Embryo transfer: factors involved in optimizing the success

Steps forward in embryo transfer technique: a retrospective study comparing direct versus afterload catheters at different time frames

PURPOSE

To assess whether embryo transfer (ET) technique can influence the clinical pregnancy rate (CPR) and its correlation with the embryo transfer difficulty.

DESIGN

This single center retrospective cohort analysis of fresh and frozen single blastocyst transfers performed between January 2016 and December 2021 included fresh and frozen single blastocyst transfers performed during the study timeframe. Direct technique was the only one used from January 2016 to September 2017. From September 2017 to March 2019, the choice between the two techniques was given by randomization, due to a clinical trial recruitment. From April 2019, only the afterload technique was used. Preimplantation genetic testing cycles and gamete donation procedures and cycles performed with external gametes or embryos were excluded. CPR was the primary outcome, while difficult transfer rate the secondary one. Univariate and multivariate logistic regressions were performed.

RESULTS

During the period, 8,189 transfers were performed. CPR of the afterload group resulted significantly higher compared to the direct group (44.69% versus 41.65%, OR 1.13, 95% CI 1.02-1.25, p = 0.017) and the rate of difficult transfers two-thirds lower (9.06% versus 26.85%, OR 0.27, 95% CI 0.24-0.31, p < 0.001).

CONCLUSION

Our study demonstrated that CPR is significantly affected by the ET technique. In particular, with the afterload protocol, both CPR and easy transfer rates increased.

TRIAL REGISTRATION

http://clinicaltrials.gov registration number: NCT05364528, retrospectively registered on 3rd of May 2022.

Simulation-based training for embryo transfer for clinicians with differing levels of expertise: an application of the American Society for Reproductive Medicine Embryo Transfer Simulator

Objective

To compare the learning curve of clinicians with different levels of embryo transfer (ET) experience using the American Society for Reproductive Medicine (ASRM) Embryo Transfer Simulator.

Design

Prospective cohort study.

Setting

Single large university-affiliated in vitro fertilization center.

Patients

Participants with 3 levels of expertise with ET were recruited: "group 1" (Reproductive Endocrinology and Infertility attendings), "group 2" (Reproductive Endocrinology and Infertility nurses, advance practice providers, or medical assistants), and "group 3" (Obstetrics and Gynecology resident physicians).

Interventions

All participants completed ET simulation training using uterine cases A, B, and C (easiest to most difficult) of the ASRM ET Simulator. Participants completed each case 5 times for a total of 15 repetitions.

Main Outcome Measures

The primary outcome was ET simulation scores analyzed at each attempt for each uterine case, with a maximum score of 155. Secondary outcomes included self-assessed comfort levels before and after the completion of the simulation and total duration of ET. Comfort was assessed using a 5-point Likert scale.

Results

Twenty-seven participants with 3 different levels of expertise with ET were recruited from December 2020 to February 2021. For cases A and B, median total scores were not significantly different between groups 1 and 3 at first or last attempts. Group 2 did not perform as well as group 3 at the beginning of case A or group 1 at the end of case B. All groups demonstrated a decrease in total time from the first attempt to the last attempt for both cases. For case C, the "difficult" uterus, groups 2 and 3 exhibited the greatest improvement in total median score: from 0 to 75 from the first to last attempt. Group 1 scored equally well from first through last attempts. Although no one from group 2 or 3 achieved a passing score with the first attempt (80% of the max score), approximately 30% had passing scores at the last attempt. Groups 1 and 3 showed a significant decrease in total time across attempts for case C. Following simulation, 100% of groups 2 and 3 reported perceived improvement in their skills. Group 3 showed significant improvement in comfort scores with Likert scores of 1.71 ± 0.76 and 1.0 ± 0.0 for the "Easy" and "Difficult" cases, respectively, before simulation and 4.57 ± 0.53 and 2.4 ± 1.1 after simulation.

Conclusions

The ASRM ET Simulator was effective in improving both technical skill and comfort level, particularly for those with little to no ET experience and was most marked when training on a difficult clinical case.

Clinical aspects of oocyte retrieval and embryo transfer. Tips and tricks for the novice and experts

Oocyte retrieval (ovum pick-up) and embryo transfer (ET) are essential steps in IVF and ICSI and over the years, the two procedures were developed in order to improve the clinical outcome. Many suggestions were proposed and applied before, during and after oocyte retrieval such as timing of HCG trigger, pre-operative pelvic scan, vaginal cleansing, type of anesthesia, type and gauge of aspiration needles, aspiration pressure, follicle flushing, and the need for prophylactic antibiotics. Similarly, many steps were suggested and implemented before, during and after ET including patient's position, type of anesthesia/analgesia, dummy (mock) ET, ultrasound-guidance, HCG injection in the uterine cavity, use of relaxing agents, full bladder, removal of the cervical mucus, flushing the cervix with culture medium, type of ET catheter, embryo loading techniques, site of embryo deposition, the use of adherence compounds, as well as bed rest after ET. Complications were also reported with oocyte retrieval and ET. The aim of this review is to evaluate the current practice of these two procedures in the light of available evidence.

The association between level of physical activity and pregnancy rate after embryo transfer: a prospective study

RESEARCH QUESTION

Is physical activity after embryo transfer, as assessed by a smart band activity tracker, associated with decreased pregnancy rates?

