Repeated pregnancy losses with multiple aneuploidies and major genomic imbalance:A case report

Rationale:If one of the partners is having balanced autosomal translocation,it is usually observed that the offspring inherit either normal chromosomes,balanced translocation identical to one of the parent or unbalanced chromosomal rearrangements of the same parental chromosome having translocation.Concern:A unique case presented with history of 8 miscarriages for genetic counseling.The last abortus material evaluation showed monosomy of chromosome X(Turner syndrome)in all the analyzed cells.There was a history of infertility and also repeated second trimester abortions on the paternal side.On the maternal side,there was a history of intellectual disability.Diagnose:History of repeated abnormal pregnancy outcomes.Wife’s karyotype is normal;however,husband shows translocation between chromosome 4 and 22.Intervention:Peripheral blood sample around 3 mL was collected for karyotype.Embryo biopsy was done and DNA was extracted and processed for whole exome sequencing.Outcomes:Wife’s karyotype is normal and husband has translocation between chromosome 4 and 22.Surprisingly,the entire pregnancy outcome including embryo screening has different,complete or partial aneuploidies of chromosomes other than chromosome 4 and 22.Main lesson:Though the translocation in one of the parent is balanced,we have to think beyond traditional ways for evaluating a couple with repeated pregnancy loss as we cannot predict the errors at cell division.Option of in vitro fertilization and preimplantation genetic diagnosis in couples having balanced translocations should be discussed so that early intervention can prevent the agony of pregnancy loss.

Antibodies Against Annexin V and Prothrombin,Their Correlation with Other Anti-phospholipid Antibodies in Recurrent Pregnancy Loss

Objective To study the findings of serum antibodies against annexin V, prothrombin, ph-inositol, ph-acid, ph-ethanolamine, ph-serine, ph-glycerol, cardiolipin, and beta2-glycoprotein I and analyze the trophoblast annexin V receptors Methods Sera from 156patients aged 26-41 years with recurrent pregnancy loss （3-7 times） were investigated. Eighty-four fertile healthy women aged 24-38 years were included in a control group. ELISA methods were used for detecting a panel of sera anti-phospholipid antibodies. Immunolocalization of annexin V receptors in 143 trophoblast specimens of 156 patients was investigated by the immunofluorescence technique using Annexin V-FITC, Apoptosis and Annexin V-CY3 commercial kits. Results Positivity for anti-phospholipid antibodies mainly against ph-serine, ph- ethanolamine, and ph-inositol was found together in 80. 8%（126 out of 156 patients）, anti-prothrombin antibodies in 12% （18）, and anti-annexin V antibodies in 13. 5% （21） women. No significant levels of anti-phospholipid antibodies were found in 6 controls. Placenta immunohistopathology also exhibited some changes manifested by the presence of apoptotic and necrotic cells in trophoblast, and very few microthrombotization in some intervillous spaces. Conclusion Our detailed study demonstrated the prevalence of majority of antiphospholipid antibodies as a high risk factor for repeated reproductive failure. Very low microthrombosis in placentas could be explained by the changes of haemocoagulation properties out of uterus.

Expression of TET and 5-HmC in Trophoblast Villi of Women with Normal Pregnancy and with Early Pregnancy Loss

Increasing evidence suggests that epigenetic dysfunction may influence the stability of normal pregnancy. The ten-eleven translocation （TET） family and 5-hydroxymethylcytosine （5-hmC） were found to be linked with epigenetic reprogramming. The present study aimed to examine the expression of the TET family and 5-hmC in the villi of human embryos and compared their expression between normal pregnancy and early pregnancy loss （EPL）. Embryonic villi were collected from normal pregnant women （control） experiencing medical abortion and from EPL patients at gestation ages of 6, 7 and 8 weeks. The mRNAs of TET family were analysed using quantitative polymerase chain reaction （qPCR）, and TET proteins using Western blotting and immunohistochemical analysis. The MethylFlashTM Kit was used to quantify the absolute amount of 5-methylcytosine （5-mC） and 5-hmC. Our results showed that the expression of the TETs and 5-hmC in the normal villus decreased with increasing gestational age. Immunohistochemistry revealed that the TET proteins were expressed in the cytoplasm of trophoblasts and their expression was the highest in the 6-week tissue samples, which was consistent with the qPCR and Western blot results. The expression of TET1, TET2, and TET3 was lower in the villi in EPL group than in normal pregnancy group （P〈0.05 for all）. It was concluded that the TET family and 5-hmC are critical in epigenetic reprogramming of human embryo. The findings also suggest that a deficiency of TETs in the villus might be associated with human EPL.

