Does adding endometrial scratching to diagnostic hysteroscopy improve pregnancy rates in women with recurrent in-vitro fertilization failure?

Endometrial scratching during hysteroscopy in women undergoing in vitro fertilization: a systematic review and meta-analysis

Objective

Endometrial scratching (ES) during hysteroscopy before embryotransfer (ET) remains doubtable on whether it benefits the reproductive outcomes. The optimal technique is not clear and repeated implantation failure as a challenging field in in vitro fertilization (IVF) seems to be the springboard for clinicians to test its effectiveness.

Methods

Medline, PMC, ScienceDirect, Scopus, CENTRAL, Google Scholar were searched from their inception up to April 2023 for studies to evaluate the effectiveness of adding endometrial scratching during hysteroscopy before ET.

Results

The initial search yielded 959 references, while 12 eligible studies were included in the analyses, involving 2,213 patients. We found that hysteroscopy and concurrent ES before ET resulted in a statistically significant improvement in clinical pregnancy rate (CPR) [RR = 1.50, (95% CI 1.30-1.74), p < 0.0001] and live birth rate (LBR) [RR = 1.67, (95% CI 1.30-2.15), p < 0.0001] with no statistically significant difference on miscarriage rate [RR = 0.80 (95% CI 0.52-1.22), p = 0.30].

Conclusion

Our meta-analysis suggests that hysteroscopy with concurrent ES may be offered in IVF before ET as a potentially improving manipulation. Future randomized trials comparing different patient groups would also provide more precise data on that issue, to clarify specific criteria in the selection of patients.

Systematic Review Registration

PROSPERO (CRD42023414117).

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.

Emerging trends and frontier research on recurrent implantation failure: a bibliometric analysis

Background

Recurrent implantation failure (RIF) has been recognized to be a major obstacle to the successful application of artificial reproduction technologies. In this study, the trends in RIF research were examined through a bibliometric analysis evaluating relevant literature quantitatively and qualitatively.

Methods

A total of 1,764 publications from 2000 to 2020 were downloaded from the Web of Science Core Collection (WoSCC). Relevant articles were searched using the term "recurrent implantation failure" and other synonyms of this term. Using Excel 2013, CiteSpace V, and VOSviewer 1.6.10 software, data extracted from the literature, including countries/regions, institutions, journals, keywords, and trends, were analyzed. Next, a clustered network was constructed based on 46,718 references cited by the 1,764 publications to determine the top 10 cocited articles.

Results

The annual number of publications on RIF progressively increased over time. The highest number of publications were from the United States. Analysis of the cocited reference cluster showed that "endometrial injury", "platelet-rich plasma", "chronic endometritis" and "extracellular vesicles" were the hotspots in RIF research. Burst detection analysis of the top keywords showed that "hysteroscopy" and "improvement" are emerging research foci.

Conclusions

This study clarifies the current research status and evolution of research in the field of RIF. New therapeutic interventions designed to improve pregnancy outcomes are the focus of current research and are expected to dominate future research in the field of RIF.

Cumulative live birth rates in egg donor IVF cycles with or without endometrial scratching: is there a residual effect in subsequent embryo transfers? Follow-up results of a RCT in clinical practice

INTRODUCTION

Endometrial scratching (ES) is a simple technique that has been claimed to improve pregnancy rates in patients undergoing assisted reproduction techniques. Our objective was to acknowledge the effects of ES in subsequent embryo transfers by assessing the cumulative live birth rates (LBR) in patients undergoing egg-donor in vitro fertilization (IVF).

MATERIAL AND METHODS

We performed a follow-up analysis of the cumulative reproductive outcomes of the 352 patients included in the Endoscratch Trial (NCT03108157) during the twelve months following the randomization date. We compared the outcomes of patients who underwent an ES for the second and/or successive embryo transfers versus those who did not have an ES performed, in order to determine a possible carry over effect that could lead to different LBR in these groups.

