Local injury to the endometrium in controlled ovarian hyperstimulation cycles improves implantation rates

Endometrial Proliferative Phase-Centered View of Transcriptome Dynamics across the Menstrual Cycle

The endometrium, the inner mucosal lining of the uterus, undergoes complex molecular and cellular changes across the menstrual cycle in preparation for embryo implantation. Transcriptome-wide analyses have mainly been utilized to study endometrial receptivity, the prerequisite for successful implantation, with most studies, so far, comparing the endometrial transcriptomes between (i) secretory and proliferative endometrium or (ii) mid-secretory and early secretory endometrium. In the current study, we provide a complete transcriptome description of the endometrium across the entire menstrual cycle and, for the first time, comprehensively characterize the proliferative phase of the endometrium. Our temporal transcriptome analysis includes five time points including the mid-proliferative, late proliferative (peri-ovulatory phase), early secretory, mid-secretory, and late secretory phases. Thus, we unveil exhaustively the transitions between the consecutive proliferative and secretory phases, highlighting their unique gene expression profiles and possible distinct biological functions. The transcriptome analysis reveals many differentially expressed genes (DEGs) across the menstrual cycle, most of which are phase-specific. As an example of coordinated gene activity, the expression profile of histone-encoding genes within the HIST cluster on chromosome 6 shows an increase in cluster activity during the late proliferative and a decline during the mid-secretory phase. Moreover, numerous DEGs are shared among all phases. In conclusion, in the current study, we delineate the endometrial proliferative phase-centered view of transcriptome dynamics across the menstrual cycle. Our data analysis highlights significant transcriptomic and functional changes occurring during the late proliferative phase-an essential transition point from the proliferative phase to the secretory phase. Future studies should explore how the biology of the late proliferative phase endometrium impacts the achievement of mid-secretory endometrial receptivity or contributes to molecular aberrations leading to embryo implantation failure.

Intra-horn insemination in the alpaca Vicugna pacos: Copulatory wounding and deep sperm deposition

Alpacas (Vicugna pacos) are reported to be the rare mammal in which the penis enters the uterus in mating. To date, however, only circumstantial evidence supports this assertion. Using female alpacas culled for meat, we determined that the alpaca penis penetrates to the very tips of the uterine horns, abrading the tract and breaking fine blood vessels. All female alpacas sacrificed one hour or 24 hours after mating showed conspicuous bleeding in the epithelium of some region of their reproductive tract, including the hymen, cervix and the tips of each uterine horn, but typically not in the vagina. Unmated females showed no evidence of conspicuous bleeding. Histological examination of mated females revealed widespread abrasion of the cervical and endometrial epithelium, injuries absent in unmated females. Within one hour of mating, sperm were already present in the oviduct. The male alpaca's cartilaginous penis tip with a hardened urethral process is likely responsible for the copulatory abrasion. The entire female reproductive tract interacts with the penis, functioning like a vagina. Alpacas are induced ovulators, and wounding may hasten delivery of the seminal ovulation-inducing factor beta-NGF into the female's blood stream. There is no evidence of sexual conflict in copulation in alpaca, and thus wounding may also be one of a variety of mechanisms devised by mammals to induce a beneficial, short-term inflammatory response that stimulates blastocyst implantation, the uterine remodeling associated with placental development, and thus the success of early pregnancy.

When the Embryo Meets the Endometrium: Identifying the Features Required for Successful Embryo Implantation

Evaluation of the optimal number of embryos, their quality, and the precise timing for transfer are critical determinants in reproductive success, although still remaining one of the main challenges in assisted reproduction technologies (ART). Indeed, the success of in vitro fertilization (IVF) treatments relies on a multitude of events and factors involving both the endometrium and the embryo. Despite concerted efforts on both fronts, the overall success rates of IVF techniques continue to range between 25% and 30%. The role of the endometrium in implantation has been recently recognized, leading to the hypothesis that both the "soil" and the "seed" play a central role in a successful pregnancy. In this respect, identification of the molecular signature of endometrial receptivity together with the selection of the best embryo for transfer become crucial in ART. Currently, efforts have been made to develop accurate, predictive, and personalized tests to identify the window of implantation and the best quality embryo. However, the value of these tests is still debated, as conflicting results are reported in the literature. The purpose of this review is to summarize and critically report the available criteria to optimize the success of embryo transfer and to better understand current limitations and potential areas for improvement.

Endometrial biopsy performed before the first in vitro fertilization does not impact the early pregnancy rate

Endometrial biopsy (EB) has been showed to increase the rate of clinical pregnancy in patients who underwent in vitro fertilization (IVF) failures. The purpose of this work was to assess the impact of an EB performed before the first in IVF on the early pregnancy rate. Be One study is a prospective, single-centre, randomized, open-label study. In this parallel study, patients were evenly split into two groups. In one group, patients underwent an EB between days 17 and 22 of the menstrual cycle that precedes the ovarian stimulation. In the other group (control), no EB was performed. The hCG-positive rate (early pregnancy rate) was evaluated on day 14 after the ovarian puncture. In total, 157 patients were randomized in the EB group and 154 patients were in the control group. The early pregnancy rate was 33.1% (52/157) in the EB group and 29.9% (46/154) in the control group (p = 0.54). Other parameters, including perforation, endometritis, or pain level were reassuring. An EB performed during the luteal phase of the menstrual cycle preceding the stimulation of the first IVF did not increase early pregnancy rate.

Stratified analysis of clinical pregnancy outcomes of sequential embryo transfer in frozen embryo transfer cycles based on different factors: a retrospective study

OBJECTIVE

To explore the effect of sequential embryo transfer (ET) on the pregnancy outcome of frozen-thawed embryo transfer (FET) cycle and the indications of sequential transfer.

METHODS

A total of 1440 FET cycles were enrolled in this retrospective study, of which 1080 patients received conventional ET and 360 patients received sequential ET. Further stratified analysis was performed according to the number of previous failed cycles, the number of embryos transferred and the stage of blastocyst (day 5 or 6, denoted D5 or D6) transferred. Comparison of pregnancy rates, implantation rate, miscarriage rate and multiple pregnancy rate among the groups of patients.

RESULTS

The clinical pregnancy rate and implantation rate of the sequential ET group were higher than those of the conventional ET group (P < 0.01); however, there was no statistical difference in multiple pregnancy rate and miscarriage rate (P > 0.05). In sequential transfer, the number of transferred embryos (2 or 3) and the stage of transferred blastocysts (D5 or D6) had no effect on clinical pregnancy rate, implantation rate, multiple pregnancy rate and miscarriage rate (P > 0.05). In patients with three or more previous failure cycles, the sequential ET group showed higher clinical pregnancy rate and implantation rate (P > 0.05).

CONCLUSIONS

Compared with conventional ET in FET cycle, sequential ET strategy could significantly improve the clinical pregnancy rate and implantation rate. In sequential transfer, patients with three embryos transferred don't have higher pregnancy rate and implantation rate. Besides, sequential transfer is more suitable for patients with repeated implantation failures (RIF), and increase the utilization rate of D6 blastocysts.

Comparative effectiveness and safety of 36 therapies or interventions for pregnancy outcomes with recurrent implantation failure: a systematic review and network meta-analysis

PURPOSE

To investigate the effectiveness and safety of 36 different therapies for recurrent implantation failure (RIF) patients.

METHODS

We searched PubMed, Embase, the Cochrane Library (CENTRAL), Web of Science, and China National Knowledge Internet (CNKI) from inception to August 24, 2022, with language in both English and Chinese. Randomized controlled trials (RCTs) and observational studies that provided data with one of pregnancy outcomes on RIF patients were included in the network meta-analysis (NMA). The odds ratios (OR) and 95% credible interval (CrI) on pregnancy outcomes were summarized by NMA with a random-effects model. We also analyzed data from only RCTs and compared whether the optimal treatment is the same for different failed embryo transfer attempts.

RESULTS

The total of 29,906 RIF patients from 154 clinical studies (74 RCTs and 80 non-RCTs) were included in the NMA. In terms of implantation rate (IR), growth hormone (GH) (OR: 3.32, 95% CrI: 1.95-5.67) is the best treatment in all included studies; IVIG+PBMC (5.84, 2.44-14.1) is the best for clinical pregnancy rate (CPR); hyaluronic acid (HA) (12.9, 2.37-112.0) for live birth rate (LBR); and aspirin combined with glucocorticoids (0.208, 0.0494-0.777) for miscarriage rate (MR). The two-dimensional graphs showed that GH could maximize IR and CPR simultaneously; HA and GH could simultaneously increase IR and LBR to a large extent; HA could maximize IR and minimize MR.

CONCLUSION

IVIG+PBMC, GH, and embryo medium enriched with HA could significantly improve pregnancy outcomes in patients with RIF. It appears that combination therapy is a potential administration strategy.

TRIAL REGISTRATION

This study has been registered on PROSPERO (CRD42022353423).

Autologous bone marrow-derived nucleated cell (aBMNC) transplantation improves endometrial function in patients with refractory Asherman's syndrome or with thin and dysfunctional endometrium

PURPOSE

The purpose was to evaluate the effect of intrauterine injection of aBMNC on the endometrial function in patients with refractory Asherman's syndrome (AS) and/or thin and dysfunctional endometrium (TE).

STUDY DESIGN

This is a prospective, experimental, non-controlled study MATERIAL AND METHODS: The study was carried out between December 2018 and December 2020 on 20 patients, who were of age < 45 years and had oligo/amenorrhea and primary infertility due to refractory AS and/or TE. One hundred ml BM was extracted. aBMNC cells were separated according to generic volume reduction protocol by using the Cell Separation System SEPAX S-100 table top centrifuge system. We have evaluated CD34+, mononuclear cell (MNC), and total nucleated cell (TNC) counts. The transplantation aBMNC was performed by two intrauterine injections at an interval of one week, transvaginally into the endometrial-myometrial junction by an ovum aspiration needle. Midcyclic endometrial thickness (ET) and gestations after transplantation were evaluated.