Comparative Study between the Use of Regular Folic Acid Supplement versus the Use of L-Methyl Folate in Patients with Methyl Tetrahydrofolate Reductase (MTHFR) Gene Mutation with Recurrent Pregnancy Loss

Background: Methylfolate is the active metabolite of folate that is important for DNA repair, synthetized under the effect of MTHFR (methyl-tetrahydro-folatereductase) enzyme. Patients with MTHFR gene mutation have low levels of biologically active methyfolate. Those patients have high homocysteine levels causing vasculopathy and inadequate feto-maternal circulation. Aim of the Work: To predict the potential benefit of use of methylfolate instead of use of the regular folic acid in patients with MTHFR gene mutation with history of RPL (recurrent pregnancy loss). Subjects and Methods: Study was performed on 100 women. All women had experienced at least two consecutive miscarriages first trimester abortion. All patients were positive of having MTHFR gene mutation. Patients were divided into two groups in terms of 1st trimester drug intake. The 1st group recieved a regular folic acid supplement in a dose of 5 mg per day starting from the day of positive pregnancy test till the end of the first trimester. The 2nd group recieved L-methylfolate supplement in a dose of 1000 mcg per day starting from the day of positive pregnancy test till the end of the first trimester. Then both groups were compared in terms of abortion rates, pregnancy continuation rates and the development of other major obstetric complications. Results: Patients in 1st group had no associated pregnancy related complications in 56%, PE in 14%, PROM in 18% and PTL in 12% of cases. On the other hand, patients in 2nd group had no associated pregnancy related complications in 78%, PE in 6%, PROM in 8% and PTL in 8% of cases 54% of patients on folate group ended in abortion, while only 16% of patients on methylfolate group had abortion. 24% of patients on folate group had PTL, compared to 8% of patient who had had PTL in methylfolate group. 22% of patients in the 1st group continued pregnancy to full term, while 60% of 2nd group continued pregnancy to full term. Conclusion and Recommendations: The use of methyl-folate supplement during the first trimester of in patients with history of RPL and positive MTHFR gene mutation should be a routine practice instead of the regular folate supplement as it improves pregnancy continuation rates and decreases occurrence of associated pregnancy co-morbidities as preterm labor and preeclampsia.

Association between eNOS gene promoter polymorphism (-786T>C) and idiopathic recurrent pregnancy loss in Iranian women

Objective:To investigate the frequency of-786T>C variant in endothelial nitric oxide synthase(eNOS)gene promoter in Iranian women with recurrent pregnancy loss.Methods:Blood samples were obtained from 100 unrelated women affected by recurrent pregnancy loss and 100 unaffected women as the controls.Genomic DNA was extracted and-786T>C polymorphism in eNOS gene promoter was investigated by PCR-RFLP method.Statistical analyses and Hardy-Weinberg equilibrium in the groups of patients and controls were performed by Chi-square test and SPSS standard software(Version 21).Results:The frequency of homozygous TT was 40%in cases and 46%in the control group;the frequency of CC was 7%in cases and 5%in the control group;frequency heterozygote TC was 53%in cases and 49%in the control group.Genotype frequencies between the two groups showed no significant differences(P>0.05).Conclusions:The-786T>C polymorphism is not more frequent in recurrent pregnancy loss in this population.

In vitro fertilization-embryo transfer in patients with unexplained recurrent pregnancy loss

