Outcome of in vitro fertilization after transabdominal ultrasound–assisted embryo transfer with a full or empty bladder

Evidence and consensus on technical aspects of embryo transfer

BACKGROUND

Ultrasound-guided embryo transfer (US-GET) is a widely performed procedure, but standards for the best practice are not available.

OBJECTIVE AND RATIONALE

This document aims to provide an overview of technical aspects of US-GET after considering the published data and including the preparation for the embryo transfer (ET) procedure, the actual procedure, the post-procedure care, associated pathologies, complications and risks, quality assurance and practitioners’ performance.

SEARCH METHODS

A literature search for evidence on key aspects of the ET procedure was carried out from database inception to November 2021. Selected papers (n = 359) relevant to the topic were analysed by the authors. The following key points were considered in the papers: whether ultrasound (US) practice standards were explained, to what extent the ET technique was described and whether complications or incidents and how to prevent such events were reported. In the end, 89 papers could be used to support the recommendations in this document, which focused on transabdominal US-GET.

OUTCOMES

The relevant papers found in the literature search were included in the current document and described according to the topic in three main sections: requirements and preparations prior to ET, the ET procedure, and training and competence for ET. Recommendations are provided on preparations prior to ET, equipment and materials, ET technique, possible risks and complications, training and competence. Specific aspects of the laboratory procedures are covered, in particular the different loading techniques and their potential impact on the final outcomes. Potential future developments and research priorities regarding the ET technique are also outlined.

LIMITATIONS, REASONS FOR CAUTION

Many topics were not covered in the literature review and some recommendations were based on expert opinions and are not necessarily evidence based.

WIDER IMPLICATIONS

ET is the last procedural step in an ART treatment and is a crucial step toward achieving a pregnancy and live birth. The current paper set out to bring together the recent developments considering all aspects of ET, especially emphasizing US quality imaging. There are still many questions needing answers, and these can be subject of future research.

STUDY FUNDING/COMPETING INTEREST(S)

No funding. ADA has received royalties from CRC Press and personal honorarium from Cook, Ferring and Cooper Surgical. The other co-authors have no conflicts of interest to declare that are relevant to the content of this article.

Interventions to optimize embryo transfer in women undergoing assisted conception: a comprehensive systematic review and meta-analyses

BACKGROUND

Several interventions and techniques are suggested to improve the outcome of embryo transfer (ET) in assisted conception. However, there remains no consensus on the optimal practice, with high variations among fertility specialists.

OBJECTIVE AND RATIONALE

We conducted a comprehensive systematic review and meta-analyses of randomized controlled trials (RCTs) aiming to identify effective interventions that could be introduced around the time of ET to improve reproductive outcomes.

SEARCH METHODS

We searched the electronic databases (MEDLINE, EMBASE and Cochrane CENTRAL) from inception until March 2021 using a multi-stage search strategy of MeSH terms and keywords, and included all RCTs that evaluated an intervention in the 24-h period before/after ET in women undergoing IVF/ICSI. Our primary outcome was clinical pregnancy rate post-ET confirmed as viable pregnancy on ultrasound scan. We assessed the risk of bias in included trials and extracted data in duplicate. We pooled data using a random-effect meta-analysis and reported using risk ratio (RR) with 95% CI. We explored publication bias and effect modifiers using subgroup analyses.

OUTCOMES

Our search yielded 3685 citations of which we included 188 RCTs (38 interventions, 59 530 participants) with a median sample size of 200 (range 26-1761). The quality of included RCTs was moderate with most showing a low risk of bias for randomization (118/188, 62.8%) and attrition (105/188, 55.8%) but there was a significant risk of publication bias (Egger's test P = 0.001). Performing ET with ultrasound guidance versus clinical touch (n = 24, RR 1.265, 95% CI 1.151-1.391, I2 = 38.53%), hyaluronic acid versus routine care (n = 9, RR 1.457, 95% CI 1.197-1.261, I2 = 46.48%) and the use of a soft versus hard catheter (n = 27, RR 1.122, 95% CI 1.028-1.224, I2 = 57.66%) led to higher clinical pregnancy rates. Other pharmacological add-ons also showed a beneficial effect including granulocyte colony-stimulating factor (G-CSF: n = 4, RR 1.774, 95% CI 1.252-2.512, I2 = 0), Atosiban (n = 7, RR 1.493, 95% CI 1.184-1.882, I2 = 68.27%) and hCG (n = 17, RR 1.232, 95% CI 1.099-1.382, I2 = 57.76%). Bed rest following ET was associated with a reduction in clinical pregnancy (n = 6, RR 0.857, 95% CI 0.741-0.991, I2 = 0.01%). Other commonly used interventions, such as non-steroidal anti-inflammatory drugs, prophylactic antibiotics, acupuncture and cervical mucus removal, did not show a significant benefit on reproductive outcomes. Our effect estimates for other important outcomes, including miscarriage and live birth, were limited by the varied reporting across included RCTs.