RESULTS

The mean TNC, MNC, and CD34+ cells were 11.55 ± 4.7 × 108, 3.85 ± 2.01 × 108, and 7.00 ± 2.88 × 106 at first injection, respectively, and 6.85 ± 2.67 × 108, 2.04 ± 1.11 × 108, and 3.44 ± 1.31 × 106 at second injection, respectively. The maximum posttransplantation ET was significantly higher than the maximum pretransplantation ET: 2.97 ± 0.48 vs. 5.76 ± 1.19 (mean ± standard deviation, p < 0.01). Twelve patients had frozen-thaw embryo transfers after the study. In 42% (n = 5 of 12) of the patients, pregnancy was achieved. One of the five patients delivered a healthy baby at term.

CONCLUSIONS

Autologous BMNC transplantation may contribute to endometrial function in patients with AS and/or TE.

Endometrial Injury Upregulates Expression of Receptivity Genes in Women with Implantation Failure

BACKGROUND

Homeobox genes A10 (HOXA10) and A11 (HOXA11), members of the abdominal B gene family, are responsible for embryonic survival and implantation. This study was planned to investigate whether endometrial injury alters the expression of both transcripts in women with implantation failure.

METHODS

A total of 54 women with implantation failure were divided into two equal groups as experimental (scratching) and sham (no scratching). Participants in the scratching group were exposed to endometrial injury in the mid-luteal phase, and those in the sham group were exposed to endometrial flushing. The scratching group, but not the sham group, underwent prior endometrial sampling. A second endometrial sampling was performed on the scratching group in the mid-luteal phase of the following cycle. The mRNA and protein levels of the HOXA10 and 11 transcripts were determined in endometrial samples collected before and after injury/flushing. Participants in each group underwent IVF/ET in the cycle after the second endometrial sampling.

RESULTS

Endometrial injury caused a 60.1-fold (p < 0.01) increase in HOXA10 mRNA and a 9.0-fold increase in HOXA11 mRNA (p < 0.02). Injury resulted in a significant increase in both HOXA10 (p < 0.001) and HOXA11 protein expression (p < 0.003). There was no significant change in HOXA10 and 11 mRNA expressions after flushing. Clinical pregnancy, live birth, and miscarriage rates of the both groups were similar.

CONCLUSIONS

Endometrial injury increases homeobox transcript expression at both mRNA and protein levels.

Recurrent Abortion and the Involvement of Killer-Cell Immunoglobulin-like Receptor (KIR) Genes, Activated T Cells, NK Abnormalities, and Cytokine Profiles

Immune tolerance at the feto-maternal interface is crucial for the growth of the semi-allograft fetus in the womb. The outcome of pregnancy is dependent on a fine balance between various immunological forces. For a long time, the potential role of the immune system in pregnancy disorders has remained enigmatic. Current evidence has revealed that natural killer (NK) cells are the predominant immune cell population in the uterine decidua. NK cells cooperate with T-cells to provide an optimal microenvironment for the growth of the developing fetus by producing cytokines, chemokines, and angiogenic factors. These factors support trophoblast migration and angiogenesis which regulates the process of placentation. NK cells differentiate between "self" and "non-self" through their surface receptors known as killer-cell immunoglobulin-like receptors (KIRs). They induce immune tolerance through communication via their KIR and fetal human leucocyte antigens (HLA). KIRs are surface receptors of NKs that comprise both activating and inhibiting receptors. Due to the wide diversity manifested by its genes, the KIR repertoire is different in each individual. Significant evidence has implicated KIRs in recurrent spontaneous abortion (RSA); however, maternal KIR gene diversity in RSA is still unclear. Research has shown that immunological aberrancies including activating KIRs, NK abnormalities, and T cell downregulation are risk factors for RSA. In this review, we discuss relevant data from experimental studies on NK cell abnormalities, KIR, and T-cells in the incidence of recurrent spontaneous abortion.

Effects of sequential cleavage and blastocyst embryo transfer on pregnancy outcomes in patients with poor ovarian response

The management of patients with poor ovarian response (POR) remains a major challenge for fertility specialists in in vitro fertilization-embryo transfer (IVF-ET). In this retrospective cohort study, we aimed to evaluate the clinical effect of sequential transfer on pregnancy outcomes in patients with POR. A total of 3579 POR patients who underwent the first frozen embryo transfer (FET) cycle were enrolled from January 2018 to April 2021. The patients were divided into three groups according to the embryo transfer (ET) strategy adopted: a study group that included POR patients in whom a cleavage-stage embryo (day 3) and a blastocyst (day 5/6) were transferred (sequential transfer group), and two control groups in whom two cleavage-stage embryos (D3-dET group) or two blastocysts (D5/6-dET group) were transferred. The study group was matched with the control groups at a ratio of 1:4 by propensity score matching (PSM). The main pregnancy outcomes measured were the live birth rate and multiple pregnancy rate. After PSM, the live birth rate in the sequential transfer group was significantly higher than that in the D3-dET group (44.2% vs. 34.3%, P = 0.019), and was similar to that in the D5/6-dET group (44.2% vs. 45.3%; P = 0.90). In addition, there was no increase in the risk of multiple pregnancy among POR patients undergoing sequential transfer compared with both D3-dET (26.7% vs. 25.6%, P = 0.85) and D5/6-dET (26.7% vs. 28.4%, P = 0.97) groups. These findings imply that sequential transfer is an effective option for POR patients and could be utilized after careful consideration.

The Effect of Endometrial Scratch on Pregnancy Rate in Women with Previous Intrauterine Insemination Failure: a Systematic Review and Meta-analysis of Randomized Controlled Trials

The objective of this study was to evaluate the impact of endometrial scratch on the pregnancy rate among women with previous failed intrauterine insemination (IUI). A systematic search was done in PubMed, Cochrane Library, Scopus, and ISI web of science from inception to November 2021. We selected randomized clinical trials (RCTs) that compared endometrial scratch in the intervention group versus placebo or no intervention in the control group among infertile women with previous failure of IUI regarding different pregnancy outcomes. Revman software was utilized for performing our meta-analysis. Our main outcomes were biochemical pregnancy, clinical pregnancy, and live birth rates. Five RCTs met our inclusion criteria with a total number of 989 patients. We found endometrial scratch significantly improved the biochemical and clinical pregnancy rates in comparison with the control group among women with previous IUI failure (p < 0.001). Moreover, the live birth rate was significantly increased among the endometrial scratch group (RR = 2.00, 95% CI [1.20, 3.34], p = 0.008). In conclusion, endometrial scratch is effective in improving pregnancy outcomes among women with previous IUI failure. More trials are required to confirm our findings.

Impact of endometrial scratching on reproductive outcome in patients: A systematic review and meta-analysis

BACKGROUND

Endometrial scratching (ES) has demonstrated initial success in women with recurrent implantation failure, but the effect in women with 1 previous assisted reproductive technology (ART) failure is unknown. This meta-analysis aimed to evaluate the impact of ES as a treatment in clinical outcomes for women with at least 1 failed in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)/Intrauterine Insemination (IUI).

METHODS

PubMed, Medline, Embase, Cochrane Library, Web of Science, CNKI, and EMCC databases were searched for randomized controlled trial studies utilizing endometrial scratching for infertility women with at least 1 failed assisted reproductive technology (ART) to collect pregnancy outcomes, including clinical pregnancy rate (CPR), embryo implantation rate (IR), miscarriage rate (MR), live birth rate (LBR), and multiple pregnancy rate (MPR).

RESULTS

Sixteen randomized controlled trial (RCT) studies were included in this meta-analysis, including 1770 women in the intervention group and 1934 women in the control group. Overall, the CPR, IR and LBR were significantly higher in the intervention group than in the control group (for CPR, n = 1430, 16 studies, P = .0002, risk ratio (RR) = 1.59, 95% confidence interval [CI] [1.24, 2.03]; for IR, n = 859, 10 studies, P = .0003, RR = 1.67, 95% CI [1.26, 2.21]; for LBR, n = 156, 6 studies, P = .0005, RR = 1.59, 95% CI [1.22, 2.06]). Nonetheless, there was no significant difference in MR (n = 344, 11 studies, P = .62, risk ratio (RR) = 0.92, 95% confidence interval [CI] [0.66, 1.29]) and MPR (n = 98, 3 studies, P = .39, risk ratio (RR) = 0.81, 95% confidence interval [CI] [0.51, 1.30]) between the intervention group and the control group.

CONCLUSION

Endometrial scratching is considered to enhance the reproductive outcomes of embryo implantation. Additional randomized controlled studies are recommended to identify the appropriate time of invasion and the applicable population to confirm whether it can become a routine operation.

Chronic endometritis in recurrent implantation failure: Use of prednisone and IVF outcome

In recurrent implantation failure patients (RIF), the main criteria for diagnosis of chronic endometritis, is the presence of plasma cells CD138⁺ in endometrial biopsy. The aim of the present study was to evaluate if treatment with prednisone, in patients with RIF and chronic endometritis, improve IVF outcome. A retrospective study was performed between 2019 and 2020. A total of 27 patients with RIF and an endometrial biopsy positive for CD56⁺ cells were enrolled. The treatment with prednisone 10 mg per day is began together with controlled ovarian stimulation (COS). Among endometrial biopsies, 13 (48.14%) were positive also for CD138 cells, and an antibiotic treatment was added. In all patients, after therapy, in the subsequent IVF cycle, the clinical pregnancy rate was 25.9% and the live birth rate was 22.2%. Analysing pregnancies according to the percentage of CD 56 cells on endometrial biopsy, the live birth rate in the subgroup of patients with marked endometritis (defined by the presence of >10% CD56⁺cells) was 29.41%, while in the subgroup with mild endometritis (CD 56 >5% and <10%) was 10%. In the subgroup with mild endometritis with CD 138 positive the live birth was 25%, while in patients with CD 138 negative no live birth were observed. In patients with RIF the count of at least two cell types (CD 138 and CD 56 cells) on endometrial biopsies is advisable. Our study suggests a benefit of prednisone and antibiotic treatment on live birth rate in a subsequent IVF cycle.

Endometrial scratch to increase live birth rates in women undergoing first-time in vitro fertilisation: RCT and systematic review

BACKGROUND

In vitro fertilisation is a widely used reproductive technique that can be undertaken with or without intracytoplasmic sperm injection. The endometrial scratch procedure is an in vitro fertilisation 'add-on' that is sometimes provided prior to the first in vitro fertilisation cycle, but there is a lack of evidence to support its use.