DESIGN

Prospective observational cohort study comprising infertile women aged < 38 years, who had undergone fewer than three previous embryo transfers, achieved a good ovarian response and were undergoing frozen-thawed embryo transfer in a tertiary-referral centre. A validated smart band activity tracker was used to assess physical activity level immediately after the embryo transfer and until the pregnancy test. No specific recommendations were given to participants on level or intensity of physical activity. Physicians and patients were blinded to the data stored in the pedometer. Primary outcome was ongoing pregnancy rate.

RESULTS

Fifty women met the inclusion criteria. Ongoing pregnancy rate was 30%. In a pooled analysis, participants walked significantly fewer steps per day on the day of embryo transfer compared with the first 2 days after embryo transfer (4075, interquatile range [IQR] 2932-5592 versus 5204, IQR4203-8584, P = 0.01). No significant difference was observed between pregnant women and non-pregnant women in the median steps per day after embryo transfer until serum beta-HCG was measured (7569, IQR 6008-10884 versus 6572.5, IQR 5299-8786, P = 0.43). No significant difference was observed in the median number of steps on the day of embryo transfer or the first 2 days after embryo transfer between pregnant and non-pregnant women.

CONCLUSIONS

A quantitative objective assessment of the association between physical activity and pregnancy rates after frozen-thawed embryo transfer was conducted. Ambulation after embryo transfer has no adverse effect on pregnancy rates and, therefore, women should resume regular activity immediately after embryo transfer.

A New Concept in Minimally Invasive Embryo Transfer

Considerable variation in embryo transfer (ET) catheter types, diverging opinions on their quality and functionality, complications following the insertion of catheters, low efficiency of the application of ET methods in humans, and their widely varying efficiency in animals demonstrate the need to improve ET methods and to look for new types of catheters. Such an opportunity is offered by the introduction of catheters made of new-generation biomaterials. This study was aimed to introduce a new generation of biomaterials into reproductive biotechnology. New-generation materials were compared with materials that have been used for many years, and the functionality of newly produced catheters was compared in vivo. Five types of biomaterials were tested: polycaprolactone (PCL), dibutyryl chitin (DBC), polypropylene (PP), polyethylene (PE) and polylactide (PLA). The study was carried out in two stages. Firstly, the basic utility parameters such as geometric stability, surface structure and catheter resistance were evaluated. Subsequently, the biocompatibility of selected biomaterials in embryo cultures was examined, and the development potential of the obtained blastocysts was evaluated. In the second stage, in vivo with live animals, the biomaterials were tested for biocompatibility and the obtained catheters were examined for their ET functionality. Efficiency with the use of the newly produced catheters was determined, the quality of the blastocysts obtained after embryo culture in the uterus was assessed, and oviducts were subjected to histopathological examination after embryo transfer. Of the tested biomaterials, only polyethylene (PE) showed adequate biological and material properties and proved suitable for production of ET catheters.

Effect of embryo transfer depth on IVF/ICSI outcomes: A randomized clinical trial

Background

Although there has been remarkable advancement in the field of assisted reproductive technology, implantation failure remains a significant issue in most infertile couples receiving these treatments. Embryo transfer is important in assisted reproductive technology and directly affects the implantation rates and pregnancy outcomes.

Objective

To assess the effect of two different distance embryo transfer sites from fundal endometrial surface on the outcomes of in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles.

Materials and Methods

A total of 180 women who were candidate for IVF/ ICSI/ embryo transfer in Yazd Research and Clinical Center for Infertility were equally assigned to two groups based on the distance between the fundal endometrial surface and catheter tip to investigate implantation, chemical and clinical pregnancy (group A: 15 ± 5 mm and group B: 25 ± 5 mm, respectively).

Results

The subjects in the group B showed significantly higher implantation rate, chemical and clinical pregnancy rate compared to the group A (p = 0.03, 0.01, 0.04, respectively). The rate of ongoing pregnancy and miscarriage indicated no significant differences between groups (p = 0.21, 0.27, respectively).

Conclusion

In conclusion, our study showed that the depth of embryo replacement inside the uterine cavity at a distance of 25 ± 5 mm beneath fundal endometrial surface have better effects on the pregnancy outcomes of IVF/ICSI cycles and can be considered as an important factor to improve the success of IVF cycles.

Does the Time of Starting Progesterone Luteal Support Affect Embryo Transfer in Long Agonist Protocol Downregulated ICSI Cycles? A Randomized Controlled Trial

The aim of this study was to compare the effects of starting progesterone (P4) luteal support (LS) on day of egg retrieval (ER) or day of embryo transfer (ET) on the ratio of difficult ET and cycle outcome. This was a RCT ( ClinicalTrials.gov Identifier: NCT03040830) carried out at Mansoura Integrated Fertility Center (MIFC), Mansoura, Egypt, from November 2015 to January 2017. A total of 171 eligible long agonist ICSI cases were randomly allocated on day of ER into group A (86) starting LS as daily IM 100 mg P4 on day of ER and group B (85) starting P4-LS on day of ET. Difficult ET was defined as blood on ET catheter and/or sounding or dilating the cervix. Primary outcome was the overall ratio of difficult ET and ratios on day 3 and 5 ET. Secondary outcome was the ongoing pregnancy rate (OPR) and implantation rate (IR). The results are presented as % for groups A and B respectively: overall difficult ET (44.1, 24.7) (p = 0.009); day 3 difficult ET (23.2, 24.4) (p = 0.45); day 5 difficult ET (62.7, 25.6) (p = 0.001); overall OPR (38.3, 44.7) (p = 0.43); day 3 ET OPR (41.8, 33.3) (p = 0.51); day 5 ET OPR (34.8, 57.5) (p = 0.048); overall IR (20.0, 22.5) (p = 0.62); day 3 ET IR (17.8, 13.4) (p = 0.44); day 5 ET IR (22, 34.1) (p = 0.09). In conclusion, starting P4 luteal support on egg retrieval day is associated with significantly higher ratio of difficult embryo transfer and lower ongoing pregnancy rate and tendency to lower IR in day 5 ET, so starting P4-LS on day of ET is recommended.

