial growth factor receptor 2 signaling pathway, and cell cycle pathways were mainly involved. Moreover, a PPI network was constructed, and the three most significant submodules were mainly involved in rRNA processing and the regulation of proteolysis. The following ten DEGs with high degrees of connectivity were identified as hub genes:CDC42,VEGFA,MAP2K1,APP,CYCS,UBE2I,PLEK,LMNA,SMAD2, andATRX.Conclusion: Key genes and pathways identified in this study could improve our understanding of the underlying molecular events in RIF and be used as potential biomarkers and therapeutic targets. Further studies are required to confirm these results and explore the functions of hub genes in the endometrium during the implantation window in patients with RIF.

Preimplantation genetic testing for aneuploidy improves clinical outcomes in patients with repeated implantation failure

Objective:The objective of this study is to study whether preimplantation genetic testing for aneuploidy(PGT-A)improves the clinical outcomes of infertile patients with repeated implantation failure(RIF)undergoing frozen-thawed embryo transfer.Methods:This is a retrospective analysis of clinical pregnancy,live birth,miscarriage rates,and obstetric and perinatal outcomes of women with RIF with or without PGT-A.Statistical analyses of categorical data were performed using propensity score matching(PSM),χ^(2)test,and Student’s t test.Results:We enrolled 466 patients with RIF,of which,209 were in the RIF-PGT-A group.The rate of euploid blastocysts was significantly associated with age and day 5 or 6 blastocysts.There were significant differences between the RIF-PGT-A group and the RIF-non-PGT-A group across several parameters.After PSM,positive serum human chorionic gonadotropin(56.9%and 33.9%,P<0.01),clinical pregnancy(49.5%and 31.2%,P<0.01),live birth(43.1%and 25.7%,P<0.01),and fetal heart rates(50.0%and 29.8%,P<0.01)per transfer were significantly higher in the RIF-PGT-A group.Conclusion:Elective single-embryo transfer PGT-A can minimize the risk of obstetric and perinatal outcomes,especially fetal body weight,in women with RIF.Additionally,PGT-A can significantly improve pregnancy and live birth rates.

Surface demineralized freeze-dried bone allograft followed by reimplantation in a failed mandibular dental implant

The removal of a failed implant with high torque causes significant damage to the surrounding tissue,compromising bone regeneration and subsequent osseointegration in the defect area.Here,we report a case of carrier screw fracture followed by immediate implant removal,bone grafting and delayed reimplantation.A dental implant with a fractured central carrier screw was removed using the bur-forceps technique.The resulting three-wall bone defect was filled with granular surface demineralized freeze-dried bone allograft(SD-FDBA).Cone-beam computerized tomography was performed at 1week,6months and 15months postoperatively and standardized for quantitative evaluation.The alveolar bone width and height at 15months post-surgery were about 91%of the original values,with a slightly lower bone density,calculated using the gray value ratio.The graft site was reopened and was found to be completely healed with dense and vascularized bone along with some residual bone graft.Reimplantation followed by restoration was performed 8months later.The quality of regenerated bone following SD-FDBA grafting was adequate for osseointegration and longterm implant success.The excellent osteogenic properties of SD-FDBA are attributed to its human origin,cortical bone-like structure,partly demineralized surfaces and bone morphogenetic protein-2-containing nature.Further investigation with more cases and longer follow-up was required to confirm the final clinical effect.

Stromal cell decidualization and embryo implantation: a vulnerable step leading to successful pregnancy

Endometrial stromal cell decidualization is a crucial step in endometrial remodeling during pregnancy.Decidualization is controlled by orchestrated ovarian hormones,followed by the activation of various downstream signaling pathways.Accumulating evidence has shown multiple functions of decidualized endometrial stromal cells during embryo implantation,including tissue remodeling,antioxidative stress,angiogenesis,and immune tolerance.The distinct secretomes of decidualized stromal cells also reveal their intensive interactions with epithelial,endothelial,and immune cells.However,aberrant decidualization leads to pregnancy failures,such as recurrent pregnancy loss and repeated implantation failure.This review aimed to provide an overview of the molecular mechanisms underlying the divergent functions of decidualized endometrial stromal cells and their potential clinical applications.Moreover,the use of single-cell RNA sequencing data further enhances our understanding of these biological processes.This review discusses decidualization-related signaling pathways that serve as potential therapeutic targets for treating implantation failure in in vitro fertilization and provides novel approaches to investigate the underlying causes of female infertility.