RESULTS

Our analysis reveals that both groups (with and without ES performed before the first embryo transfer) had similar cumulative LBR (69.9% vs 65.9% in group A and B respectively, RR: 1.20, 95% confidence interval (CI): 0.92 - 1.22, p= 0.42). When we analyzed the results comparing patients who had received at least an ES before any of the embryo transfers during that period, we did not find any differences in LBR either (68.0% in patients with at least an ES and 67.8% in patients without ES, RR 1.00, 95%CI 0.87 - 1.16, p= 0.96).

CONCLUSION

According to our results, we cannot state that ES has a long term effect on endometrial receptivity of egg recipients as cumulative LBR do not differ from those of patients who do not receive it.

Endometrial injury concurrent with hysteroscopy increases the expression of Leukaemia inhibitory factor: a preliminary study

OBJECTIVE

It is not known by which mechanism endometrial injury increases pregnancy rates. Leukaemia inhibitory factor (LIF) is a cytokine involved in wound healing and implantation. The aim of this study was to determine the change in endometrial LIF mRNA expression before and after mechanical injury during hysteroscopy.

METHODS

Forty patients with a history of two or more unsuccessful implantations who decided to undergo hysteroscopy in the proliferative phase were divided into two equal groups: one with endometrial injury (scratching group) and the other with noninjury (control group). Endometrial sampling was conducted before injury on the patients in the scratching group, and then injury was performed with monopolar needle forceps. Only diagnostic hysteroscopy was performed on the patients in the control group. Endometrial tissues were collected using a Pipelle catheter between Days 20 and 23 of the mid-luteal phase of the next cycles in both the scratching and control groups. Endometrial LIF mRNA expression was evaluated with the use of reverse-transcription polymerase chain reactions.

RESULTS

Relative changes in mRNA expression levels of the LIF gene in endometrial samples taken before and after injury were calculated using the 2-ΔΔCt method, and the fold changes obtained were compared between and within the groups. Compared with preinjury values, an 11.1-fold increase was found in postinjury LIF mRNA expression in patients with monopolar forceps injury (p < 0.001). There was a 3.9-fold significant increase in postinjury LIF mRNA levels compared with those in the control group (p < 0.02).

CONCLUSIONS

The fertility-promoting effect of hysteroscopy-guided mechanical endometrial injury may be mediated by LIF mRNA.

The effect of endometrial scratch on pregnancy outcomes of frozen-thawed embryo transfer: a propensity score-matched study

AIMS

To study the effect of endometrial scratch (ES) performed on Days 2 to 5 of the menstrual cycle on pregnancy outcomes of frozen-thawed embryo transfer (FET).

MATERIALS AND METHODS

We conducted a retrospective study including 5769 women undergoing FET from January 2018 to August 2019. The endometrial scratching group (group ES) consisted of 827 patients and the control group (group non-ES) comprised 4942 patients. A propensity score matching (PSM) method using the nearest neighbor matching at a proportion of 1:1 was performed. Subsequently, we compared the pregnancy outcomes of each group after PSM.

RESULTS

After PSM, there were significant differences in implantation (36.1% vs. 47.0%, p = .005), clinical pregnancy (45.4% vs. 58.3%, p = .007), and live birth (33.5% vs. 47.2%, p = .003) rates in matched patients with two previous implantation failures. In the matched patients with at least three previous implantation failures, we also detected increase rates of implantation (31.0% versus 40.1%, p = .028), clinical pregnancy (39.8% versus 57.0%, p = .019), live birth (32.3% versus 47.3%, p = .036). In contrast, no significant difference in pregnancy outcomes was found in women with no previous implantation failure or only one failure.

CONCLUSIONS

Endometrial scratch on day 2 to day 5 of the menstrual cycle in women with at least two previous implantation failures who underwent FET increased their implantation, clinical pregnancy, and live birth rates, and did not increase miscarriage or ectopic pregnancy rates compared to the non-ES group.

Association between Endometrial Polyps and Chronic Endometritis: Is It Time for a Paradigm Shift in the Pathophysiology of Endometrial Polyps in Pre-Menopausal Women? Results of a Systematic Review and Meta-Analysis

BACKGROUND

Chronic endometritis (CE) and endometrial polyps (EPs) are common conditions in reproductive age women. CE is an infectious disorder of the endometrium characterized by signs of chronic inflammation at hysteroscopic and histological analyses. EPs are abnormal endometrial growths containing glands, stroma and blood vessels projecting from the lining of the uterus. During the last years, different authors have investigated the correlation between CE and EPs, with controversial results. The aim of this study was to summarize available evidence on the potential correlation between CE and EPs.

