Does the timing of mock embryo transfer trial improve implantation in intracytoplasmic sperm injection cycles?

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.

A randomised controlled trial to assess the clinical effectiveness and safety of the endometrial scratch procedure prior to first-time IVF, with or without ICSI

STUDY QUESTION

What is the clinical-effectiveness and safety of the endometrial scratch (ES) procedure compared to no ES, prior to usual first time in vitro fertilisation (IVF) treatment?

SUMMARY ANSWER

ES was safe but did not improve pregnancy outcomes when performed in the mid-luteal phase prior to the first IVF cycle, with or without intracytoplasmic sperm injection (ICSI).

WHAT IS KNOWN ALREADY

ES is an ‘add-on’ treatment that is available to women undergoing a first cycle of IVF, with or without ICSI, despite a lack of evidence to support its use.

STUDY DESIGN, SIZE, DURATION

This pragmatic, superiority, open-label, multi-centre, parallel-group randomised controlled trial involving 1048 women assessed the clinical effectiveness and safety of the ES procedure prior to first time IVF, with or without ICSI, between July 2016 and October 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants aged 18–37 years undergoing their first cycle of IVF, with or without ICSI, were recruited from 16 UK fertility clinics and randomised (1:1) by a web-based system with restricted access rights that concealed allocation. Stratified block randomisation was used to allocate participants to TAU or ES in the mid-luteal phase followed by usual IVF with or without ICSI treatment. The primary outcome was live birth after completing 24 weeks gestation within 10.5 months of egg collection.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 1048 women randomised to TAU (n = 525) and ES (n = 523) were available for intention to treat analysis. In the ES group, 453 (86.6%) received the ES procedure. IVF, with or without ICSI, was received in 494 (94.1%) and 497 (95.0%) of ES and TAU participants respectively. Live birth rate was 37.1% (195/525) in the TAU and 38.6% (202/523) in the ES: an unadjusted absolute difference of 1.5% (95% CI −4.4% to 7.4%, P = 0.621). There were no statistical differences in secondary outcomes. Adverse events were comparable across groups.

LIMITATIONS, REASONS FOR CAUTION

A sham ES procedure was not undertaken in the control group, however, we do not believe this would have influenced the results as objective fertility outcomes were used.

WIDER IMPLICATIONS OF THE FINDINGS

This is the largest trial that is adequately powered to assess the impact of ES on women undergoing their first cycle of IVF. ES was safe, but did not significantly improve pregnancy outcomes when performed in the mid-luteal phase prior to the first IVF or ICSI cycle. We recommend that ES is not undertaken in this population.

STUDY FUNDING/COMPETING INTEREST(S)

Funded by the National Institute of Health Research. Stephen Walters is an National Institute for Health Research (NIHR) Senior Investigator (2018 to present) and was a member of the following during the project: National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Clinical Trials and Evaluation Committee (2011–2017), NIHR HTA Commissioning Strategy Group (2012 to 2017); NIHR Programme Grants for Applied Research Committee (2020 to present); NIHR Pre doctoral Fellowship Committee (2019 to present). Dr. Martins da Silva reports grants from AstraZeneca, during the conduct of the study; and is Associate editor of Human Reproduction and Editorial Board member of Reproduction and Fertility. Dr. Bhide reports grants from Bart's Charity and grants and non-financial support from Pharmasure Pharmaceuticals outside the submitted work.

TRIAL REGISTRATION NUMBER

ISRCTN number: ISRCTN23800982.

TRIAL REGISTRATION DATE

31 May 2016

DATE OF FIRST PATIENT’S ENROLMENT

04 July 2016

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 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.

Endometrial injury in women undergoing assisted reproductive techniques

BACKGROUND

Implantation of an embryo within the endometrial cavity is a critical step in assisted reproductive techniques (ART). Previous research has suggested that endometrial injury - intentional damage to the endometrium - can increase the probability of pregnancy in women undergoing ART.

OBJECTIVES

To assess the effectiveness and safety of endometrial injury performed before embryo transfer in women undergoing ART.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), the Database of Abstracts of Reviews of Effects (DARE), MEDLINE, EMBASE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Latin American Caribbean Health Sciences Literature (LILACS) and ClinicalTrials.gov. The original search was performed in November 2011, and further searches were done in March 2014 and January 2015.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Two independent review authors screened studies and extracted data which were checked by a third review author. Two review authors independently assessed risk of bias. We contacted and corresponded with study investigators as required and analysed data using risk ratio (RR) and a random-effects model. We assessed the quality of the evidence by using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) criteria.