OBJECTIVES

(1) To assess the clinical effectiveness, safety and cost-effectiveness of endometrial scratch compared with treatment as usual in women undergoing their first in vitro fertilisation cycle (the 'Endometrial Scratch Trial') and (2) to undertake a systematic review to combine the results of the Endometrial Scratch Trial with those of previous trials in which endometrial scratch was provided prior to the first in vitro fertilisation cycle.

DESIGN

A pragmatic, multicentre, superiority, open-label, parallel-group, individually randomised controlled trial. Participants were randomised (1 : 1) via a web-based system to receive endometrial scratch or treatment as usual using stratified block randomisation. The systematic review involved searching electronic databases (undertaken in January 2020) and clinicaltrials.gov (undertaken in September 2020) for relevant trials.

SETTING

Sixteen UK fertility units.

PARTICIPANTS

Women aged 18-37 years, inclusive, undergoing their first in vitro fertilisation cycle. The exclusion criteria included severe endometriosis, body mass index ≥ 35 kg/m² and previous trauma to the endometrium.

INTERVENTIONS

Endometrial scratch was undertaken in the mid-luteal phase of the menstrual cycle prior to in vitro fertilisation, and involved inserting a pipelle into the cavity of the uterus and rotating and withdrawing it three or four times. The endometrial scratch group then received usual in vitro fertilisation treatment. The treatment-as-usual group received usual in vitro fertilisation only.

MAIN OUTCOME MEASURES

The primary outcome was live birth after completion of 24 weeks' gestation within 10.5 months of egg collection. Secondary outcomes included implantation, pregnancy, ectopic pregnancy, miscarriage, pain and tolerability of the procedure, adverse events and treatment costs.

RESULTS

One thousand and forty-eight (30.3%) women were randomised to treatment as usual (n = 525) or endometrial scratch (n = 523) and were followed up between July 2016 and October 2019 and included in the intention-to-treat analysis. In the endometrial scratch group, 453 (86.6%) women received the endometrial scratch procedure. A total of 494 (94.1%) women in the treatment-as-usual group and 497 (95.0%) women in the endometrial scratch group underwent in vitro fertilisation. The live birth rate was 37.1% (195/525) in the treatment-as-usual group and 38.6% (202/523) in the endometrial scratch group: an unadjusted absolute difference of 1.5% (95% confidence interval -4.4% to 7.4%; p = 0.621). There were no statistically significant differences in secondary outcomes. Safety events were comparable across groups. No neonatal deaths were recorded. The cost per successful live birth was £11.90 per woman (95% confidence interval -£134 to £127). The pooled results of this trial and of eight similar trials found no evidence of a significant effect of endometrial scratch in increasing live birth rate (odds ratio 1.03, 95% confidence interval 0.87 to 1.22).

LIMITATIONS

A sham endometrial scratch procedure was not undertaken, but it is unlikely that doing so would have influenced the results, as objective fertility outcomes were used. A total of 9.2% of women randomised to receive endometrial scratch did not undergo the procedure, which may have slightly diluted the treatment effect.

CONCLUSIONS

We found no evidence to support the theory that performing endometrial scratch in the mid-luteal phase in women undergoing their first in vitro fertilisation cycle significantly improves live birth rate, although the procedure was well tolerated and safe. We recommend that endometrial scratch is not undertaken in this population.

TRIAL REGISTRATION

This trial is registered as ISRCTN23800982.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 10. See the NIHR Journals Library website for further project information.

Human implantation: The complex interplay between endometrial receptivity, inflammation, and the microbiome

Human embryo implantation is an intricate spatiotemporal process that involves the intimate association between the embryo and the endometrium of the mother. During implantation, the endometrium undergoes a dynamic cascade of gene activation and repression, largely driven by autocrine, paracrine, and endocrine action. Steroid hormones, such as estrogen and progesterone, act on a variety of targets including cellular adhesion molecules (CAMs), cytokines, and growth factors to facilitate the implantation process. Given the synchrony required to achieve implantation, it is unsurprising that embryo implantation represents a substantial problem for infertility patients. This is due to a complex interplay taking place at the level of the endometrium. This review discusses the intricacies of embryo implantation including the window of implantation, the cyclical phases of the endometrium, the implantation process itself, and features of endometrial receptivity. Additionally, we will discuss new research regarding inflammatory reproductive biology, epigenetics and microRNA, and the role of the vaginal and endometrial microbiome in implantation. A better understanding of embryo implantation and the interactions occurring at the level of the blastocyst and the endometrium will improve patient care for infertile patients who experience this frustrating challenge.

TNF-α Regulated Endometrial Stroma Secretome Promotes Trophoblast Invasion

Successful implantation requires the coordinated migration and invasion of trophoblast cells from out of the blastocyst and into the endometrium. This process relies on signals produced by cells in the maternal endometrium. However, the relative contribution of stroma cells remains unclear. The study of human implantation has major technical limitations, therefore the need of in vitro models to elucidate the molecular mechanisms. Using a recently described 3D in vitro models we evaluated the interaction between trophoblasts and human endometrial stroma cells (hESC), we assessed the process of trophoblast migration and invasion in the presence of stroma derived factors. We demonstrate that hESC promotes trophoblast invasion through the generation of an inflammatory environment modulated by TNF-α. We also show the role of stromal derived IL-17 as a promoter of trophoblast migration through the induction of essential genes that confer invasive capacity to cells of the trophectoderm. In conclusion, we describe the characterization of a cellular inflammatory network that may be important for blastocyst implantation. Our findings provide a new insight into the complexity of the implantation process and reveal the importance of inflammation for embryo implantation.

Endometrial scratch injury in infertile women seeking conception through natural or intrauterine insemination cycles: A systematic review and meta-analysis

OBJECTIVE

Implantation failure is a major cause of infertility. To evaluate the value of ESI in infertile women undergoing natural or IUI cycles.

METHODS

Screening of MEDLINE, CENTRAL, other bases from inception to June 2021 using the keywords related to endometrial scratch, implantation, infertility, and IUI. RCTs of intentional endometrial injury in couples seeking fertility through natural or IUI cycles were included. All types of ESI with variable intensity (mild to moderate or severe), at different times of the cycle (preceding follicular, preceding luteal, same follicular or two times), single or double compared to none, placebo or other active interventions were included. Twenty-five studies included 4234 women (five natural [774 women], 20 IUI [3460 women]) fulfilled the inclusion criteria. Extracted data included settings of the study, sample size, participant characteristics, intervention details and outcome parameters. The primary outcome was the clinical pregnancy rate.

RESULTS

ESI increased clinical pregnancy rate from 16.1% (62/386) to 26.5% (103/388) and from 11.4% (186/1627) to 22.25% (408/1833), P = 0.004 and <0.001 in natural and IUI cycles, respectively. ESI increased live birth rate from 26.6% (42/158) to 37.6% (59/157) (P = 0.250) and from 11.2% (36/322) to 18% (58/322) (P = 0.020) in natural and IUI cycles, respectively.

CONCLUSION

ESI increased both clinical pregnancy and ongoing pregnancy rates significantly in natural and IUI cycles. However, there is marked methodological heterogeneity among the different studies in defining the outcome parameters.

Sequential cleavage and blastocyst embryo transfer and IVF outcomes: a systematic review

BACKGROUND

Sequential embryo transfer has been proposed as a way to improve embryo implantation in women for in vitro fertilization (IVF), but the effect on pregnancy outcomes remains ambiguous. This systematic review was conducted to investigate the efficacy of sequential embryo transfer on IVF outcomes.

METHODS

A literature search was performed in the PubMed, Web of Science, Cochrane Library, ScienceDirect and Wanfang databases. Data were pooled using a random- or fixed-effects model according to study heterogeneity. The results are expressed as relative risks (RRs) with 95% confidence intervals (CIs). Heterogeneity was evaluated by the I² statistic. The study protocol was registered prospectively on INPLASY, ID: INPLASY202180019.

RESULTS

Ten eligible studies with 2658 participants compared sequential embryo transfer and cleavage transfer, while four studies with 513 participants compared sequential embryo transfer and blastocyst transfer. The synthesis results showed that the clinical pregnancy rate was higher in the sequential embryo transfer group than in the cleavage embryo transfer group (RR 1.42, 95% CI 1.26-1.60, P< 0.01) for both women who did experience repeated implantation failure (RIF) (RR 1.58, 95% CI 1.17-2.13, P< 0.01) and did not experience RIF (Non-RIF) (RR 1.44, 95% CI 1.20-1.66, P< 0.01). However, sequential embryo transfer showed no significant benefit over blastocyst embryo transfer.

CONCLUSION

The current systematic review demonstrates that sequential cleavage and blastocyst embryo transfer improve the clinical pregnancy rate over conventional cleavage embryo transfer. For women with adequate embryos, sequential transfer could be attempted following careful consideration. More high-grade evidence from prospective randomized studies is warranted.

Role of Maternal Infections and Inflammatory Responses on Craniofacial Development

Pregnancy is a tightly regulated immunological state. Mild environmental perturbations can affect the developing fetus significantly. Infections can elicit severe immunological cascades in the mother's body as well as the developing fetus. Maternal infections and resulting inflammatory responses can mediate epigenetic changes in the fetal genome, depending on the developmental stage. The craniofacial development begins at the early stages of embryogenesis. In this review, we will discuss the immunology of pregnancy and its responsive mechanisms on maternal infections. Further, we will also discuss the epigenetic effects of pathogens, their metabolites and resulting inflammatory responses on the fetus with a special focus on craniofacial development. Understanding the pathophysiological mechanisms of infections and dysregulated inflammatory responses during prenatal development could provide better insights into the origins of craniofacial birth defects.

Hysteroscopic endometrial peeling as a different approach to endometrial scratching. Case series report

STUDY QUESTION

Does hysteroscopic endometrial peeling improve reproductive outcomes in women with implantation failure?

DESIGN

In this case series, 66 women underwent an hysteroscopic endometrial peeling and subsequently, a single frozen embryo transfer.