WIDER IMPLICATIONS

Using ultrasound guidance, soft catheters and hyaluronic acid at the time of ET appears to increase clinical pregnancy rates. The use of Atosiban, G-CSF and hCG showed a trend towards increased clinical pregnancy rate, but larger trials are required before adopting these interventions in clinical practice. Bed rest post-ET was associated with a reduction in clinical pregnancy and should not be recommended.

Ultrasound versus 'clinical touch' for catheter guidance during embryo transfer in women

BACKGROUND

Many women undergoing an assisted reproductive technology (ART) cycle will not achieve a live birth. Failure at the embryo transfer stage may be due to lack of good-quality embryo/s, lack of uterine receptivity, or the transfer technique itself. Numerous methods, including the use of ultrasound guidance for proper catheter placement in the endometrial cavity, have been suggested as more effective techniques of embryo transfer. This review evaluates the efficacy of ultrasound-guided embryo transfer (UGET) compared with 'clinical touch' (CTET), which is the traditional method of embryo transfer and relies on the clinician's tactile senses to judge when the transfer catheter is in the correct position.

OBJECTIVES

To determine whether ultrasound guidance compared with clinical touch improves pregnancy outcomes in women undergoing embryo transfer during ART cycles.

SEARCH METHODS

For the 2016 update of this review, we ran updated searches in the Cochrane Gynaecology and Fertility Group trials register (May 2015), the Cochrane Central Register of Controlled Trials (the Cochrane Library, May 2015), MEDLINE (2009 to May 2015), and EMBASE (2009 to May 2015). We also handsearched relevant conference proceedings: American Society for Reproductive Medicine (ASRM), European Society for Human Reproduction and Embryology (ESHRE), and International Federation of Gynecology and Obstetrics (FIGO). There were no language restrictions.

SELECTION CRITERIA

We included only randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and quality of trials and extracted data from those selected. We calculated odds ratio (OR) and 95% confidence interval (CI) for dichotomous outcomes. No outcomes were reported using continuous data. We assessed the overall quality of the evidence for the main findings using the GRADE working group methods.

MAIN RESULTS

This systematic review now has 21 included studies (four of which we added in the 2016 update), two studies awaiting assessment, and 47 excluded studies. In total, data for meta-analyses were available in 21 trials (n = 6218 women), of which only four reported live births.UGET was associated with an increased chance of a live birth/ongoing pregnancy compared with CTET (OR 1.47, 95% CI 1.30 to 1.65; 13 trials; n = 5859 women; I(2) = 74%; low-quality evidence). Sensitivity analysis by including only trials with low risk of selection bias or by using a random-effects model did not alter the effect. We estimate that for women with a chance of a live birth/ongoing pregnancy of 23% using CTET, this would increase to between 28% and 33% using UGET. We considered the quality of the evidence using GRADE methodology to be low.UGET was associated with an increase in the chance of a clinical pregnancy (OR 1.31, 95% CI 1.17 to 1.45; 20 trials; n = 6711 women; I(2) = 42%; moderate-quality evidence). We identified no differences between groups for the incidence of adverse events including multiple pregnancy, ectopic pregnancy, or miscarriage. These events were relatively rare, and sample sizes limited the ability to detect such differences.

AUTHORS' CONCLUSIONS

The evidence suggests ultrasound guidance improves the chance of live birth/ongoing and clinical pregnancies compared with clinical touch, without increasing the chance of multiple pregnancy, ectopic pregnancy, or miscarriage. Methodological limitations included: only four studies reporting details of both computerised randomisation techniques and adequate allocation concealment, only four studies reported on the outcome of live birth, and none of the nine studies that reported on ongoing pregnancy reported on live birth, suggesting possible reporting bias. Adequate reporting of randomisation and allocation concealment will improve the quality of future studies. The primary outcome measure of future studies should be the reporting of live births per woman randomised.

Ultrasound guidance during embryo transfer: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To summarize the current evidence on the effect of using ultrasound (US) guidance during embryo transfer (ET).

METHODS

In this systematic review, we included randomized controlled trials examining the effect of the use of US guidance during ET; data from studies using the same catheter type in study arms were not pooled with the results from studies that used different catheter types.