Sperm DNA fragmentation, recurrent implantation failure and recurrent miscarriage

Evidence is increasing that the integrity of sperm DNA may also be related to implantation failure and recurrent miscarriage （RM）. To investigate this, the sperm DNA fragmentation in partners of 35 women with recurrent implantation failure （RIF） following in vitro fertilization, 16 women diagnosed with RM and seven recent fathers （control） were examined. Sperm were examined pre- and post-density centrifugation by the sperm chromatin dispersion （SCD） test and the terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） assay. There were no significant differences in the age of either partner or sperm concentration, motility or morphology between three groups. Moreover, there were no obvious differences in sperm DNA fragmentation measured by either test. However, whilst on average sperm DNA fragmentation in all groups was statistically lower in prepared sperm when measured by the SCD test, this was not seen with the results from the TUNEL assay. These results do not support the hypothesis that sperm DNA fragmentation is an important cause of RIF or RM, or that sperm DNA integrity testing has value in such patients. It also highlights significant differences between test methodologies and sperm preparation methods in interpreting the data from sperm DNA fragmentation tests.

Endometrial MicroRNA Signature during the Window of Implantation Changed in Patients with Repeated Implantation Failure

Background： At present, a diagnostic tool with high specificity for impaired endometrial receptivity, which may lead to implantation failure, remains to be developed. We aimed to assess the different endometrial microRNA （miRNA） signatures for impaired endometrial receptivity by microarray analysis. Methods： A total of 12 repeated implantation failure （RIF） patients and I0 infertile patients, who conceived and delivered after one embryo transfer attempt, were recruited as RIF and control groups, respectively. Endometrial specimens from the window of implantation （WOI） were collected from these two groups. MiRNA microarray was conducted on seven and five samples from the RIF and control groups, respectively. Comparative, functional, and network analyses were performed for the microarray results. Quantitative real-time polymerase chain reaction （PCR） was performed on other samples to validate the expression of specific miRNAs. Results： Compared with those in the control group, the expression levels of 105 miRNAs in the RIF group were found to be significantly up- or down-regulated （at least 2-fold） by microarray analysis. The most relevant miRNA functional sets of these dysregulated miRNAs were miR-30 family, human embryonic stern cell regulation, epithelial-mesenchymal transition, and miRNA tumor suppressors by tool for annotations ofmicroRNA analysis. Network regulatory analysis found 176 miRNA-mRNA interactions, and the top 3 core miRNAs were has-miR-4668-5p, has-miR-429, and has-miR-5088. Expression levels of the 18 selected miRNAs in new samples by real-time PCR were found to be regulated with the same trend, as the result ofmicroarray analysis. Conclusions： There is a significant different expression of certain miRNAs in the WOI endometrium for RIF patients. These miRNAs may contribute to impaired endometrial receptivity.

Clinical Observations of Sequential Therapy with Chinese Medicine and Hysteroscopic Mechanical Stimulation of the Endometrium in Infertile Patients with Repeated Implantation Failure Undergoing Frozen-Thawed Embryo Transfer

Objectives： To investigate the clinical effect of sequential therapeutic intervention Yupei Qisun [compensating for weakness by invigorating Kidney （Shen） and Spleen （Pi） in advance] in Chinese medicine （CM） and hysteroscopic endometrial mechanical stimulation on the treatment of infertile patients with repeated implantation failure （RIF）; and to study the differences in patients＇ endometrial thickness and type on the day of embryo transfer, serum hormone levels on embryo transfer day and clinical pregnancy outcomes. Methods： In the clinical study, 168 frozen-thawed embryo transfer （FET） cycles for couples with RIF conforming to the research protocol were randomly divided into three groups： a CM group with 56 cycles （CM combined with FET）, a hysteroscopy group with 55 cycles （hysteroscopic endometfial mechanical stimulation）, and a control group with 57 cycles （conventional FET）. Differences in endometrial thickness on the embryo transfer day, levels of serum estradiol （E2） and progesterone （P） on the embryo transfer day, the E2/P ratio on the embryo transfer day, biochemical and clinical pregnancy rates, implantation rate, abnormal pregnancy rate and other indices were compared among the three groups. Results： Endometrial thickness, E2 and P levels, and the EJP ratio on embryo transfer day and other factors had no significant differences among groups. The biochemical pregnancy, clinical pregnancy, and implantation rates of the CM and hysteroscopy groups were significantly higher than the control group （P〈0.05）, and there were no significant differences between these two groups. The abnormal pregnancy rate had no significant difference among the three groups. Conclusions： Sequential therapy of Yupei Qisun could significantly improve the clinical outcomes of RIF-FET cycles, being equivalent to hysteroscopic endometrial mechanical stimulation, and provided a reliable method to treat such infertile couples.