RESULTS

After the exclusion of patients with intraoperative incidental findings, pregnancy was achieved in 63% (42/66) of the women who underwent hysteroscopic endometrial peeling and subsequently a single frozen embryo transfer, clinical pregnancy rate was observed in 57% (38/66) of the patients and, clinical pregnancy loss occurred in 10% (4/38).

CONCLUSION

this novel surgical technique seems to increase implantation as well as clinical pregnancy rates in women with repeated implantation failure. We can hypothesize that the controlled and subtle degree of endometrial injury generated by the peeling generates an inflammatory cascade that enhances implantation.

Is Endometrial Scratching Beneficial for Patients Undergoing a Donor-Egg Cycle with or without Previous Implantation Failures? Results of a Post-Hoc Analysis of an RCT

Endometrial scratching (ES) has been proposed as a useful technique to improve outcomes in in vitro fertilization (IVF) cycles, particularly in patients with previous implantation failures. Our objective was to determine if patients undergoing egg-donor IVF cycles had better live birth rates after ES, according to their previous implantation failures. Secondary outcomes were pregnancy rate, clinical pregnancy rate, ongoing pregnancy rate, miscarriage rate, and multiple pregnancy rate. We analysed the results of 352 patients included in the Endoscratch Trial (NCT03108157). A total of 209 were patients with one or no previous implantation failures (105 with an ES done in the previous cycle, group A1, and 104 without ES, group B1), and 143 were patients with at least two previous failed implantations (71 patients with ES, group A2, and 72 without ES, group B2). We found an improvement in pregnancy rates (62.9% in group A1 vs. 55.8% in group B1 vs. 70.4% in group A2 vs. 76.4% in group B2, p = 0.028) in patients with at least two previous implantation failures, but this difference was not statistically different when we compared clinical pregnancy rates (59.1% vs. 51.0% vs. 64.8% vs. 68.1% in groups A1, B1, A2 and B2, respectively, p = 0.104) and live birth rates (52.4% vs. 43.3% vs. 57.8% vs. 55.6% in groups A1, B1, A2 and B2, respectively, p = 0.218). According to these results, we conclude that there is no evidence to recommend ES in egg-donor IVF cycles, regardless of the number of previous failed cycles.

Comparison of pregnancy outcome in intrauterine insemination-candidate women with and without endometrial scratch injury: An RCT

Background

Endometrial scratch injury is considered controversial in increasing the success rate of assisted reproductive technology.

Objective

To compare the pregnancy outcomes in women undergoing intrauterine insemination with and without an endometrial scratch.

Materials and Methods

In this randomized clinical trial, 150 women referred to the Fatemieh Hospital, Hamadan, Iran who were candidates for IUI between December 2017 and December 2018 were randomly assigned into two groups (n = 75/each) with or without an endometrial scratch (as case and control groups, respectively). Women in both groups were in proper and identical protocol for IUI. Chemical and clinical pregnancies, abortion, and live birth rate, also pregnancy complications were compared between the groups.

Results

Chemical and clinical pregnancy rates were higher in the case than the control group (p = 0.25, p = 0.54, respectively). In the case group, the abortion and multiple gestation rates were 14.3% and 4.3%, respectively, while it was 5% in the control group (p = 0.60, p = 0.54 respectively). The endometrium thickness on day 21 was higher in the case group than the control (p = 0.01).

Conclusion

Endometrial scratching in intrauterine insemination women is not associated with an increase in both clinical and clinical pregnancy rates, however, studies with a larger sample size are recommended to evaluate this intervention.

Endometrial injury in women undergoing in vitro fertilisation (IVF)

BACKGROUND

Implantation of an embryo within the endometrial cavity is a critical step in the process of in vitro fertilisation (IVF). Previous research has suggested that endometrial injury (also known as endometrial scratching), defined as intentional damage to the endometrium, can increase the chance of pregnancy in women undergoing IVF.

OBJECTIVES

To assess the effectiveness and safety of endometrial injury performed before embryo transfer in women undergoing in vitro fertilisation (IVF) including intracytoplasmic sperm injection (ICSI) and frozen embryo transfer.

SEARCH METHODS

In June 2020 we searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, LILACS, DARE and two trial registries. We also checked the reference sections of relevant studies and contacted experts in the field for any additional trials.

SELECTION CRITERIA

Randomised controlled trials comparing intentional endometrial injury before embryo transfer in women undergoing IVF, versus no intervention or a sham procedure.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Two independent review authors screened studies, evaluated risk of bias and assessed the certainty of the evidence by using GRADE (Grading of Recommendation, Assessment, Development and Evaluation) criteria. We contacted and corresponded with study investigators as required. Due to the high risk of bias associated with many of the studies, the primary analyses of all review outcomes were restricted to studies at a low risk of bias for selection bias and other bias. Sensitivity analysis was then performed including all studies. The primary review outcomes were live birth and miscarriage.

MAIN RESULTS

Endometrial injury versus control (no procedure or a sham procedure) A total of 37 studies (8786 women) were included in this comparison. Most studies performed endometrial injury by pipelle biopsy in the luteal phase of the cycle before the IVF cycle. The primary analysis was restricted to studies at low risk of bias, and included eight studies. The effect of endometrial injury on live birth is unclear as the result is consistent with no effect, or a small reduction, or an improvement (odds ratio (OR) 1.12, 95% confidence interval (CI) 0.98 to 1.28; participants = 4402; studies = 8; I² = 15%, moderate-certainty evidence). This suggests that if the chance of live birth with IVF is usually 27%, then the chance when using endometrial injury would be somewhere between < 27% and 32%. Similarly, the effect of endometrial injury on clinical pregnancy is unclear (OR 1.08, 95% CI 0.95 to 1.23; participants = 4402; studies = 8; I² = 0%, moderate-certainty evidence). This suggests that if the chance of clinical pregnancy from IVF is normally 32%, then the chance when using endometrial injury before IVF is between 31% and 37%. When all studies were included in the sensitivity analysis, we were unable to conduct meta-analysis for the outcomes of live birth and clinical pregnancy due to high risk of bias and statistical heterogeneity. Endometrial injury probably results in little to no difference in chance of miscarriage (OR 0.88, 95% CI 0.68 to 1.13; participants = 4402; studies = 8; I² = 0%, moderate-certainty evidence), and this result was similar in the sensitivity analysis that included all studies. The result suggests that if the chance of miscarriage with IVF is usually 6.0%, then when using endometrial injury it would be somewhere between 4.2% and 6.8%. Endometrial injury was associated with mild to moderate pain (approximately 4 out of 10), and was generally associated with some minimal bleeding. The evidence was downgraded for imprecision due to wide confidence intervals and therefore all primary analyses were graded as moderate certainty. Higher versus lower degree of injury Only one small study was included in this comparison (participants = 129), which compared endometrial injury using two different instruments in the cycle prior to the IVF cycle: a pipelle catheter and a Shepard catheter. This trial was excluded from the primary analysis due to risk of bias. In the sensitivity analysis, all outcomes reported for this study were graded as very-low certainty due to risk of bias, and as such we were not able to interpret the study results.

AUTHORS' CONCLUSIONS

The effect of endometrial injury on live birth and clinical pregnancy among women undergoing IVF is unclear. The results of the meta-analyses are consistent with an increased chance, no effect and a small reduction in these outcomes. We are therefore uncertain whether endometrial injury improves the chance of live birth or clinical pregnancy in women undergoing IVF. Endometrial injury does not appear to affect the chance of miscarriage. It is a somewhat painful procedure associated with a small amount of bleeding. In conclusion, current evidence does not support the routine use of endometrial injury for women undergoing IVF.

The Addition of Endometrial Injury to Freeze-All Strategy in Women with Repeated Implantation Failures

(1) Background: Recurrent implantation failure (RIF) after IVF remains a challenging topic for fertility specialists and a frustrating reality for patients with infertility. Various approaches have been investigated and applied towards the improvement of clinical outcomes. Through a nonrandomized clinical trial, we evaluated the effect of the combination of hysteroscopic endometrial injury and the freeze-all technique on pregnancy parameters in a cohort of RIF patients; (2) Methods: The study group comprised of 30 patients with RIF that underwent a hysteroscopic endometrial injury prior to a frozen embryo transfer cycle; another 30 patients with RIF, comprising the control group, underwent a standard frozen cycle with no adjuvant treatment before. Live birth comprised the primary outcome. Logistic and Poisson regression analyses were implemented to reveal potential independent predictors for all outcomes. (3) Results: Live birth rates were similar between groups (8/30 vs. 3/30, p = 0.0876). Biochemical and clinical pregnancy and miscarriages were also independent of the procedure (p = 0.7812, p = 0.3436 and p = 0.1213, respectively). The only confounding factor that contributed to biochemical pregnancy was the number of retrieved oocytes (0.1618 ± 0.0819, p = 0.0481); (4) Conclusions: The addition of endometrial injury to the freeze-all strategy in infertile women with RIF does not significantly improve pregnancy rates, including live birth. A properly conducted RCT with adequate sample size could give a robust answer.

The effect of topical endometrial scratching on pregnancy outcome in women with previous failure of intrauterine insemination: A non-randomized clinical trial

BACKGROUND

The prevalence of infertility is increasing worldwide and the treatment is one of the important issues.

OBJECTIVE

This study aimed to evaluate the effect of local endometrial scratching on pregnancy outcomes in women with previous failure of intrauterine insemination.

MATERIALS AND METHODS

This non-randomized clinical trial study was performed on 336 women referred to the infertility clinic of Ali ebn-e Abitaleb Hospital of Zahedan (between May and November 2019). Women were divided into two groups: endometrial scratch as case and a control group. In the case group (n = 173), endometrial scratching was performed on days 8-9 of the menstrual cycle in addition to routine infertility treatments, while in the control group (n = 163), only routine treatment was performed. Chi-square test was used to compare the frequency of male factor severity and the percentage of successful pregnancies between both groups and was used to investigate the effect of male factor on the fertility rate in each group (moderate male factor and mild male factor).

RESULTS

The mean age of the women was 28.4 ± 5.2 yr. The success rate of pregnancy in the case group was 12.3% and in the control group 11%, which were not statistically significant (p = 0.697).