RESULTS

Twenty-one studies were included in the quantitative analysis: 18 compared 'US guidance' with 'clinical touch', of which one was subsequently excluded from the quantitative meta-analysis owing to a lack of available data, three studies compared transvaginal US guidance with transabdominal US guidance, and one study compared 'hysterosonometry before ET' with US guidance. Comparison of the use of US guidance with clinical touch, in studies that used the same catheter type in the study arms, indicated a benefit of using US guidance during ET on the rates of live birth (relative risk (RR), 1.48 (95% CI, 1.16-1.87)), based on two studies involving 888 women with moderate-quality evidence, and on the rates of clinical pregnancy (RR, 1.32 (95% CI, 1.18-1.46)), based on 13 studies involving 3641 women with high-quality evidence. However, when comparing the use of US guidance with clinical touch in studies that used different catheter types, the results suggest that using US guidance during ET has no effect on the rates of reproductive outcome: live birth (RR, 0.99 (95% CI, 0.83-1.19)), based on one study involving 1649 women with moderate-quality evidence; clinical pregnancy (RR, 1.04 (95% CI, 0.89-1.21)), based on five studies involving 2949 women with moderate-quality evidence. The estimates for the rate of miscarriage and for the other identified comparisons were imprecise.

CONCLUSIONS

The available evidence suggests that there is a benefit of using US guidance during ET. However, both US-guided transfer and clinical touch should be considered acceptable, as the benefit of US is not large and should be balanced against the increased cost and need to change the catheter type. More studies are required before conclusions can be drawn regarding the effect of other techniques on reproductive outcome.

Individualized embryo transfer training: timing and performance

STUDY QUESTION

How long is the individualized training and the stability of competence for the embryo transfer (ET) technique?

SUMMARY ANSWER

The embryo transfer technique is easy-to-learn, hardly unlearned, and training should be individualized by monitoring with learning curve-cumulative summation (LC-CUSUM) curves.

WHAT IS KNOWN ALREADY

Like many medical procedures, embryo transfer is an operator-dependent technique. Individualized or standardized training of these medical procedures should be monitored to determine when competence is acquired.

STUDY DESIGN, SIZE, DURATION

This prospective, monocentric study involving five embryo transfer trainees was carried out between August 2011 and November 2012.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was carried out in a large private clinic. Five gynaecologist trainees during their first year of assisted reproduction subspecialty performed embryo transfer for patients undergoing either fresh IVF, oocyte donor IVF, or frozen embryo transfer. There were 586 embryo transfers performed in 96 sessions of 3-10 embryo transfers each. An embryo transfer was considered successful if it gave rise to a positive pregnancy test 14 days later. LC-CUSUM and cumulative summation (CUSUM) curves were used to determine when competence was acquired and whether it was maintained over time, respectively. The length of time between two consecutive sessions was assessed for an effect on consolidation of the acquired competence.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed that all five trainees became proficient in embryo transfer by procedure 15 (after procedure 15, 9, 7, 13 and 9, respectively). Once competence was achieved, one of the five trainees showed a loss of proficiency. After having acquired competence, the median pregnancy rate per embryo transfer session was significantly lower when the interval between consecutive embryo transfer sessions was ≥10 days compared with <10 days (20.0 versus 46.7%; P = 0.006).

LIMITATIONS, REASONS FOR CAUTION

The patient groups included in the study were heterogeneous (IVF, oocyte donor IVF and frozen embryo transfer) and their outcomes are very variable; thus the distribution and proportion of these groups can determine the timing of competence acquisition. Our data show that low numbers of embryo transfer are needed to acquire competence, but since a relative high percentage of embryo transfers in our practice are from oocyte donor IVF, extrapolation of the findings to other clinical context should be done with caution.

WIDER IMPLICATIONS OF THE FINDINGS

Personalized embryo transfer training is feasible and useful, allowing clinics, on one hand, to offer a maximum chances of pregnancy with fully trained personnel, and the other hand, to avoid the superfluous and costly overtraining of already proficient trainees. Furthermore, it is advisable to maintain a short interval of time between consecutive embryo transfer sessions after a trainee has acquired competence, to avoid a significant drop in the resulting pregnancy rate.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported in part by funding from Fundació Privada EUGIN. There are no conflicts of interest to declare.