Background:Empiric therapy for patients with unexplained recurrent pregnancy loss(URPL)is not precise.Some patients will ask for assisted reproductive technology due to secondary infertility or advanced maternal age.The clinical outcomes of URPL patients who have undergonein vitro fertilization-embryo transfer(IVF-ET)require elucidation.The IVF outcome and influencing factors of URPL patients need further study.Methods:A retrospective cohort study was designed,and 312 infertile patients with URPL who had been treated during January 2012 to December 2015 in the Reproduction Center of Peking University Third Hospital were included.By comparing clinical outcomes between these patients and those with tubal factor infertility(TFI),the factors affecting the clinical outcomes of URPL patients were analyzed.Results:The clinical pregnancy rate(35.18%vs.34.52%in fresh ET cycles,P=0.877;34.48%vs.40.27%in frozen-thawed ET cycles,P=0.283)and live birth rate(LBR)in fresh ET cycles(27.67%vs.26.59%,P=0.785)were not significantly different between URPL group and TFI group.URPL group had lower LBR in frozen-thawed ET cycles than that of TFI group(23.56%vs.33.56%,P=0.047),but the cumulative LBRs(34.69%vs.38.26%,P=0.368)were not significantly different between the two groups.The increased endometrial thickness(EMT)on the human chorionic gonadotropin day(odds ratio[OR]:0.848,95%confidence interval[CI]:0.748-0.962,P=0.010)and the increased number of eggs retrieved(OR:0.928,95%CI:0.887-0.970,P=0.001)were protective factors for clinical pregnancy in stimulated cycles.The increased number of eggs retrieved(OR:0.875,95%CI:0.846-0.906,P<0.001),the increased two-pronucleus rate(OR:0.151,95%CI:0.052-0.437,P<0.001),and increased EMT(OR:0.876,95%CI:0.770-0.997,P=0.045)in ET day were protective factors for the cumulative live birth outcome.Conclusion:After matching ages,no significant differences in clinical outcomes were found between the patients with URPL and the patients with TFI.A thicker endometrium and more retrieved oocytes increase the probability of pregnancy in fresh transfer cycles,but a better normal fertilization potential will increase the possibility of a live birth.

Sperm DNA fragmentation in Chinese couples with unexplained recurrent pregnancy loss

We aimed to study the association between sperm DNA fragmentation and recurrent pregnancy loss(RPL)in the Chinese population via a retrospective observational study of Chinese couples who had experienced RPL between May 2013 and August 2018.The study population included 461 men from couples with RPL and 411 men from a control group(couples with clinical pregnancy via in v/tro fertiIization owing to female causes).Routine semen analysis,sperm chromatin analysis,and microscopic(high-power)morphological analysis were performed using semen samples.Semen samples were assessed for volume,sperm count,and motility.The sperm DNA fragmentation index(DFI)was calculated,and the median DFI was obtained.Men were categorized as having normal(37.8%;DFI<15.0%),moderate(33.6%;15.0%<DFI<30.0%),or severe(28.6%;DFI A30.0%)DNA fragmentation levels.The percentage of men with severe DNA fragmentation was significantly higher in the RPL(42.3%)group than that in the control group(13.1%),whereas the percentage of men with normal levels of DNA fragmentation was significantly lower in the RPL group(22.8%)tha n that in the control group(54.7%).Subsequent analysis also dem on strated that the sperm DNA fragmentation rate had a moderate reverse correlation with the sperm progressive motility rate(r=-0.47,P<0.001)and the total motile sperm count(r=-0.31,P<0.001).We found a positive correlation between RPL and sperm DNA fragmentation.The results suggest that increased sperm DNA damage is associated with RPL.

Retrospective Cohort Study of Preimplantation Genetic Testing for Aneuploidy with Comprehensive Chromosome Screening versus Nonpreimplantation Genetic Testing in Normal Karyotype,Secondary Infertility Patients with Recurrent Pregnancy Loss

Objective:To evaluate whether preimplantation genetic testing for aneuploidy(PGT-A)with comprehensive chromosome screening increases live birth rate(LBR)in normal karyotype couples with recurrent pregnancy loss(RPL).Methods:A retrospective cohort follow-up study of 506 couples with RPL was conducted between April 2014 and March 2017.Couples were allocated to two groups according to their decision to choose PGT-A or not.The primary outcome was LBR per start/transfer cycle;secondary outcomes were ongoing pregnancy rate and miscarriage rate.Statistical analyses were conducted using univariate and multivariate logistic regression models adjusted for maternal age.Results:LBR per start(26.6%vs.15.4%,relative risk[RR]:2.66,95%confidence interval[CI][1.69-4.20],P<0.0001;adjusted RR[aRR]:2.40,95%CI[1.49-3.86],P=0.0004)and per transfer(44.9%vs.25.1%,RR:3.00,95%CI[1.96-4.60],P<0.0001;aRR:2.64,95%CI[1.68-4.14],P<0.0001)was significantly higher in the PGT-A group than in the non-PGT-A group.The miscarriage rate was significantly lower in the PGT-A group compared to the non-PGT-A group(15.7%vs.34.6%,RR:0.27,95%CI[0.13-0.57],P=0.00005;aRR:0.26,95%CI[0.12-0.57],P=0.0007).Conclusions:LBR per start cycle following PGT-A is significantly higher,and risk of miscarriage is significantly lower among infertile couples with RPL,irrespective of maternal age.PGT-A should be recommended to infertile couples with RPL.