CONCLUSION

Overall, the results of this study showed that endometrial scratching had no effect on the pregnancy rate.

The proliferative phase endometrium in IVF/ICSI: an in-cycle molecular analysis predictive of the outcome following fresh embryo transfer

STUDY QUESTION

Does an early proliferative phase endometrial biopsy harvested during ovarian stimulation harbour information predictive of the outcome following fresh embryo transfer (ET) in that same cycle?

SUMMARY ANSWER

Transcriptome analysis of the whole-tissue endometrium did not reveal significant differential gene expression (DGE) in relation to the outcome; however, the secretome profile of isolated, cultured and in vitro decidualized endometrial stromal cells (EnSCs) varied significantly between patients who had a live birth compared to those with an implantation failure following fresh ET in the same cycle as the biopsy.

WHAT IS KNOWN ALREADY

In the majority of endometrial receptivity research protocols, biopsies are harvested during the window of implantation (WOI). This, however, precludes ET in that same cycle, which is preferable as the endometrium has been shown to adapt over time. Endometrial biopsies taken during ovarian stimulation have been reported not to harm the chances of implantation, and in such biopsies DGE has been observed between women who achieve pregnancy versus those who do not. The impact of the endometrial proliferative phase on human embryo implantation remains unclear, but deserves further attention, especially since in luteal phase endometrial biopsies, a transcriptional signature predictive for repeated implantation failure has been associated with reduced cell proliferation, possibly indicating proliferative phase involvement. Isolation, culture and in vitro decidualization (IVD) of EnSCs is a frequently applied basic research technique to assess endometrial functioning, and a disordered EnSC secretome has previously been linked with failed implantation.

STUDY DESIGN, SIZE, DURATION

This study was nested in a randomized controlled trial (RCT) investigating the effect of endometrial scratching during the early follicular phase of ovarian stimulation on clinical pregnancy rates after IVF/ICSI. Of the 96 endometrial biopsies available, after eliminating those without fresh ET and after extensive matching in order to minimize the risk of potential confounding, 18 samples were retained to study two clinical groups: nine biopsies of patients with a live birth versus nine biopsies of patients with an implantation failure, both following fresh ET performed in the same cycle as the biopsy. We studied the proliferative endometrium by analysing its transcriptome and by isolating, culturing and decidualizing EnSCs in vitro. We applied this latter technique for the first time on proliferative endometrial biopsies obtained during ovarian stimulation for in-cycle outcome prediction, in an attempt to overcome inter-cycle variability.

PARTICIPANTS/MATERIALS, SETTING, METHODS

RNA-sequencing was performed for 18 individual whole-tissue endometrial biopsies on an Illumina HiSeq1500 machine. DGE was analysed three times using different approaches (DESeq2, EdgeR and the Wilcoxon rank-sum test, all in R). EnSC isolation and IVD was performed (for 2 and 4 days) for a subset of nine samples, after which media from undifferentiated and decidualized cultures were harvested, stored at -80°C and later assayed for 45 cytokines using a multiplex suspension bead immunoassay. The analysis was performed by partial least squares regression modelling.

MAIN RESULTS AND THE ROLE OF CHANCE

After correction for multiple hypothesis testing, DGE analysis revealed no significant differences between endometrial samples from patients who had a live birth and those with an implantation failure following fresh ET. However secretome analysis after EnSC isolation and culture, showed two distinct clusters that clearly corresponded to the two clinical groups. Upon IVD, the secretome profiles shifted from that of undifferentiated cells but the difference between the two clinical groups remained yet were muted, suggesting convergence of cytokine profiles after decidualization.

LIMITATIONS, REASONS FOR CAUTION

Caution is warranted due to the limited sample size of the study and the in vitro nature of the EnSC experiment. Validation on a larger scale is necessary, however, hard to fulfil given the very limited availability of in-cycle proliferative endometrial biopsies outside a RCT setting.

WIDER IMPLICATIONS OF THE FINDINGS

These data support the hypothesis that the endometrium should be assessed not only during the WOI and that certain endometrial dysfunctionalities can probably be detected early in a cycle by making use of the proliferative phase. This insight opens new horizons for the development of endometrial tests, whether diagnostic or predictive of IVF/ICSI treatment outcome.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Fonds Wetenschappelijk Onderzoek (FWO, Flanders, Belgium, 11M9415N, 1 524 417N), Wetenschappelijk Fonds Willy Gepts (WFWG G160, Universitair Ziekenhuis Brussel, Belgium) and the National Medicine Research Council (NMRC/CG/M003/2017, Singapore). There are no conflicts of interests.

TRIAL REGISTRATION NUMBER

NCT02061228.

Follicular-phase endometrial scratching: a truncated randomized controlled trial

STUDY QUESTION

Does intentional endometrial injury (scratching) during the follicular phase of ovarian stimulation (OS) increase the clinical pregnancy rate (CPR) in ART?

SUMMARY ANSWER

CPR did not vary between the endometrial injury and the control group, but the trial was underpowered due to early termination because of a higher clinical miscarriage rate observed in the endometrial injury arm after a prespecified interim analysis.

WHAT IS KNOWN ALREADY

Intentional endometrial injury has been put forward as an inexpensive clinical tool capable of enhancing endometrial receptivity. However, despite its widespread use, the benefit of endometrial scratching remains controversial, with several recent randomized controlled trials (RCTs) being unable to confirm its added value. So far, most research has focused on endometrial scratching during the luteal phase of the cycle preceding the one with embryo transfer (ET), while only a few studies investigated in-cycle injury during the follicular phase of OS. Also, the persistence of a scratch effect in subsequent treatment cycles remains unclear and possible harms have been insufficiently studied.

STUDY DESIGN, SIZE, DURATION

This RCT was performed in a tertiary hospital setting between 3 April 2014 and 8 October 2017. A total of 200 women (100 per study arm) undergoing IVF/ICSI in a GnRH antagonist suppressed cycle followed by fresh ET were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were randomized with a 1:1 allocation ratio to either undergo a pipelle endometrial biopsy between Days 6 and 8 of OS or to be in the control group.The primary outcome was CPR. Secondary outcomes included biochemical pregnancy rate, live birth rate (LBR), early pregnancy loss (biochemical pregnancy losses and clinical miscarriages), excessive procedure pain/bleeding and cumulative reproductive outcomes within 6 months of the study cycle.

MAIN RESULTS AND THE ROLE OF CHANCE

The RCT was stopped prematurely by the trial team after the second prespecified interim analysis raised safety concerns, namely a higher clinical miscarriage rate in the intervention group. The intention-to-treat CPR was similar between the biopsy and the control arm (respectively, 44 versus 40%, P = 0.61, risk difference = 3.6 with 95% confidence interval = -10.1;17.3), as was the LBR (respectively, 32 versus 36%, P = 0.52). The incidence of a biochemical pregnancy loss was comparable between both groups (10% in the intervention group versus 15% in the control, P = 0.49), but clinical miscarriages occurred significantly more frequent in the biopsy group (25% versus 8%, P = 0.032). In the intervention group, 3% of the patients experienced excessive procedure pain and 5% bleeding. The cumulative LBR taking into account all conceptions (spontaneous or following ART) within 6 months of randomization was not significantly different between the biopsy and the control group (54% versus 60%, respectively, P = 0.43).

LIMITATIONS, REASONS FOR CAUTION

The trial was stopped prematurely due to safety concerns after the inclusion of 200 of the required 360 patients. Not reaching the predefined sample size implies that definite conclusions on the outcome parameters cannot be drawn. Furthermore, the pragmatic design of the study may have limited the detection of specific subgroups of women who may benefit from endometrial scratching.

WIDER IMPLICATIONS OF THE FINDINGS

Intentional endometrial injury during the follicular phase of OS warrants further attention in future research, as it may be harmful. These findings should be taken in consideration together with the growing evidence from other RCTs that scratching may not be beneficial.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by 'Fonds Wetenschappelijk Onderzoek' (FWO, Flanders, Belgium, 11M9415N, 1524417N). None of the authors have a conflict of interest to declare with regard to this study.

Dysregulation of the interleukin-17A pathway in endometrial tissue from women with unexplained infertility affects pregnancy outcome following assisted reproductive treatment

STUDY QUESTION

Which transcriptomic alterations in mid-luteal endometrial scratch biopsies, taken prior to the assisted reproductive treatment (ART) treatment cycle are associated with unsuccessful pregnancy?

SUMMARY ANSWER

Dysregulated interleukin-17 (IL-17) pathway components are demonstrated in women who fail to become pregnant after ART.

WHAT IS KNOWN ALREADY

Implantation failure is now recognised as a critical factor in unexplained infertility and may be an important component of failed ART.

STUDY DESIGN, SIZE, DURATION

Using a prospective longitudinal study design, 29 nulliparous women with unexplained infertility undergoing ART were recruited between October 2016 and February 2018. Mid-luteal stage endometrium and matched serum samples were collected, and patients underwent a single embryo transfer in the subsequent cycle. RNA-seq analysis of endometrial biopsies was performed on the discovery cohort (n = 20).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Gene set enrichment analysis of the differentially expressed genes (DEGs) was performed. Endometrium and serum were then prepared for IL-17A analysis by ELISA.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 204 differentially expressed protein-coding genes identified in tissue from women who became pregnant (n = 9) compared with tissue from women who failed to become pregnant (n = 11) (false discovery rate; P < 0.05). Of the 204 DEGs, 166 were decreased while 38 were increased in the pregnant compared to the non-pregnant groups. Gene set enrichment analysis of the DEGs identified an over-representation of IL-17 and Pl3K-Akt signalling pathways. All the DEGs within the IL-17 signalling pathway (MMP3, MMP1, IL1β, LCN2, S100A9 and FOSL1) demonstrated decreased expression in the pregnant group. Serum IL-17 protein levels were increased in the non-pregnant discovery cohort (n = 11) and these findings were confirmed a validation cohort (n = 9).

LIMITATIONS, REASONS FOR CAUTION

Limitations of our study include the cohort size and the lack of aneuploidy data for the embryos; however, all embryos transferred were single good or top-quality blastocysts.