Does nifedipine improve outcomes of embryo transfer?: Interim analysis of a randomized, double blinded, placebo-controlled trial

BACKGROUND

Implantation failure is the main factor affecting the success rate of in vitro fertilization (IVF) procedures. Studies have reported that uterine contractions (UC) at the time of embryo transfer (ET) were inversely related to implantation and pregnancy rate, hence reducing the success of IVF treatments. Various pharmacological agents, with the exception of calcium channel blockers, have been investigated to improve ET outcomes by reducing UC. Thus, a double-blinded randomized, placebo-controlled trial was conducted to determine whether nifedipine, a calcium channel blocker with potent smooth muscle relaxing activity and an excellent safety profile, can improve the outcome of patients undergoing ET treatments.

METHODS

Ninety-three infertile women were recruited into 1 of 2 groups: placebo (n = 47) or nifedipine 20 mg (n = 46). Study participants were admitted 30 minutes prior to ET and given either tablet after their baseline vital signs were recorded. They then underwent ET and were observed for adverse events for another 30 minutes post-ET. Follow up of the participants' outcomes was conducted via electronic medical records. The primary outcomes are implantation and clinical pregnancy rates. Secondary outcomes include any maternal or fetal adverse events, miscarriage, pregnancy, live births, and neonatal outcomes. Resulting data were then analyzed using t test, Pearson chi-square test, and Fisher exact test to compare outcomes between the 2 groups.

RESULTS

No statistical differences in the implantation rate (42.6% vs 39.1%, P = .737, rate ratio 0.868, 95% confidence interval [CI]: 0.379-1.986) and the clinical pregnancy rate (23.4% vs 26.1%, P = .764, rate ratio 1.155, 95% CI: 0.450-2.966) were detected between the placebo and the treatment groups. In addition, no statistical significance between the placebo and the treatment groups for any secondary outcomes were detected.

CONCLUSIONS

This double blinded, randomized, and placebo-controlled trial demonstrated that the single use of 20 mg nifedipine given 30 minutes before embryo transfer did not improve the implantation rate or the clinical pregnancy rate of the infertility treatment. Further studies are required to demonstrate the clinical benefits and risks of nifedipine usage in embryo transfer.

Numerical simulation of embryo transfer: how the viscosity of transferred medium affects the transport of embryos

Background

Embryo transfer (ET) is a key step of assisted reproductive procedures, where the transferred medium containing the embryos is injected into the uterine cavity through a transcervical catheter and blended with intrauterine fluid in the uterine cavity. This procedure determines the delivery sites of embryos in the uterine cavity and has crucial impact on the implantation. Due to practical restrictions and ethical issues, it is often difficult to perform an in vivo study in humans to examine factors that affect the motions and delivery of embryos during ET. Alternatively, mathematical modeling is a powerful tool to that end.

Results

A computational model is developed to simulate the intrauterine mixing flow and track the embryo motions. Two important factors affecting the intrauterine flow are studied via this model: the viscosity of the transferred medium and the injection speed. Numerical results show that the dispersion pattern and the final delivery sites of the embryos are significantly influenced by the viscosity of the transferred medium. Specially, increasing the transferred medium viscosity close to that of the uterine fluid can enhance the probability that the embryos are delivered close to the fundus and keep them from being dragged backward to the cervix during catheter withdrawal. In addition, a slow injection speed can lower the driving force on the embryo during ET, which can prevent the embryo from being injured.

Conclusions

Based on our study, the practice of using a transferred medium with similar viscosity to that of the uterine fluid and a slow injection speed is recommended for real embryo transfer procedures in clinic.

Prospective Randomized Trial Comparing Embryo Transfers of Cases with and without Catheter Rotation during Its Withdrawal

OBJECTIVE

To compare embryo transfer (ET) technique based on catheter rotation during its withdrawal in cases with unexplained infertility in a prospective, randomized trial (NCT03097042).

METHODS

Two hundred intracytoplasmic sperm injection (ICSI) patients undergoing ET with cleaving or blastocyst-stage fresh embryos were randomized into 2 groups: cases with (n = 100), and without (n = 100) catheter rotation during its withdrawal. Groups were matched for age and some clinical parameters. A soft catheter was used to transfer a single embryo with catheter rotation during its withdrawal in the study group and without rotation in the control. The use of a stiff catheter or tenaculum was not needed in any case. Groups were compared in terms of cycle characteristics and clinical pregnancy rates.