In vitro Fertilization with Single-nucleotide Polymorphism Microarray-based Preimplantation Genetic Testing for Aneuploidy Significantly Improves Clinical Outcomes in Infertile Women with Recurrent Pregnancy Loss:A Randomized Controlled Trial

Objective:To evaluate the effect of preimplantation genetic testing for aneuploidy(PGT-A)in infertile patients with recurrent pregnancy loss(RPL).Methods:A prospective randomized clinical trial was performed in a university-affiliated fertility center in Shanghai,China.Patients in the PGT-A group underwent blastocyst biopsy followed by single-nucleotide polymorphism microarray-based PGT-A and single euploid blastocyst transfer,whereas patients in the control group underwent routine in vitro fertilization/ICSI procedures and frozen embryo transfer of 1-2 embryos selected according to morphological standards.Results:Two hundred and seven infertile patients with RPL were included in this study and randomly assigned to either the control or the PGT-A group.Baseline variables and cycle characteristics were comparable between the two groups.The results showed that PGT-A significantly improved the ongoing pregnancy rate(55.34%vs.29.81%)as well as the live birth rate(48.54%vs.27.88%)and significantly reduced the miscarriage rate(0.00%vs.14.42%)on a per-patient analysis.A significant increase in cumulative ongoing pregnancy rates over time was observed in the PGT-A group.Subgroup analysis showed that the significant benefit diminished for patients who attempted≥2 PGT-A cycles.Conclusions:PGT-A significantly improved the ongoing pregnancy and live birth rate,while reduced miscarriage rate in infertile RPL patients.However,the significance diminished in patients attempting≥2 cycles;thus,further studies are warranted to explore the most cost-effective number of attempts in these patients to avoid overuse.

Understanding recurrent pregnancy loss:recent advances on its etiology,clinical diagnosis,and management

Recurrent pregnancy loss(RPL)has become an important reproductive health issue worldwide.RPL affects about 2%–3%of reproductive-aged women,and makes serious threats to women’s physical and mental health.However,the etiology of approximately 50%of RPL cases remains unknown(unexplained RPL),which poses a big challenge for clinical management of these patients.RPL has been widely regarded as a complex disease where its etiology has been attributed to numerous factors.Heretofore,various risk factors for RPL have been identified,such as maternal ages,genetic factors,anatomical structural abnormalities,endocrine dysfunction,prethrombotic state,immunological factors,and infection.More importantly,development and applications of next generation sequencing technology have significantly expanded opportunities to discover chromosomal aberrations and single gene variants responsible for RPL,which provides new insight into its pathogenic mechanisms.Furthermore,based upon patients’diagnostic evaluation and etiologic diagnosis,specific therapeutic recommendations have been established.This review will highlight current understanding and recent advances on RPL,with a special focus on the immunological and genetic etiologies,clinical diagnosis and therapeutic management.

Factor XIII VaU34Leu polymorphism and risk of recurrent pregnancy loss in Iranian population： a case control study

BACKGROUND： Recurrent pregnancy loss （RPL） is a heterogeneous condition and thrombophilias have been considered as a probable cause. OBJECTIVE： The aim of this study was to investigate the prevalence of the coagulation factor XIII Va134Leu polymorphism among women with unexplained RPL. METHODS： A total of 140 women with a history of unexplained RPL and 100 age-matched healthy fertile women were recruited. The presence of FXIII Va134Leu polymorphism among the cases and controls was investigated using PCR-RFLP method. RESULTS： Genotype analyses of the subjects revealed that the patients had a significantly higher prevalence of V/L and L/L than the controls （P〈 0.05）： 33.5% vs. 15%, and 9.2% vs. 2%, respectively. CONCLUSION： These results indicate a significant association between FXIII Va134Leu polymorphism and unexplained RPL in the Iranian patient.

Successful pregnancy outcome with comprehensive treatment after 13 consecutive pregnancy losses

R urrent pregnancy loss （RPL） is defined as two or ore failed clinical pregnancies. Up to 50% of RPL does not have a clear etiology.1 Increased resistance to blood flow in the uterine arteries has been found in women with unexplained RPL, and even greater resistance has been detected in women with RPL and auto-antibodies.2 However, vascular changes and pregnancy outcomes after the treatment for RPL patients with abnormal uterine artery flow remain poorly studied.