The number and cytotoxicity and the expression of cytotoxicity-related molecules in peripheral natural killer(NK)cells do not predict the repeated implantation failure(RIF)for the in vitro fertilization patients

Natural killer(NK)cells are thought to play a key role in the successful establishment of a pregnancy by facilitating immunological adaptation of the semi-allogeneic developing embryo.The aim of this study was to explore the cell number,immunophenotypic characteristics,and activities of peripheral blood NK cells in women with repeated implantation failure(RIF).Peripheral blood was obtained from 27 women with RIF and 11 healthy,fertile controls during the middle luteal phase of the menstrual cycle.CD3^-CD56^+NK cells were quantified and analyzed by flow cytometry for the expression of cytolytic molecules(granzyme B,granulysin,and perforin)as well as cell surface receptors responsible for NK cell activation or inhibition(NKG2D,NKp30,NKp46,CD158a,CD158b).NK cytotoxicity was measured at three effector-to-target cell ratios.Women with RIF and fertile controls did not differ significantly in the percentage of circulating CD3CD56t NK cells,or in the proportions of these cells that expressed granzyme B,granulysin,or perforin.The two groups also did not differ significantly in the proportions of NK cells expressing the receptors NKG2D,NKp30,NKp46,CD158a or CD158b.General linear model analysis showed that NK cytotoxicity increased with effector-to-target cell ratio.However,NK cytotoxicity did not differ significantly between patients with RIF and fertile controls.These results suggest that RIF is not associated with significant alterations in the number or function of peripheral blood NK cells.

Revised Super-long Down-regulation Protocol Improves the Outcome of Infertile Patients with Repeated Implantation Failure in IVF/ICSI-ET

Objective To investigate the outcome of revised super-long down-regulation protocol （RSDP） for in vitro fertilization / intracytoplasmic sperm injection-embryo transfer （1VF/1CS1-ET） in the special infertile patients with repeated implantation failure （RIF）. Methods Patients with RIF were divided into RSDP group and routine long downregulation protocol （RLDP） group. In RSDP group, gonadotropin releasing hormone agonist （GnRHa） was injected intramuscularly by 2.5 mg in mid-luteal phase for the ftrst time and 1.25 mg after 28 d; gonadotropin （Gn） was started 14 d later after the second GnRHa dose. IVF/ICSI-ET was performed according to the routine procedure. The clinical outcomes of RSDP group were compared with those of RLDP group. Results In RSDP group, the number of retrieved oocytes and valid embryos was significantly lower （P〈0.05）; there were no significant differences about fertilization rate （P〉0. 05）; both good-quality embryo rate and implantation rate were significantly increased （P〈0. 005）; clinical pregnancy rate was obviously improved （P〈0. 05）, as compared with RLDP group.Conclusion RSDP can improve the IVF outcomes significantly in RIF patients.

Endometrial Collagen Fibril Hyperplasia is Associated with Implantation Failure in Women Undergoing IVF-ET

Objective To analyse the effects of controlled ovarian hyperstimulation （ COH） on the endometrial expression of collagen fibril （CF） during the peri-implantation period in patients undergoing IVF, and its relation to endometrial receptivity （ER） in repeated implantation failure（RIF）. Methods Peripheral blood and endometrial biopsies were obtained from 45 infertile women on days 5, 7 or 9 after oocytes retrieval or ovulation in a stimulated cycle （SC） and natural cycle （NC） respectively. CF was assayed by transmission electron microscope and quantified by modified Masson dyeing. The outcome of subsequent embryo transfer（ET） was observed. Results Levels of both E2 and progesterone were higher in the peripheral blood in SC than in NC. Also the expression of CF in the stroma in each secretory phase was increased significantly in SC （P 〈O.05）. After embryo transferring, expression levels of CF in the pregnancy group dropped between the mid- and late-secretory phase, but no change in the non-pregnancy group. In the same term, all patients undergone endometrial curettage had higher pregnancy rate than those without. Conclusion Imbalance of production and degradation of endometrial CF in the secretory phase resulting from COH may be the cause of defective ER and implantation failure in some RIF patients. Endometrial curettage may improve implantation rate by inducing appropriate CF hyperplasia and degradation.

Advances in the Treatment of Recurrent Implantation Failure

Recurrent implantation failure(RIF)is a syndrome of complex etiology.Excluding the involvement of embryonic factors,RIF is characterized by women aged≤40 years who fail to achieve clinical pregnancy after at least four high-quality embryos transfer in a minimum of three fresh or frozen cycles.However,current methods in the treatment of RIF are controversial.So far,there are no reports of any criteria or guidelines,and the mechanism of RIF is still not clear.Herein,we summarize the pathogenesis of RIF and highlight recent methods in its treatment,to provide reference for the basic and clinical research on RIF.