RESULTS

Pregnancy rate was significantly higher in the study group (41 vs. 26%, p = 0.04). Clinical pregnancy rate was also significantly higher in the study group (39 vs. 25%, OR 1.9 [1.1-3.5], p = 0.05). On the other hand, the ongoing pregnancy rate was similar between the 2 groups (33 vs. 23%, p = 0.2).

CONCLUSION

Catheter rotation during its withdrawal may be associated with increased pregnancy and clinical pregnancy rates; however, the difference in ongoing pregnancy rates did not reach statistical significance.

A double-blinded, randomized, placebo-controlled trial assessing the effects of nifedipine on embryo transfer: Study protocol

INTRODUCTION

Implantation failure is the main factor affecting the success rate of in vitro fertilization (IVF) procedures. Studies have reported that uterine contractions (UCs) at the time of embryo transfer (ET) were inversely related to implantation and pregnancy rate, hence reducing the success of IVF treatment. Various pharmacological agents, with the exception of calcium channel blocker (CCB), have been investigated to reduce UC. In this regard, we are presenting a proposal for a double-blind randomized placebo-controlled trial. The trial aims to determine whether nifedipine, a CCB with potent smooth muscle relaxing activity and an excellent safety profile, can improve the outcome of ET.

METHODS AND ANALYSES

We will recruit 100 infertile women into one of 2 groups: placebo (n = 50) and nifedipine 20 mg (n = 50). Study participants will be admitted 30 minutes prior to ET and given either tablet after their baseline vital signs have been recorded. They will then undergo ET and be observed for adverse events for another 30 minutes post-ET. The primary outcome will be implantation rate and clinical pregnancy rate. Secondary outcomes include adverse events, miscarriage and pregnancy, and neonatal outcomes. Resulting data will then be analyzed using t test, Chi-square test, and multivariate test to compare outcomes between the 2 groups for any statistical significance. This protocol has been designed in accordance with the SPIRIT 2013 Guidelines.

Correlation of Site of Embryo Transfer with IVF Outcome: Analysis of 743 Cycles from a Single Center

OBJECTIVE

To investigate the influence of site of embryo transfer (ET) on reproductive outcome.

MATERIALS AND METHODS

A retrospective analysis of 743 ultrasound-guided ET in fresh in vitro fertilization (IVF) cycles from a single center over a period of 4 years was conducted. The distance between the fundal endometrial surface and the air bubble was measured, and accordingly, patients were divided into four groups (≤10 mm; >10 and ≤15 mm; >15 and 20 mm; >20 and <25 mm).

SETTING

Tertiary Assisted Reproductive Technology (ART) center.

PATIENTS

All patients enrolled in the IVF program undergoing ET.

INTERVENTIONS

Controlled ovarian hyperstimulation (OS), IVF, and ET.

MAIN OUTCOME MEASURES

Cleavage rate and clinical pregnancy rate.

RESULTS

Clinical pregnancy rate was significantly more in groups 2 and 3 compared to the other groups. Logistic regression analysis showed that one unit increase in embryos transfer will enhance the pregnancy outcome about 3.7 (adjusted odds ratio) times with 95% confidence limits 2.6 to 5.4. Similarly, pregnancy outcome will be 3.1 (95% confidence limits: 1.5-6.4) times higher for distance group >15 and <20 mm compared to less than 10-mm distance group. Ectopic pregnancy rates were similar in all the four groups.

CONCLUSION

The present study demonstrates that site of ET has significant difference on reproductive outcome.

A prospective study comparing two embryo-transfer soft catheters

OBJECTIVES

To compare reproductive outcomes using two different soft catheters i.e. Set TDT® and Cook® Sydney IVF. The primary outcome was defined as a positive β-human chorionic gonadotropin (β-hCG) test.

METHODS

Our prospective study recruited 68 patients undergoing in vitro fertilization cycles in a private fertility clinic in Porto Alegre, Brazil, between January 2014 and April 2016. They were divided into two groups according to the catheter that would be used for the embryo transfer, and the groups were matched by age. The total number of patients in each group was: 34 for the TDT and 34 for the Cook Sydney. All the patients were submitted to a β-hCG test 12 days after the embryo transfer for pregnancy outcome evaluation.

RESULTS

Ten out of 34 patients from the TDT group had a positive outcome for pregnancy, corresponding to 29.4%. The Cook Sydney group had 9 patients out of 34 with positive outcomes, corresponding to 26.5%. Comparing the efficacy of both catheters for the primary outcome, there was no significant difference (p>0.05) between the TDT and the Cook Sydney catheters.

CONCLUSION

The TDT and the Cook Sydney catheters efficacies were similar for embryo transfer during assisted reproductive technology cycles.

Association between leukaemia inhibitory factor gene polymorphism and pregnancy outcomes after assisted reproduction techniques

Certain gene polymorphisms are associated with implantation failure and pregnancy loss. Studies of leukaemia inhibitory factor (LIF) gene polymorphisms are scarce. The LIF single nucleotide polymorphism (SNP) thymine (T)/guanine (G) (rs929271) was studied in women to determine whether an association existed with pregnancy outcomes after intracytoplasmic sperm injection (ICSI); 411 women who underwent ICSI were recruited. DNA was extracted from the peripheral blood, and the LIF gene SNP T/G (rs929271) was genotyped using real-time polymerase chain reaction. Participants were divided into three groups according to their LIF genotype: T/T (n = 168), T/G (n = 202) and G/G (n = 41). All IVF and ICSI procedures were carried out under the same clinical and laboratory conditions. The ICSI cumulative results (from fresh plus frozen cycles) of each genotype group were analysed. The G/G genotype in women was associated with a higher implantation rate (T/T: 15.9%, T/G: 16.2%, G/G: 27.0%; P < 0.05), ongoing pregnancy rate/patient (T/T: 31.5%, T/G: 36.1%, G/G: 53.7%; P < 0.05) and ongoing pregnancy rate/transfer (T/T: 18.5%, T/G: 20.2%, G/G: 36.7%; P < 0.05). LIF SNP T/G (rs929271) seems to be a susceptibility biomarker capable of predicting implantation efficiency and pregnancy outcomes.