Do specific ultrasonography features identified at the time of early pregnancy loss predict fetal chromosomal abnormality? e A systematic review and meta-analysis

To investigate the association of specific ultrasonography features identified during the diagnosis of early pregnancy loss(EPL)and abnormal karyotype.This was a systematic review and meta-analysis conducted in accordance with PRISMA criteria.We searched PubMed,Cochrane and Ovid MEDLINE from 1977 to Jan 2017 to identify the articles that described EPL with karyotype and ultrasonography features.Risk differences were pooled to estimate the chromosomal abnormality rates in ultrasonography features,including pre-embryonic,enlarged yolk sac(YS),short crown rump length(CRL),small gestational sac(GS),symmetrical arrested growth embryo,or gestational sac with only a YS.Quality assessment of included studies was performed using Strengthening the Reporting of Observational Studies in Epidemiology(STROBE)checklists for Observational Studies(2007 version).Thirteen studies were included in the meta-analysis.Chromosomal abnormality was more likely to occur in embryonic EPL and enlarged YS.On the other hand,short CRL,small GS,symmetrical arrested growth embryo,or gestational sac with only a YS,were not associated with an increased risk of fetal chromosomal abnormality.Ultrasonography features at the time of diagnosis of EPL have limited predictive value of fetal chromosomal abnormality.

The interaction effect between advanced paternal age and paternal obesity is associated with the low implantation rate in couples with unexplained recurrent pregnancy loss

Objective:To explore the roles of advanced paternal age(APA)and abnormal paternal weight on embryo quality and pregnancy outcomes for unexplained recurrent pregnancy loss(uRPL)couples who underwent preimplantation genetic testing for aneuploidies(PGT-A).Methods:This study included 779 uRPL couples who underwent their first PGT-A cycles between 2014 and 2018.Male patients’aging and nutritional status were quantified by paternal age and body mass index(BMI).Routine semen parameters and sperm DNA fragmentation index(DFI)were used to reflect the seminal quality.Blastocyst formation rate and aneuploidy rate were used to reflect the embryo quality.Cycle cancellation rate,implantation rate,pregnancy loss rate,and live birth rate were measured to evaluate the treatment efficiency from IVF.To remove the interference of maternal age,only the women younger than 38 years old were included.After univariate screening,interaction tests were performed in a generalized linear model(GLM)to further examine the effects of paternal age and BMI on each outcome indicator.Results:In the total population(779 cycles),there were no statistical differences in aneuploidy rate,cycle cancellation rate,implantation rate,pregnancy loss rate,and live birth rate,whether stratified by paternal age or paternal BMI.Similar results occurred in the younger men(<40 y.o.,633 cycles).Conversely,among the men with advanced age(≥40 y.o.,146 cycles),there were statistical differences between the three BMI groups in four semen parameters(total sperm number,total motility,progressive motility,and total motile sperm count),implantation rate,and live birth rate.After interaction testing,the results of GLM suggested that the interaction effect between APA and paternal obesity was associated with the low implantation rate of uRPL couples.Conclusions:For the uRPL couples seeking for PGT-A treatment,if the male patients have both advanced age and obesity,their spouses are at higher risks for embryo implantation failure.

Study of the Effect of Intralipid Infusion during Pregnancy as an Additive Treatment for Reducing Pregnancy Complications Caused by Antiphospholipid Antibody Syndrome

Aim: To evaluate the safety and efficacy of intralipid infusion in addition to other lines of treatment in reduction of complications caused by antiphospholipid antibody syndrome. Methods: This study was held in the period from June 1, 2016, to December 1, 2019. This study was conducted in the Department of Obstetrics and Gynecology, Tanta University on patients attending the antenatal care clinic and also on patients attending the researcher’s private clinics for antenatal care, 105 patients were enrolled after application of strict inclusion and exclusion criteria. They were randomized into 2 groups. In group A (study group 1) the patients received in addition to the conventional basic treatment of APS, intralipid 20% (Frezenius, Clayton, NC, USA) in a dose of 4 ml diluted in 250 ml 0.9% regular saline IV and to be repeated every 2 weeks. In group B (control group 2) the patients received the conventional basic treatment of APS. The outcome measures were the incidence of pregnancy complications of APS namely fetal loss, premature delivery, IUGR and preeclampsia. Results: 49 patients were enrolled in the study group, and 48 patients were enrolled in the control group, after exclusion of the skipped cases. The demographic data and the gestational age at the beginning of the study show insignificant differences. There were insignificant differences as regard the gestational age at which the pregnancy was terminated and fetal birth weight in patients with positive ACL test, positive LA test and positive B2 however the mean gestational age at which pregnancy was terminated was higher in study group. Also, there was insignificant difference as regards no of patients who complicated with abortion or who completed to full term. But had significant decrease number of case who complicated with preeclampsia (8, 21 patients in study and control group respectively). Conclusion: Intralipid infusion is a promising treatment option for control and prevention of problems caused by antiphospholipid antibody syndrome.