WIDER IMPLICATIONS OF THE FINDINGS

These findings demonstrate dysregulated IL-17 pathway components in women who fail to become pregnant after ART. Elevated serum levels of the pro-inflammatory cytokine IL-17 may predict failure of ART in women with unexplained infertility. Future trials of anti-IL-17 therapies in this cohort warrant further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

Funding from the UCD Wellcome Institutional Strategic Support Fund, which was financed jointly by University College Dublin and the SFI-HRB-Wellcome Biomedical Research Partnership (ref 204844/Z/16/Z), is acknowledged. The authors have no competing interests.

TRIAL REGISTRATION NUMBER

NA.

Efficacy of growth hormone supplementation with ultrashort GnRH antagonist in IVF/ICSI for poor responders; randomized controlled trial

OBJECTIVES

To compare the ICSI-ET outcomes in poor responders who underwent ovarian stimulation by the ultrashort GnRH antagonist protocol with or without adjuvant GH injection.

MATERIAL AND METHODS

This randomized controlled study was conducted at Al-Azhar University from December-2018 to June-2019 upon 156 participants. All patients received the same preparations. After randomization, in the study group, women have received GH 4 IU/day subcutaneous injection from the second day of the cycle stopped one day before ovum pickup. While in the control group, women have received subcutaneous saline in the same dosing as in the study group. After intervention, all procedures were the same in both groups. The main outcome measure was the clinical pregnancy rate. Statistical analysis was based on the intention-to-treat population.

RESULTS

Both groups were comparable with regard their baseline characteristics (p-values > 0.05). Ovulation characteristics were comparable (p-values > 0.05). The level of E2 is significantly (p-value = 0.003) higher in the GH group. The oocyte retrieved number was significantly (p-value < 0.001) higher in the GH group 4.94 ± 1.77 than in the control group 3.74 ± 1.82. The mean number of MII oocytes was significantly (p-value < 0.001) higher in the GH group 3.3 ± 1.36 than in the control group 2.29 ± 1.24. Fertilization characteristics, implantation rate, pregnancy rate were comparable (p-values > 0.05).

CONCLUSION

Despite the fact that this study showed no significant increase in the clinical and chemical pregnancy rates by the addition of GH to the ultrashort antagonist protocol in poor responders, the number of retrieved oocytes was significantly higher in the GH group.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03759301.

Comparing sequential vs day 3 vs day 5 embryo transfers in cases with recurrent implantation failure: randomized controlled trial

OBJECTIVE

The recent improvement in sequential media has refocused its attention on the role of human blastocysts in ART, not only because of its advantages but also because of the possible cancellation of embryo transfer when relying on blastocyst transfer only. Hence, the idea of sequential transfer on day 3 and day 5 was proposed. Objective: To compare the pregnancy outcomes of sequential embryo transfer on day 3 and day 5, versus cleavage transfer on day 3 and blastocyst transfer on day 5 in cases of recurrent implantation failure.

METHODS

This was a prospective and randomized trial, in which 210 qualified patients with recurrent implantation failures undergoing IVF/ICSI were randomized into three groups, each group included 70 patients. Embryo transfer was performed in day 3 in the first group, day 5 (blastocyst transfer) in the second group and sequential embryo transfer in days 3 and 5 in the third group. We assessed pregnancy outcomes from all the three groups. Results: Clinical pregnancy and live birth rates were significantly higher in the sequential group than either group day-3 or day-5 of embryo transfer in cases with recurrent implantation failures.

CONCLUSIONS

Sequential embryo transfer in cases with recurrent implantation failures and adequate number of retrieved oocytes is associated with higher implantation and clinical pregnancy rates, and it is advocated for patients having an adequate number of good quality embryos.

Tubal Flushing Treatment for Unexplained Infertility

Tubal patency testing was initially introduced as a diagnostic test. However, it has been observed that some tubal patency tests also have a therapeutic effect. This therapeutic effect can be influenced by the contrast medium used during tubal flushing. In this review, we discuss current evidence associated with different methods for tubal flushing and their potential impact on reproductive outcomes in women with unexplained infertility. Furthermore, we discuss their diagnostic accuracy, safety, and cost-effectiveness.

Uterine bathing with sonography gel prior to IVF/ICSI-treatment in patients with endometriosis, a multicentre randomised controlled trial

STUDY QUESTION

What is the effect of uterine bathing with sonography gel prior to IVF/ICSI-treatment on live birth rates after fresh embryo transfer in patients with endometriosis?

SUMMARY ANSWER

After formal interim analysis and premature ending of the trial, no significant difference between uterine bathing using a pharmacologically neutral sonography gel compared to a sham procedure on live birth rate after fresh embryo transfer in endometriosis patients (26.7% vs. 15.4%, relative risk (RR) 1.73, 95% confidence interval (CI) 0.81-3.72; P-value 0.147) could be found, although the trial was underpowered to draw definite conclusions.

WHAT IS KNOWN ALREADY

Impaired implantation receptivity contributes to reduced clinical pregnancy rates after IVF/ICSI-treatment in endometriosis patients. Previous studies have suggested a favourable effect of tubal flushing with Lipiodol^® on natural conceptions. This benefit might also be explained by enhancing implantation through endometrial immunomodulation. Although recent studies showed no beneficial effect of endometrial scratching, the effect of mechanical stress by intrauterine infusion on the endometrium in endometriosis patients undergoing IVF/ICSI-treatment has not been investigated yet.

STUDY DESIGN SIZE DURATION

We performed a multicentre, patient-blinded, randomised controlled trial in which women were randomly allocated to either a Gel Infusion Sonography (GIS, intervention group) or a sham procedure (control group) prior to IVF/ICSI-treatment. Since recruitment was slow and completion of the study was considered unfeasible, the study was halted after inclusion of 112 of the planned 184 women.

PARTICIPANTS/MATERIALS SETTING METHODS

We included infertile women with surgically confirmed endometriosis ASRM stage I-IV undergoing IVF/ICSI-treatment. After informed consent, women were randomised to GIS with intrauterine instillation of ExEm-gel^® or sonography with gel into the vagina (sham). This was performed in the cycle preceding the embryo transfer, on the day GnRH analogue treatment was started. The primary endpoint was live birth rate after fresh embryo transfer. Analysis was performed by both intention-to-treat and per-protocol.

MAIN RESULTS AND THE ROLE OF CHANCE

Between July 2014 to September 2018, we randomly allocated 112 women to GIS (n = 60) or sham procedure (n = 52). The live birth rate after fresh embryo transfer was 16/60 (26.7%) after GIS versus 8/52 (15.4%) after the sham (RR 1.73, 95% CI 0.81-3.72; P-value 0.147). Ongoing pregnancy rate was 16/60 (26.7%) after GIS versus 9/52 (17.3%) in the controls (RR 1.54, 95% CI 0.74-3.18). Miscarriage occurred in 1/60 (1.7%) after GIS versus 5/52 (9.6%) in the controls (RR 0.17, 95% CI 0.02-1.44) women. Uterine bathing resulted in a higher pain score compared with a sham procedure (visual analogue scale score 2.7 [1.3-3.5] vs. 1.0 [0.0-2.0], P < 0.001). There were two adverse events after GIS compared with none after sham procedures.

LIMITATIONS REASONS FOR CAUTION

The study was terminated prematurely due to slow recruitment and trial fatigue. Therefore, the trial is underpowered to draw definite conclusions regarding the effect of uterine bathing with sonography gel on live birth rate after fresh embryo transfer in endometriosis patients undergoing IVF/ICSI-treatment.

WIDER IMPLICATIONS OF THE FINDINGS

We could not demonstrate a favourable effect of uterine bathing procedures with sonography gel prior to IVF/ICSI-treatment in patients with endometriosis.

STUDY FUNDING/COMPETING INTERESTS

Investigator initiated study. IQ Medical Ventures provided the ExEm FOAM^® kits free of charge, they were not involved in the study design, data management, statistical analyses and/or manuscript preparation, etc. C.B.L. reports receiving grants from Ferring, Merck and Guerbet, outside the submitted work. C.B.L. is Editor-in-Chief of Human Reproduction. V.M. reports grants and other from Guerbet, outside the submitted work. B.W.M. reports grants from NHMRC (GNT1176437), personal fees from ObsEva, Merck and Merck KGaA, Guerbet and iGenomix, outside the submitted work. N.P.J. reports research funding from Abb-Vie and Myovant Sciences and consultancy for Vifor Pharma, Guerbet, Myovant Sciences and Roche Diagnostics, outside the submitted work. K.D. reports personal fees from Guerbet, outside the submitted work. The other authors do not report any conflicts of interest. No financial support was provided.

TRIAL REGISTRATION NUMBER

NL4025 (NTR4198).

TRIAL REGISTRATION DATE

7 October 2013.

DATE OF FIRST PATIENT’S ENROLMENT

22 July 2014.

The impact of accurately timed mid-luteal endometrial injury in nulligravid women undergoing their first or second embryo transfer

INTRODUCTION

Endometrial injury or 'scratch' preceding an assisted reproductive therapy (ART) cycle has recently been shown not to improve livebirth rates among women undergoing ART. The objective of this study was to compare pregnancy outcomes in nulliparous women who underwent an accurately timed mid-luteal scratch biopsy prior to ART with those who did not.

METHODS

This was a prospective cohort study. Women were recruited between October 2016 and February 2018 inclusive. Women who met the inclusion criteria and who did not undergo an endometrial scratch in the study period were used as a comparison group. Patients underwent a cycle of ART in the menstrual cycle following endometrial scratch.

RESULTS

Ninety-eight women were eligible for participation in the study. There were no differences in rates of implantation (35.7% (n = 20/56) vs. 35.4% (n = 17/48); p = 1.00), clinical pregnancy (40.0% (n = 20/50) vs. 39.5% (n = 17/43); p = 1.00) or live birth (34.0% (n = 17/50) vs. 25.6% (n = 11/43); p = 0.50) per embryo transfer between those who underwent a scratch and those who did not.

CONCLUSION

Endometrial scratch is a simple, inexpensive and low-risk procedure. However, in this relatively small cohort study, no differences in rates of implantation, clinical pregnancy or live birth in women with primary infertility were determined between those who underwent a scratch and those who did not.