Post-embryo transfer interventions for assisted reproduction technology cycles

BACKGROUND

In women undergoing in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI), embryos transferred into the uterine cavity can be expelled due to many factors including uterine peristalsis and contractions, low site of deposition and negative pressure generated when removing the transfer catheter. Techniques to reduce the risk of embryo loss following embryo transfer (ET) have been described but are not standard in all centres conducting ET.

OBJECTIVES

To evaluate the efficacy of interventions used to prevent post-transfer embryo expulsion in women undergoing IVF and ICSI.

SEARCH METHODS

We searched the Menstrual Disorders and Subfertility Group Specialised Register of controlled trials to June 2014 and PubMed, MEDLINE, EMBASE, CENTRAL, PsycINFO, CINAHL, World Health Organization ICTRP, and trial registers from inception to June 2014, with no language restrictions. Additionally, we handsearched reference lists of relevant articles, and ESHRE and ASRM conference abstracts.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions used to prevent post-transfer embryo expulsion in women undergoing IVF and ICSI. Two review authors independently screened titles and abstracts and reviewed the full-texts of all potentially eligible citations to determine whether they met our inclusion criteria. Disagreements were resolved by consensus.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of included trials using standardised, piloted data extraction forms. Data were extracted to allow intention-to-treat analyses. Disagreements were resolved by consensus. The overall quality of the evidence was rated using GRADE methods.

MAIN RESULTS

We included four RCTs (n = 1392 women) which administered the following interventions: bed rest (two trials), fibrin sealant (one trial), and mechanical closure of the cervix (one trial). Our primary outcome, live birth rate, was not reported in any of the included trials; nor were the data available from the corresponding authors. For the ongoing pregnancy rate, two trials comparing more bed rest with less bed rest showed no evidence of a difference between groups (odds ratio (OR) 0.88; 95% confidence interval (CI) 0.60 to 1.31, 542 women, I(2) = 0%, low quality evidence). Secondary outcomes were sporadically reported with the exception of the clinical pregnancy rate, which was reported in all of the included trials. There was no evidence of a difference in clinical pregnancy rate between more bed rest and less bed rest (OR 0.88; 95% CI 0.60 to 1.31, 542 women, I(2) = 0%, low quality evidence) or between fibrin sealant and usual care (OR 0.98; 95% CI 0.54 to 1.78, 211 women, very low quality evidence). However, mechanical closure of the cervix was associated with a higher clinical pregnancy rate than usual care (OR 1.92; 95% CI 1.40 to 2.63, very low quality evidence). The quality of the evidence was rated as low or very low for all outcomes. The main limitations were failure to report live births, imprecision and risk of bias. Overall, the risk of bias of the included trials was high. The use of a proper method of randomisation and allocation concealment was fairly well reported, while only one trial clearly reported blinding. There was no evidence that any of the interventions had an effect on adverse event rates but data were too few to reach any conclusions.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support any specific length of time for women to remain recumbent, if at all, following embryo transfer, nor is there sufficient evidence to recommend the use of fibrin sealants added to the embryo transfer fluid. There is very limited evidence to support the use of mechanical pressure to close the cervical canal following embryo transfer. Further well-designed and powered studies are required to determine the true effectiveness and safety of these interventions.

Derivation of human decidua-like cells from amnion and menstrual blood

We induced differentiation of human amnion-derived mesenchymal stem cells (AMCs) and menstrual blood-derived mesenchymal stem cells (MMCs) into endometrial stroma-like cells, which could be useful for cell therapy to support embryo implantation. Interestingly, the expression patterns of surface markers were similar among AMCs, MMCs, and endometrial stromal cells. In addition, whereas treatment with estrogen and progesterone was not very effective for decidualizing AMCs and MMCs, treatment with 8-Br-cAMP prompted remarkable morphological changes in these cells as well as increased expression of decidualization markers (prolactin and insulin-like growth factor binding protein-1) and attenuated expression of surface markers unique to mesenchymal stem cells. These results demonstrated that bone marrow-derived stem cells, which are considered a potential source of endometrial progenitor cells, as well as AMCs and MMCs show in vitro decidualization potential, which is characteristic of endometrial stromal cells.