MAIN RESULTS

We included 14 trials that included 1063 women in the intervention groups and 1065 women in the control groups. Thirteen studies compared endometrial injury performed between day 7 of the previous cycle and day 7 of the embryo transfer (ET) cycle versus no injury, and one study compared endometrial injury on the day of oocyte retrieval versus no injury. Overall, eight of the 14 included studies were deemed to be at high risk of bias in at least one domain.In studies comparing endometrial injury performed between day 7 of the previous cycle and day 7 of the ET cycle versus no intervention or a sham procedure, endometrial injury was associated with an increase in live birth or ongoing pregnancy rate: RR 1.42, 95% confidence interval (CI) 1.08 to 1.85; P value 0.01; nine RCTs; 1496 women; I² = 53%; moderate-quality evidence. In other words, moderate-quality evidence suggests that if 26% of women achieve live birth without endometrial injury, between 28% and 48% will achieve live birth with endometrial injury. A sensitivity analysis removing the studies at high risk of bias showed no difference in effect.There was no evidence of an effect on miscarriage, however the evidence is of low-quality: RR 0.99, 95% CI 0.63 to 1.53; P value 0.06; eight RCTs; 500 clinical pregnancies; I² = 10%; low-quality evidence.Endometrial injury was also associated with an increased clinical pregnancy rate: RR 1.34, 95% CI 1.21 to 1.61; P value 0.002; 13 RCTs; 1972 women; I² = 45%; moderate-quality evidence. This suggests that if 30% of women achieve clinical pregnancy without endometrial injury, between 33% and 48% will achieve clinical pregnancy with this intervention.Endometrial injury was associated with increased pain, however the evidence was of very low quality. One study reported pain on a VAS scale: MD 4.60, 95% CI 3.98 to 5.22; P value < 0.00001; one RCT; 158 women. Two studies reported the number of pain complaints after the procedure; one recorded no events in either group, and the other reported that endometrial injury increased pain complaints: OR 8.65, 95% CI 2.49 to 30.10; P value 0.0007; one RCT; 101 women.Results from the only randomised controlled trial (RCT) comparing endometrial injury on the day of oocyte retrieval versus no injury, reported that this endometrial injury markedly decreased live birth (RR 0.31, 95% CI 0.14 to 0.69; P value 0.004; 156 women; low-quality evidence) and clinical pregnancy (RR 0.36, 95% CI 0.18 to 0.71; P value 0.003; one RCT; 156 women; low-quality evidence).

AUTHORS' CONCLUSIONS

Moderate-quality evidence indicates that endometrial injury performed between day 7 of the previous cycle and day 7 of the embryo transfer (ET) cycle is associated with an improvement in live birth and clinical pregnancy rates in women with more than two previous embryo transfers. There is no evidence of an effect on miscarriage, multiple pregnancy or bleeding. The procedure is mildly painful. Endometrial injury on the day of oocyte retrieval is associated with a reduction of clinical and ongoing pregnancy rates.Although current evidence suggests some benefit of endometrial injury, we need evidence from well-designed trials that avoid instrumentation of the uterus in the preceding three months, do not cause endometrial damage in the control group, stratify the results for women with and without recurrent implantation failure (RIF) and report live birth.

Endometrial injury in women undergoing assisted reproductive techniques

BACKGROUND

Implantation of an embryo within the endometrial cavity is a key step in assisted reproductive techniques (ART). It has been suggested that intentional endometrial injury, such as endometrial biopsy or curettage, prior to embryo transfer improves the chances of implantation and further development thereby increasing the likelihood of live birth. The effectiveness and safety of this procedure is, however, still unclear.

OBJECTIVES

To assess the effectiveness and safety of endometrial injury performed prior to embryo transfer in women undergoing ART.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), DARE, MEDLINE, EMBASE, CINAHL, LILACS, and ClinicalTrials.gov. The final search was performed in November 2011.

SELECTION CRITERIA

Randomised controlled trials comparing any kind of intentional endometrial injury prior to embryo transfer in women undergoing ART with no intervention or with a simulated (mock) procedure that could not cause endometrial injury.

DATA COLLECTION AND ANALYSIS

Data were extracted by one author and checked by a second. Assessment of the risk of bias was performed independently by two authors. We contacted and corresponded with study investigators as required. Data were analysed using Peto odds ratio (OR) and a fixed-effect model.

MAIN RESULTS

A total of 591 women from five trials were included. Clinical pregnancy was reported by all five studies and the combined analysis for clinical pregnancy per woman showed substantial heterogeneity (I(2) = 95.9%). We therefore conducted a planned subgroup analysis including four trials in the subgroup 'injury in the previous cycle' and one trial in the subgroup 'injury on the day of oocyte retrieval'. In the subgroup 'injury in the previous cycle' the procedure was performed within one month before starting ovulation induction in all four trials. This intervention resulted in a significant increase in the odds of live birth (2 trials, Peto OR 2.46; 95% CI 1.28 to 4.72; I(2) = 0%) and clinical pregnancy (4 trials, Peto OR 2.61; 95% CI 1.71 to 3.97; I(2) = 0%). The odds of miscarriage per clinical pregnancy (1 trial, Peto OR 1.13; 95% CI 0.17 to 7.45) and multiple pregnancy per clinical pregnancy (1 trial, Peto OR 0.87; 95% CI 0.23 to 3.30) were very imprecise, limiting any meaningful conclusion. No study reported pain or bleeding. In the subgroup 'injury on the day of oocyte retrieval', the intervention resulted in a significant reduction in the odds of clinical pregnancy (1 trial, Peto OR 0.30; 95% CI 0.14 to 0.63) and ongoing pregnancy (1 trial, Peto OR 0.28; 95% CI 0.13 to 0.61). The single trial in this subgroup did not report any adverse effect outcomes.

AUTHORS' CONCLUSIONS

Endometrial injury performed prior to the embryo transfer cycle improves clinical pregnancy and live birth rates in women undergoing ART. It is advisable not to perform endometrial injury on the day of oocyte retrieval because it appears to significantly reduce clinical and ongoing pregnancy rates. There is insufficient evidence regarding the effect of endometrial injury on multiple pregnancy or miscarriage and none on adverse events such as pain and bleeding.