Association between dietary inflammatory index and inflammatory biomarkers with outcomes of in vitro fertilization treatment

AIM

To investigate associations between dietary inflammatory index (DII), high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) with outcomes of in vitro fertilization treatment.

METHODS

This observational prospective study included 144 women undergoing fresh in vitro fertilization cycles who attended infertility center of Al-Zahra Hospital in Tabriz, Iran. DII was computed based on dietary intake assessed using a 3-day 24-h food record diary. Outcomes of in vitro fertilization in this study were considered fertilization rate, embryo quality and positive pregnancy test. Inflammatory biomarkers were measured on the day of embryo transfer.

RESULTS

There was no statistically significant difference between pregnant and nonpregnant women in terms of infertility and demographic characteristics, quantity of retrieved and fertilized oocytes, fertilization rate and number of transferred embryos (P > 0.05). The mean quality scores of resultant embryos (P < 0.001) and transferred embryos (P = 0.019) were significantly lower in the group of pregnant women, indicating the better quality among them. Median (percentile 25-75th) DII in the pregnant women was 1.8 (0.5-2.7) and in the nonpregnant women was 1.6 (0.3-2.6). DII was significantly related to hs-CRP (r = 0.198, P = 0.017) but not to IL-6. There were no significant relationships between DII, serum hs-CRP, IL-6 and in vitro fertilization outcomes (P > 0.05).

CONCLUSION

These findings demonstrate that serum hs-CRP and IL-6 concentration and DII are not predictive markers of in vitro fertilization cycle outcomes in women undergoing in vitro fertilization.

Maternal C-reactive protein and in vitro fertilization (IVF) cycles

Embryo implantation is accompanied by a potent inflammatory response, and a gradient of cytokines and chemokines produced by endometrial cells supports the embryo-endometrial interaction. C-reactive protein (CRP) serves as an early marker of inflammation and recent studies have illustrated that controlled ovarian hyperstimulation (COH) could increase its levels. Interestingly, a high chance of pregnancy has been reported in women who had an elevated CRP level on the day of embryo transfer. It seems an elevated systemic inflammation in the in vitro fertilization (IVF) cycle can increase the implantation and pregnancy rates. However, the results regarding the association of CRP with ART outcomes are controversial. Therefore, in this review, we aimed to describe how CRP levels change during a cycle of IVF treatment and which factors can potentially affect this pattern of change. Furthermore, the association of CRP with ART outcomes has been discussed.

Role of Regulatory T Cells in Regulating Fetal-Maternal Immune Tolerance in Healthy Pregnancies and Reproductive Diseases

Regulatory T cells (Tregs) are a specialized subset of T lymphocytes that function as suppressive immune cells and inhibit various elements of immune response in vitro and in vivo. While there are constraints on the number or function of Tregs which can be exploited to evoke an effective anti-tumor response, sufficient expansion of Tregs is essential for successful organ transplantation and for promoting tolerance of self and foreign antigens. The immune-suppressive property of Tregs equips this T lymphocyte subpopulation with a pivotal role in the establishment and maintenance of maternal tolerance to fetal alloantigens, which is necessary for successful pregnancy. Elevation in the level of pregnancy-related hormones including estrogen, progesterone and human chorionic gonadotropin promotes the recruitment and expansion of Tregs, directly implicating these cells in the regulation of fetal-maternal immune tolerance. Current studies have provided evidence that a defect in the number or function of Tregs contributes to the etiology of several reproductive diseases, such as recurrent spontaneous abortion, endometriosis, and pre-eclampsia. In this review, we provide insight into the underlying mechanism through which Tregs contribute to pregnancy-related immune tolerance and demonstrate the association between deficiencies in Tregs and the development of reproductive diseases.

Endometrial scratch injury with office hysteroscopy before IVF/ICSI: A randomised controlled trial

OBJECTIVE

Endometrial scratch injury (ESI) has been proposed to improve endometrial receptivity and thereby increase implantation rates in assisted reproductive technology (ART) treatment. ESI has been widely incorporated into clinical practice despite inconclusive evidence of its effect on reproductive outcomes. We aimed to assess pregnancy and live birth rates in subfertile women receiving ESI before IVF treatment in comparison to controls.

STUDY DESIGN

This was a randomised controlled trial (RCT) with no blinding of participants, investigators or health care personnel. Women in ART treatment were allocated to either office hysteroscopy with ESI (ESI group) or no intervention (control group). In total 184 women in IVF/ICSI treatment with minimum one previous failed IVF/ICSI cycle, were included in the final analysis. The primary outcome was positive serum hCG (s-hCG). Secondary outcomes were ongoing pregnancy and live birth rate. Only per-protocol analyses were performed as all patients included at one centre had to be excluded. The trial is registered at ClinicalTrials.gov, NCT01743391.

RESULTS

Our results showed a non-significant increase in positive s-hCG (OR 1.23, 95 % CI (0.65-2.33)), ongoing pregnancy (OR 1.52, 95 % CI (0.73-3.17)), and live birth rates (OR 1.69, 95 % CI (0.78-3.64)) per randomised woman between the ESI and the control group.

CONCLUSION

We observed no significant differences in positive s-hCG or other reproductive outcomes in the ESI vs. the control group. While the crude estimates of positive reproductive outcomes were higher in the ESI group, statistical significance was not reached, and the study was not powered to show smaller differences. However, data from this study will be re-evaluated in the context of an individual participant data meta-analysis (IPD-MA) of RCTs on ESI.

Endometrial "Scratching" An update and overview of current research

About one in every six couples is affected by sterility. Assisted reproduction procedures are currently the treatment of choice for a number of patients who desire children. Many causes of sterility can be overcome with the aid of in vitro fertilization, but successful implantation of the embryos is the major limiting factor. Failure of implantation may occur repetitively. In the treatment of sterility, many approaches have been used to overcome the barrier of implantation failure and improve the chances of successful nidation. Scratching the endometrium prior to embryo transfer has been suggested as one means of enhancing the likelihood of implantation. The current literature was examined to investigate if there was any possible benefit from endometrial scratching. The studies were divided according to whether the women suffered from recurrent implantation failure or not. In summary, it was found that unselected subfertile women generally benefit less from endometrial scratching, but scratching appears to be successful in women who have experienced repeated implantation failure. Although the heterogeneous body of data on the subject deserves further clarification. The latest data presented at “European Society of Human Reproduction and Embryology” 2018 in Barcelona suggested that the method should be abandoned.

Endometrial scratch vs no intervention in egg donation cycles: the ENDOSCRATCH trial protocol

Background

The effects of endometrial scratching (ES) on embryo implantation have been studied for many years. Several studies have shown better outcomes when performed on patients undergoing intrauterine insemination and in vitro fertilization (IVF) cycles, but many other reports have not been able to find these differences. As far as cycles with donor eggs are concerned, reported evidence is scarce. Our aim in this trial is to determine if ES is useful for those patients undergoing IVF cycles with donor eggs, in order to assure a greater homogeneity in embryo quality and endometrial preparation.

Methods

This single centre randomized controlled trial will include patients undergoing an egg donation cycle, meeting the inclusion criteria and who accept to participate in the study. Once informed consent is signed, patients will be randomly allocated to the study arm (group A) and then receive ES in the luteal phase of the cycle prior to embryo transfer, or the control arm (group B) without any intervention. All cycle data will be collected and analyzed to obtain the clinical pregnancy and the live birth rates in the two groups.

Discussion

Several studies have tried to determine the effectiveness of an ES in IVF cycles, but it is still unclear due to the heterogeneity of these reports. The aim of this study is to determine if there are differences in clinical pregnancy rate and live birth rate in egg donor cycles, when comparing an ES performed in the preceding luteal phase versus no intervention, given that embryo quality and endometrial preparation protocols will be comparable.

Trial registration

Ethical approval of version 2.0 of this trial was obtained on the 13th January 2017. It was retrospectively registered on the 5th April 2017 as the ENDOSCRATCH Trial (NCT03108157) in ClinicalTrials.gov.

Endometrial Scratching Effect on Clinical Pregnancy Rates in Patients Undergoing Egg Donor In Vitro Fertilization Cycles: the ENDOSCRATCH Randomized Clinical Trial (NCT03108157)

The potential benefit of endometrial scratching (ES) on embryo implantation is still a controversial subject. At present, the single retrospective study in egg donor IVF cycles concluded that ES has no beneficial effect. Our objective was to determine if there are differences in clinical pregnancy rates (CPR) in egg donor cycles when an ES is performed. This is a randomized controlled trial (RCT) in egg donor IVF patients conducted at ProcreaTec Fertility Center in Madrid. Three hundred fifty-two patients were included in total. One hundred sixty-one patients completed the protocol in group A and 172 patients in group B. Patients allocated to group A received an ES in the luteal phase of the cycle preceding the embryo transfer cycle. Group B patients did not receive any intervention. Primary outcome of this RCT was CPR. Secondary outcomes were implantation (IR), miscarriage (MR), ongoing pregnancy (OPR), multiple pregnancy (MulPR), and live birth rates (LBR). CPR was 104 of 161 (64.6%) in group A and 102 of 172 (59.3%) in group B (RR 1.09, 95% confidence interval (CI) (0.92-1.29); p = 0.378). OPR, MR, MulPR, and LBR were also comparable. No major complications were detected after ES and pregnancy complications were comparable. Our results show that there is no beneficial role of ES in egg donor IVF cycles, considering these patients as the ideal model as they share homogeneous embryo quality and endometrial preparation protocols. This trial was registered on April 5, 2017, as the ENDOSCRATCH trial (NCT03108157).

Endometrial hyperplasia in infertile women undergoing IVF/ICSI: A retrospective cross-sectional study

OBJECTIVE

To describe the frequency and risk factors of endometrial hyperplasia (EH) in infertile women undergoing their first IVF/ICSI treatment.

METHODS

A total of 3198 infertile women undergoing their first IVF/ICSI cycle were recruited retrospectively from a fertility treatment center. Endometrial scratching and biopsy were conducted before IVF/ICSI treatment. The relationship between EH and clinical characteristics were analyzed.