DESIGN

Systematic literature review and meta-analysis.

METHODS

Observational-studies were identified by searching electronic databases from their inception to September 2021. Only studies on pre-menopausal women were included. Statistical analysis was performed using MedCalc 16.4.3 (Ostend, Belgium) and Review Manager version 5.3 (Nordic Cochrane Centre, Cochrane Collaboration). The summary measures were reported as pooled proportion or odds ratio (OR) with 95% confidence interval (CI). The primary outcome was to evaluate the prevalence of CE in women with EPs. The secondary outcome was to determine the prevalence of CD-138-positive EPs among EPs. Tertiary outcomes were to compare the prevalence of CE in women with EPs versus women with a non-polypoid endometrium and to compare the prevalence of CE in women with a single EP versus women with multiple EPs.

RESULTS

Eight observational studies (n = 3225 patients) were included in quantitative synthesis. Pooled prevalence of CE among women with EPs was 51.35% (95% CI, 27.24-75.13%). Pooled proportion of CD-138-positive EPs among EPs was 70.73% (95% CI, 55.73-83.68%). Women with EPs showed higher prevalence of CE compared to women without EPs (OR 3.07, 95% CI 1.59-5.95). Women with ≥3 EPs had higher prevalence of CE then women with a single EP (OR 3.43, 95% CI 1.83-6.46).

CONCLUSIONS

In pre-menopausal women, CE and EPs may have a dependent relationship and may represent two consequent steps of a common pathological process.

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.

Endometrial scratching for poor responders based on the Bologna criteria in ICSI fresh embryo transfer cycles: a preliminary retrospective cohort study

Objective

This study evaluated the effect of endometrial injury on pregnancy outcomes in patients with a poor ovarian response (POR), based on the Bologna criteria, who underwent intracytoplasmic sperm injection (ICSI) cycles.

Material and Methods

Sixty-eight patients were enrolled in this retrospective cohort study. All patients in the endometrial scratching group (group 1, n=32) and control group (group 2, n=36) underwent office hysteroscopy in the early follicular phase of the cycle before controlled ovarian stimulation. Group 1 also underwent endometrial scratching. The main outcome measure was the ongoing pregnancy rate.

Results

The study groups had similar baseline demographics, including age, body mass index, duration of infertility, number of ICSI cycles, and hormone levels. However, the antral follicle count was significantly higher in group 1 than in group 2 (4.2±1.9 vs 3.3±1.8; p<0.05). There were no significant group differences in ovarian stimulation characteristics (ovarian stimulation time, trigger day endometrial thickness, number of metaphase II oocytes), number of embryos transferred, or the ratio of embryo transfer on days 3 and 5. Moreover, there were no significant differences between groups 1 and 2 in the rates of chemical pregnancy (25% vs 19.4%), clinical pregnancy (15.6% vs 11.1%) or ongoing pregnancy (9.4% vs 8.3%) (p>0.05 for all).

Conclusion

Endometrial scratching did not improve pregnancy outcomes for patients meeting the Bologna criteria for a POR to ICSI cycles using fresh embryo transfer and the GnRH antagonist protocol.

Efficacy of therapies and interventions for repeated embryo implantation failure: a systematic review and meta-analysis