Modeling Embryo Transfer into a Closed Uterine Cavity

Embryo transfer (ET) is the last manual intervention after extracorporeal fertilization. After the ET procedure is completed, the embryos are conveyed in the uterus for another two to four days due to spontaneous uterine peristalsis until the window time for implantation. The role of intrauterine fluid flow patterns in transporting the embryos to their implantation site during and after ET was simulated by injection of a liquid bolus into a two-dimensional liquid-filled channel with a closed fundal end via a liquid-filled catheter inserted in the channel. Numerical experiments revealed that the intrauterine fluid field and the embryos transport pattern were strongly affected by the closed fundal end. The embryos re-circulated in small loops around the vicinity where they were deposited from the catheter. The transport pattern was controlled by the uterine peristalsis factors, such as amplitude and frequency of the uterine walls motility, as well as the synchronization between the onset of catheter discharge and uterine peristalsis. The outcome of ET was also dependent on operating parameters such as placement of the catheter tip within the uterine cavity and the delivery speed of the catheter load. In conclusion, this modeling study highlighted important parameters that should be considered during ET procedures in order to increase the potential for pregnancy success.

Implantation Failure, Etiology, Diagnosis and Treatment

Embryonic implantation is a complex interaction between the embryo and the endometrium. Despite great investigative effort this process is still obscure. Contrary to the great advancement in patient care, follicular recruitment, oocyte quality and aspiration, embryo quality, culture and cryopreservation, our understanding of the implantation process did not enhance as much, and the tools to intervene within this process are limited. The implantation of the transferred embryos still remains the major limiting factor in IVF. Here we will review the current literature on the maternal (uterine, hematologic, immunologic and others) and embryonic factors that are associated with repeated implantation failure (RIF) and describe the various therapeutic approaches to cope with them. In addition, we will present our conclusive recommendations on how to investigate and manage RIF based on the literature and our own experience.

Techniques for preparation prior to embryo transfer

BACKGROUND

Embryo transfer (ET) is the final and most vulnerable step in in vitro fertilisation (IVF) treatment. Pregnancy rates after ET may be influenced by several factors including cervical preparation, the performance of a dummy or mock transfer, the choice of catheter, the use of ultrasound guidance, removing the mucus or blood on the catheter, and straightening of the utero-cervical angle. Recent research has focused on improving the embryo transfer technique in the hope of increasing the success rates of IVF. This review focused on preparation techniques as it is unclear whether these simple interventions will make ET an easier procedure with higher success rates and lower complication rates.

OBJECTIVES

To determine whether different preparation techniques prior to ET result in improved IVF outcomes.

SEARCH STRATEGY

The Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CINAHL, and PsycINFO were searched (November 2008). The citation lists of relevant publications, reviews, and included studies were handsearched. Experts in the field were contacted to identify any unpublished trials.

SELECTION CRITERIA

Only truly randomised controlled trials of the interventions straightening the utero-cervical angle, dummy transfer prior to ET, cervical and endometrial preparation, and embryo afterloading were included. The primary outcomes were live birth rate and pregnancy rate per woman randomised. Participants were women with any type of subfertility undergoing IVF treatment and reaching the ET stage.

DATA COLLECTION AND ANALYSIS

Two review authors critically appraised potentially eligible studies. Ten studies were included in this review and data were independently extracted by two review authors. Disagreements were resolved by discussion and involvement of a third author. Risk of bias was also independently assessed by two authors. Dichotomous outcome data were expressed as Peto odds ratios. Subgroup analysis and the investigation of heterogeneity were planned.

MAIN RESULTS

At the time of ET, there was no evidence of benefit with the following interventions: full bladder, removal of cervical mucus, flushing the endocervical canal or the endometrial cavity. We did not identify any eligible studies for dummy transfer, changing patient position, the use of a tenaculum, or embryo afterloading.

AUTHORS' CONCLUSIONS

On the basis of the evidence in this review, no specific implications for practice are made. It is recommended, in general, that more, larger studies are done on ET preparation techniques. The studies need to be of a higher quality with better explained methods, more specified inclusion and exclusion criteria, and more participants.

Post-embryo transfer interventions for in vitro fertilization and intracytoplasmic sperm injection patients

BACKGROUND

Techniques for embryo transfer (ET) are being developed, optimized, and standardized to provide the best outcomes.This includes methods to reduce the risk of embryo loss following ET.

OBJECTIVES

To systematically locate, analyse, and review the best available evidence regarding the effectiveness of post-ET techniques for women undergoing in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

SEARCH STRATEGY

We searched electronic databases; reference lists of primary studies, review articles, and relevant publications; and conference abstracts. No language restrictions were applied.

SELECTION CRITERIA

Screening and selection of 2436 possible trial citations were performed independently by two review authors. Four prospective, truly randomised trials met the inclusion criteria. The trials compared two competing post ET interventions or an intervention versus no treatment in women undergoing IVF and ICSI.

DATA COLLECTION AND ANALYSIS

Two review authors independently collected data and assessed risk of bias using a standardized data extraction form. Individual outcome data were extracted to support an intention-to-treat analysis.

MAIN RESULTS

The primary outcome, live birth rate, was not reported in any of the included trials. The ongoing pregnancy rate was only available for one trial that compared immediate ambulation with 30 minute bed rest, with no evidence of an effect with bed rest (OR 1.00; 95% CI 0.54 to 1.85).Secondary outcomes were sporadically reported with the exception of clinical pregnancy rate, which was reported in all of the included trials. There was no significant difference between less bed rest and more rest (OR 1.13; 95% CI 0.77 to 1.67). Nor was there any significant difference between the use of a fibrin sealant and control (OR 0.98; 95% CI 0.54 to 1.78). Even so, there was a significantly higher probability of pregnancy following mechanical closure of the cervix compared with no intervention (OR 1.92; 95% CI 1.40 to 2.63).The risk of bias of the included studies was variable. The reporting of a proper method of randomisation and allocation concealment was demonstrated in the majority of trials, while only one trial was reported to be blinded.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support a certain amount of time for women to remain recumbent following ET, or to support the use of fibrin sealants. Finally, there is limited evidence to support the use of mechanical closure of the cervical canal following ET. Further well-designed and powered studies are required to determine the true effect, if any, of these and other post ET techniques for women undergoing IVF and ICSI.