Comparative analysis between endometrial proteomes of pregnant and non-pregnant ewes during the peri-implantation period

Background： Early pregnancy failure has a profound impact on both human reproductive health and animal production. 2/3 pregnancy failures occur during the peri-implantation period; however, the underlying mechanism（s） remains unclear. Well-organized modification of the endometrium to a receptive state is critical to establish pregnancy Aberrant endometrial modification during implantation is thought to be largely responsible for early pregnancy loss. Result： In this study, using well-managed recipient ewes that received embryo transfer as model, we compared the endometrial proteome between pregnant and non-pregnant ewes during implantation period. After embryo transfer, recipients were assigned as pregnant or non-pregnant ewes according to the presence or absence of an elongated conceptus at Day 17 of pregnancy. By comparing the endometrial proteomic profiles between pregnant and non-pregnant ewes, we identified 94 and 257 differentially expressed proteins （DEPs） in the endometrial caruncular and intercaruncular areas, respectively. Functional analysis showed that the DEPs were mainly associated with immune response, nutrient transport and utilization, as well as proteasome-mediated proteolysis. Conclusion： These analysis imply that dysfunction of these biological processes or pathways of DEP in the endometrium is highly associated with early pregnancy loss. In addition, many proteins that are essential for the establishment of pregnancy showed dysregulation in the endometrium of non-pregnant ewes. These proteins, as potential candidates, may contribute to early pregnancy loss.

Future directions of clinical laboratory evaluation ol pregnancy

In recent years, our understanding of how the immune system interacts with the developing fetus and placenta has greatly expanded. There are many laboratories that provide tests for diagnosis of pregnancy outcome in women who have recurrent pregnancy loss （RPL） or pre-eclampsia. These tests are based on the premise that immune response to the fetus is equivalent to the adaptive immune response to a transplant. New understanding leads to the concept that the activated innate response is vital for pregnancy and this can result in more effective testing and treatment to prevent an abnormal pregnancy in the future. We describe here only three such areas for future testing： one area involves sperm and semen and factors necessary for successful fertilization; another area would determine conditions for production of growth factors necessary for implantation in the uterus; finally, the last area would be to determine conditions necessary for the vascularization of the placenta and growing fetus by activated natural killer （NK） cells （combinations of killer cell immunoglobulin-like receptor （KIR） family genes with HLA-C haplotypes） that lead to capability of secreting angiogenic growth factors. These areas are novel but understanding their role in pregnancy can lead to insight into how to maintain and treat pregnancies with complicating factors.

A comparison of implantation, miscarriage and pregnancy rates of single and double day 3 embryo transfer between fresh and frozen thawed transfer cycles： a retrospective study

Background Reduced endometrial receptivity in hyperstimulated cycles may lead to a lower implantation rate and a lower clinical pregnancy rate,but it is unclear if it is also associated with an increase in pregnancy loss rate.The aim of this study was to compare the implantation,miscarriage,and pregnancy rates between fresh and frozen thawed transfer of one or two day-3 embryos,with a view to understanding whether or not reduced endometrial receptivity encountered in hyperstimulated cycles is associated with an increase in miscarriage rate.Methods This study involved a consecutive series of 1 551 single day-3 embryo transfer cycles and consecutive 5 919 double day-3 embryo transfer cycles in the Assisted Reproductive Unit of the Sir Run Run Shaw Hospital,Hangzhou,China,between January 2010 and December 2012.Results The implantation and clinical pregnancy rates （single embryo 30.7％ and double embryos 33.4％ and 51.4％）using fresh cycle were both significantly lower than that of frozen-thawed cycles （single embryo 35.8％ and double embryos 38.1％ and 57.8％）.There was no difference in biochemical loss or clinical miscarriage rates between the two groups.Conclusions Impairment of endometrial receptivity associated with ovarian hyperstimulation leads to implantation failure at a very early stage,resulting in an increased number of non-pregnancy.It does not lead to increase in biochemical or clinical losses.The significantly reduced ongoing pregnancy rates in both fresh single and double embryo transfer are therefore due to failure to achieve a pregnancy,rather than pregnancy loss after conception.