RESULTS

EH without atypia, atypical hyperplasia, and endometrial cancer (EC) were diagnosed in 94 (2.94%), three (0.093%), and two (0.063%) women, respectively. The frequencies of EH were higher in patients with abnormal uterine bleeding (i.e. menstrual cycle irregularity in terms of frequency, volume, or length; 6.8% vs. 1.6%, P < 0.001, OR = 4.42), obesity (4.1% vs. 2.7%, P = 0.044, OR = 1.55), and elevated fasting glucose (4.6% vs. 2.5%, P = 0.017, OR = 1.85). In the multivariate analyses, all the three factors (abnormal uterine bleeding, obesity, elevated fasting glucose) were independently associated with risk of EH. In the subgroup analysis, among women with abnormal uterine bleeding, the frequency of EH in the elevated fasting glucose group was 10.7%, which was higher than that of the normal fasting glucose group (5.6%), even after adjustment for BMI (P = 0.014, OR = 1.53).

CONCLUSION

The frequency of EH in infertile women undergoing their first IVF/ICSI treatment was approximately 3%. Elevated fasting glucose was an independent risk factor for EH in infertile women undergoing IVF/ICSI.

Intentional endometrial injury increases embryo implantation potentials through enhanced endometrial angiogenesis†

Embryo implantation rates have been found to be enhanced by precedent endometrial injuries, but the underlying mechanism is not fully investigated. Endometrial inflammation occurs both at peri-implantation period and after endometrial injury, in which vascular reaction is a distinctive feature of inflammation. In this study, intentional endometrial injury was done with a 0.7-mm-diameter brush inserted into the left uterine horn of female ICR mice, then turned around 720° (group 2), and the right uterine horn served as the controls without endometrial injuries (group 1). Intraperitoneal equine chorionic gonadotropin 2.5 IU was injected, followed by human chorionic gonadotropin 10 IU injection, and the uterus was dissected 5 days later, roughly at the peri-implantation period. The peri-implantation endometrium was obtained, and angiogenesis protein array revealed that matrix metalloproteinase-3 (MMP-3), plasminogen activator inhibitor-1 (PAI-1), insulin-like growth factor binding protein 1 (IGFBP-1), and IL-1α were more strongly expressed in injured endometrium (group 2) than in the controls (group 1). Immunohistochemical CD34 staining was more prominently expressed in group 2 uterus, and the treatment with LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, significantly decreased CD34 immunopositive cells. The capabilities of permeability, proliferation, tube formation, and migration of mouse endometrial endothelial cells were significantly enhanced in group 2 than in group 1. Our results demonstrate that enhanced endometrial angiogenesis is a possible mechanism accounting for the increased endometrial receptivity after endometrial injury.

The impact of intentional endometrial injury on reproductive outcomes: a systematic review and meta-analysis

BACKGROUND

Endometrial injury is an intentional damage made to the endometrium, usually produced by a Pipelle catheter. Over the last two decades, endometrial injury has been studied to improve implantation rates and decrease the incidence of implantation failure in invitro fertilization (IVF) cycles. Recently, additional studies of endometrial injury, performed not only in patients with implantation failure but also in intrauterine insemination cycles, have been conducted, and the endometrial injury made by hysteroscopy has been researched. The evidence describing the impact of endometrial injury is controversial; therefore, we conducted a systematic review and meta-analysis to examine the issue.

OBJECTIVE AND RATIONALE

Our objective is to review the research that has been done until now and perform a meta-analysis regarding endometrial injury and its influence on implantation success and pregnancy rates in patients with at least one failed IVF cycle. In particular, we aim to study the efficacy of the procedure and look for confounding factors, such as maternal age, in assessing the efficacy of endometrial injury.

SEARCH METHODS

The systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Study protocol can be assessed at PROSPERO International prospective register of systematic reviews (registration number CRD42018092773). Searches were conducted by an experienced research librarian in the following databases: MEDLINE(R) using the OvidSP interface and PUBMED, Embase, Web of Science and Cochrane Library. This review considered for inclusion randomized-controlled trials examining the success of performing local endometrial injury on IVF outcomes in women with previous failed IVF cycles.

OUTCOMES

Ten studies, comprising a total of 1260 patients, were selected. Overall, when studying the effect of endometrial injury on clinical pregnancy rates (CPRs) and live birth rates (LBRs), higher rates were shown in the endometrial injury group. However, endometrial injury did not significantly improve CPRs and LBRs, when considering sub-group analyses of studies including patients with two or more failed IVF cycles, studies examining older patients or studies which did not include hysteroscopy. There was no significant difference found regarding multiple pregnancy rates, while a handful of studies showed an improvement in miscarriage rates.

WIDER IMPLICATIONS

Endometrial injury should be used restrictively and not routinely in clinics. Maternal age and number of previous failed treatment cycles may be contributing factors which can influence the results when studying the effect of endometrial local injury. It is possible that the relative contribution of endometrial receptivity to the chances of implantation decreases with any additional failed cycle. The optimal study to prove the efficacy of local endometrial injury on implantation and pregnancy rates, should be a random-controlled trial studying the effect of local endometrial injury in oocyte donation cycles, in recipients with repeated implantation failure. This kind of study will conclude whether local endometrial injury is an efficient procedure with minimum confounding factors, and may assist in defining the population, even outside of donation cycles, that will benefit from the procedure.

Effect of endometrial injury during menstruation on clinical outcomes in frozen-thawed embryo transfer cycles: A randomized control trial

Aim

To explore the clinical effect of endometrial injury (EI) on the third day of the menstrual cycle before frozen–thawed embryo transfer (frozen–thawed ET) on patients experienced two or more implantation failures.

Methods

A total of 200 patients who suffered at least two failed hormone‐replacement therapies and frozen–thawed ET were randomly divided into two groups: EI group and control group (n = 100 in each group). Patients in the EI group received local EI with a Pipelle catheter on the third day of the menstrual cycle before frozen–thawed ET. Primary outcomes were live birth, clinical pregnancy and implantation rates. Secondary outcomes were biochemical, multiple and ectopic pregnancy rates and abortion rates.

Results

The rate of live birth in EI group (51.00%) was significantly higher than that of control group (36.00%) (P = 0.032). Clinical pregnancy and implantation rates in EI group were significantly higher comparing to control group (64.00% vs 48.00%, P = 0.023 and 46.74% vs 30.11%, P = 0.001). The rate of multiple pregnancy in EI group (37.50%) was significantly higher than that of control group (18.75%) (P = 0.031). No significant difference in ectopic pregnancy rate and abortion rate was observed between EI group and control group.

Conclusion

Applying EI to patients experienced two or more implantation failures on the third day of the menstrual cycle before frozen–thawed ET can improve clinical outcomes.

In vitro fertilization add-ons for the endometrium: it doesn't add-up

The probability of live birth from an in vitro fertilization (IVF) cycle is modest. Many additional treatments (add-ons) are available which promise to improve the success of IVF. This review summarizes the current evidence for common IVF add-ons which are suggested to improve endometrial receptivity. Systematic reviews of randomized controlled trials and individual trials were included. Five add-ons were included: immune therapies, endometrial scratching, endometrial receptivity array, uterine artery vasodilation, and human chorionic gonadotropin instillation. The results suggest there is no robust evidence that these add-ons are effective or safe. Many IVF add-ons are costly, consuming precious resources which may be better spent on evidence-based treatments or further IVF. Large randomized controlled trials and appropriate safety assessment should be mandatory before the introduction of IVF add-ons into routine practice.

Endometrial preparation for third-party parenting and cryopreserved embryo transfer

The advent of third party parenting ushered in the era of artificial stimulation of the endometrium. Initially intended only for patients with ovarian failure, exogenous induction of endometrial receptivity was quickly shown to be as good as natural endometrial preparation, with the advantage that the timing of embryo transfer could be controlled. It is perhaps surprising that even though the ovary produces a variety of steroids, that estradiol (E₂) and progesterone (P) alone would be needed to achieve optimal receptivity; no other substance has ever been shown to improve on the basic regimen of E₂ and P. A variety of routes of administration are available for both E₂ and P and physiologic (or supraphysiologic) serum or endometrial tissue levels of both can be achieved. The optimal duration of E₂ stimulation and the timing of the onset of P administration continue to be debated, but it appears that imitating the sequence that normally occurs in nature leads to optimal results. The poorly responsive endometrium and cases of recurrent implantation failure remain a challenge, but the clear majority of patients can successfully achieve pregnancy as long as embryos of adequate quality are transferred.

Association of IL-1 and TNF-α Levels in Endometrial Secretion and Success of Embryo Transfer in IVF/ICSI Cycles

Background

In this work, we have determined the levels of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-α), which function as cytokines in endometrial receptivity, through the endometrial secretion within the eligible individuals and thus studied their relationships with the success or failure of pregnancy in in vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) cycles.

Materials and Methods

In this prospective study, 76 women were selected for their first IVF/ICSI and met the study inclusion criteria. All of the patients have undergone the endometrial secretion aspiration prior to performing the oocyte collection. The levels of IL-1and TNF-α were analyzed by the means of enzyme-linked immunosorbent assay method, using special standard kits. The patients were requested to undergo the serum human chorionic gonadotropin measurements and ultrasound evaluation for the purpose of detecting successful implantations and pregnancies.

Results

Among the 76 subjects of the study, 33 (43.4%) patients had a positive beta-human chorionic gonadotropin (β-hCG) and 44 (56.6%) resulted in a negative β-hCG. It should be also noted that through the patients with positive β-hCG, 23 (30.3%) of them displayed fetal heart rate in their transvaginal sonography (TVS). Compared to the group with failed pregnancies and their cytokine levels, we perceived a higher concentration of IL-1 in the group containing successful chemical pregnancies (P=0.00). However, there was no significant difference in terms of clinical pregnancy in the IL-1 levels between the two groups (P=0.06). In addition, there was not any notable difference in the levels of TNF-α between the two groups, neither in terms of chemical nor clinical pregnancy (P=0.8 and P=0.6, respectively).

Conclusion

The current study suggests that higher concentrations of IL-1 in endometrial secretions could be as- sociated with improved endometrial receptivity and IVF outcome. With regards to TNF-α, no statistically significant difference was observed between the groups of with and without successful pregnancies.