Hysteroscopic evaluation of endocervical and endometrial lesions observed after different procedures of embryo transfer: a prospective comparative study

OBJECTIVE

Endocervical and endometrial damage observed after different procedures of embryo transfer (ET) were investigated using diagnostic hysteroscopy.

STUDY DESIGN

Prospective, descriptive and comparative study, in an Infertility centre, University Hospital. Hundred consecutive infertile patients with a normal uterine cavity, included in an IVF program, were enrolled between May 1st, 2006 and April 30th, 2007. All the patients had a diagnostic hysteroscopy immediately after trial ET using soft ET catheters: (i) IVF Sydney Set (Cook, Limerick, Ireland) (n=27), (ii) Elliocath (Ellios, Paris, France) (n=34), (iii) Frydman classic 4.5 (CCD, Paris, France) (n=19), and rigid ET catheters: Memory Frydman 4.5 (CCD, Paris, France) (n=20). All the procedures were recorded and blindly reviewed. Data were analyzed using a Kruskal-Wallis test for age and severity of endometrial lesions, or Fisher's exact test for binary criteria.

RESULTS

Endocervical lesions were more frequently encountered in the soft (63%) and rigid (85%) Frydman's catheter groups compared to other groups (Elliocath: 29%, IVF Sydney Set: 26%; p<0.0001). Presence of blood on the catheter, and endometrial lesions were significantly less frequent in soft catheter groups compared to the rigid catheter group (p<0.0001). Severe endometrial lesions were less frequently observed when soft catheters were used (85%, 53%, 32%, 11% for Memory Frydman, Frydman classic, Elliocath and IVF Sydney Set, respectively; p<0.0001). The presence of blood on the catheter signed severe endometrial lesions.

CONCLUSION

All ET catheters can lead to endocervical and endometrial damage. Severe endometrial lesions were less frequent when soft catheters were used.

[Views of each member of an Assisted Reproductive Technologies centre on the embryo transfer procedure]

The embryo transfer (ET) is probably the key step of Assisted Reproductive Technologies (ART), end point of the collaboration of a multidisciplinary clinical team and an infertile couple. Thus, a perfect knowledge of available data regarding ET is required to optimize the results of ART. Indeed, numerous published studies demonstrate the impact of defined parameters onto the effectiveness of ET procedure. The aim of this study is to provide views of physicians dealing with ART, i.e. endocrinologist, ultrasound scan specialist, surgeon and biologist to put in perspective questions and answers about ET.

Removal of cervical mucus prior to embryo transfer improves pregnancy rates in women undergoing assisted reproduction

The removal of cervical mucus during embryo transfer has been postulated to increase the pregnancy and implantation rates by not interfering with embryo implantation. Even so, this is a time-consuming procedure that may increase the incidence of difficult transfers by removing the naturally lubricant mucus. In addition, any cervical manipulations at the time of embryo transfer may cause unwarranted uterine contractions. In this prospective, controlled study, 286 women undergoing embryo transfer between January and May 2006 were divided into two groups according to whether the cervical mucus was scheduled to be aspirated (group A) or not (group B). The two groups were similar with regards to the demographics, cause of infertility, characteristics of ovarian stimulation and embryos transferred. Even so, the clinical pregnancy rate was significantly higher in group (A) than group (B) (OR = 2.18, 95% CI = 1.32-3.58), although there were easier transfers in group (B) than group (A) (OR = 3.00, 95% CI = 1.05-8.55). This demonstrates that even though embryo transfers were easier to perform when the cervical mucus was left in place, aspiration resulted in an increased chance of clinical pregnancy.

In vitro simulations of embryo transfer in a laboratory model of the uterus

Embryo transfer (ET) is the final manual intervention during which the newly formed embryo is placed within the uterus by a transcervical catheter. The loading of the syringe-catheter complex with the transferred volume consists of the transfer media (which contains the embryos) separated by air spaces on both sides. The dynamics involved in injecting the syringe-catheter complex is not well understood nor has it been investigated to date. We developed an in vitro experimental setup for simulations of ET into a rigid transparent uterine model. The catheter was loaded in sequences of liquid and air as it is in the clinical setting. The transferred liquid was colored with a dye and its dispersion within the uterine cavity was recorded by a video camera. The results demonstrated, for the first time, the importance of having a gas phase in the catheter load. The resulting air bubbles within the uterus were carried upward towards the fundus by buoyant forces, thereby dragging behind them the transferred liquid which contained the embryos. This could be expected to substantially increase the probability for the embryos to be present near the fundal wall at the time window for implantation. There was also evidence of a dependency of the rate of injection upon the catheter load into the uterus: a low speed generated several air bubbles which led to more of the transferred liquid being carried towards the fundal end, thus possibly enhancing the potential for implantation.