The aim of the present systematic review and meta-analysis was to assess the effect of the different therapeutic options for repeated embryo implantation failure (RIF) on a subsequent IVF cycle outcome. Twenty-two RCTs and nineteen observational studies were included. Pooling of results showed a beneficial effect of intrauterine PBMC infusion on both CPR (RR 2.18; 95% CI 1.58-3.00; p < 0.00001; OR 2.03; 95% CI 1.22-3.36; p = 0.006) and LBR (RR 2.41; 95% CI 1.40-4.16; p = 0.002; OR 3.73; 95% CI 1.13-12.29; p = 0.03), of subcutaneous G-CSF administration on CPR (RR 2.29; 95% CI 1.58-3.31; p < 0.0001) and of intrauterine PRP infusion on CPR (RR 2.45; 95% CI 1.55-3.86; p = 0.0001). Observational studies also demonstrated a positive effect of IVIG and intrauterine hCG infusion on both CPR and LBR and of atosiban on CPR. Studies investigating intrauterine G-CSF infusion, LMWH, intravenous intralipid, hysteroscopy, blastocyst-stage ET, ZIFT, PGT-A and AH failed to observe an impact on IVF outcome. The quality of the evidence that emerged from RCTs focused on intrauterine PBMC infusion and subcutaneous G-CSF administration was moderate. For all other therapies/interventions it varied from low to very low. In conclusion, intrauterine PBMC infusion and subcutaneous G-CSF administration are the most promising therapeutic options for RIF. However, further well conducted RCTs are necessary before their introduction into clinical practice.

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).

Effect of hysteroscopy before starting in-vitro fertilization for women with recurrent implantation failure: A meta-analysis and systematic review

OBJECTIVE

To study if hysteroscopy (HSC) before starting an in-vitro fertilization (IVF) cycle improves IVF outcomes in women with recurrent implantation failure (RIF).

METHODS

The Medline, Cochrane, EMBASE, and Google Scholar databases were searched using the following keywords until March 31, 2017: in-vitro fertilization; infertility; hysteroscopy; recurrence; embryo implantation; and pregnancy. Randomized controlled trials (RCTs), two-arm prospective studies, and retrospective studies were included.

RESULTS

Three RCTs, 3 nonrandomized prospective studies, and 2 retrospective cohort studies were included. The eligible studies included 3932 women with RIF: 1841 in the HSC group and 2091 in the control group. The clinical pregnancy rate and implantation rate was significantly higher in the HSC group compared with the control group (for clinical pregnancy rate, pooled odds ratio [OR] = 1.64, 95% confidence intervals [CI]: 1.30-2.07, P < 0.001; for implantation rate, pooled OR = 1.22, 95% CI: 1.02-1.45, P = 0.025). The live birth rate (pooled OR = 1.30, 95% CI: 0.90-1.88, P = 0.168) and the miscarriage rate (pooled OR = 0.94, 95% CI: 0.66-1.35, P = 0.744) of the 2 groups were not statistically significantly.

CONCLUSIONS

HSC improved the implantation rate and clinical pregnancy rates, but failed to improve live birth rate and did not affect the miscarriage rate in women with RIF undergoing IVF. Since HSC plays a significant role in pregnancy and birth outcomes of women with RIF, further studies are warranted.

Hysteroscopy after repeated implantation failure of assisted reproductive technology: A meta-analysis

We conducted this meta-analysis to explore the prognostic value of outpatient (or office) hysteroscopy (OH) preceding in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles in women who had experienced repeated implantation failure (RIF), particularly in regard to the conflicting evidence reported by previous studies. Two reviewers independently searched Pubmed, MEDLINE, Web of Science, Cochrane Library and Embase to identify all publications of clinical trials of hysteroscopy with or without endometrial biopsy in RIF patients. The primary outcome measures were clinical pregnancy rate (CPR) and live birth rate (LBR). Pooled relative ratios (RRs) with 95% confidence intervals (CIs) were calculated. Publication bias was detected using funnel plots and Egger's regression tests. Six eligible studies comprising 4143 patients were included. The CPR and LBR were both significantly higher in RIF patients with OH than RIF patients without OH (CPR: RR 1.34, 95% CI 1.14-1.57, P < 0.05; LBR: RR 1.29, 95% CI 1.03-1.62, P < 0.05). Subgroup analysis revealed a significant association between OH and CPR in Asia (CPR: RR 1.49, 95% CI 1.31-1.69; P < 0.05) rather than in Europe (CPR: RR 1.08, 95% CI 0.93-1.26; P = 0.291). However, there was no evidence of a significant difference in either CPR or LBR between the normal and abnormal OH groups (CPR: RR 0.92, 95% CI 0.83-1.02, P = 0.12; LBR: RR 0.76, 95% CI 0.37-1.56, P = 0.450). Hysteroscopy may potentially improve pregnancy outcomes in patients with RIP.