Investigation and treatment of repeated implantation failure following IVF-ET

Pregnancy rate following one cycle of IVF and ET can be as high as 60%. But even in the very successful units, some couples fail repeatedly. The causes for repeated implantation failure (RIF) may be because of reduced endometrial receptivity, embryonic defects or multifactorial causes. Various uterine pathologies, such as thin endometrium, altered expression of adhesive molecules and immunological factors, may decrease endometrial receptivity, whereas genetic abnormalities of the male or female, sperm defects, embryonic aneuploidy or zona hardening are among the embryonic reasons for failure of implantation. Endometriosis and hydrosalpinges may adversely influence both. In this mini review, we discuss the suggested methods for evaluation and treatment of RIF: repeated hysteroscopy, myomectomy, endometrial stimulation, immunotherapy, preimplantation genetic screening (PGS), assisted hatching, zygote intra-Fallopian transfer (ZIFT), co-culture, blastocyst transfer, cytoplasmic transfer, tailoring stimulation protocols and salpingectomy for hydrosalpinges.

Impact of hypnosis during embryo transfer on the outcome of in vitro fertilization-embryo transfer: a case-control study

OBJECTIVE

To investigate whether hypnosis during ET contributes to successful IVF/ET outcome.

DESIGN

Case-control clinical study.

SETTING

Academic Fertility and IVF Unit, Soroka Medical Center, Beer-Sheva, Israel.

PATIENT(S)

Infertile couples undergoing IVF.

INTERVENTION(S)

Ninety-eight IVF/ET cycles with hypnosis during the ET procedure were matched with 96 regular IVF/ET cycles.

MAIN OUTCOME MEASURES

Comparison of clinical pregnancy and implantation rates between the two groups.

RESULT(S)

We obtained 52 clinical pregnancies out of 98 cycles (53.1%) with an implantation rate of 28% among hypnosis IVF/ET cycles, and 29 out of 96 (30.2%) clinical pregnancies and an implantation rate of 14.4% in the control cycles. Our overall IVF program pregnancy rate for the same period was 32.1%. Logistic regression analysis was performed emphasizing the positive contribution of hypnosis to the IVF/ET conception rates.

CONCLUSION(S)

This study suggests that the use of hypnosis during ET may significantly improve the IVF/ET cycle outcome in terms of increased implantation and clinical pregnancy rates. Furthermore, it seems that the patients' attitude to the treatment was more favorable.

Effect of using an echogenic catheter for ultrasound-guided embryo transfer in an IVF programme: a prospective, randomized, controlled study

BACKGROUND

Recent evidence showed that ultrasound-guided embryo transfer significantly increases successful implantation compared to the clinical touch method. It has been postulated that new echodense catheters which are more readily detectable by ultrasound may refine transfer techniques even more, thus improving IVF outcome.

METHODS

A prospective, randomized, controlled trial comparing IVF outcome for women undergoing embryo transfer under ultrasound guidance by a single healthcare provider with random assignment according to a computer-generated randomization table to either standard soft Wallace catheter (standard catheter group, n=95) or the new echogenic soft Wallace catheter (echogenic catheter group, n=98).

RESULTS

The use of the echodense catheter facilitated catheter identification under ultrasound, and thus the duration of the embryo transfer procedure since the loaded catheter was handed to the physician and up to embryo discharge was significantly shorter in the echogenic catheter group as compared with the standard catheter group. There were 39 and 53 clinical pregnancies in the standard catheter (41%) and echogenic catheter (54.1%) groups, respectively. This was not statistically significant (P=0.08) according to the OR (0.6) and CIs (0.33-1.04). However, twin pregnancy rate was significantly increased (P<0.01) with the use of the new catheter which was the underlying source for obtaining significant increase in implantation rate in this group (37.1%) as compared with the standard catheter group (23.2%).

CONCLUSION

This pilot study suggests that the use of the echogenic Wallace catheter simplifies ultrasound-guided embryo transfer but not definite benefit in terms of pregnancy rates was obtained. In contrast, the use of the new catheter was associated with a significant increase in the number of twin pregnancies.

Implantation sites after embryo transfer into the central area of the uterine cavity

A total of 63 pregnancies (47 singleton, 15 twin, 1 triplet) from intracytoplasmic sperm injection cycles were analysed. In all embryo transfers, the catheter was introduced into the endometrial cavity guided by abdominal ultrasound, with the catheter tip placed at the middle point of the endometrial cavity. Gestational sacs (GS) were located 21-24 days after transfer (gestational age=5 weeks) by two-dimensional and three-dimensional transvaginal ultrasound. The uterine cavity was divided into three parts: upper, middle and lower. Furthermore, the upper region was subdivided into right, middle and left areas, and the middle region was subdivided into right and left areas. The frequency of gestational sacs in each area was evaluated. In singleton pregnancies 66.0% (31/47) of the GS were detected in the upper region, 29.8% (14/47) in the middle region and 4.2% (2/47) in the lower region. In multiple pregnancies (twins and triplet) 45.5% (15/33) of the GS were detected in the upper region, 51.5% (17/33) in the middle region and 3.0% (1/33) in the lower region. In conclusion, the results demonstrate that when embryos are transferred to the central area of the uterine cavity there is an increase in implantation rate in the middle region compared with the rate expected in naturally conceived pregnancies (9-15%).