Ultrasound versus 'clinical touch' for catheter guidance during embryo transfer in women

BACKGROUND

Many women undergoing an Assisted Reproductive Technology (ART) cycle will not achieve a live birth. Failure at the embryo transfer stage may be due to lack of good quality embryo/s, lack of uterine receptivity, or the transfer technique itself. Numerous methods, including the use of ultrasound guidance for proper catheter placement in the endometrial cavity, have been suggested as a more effective technique of embryo transfer. This review evaluates the effectiveness of ultrasound guided embryo transfer (UGET) compared with 'clinical touch' (CTET) the traditional method of embryo transfer.

OBJECTIVES

To determine whether ultrasound guidance influences treatment outcomes in women undergoing embryo transfer (ET) during assisted reproductive technology (ART) cycles.

SEARCH STRATEGY

Electronic databases were searched in November 2009. We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched November 2009), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2009), MEDLINE (1970-2009), EMBASE (1985-2009), BIO Extracts (1980-2009). Relevant conference proceedings were also hand searched (ASRM, ESHRE and FIGO).

SELECTION CRITERIA

Only randomised controlled trials were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility and quality of trials and extracted data from those selected.

MAIN RESULTS

This update identified 59 potential trials of which 42 were excluded. Data for analysis was available in seventeen studies. One study reported live births and personal communication resulted in data relating to this outcome being obtained in two additional studies. There is no evidence of a significant difference in the outcome of live birth (OR 1.14 (95%CI0.93 to 1.39; P=0.02) although heterogeneity was high (64%) and the results should be interpreted with caution. Seven studies reported on ongoing pregnancies. The ongoing pregnancies per woman randomised associated with UGET (441/1254) was significantly higher than for clinical touch (350/1218) OR 1.38, 95%CI 1.16 to 1.64, P<0.0003). No statistically significant differences in the incidence of adverse events were identified between the comparison groups. These events are relatively rare and sample sizes limit the ability to detect such differences.

AUTHORS' CONCLUSIONS

The studies are limited by their quality with only two studies reporting details of both computerised randomisation techniques and adequate allocation concealment. Ultrasound guidance does appear to improve the chances of live/ongoing and clinical pregnancies compared with clinical touch methods. The quality of future studies should be improved with adequate reporting of randomisation, allocation concealment, and power calculations. The primary outcome measure of future studies should be the reporting of live births per woman randomised.

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.

Ultrasound-guided embryo transfer does not offer any benefit in clinical outcome: a randomized controlled trial

BACKGROUND

Ultrasound-guided embryo transfer (ET) is widely suggested as a standard clinical practice that improves overall embryo implantation and pregnancy rates. Various studies of this issue suffer from methodological pitfalls, so that a randomized controlled trial, which overcomes these problems, might be valuable.

METHODS

Three hundred women aged <40, who underwent fresh ET, were included in this randomized, double-blind controlled trial. The K-J-SPPE echo tip soft catheter was used for the ultrasound-guided ET and the traditional K-Soft catheter for ETs not using ultrasound. One experienced operator performed all ETs. The primary study outcome was overall pregnancy rate (defined as the number of positive hCG results per transfer).

RESULTS

No significant differences between groups were found regarding baseline patient and embryological characteristics, except for male factor and unexplained infertility (higher in the blind and ultrasound-guided ET group, respectively, P < 0.05). Overall pregnancy rates were 53.3 and 51.3% in the ultrasound-guided and blind ET group, respectively. Two ectopic pregnancies were reported in each group. Difficulty in cervical negotiation did not differ between the two groups.

CONCLUSIONS

In patients undergoing ET by an experienced operator, ultrasound guidance did not provide any benefit in terms of overall clinical pregnancy and embryo implantation rates.

Ultrasound versus 'clinical touch' for catheter guidance during embryo transfer in women

BACKGROUND

Many women undergoing an Assisted Reproductive Technology (ART) cycle will not achieve a live birth. Failure at the embryo transfer stage may be due to poor embryo quality, lack of uterine receptivity, or the transfer technique itself. Numerous methods, including the use of ultrasound guidance for proper catheter placement in the endometrial cavity, have been suggested as a means of improving the technique of embryo transfer. This review evaluates the effectiveness of ultrasound (UGET) in comparison with 'clinical touch' embryo transfer (CTET) the traditional method of embryo transfer.

OBJECTIVES

:To determine whether ultrasound guidance influences treatment outcomes in women undergoing embryo transfer (ET) during assisted reproductive technology (ART) cycles.

SEARCH STRATEGY

All electronic databases were searched on 20 th August 2006. We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched August 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2006), MEDLINE (1970-2006), EMBASE (1985-2006), BIO Extracts (1980-2006). Relevant conference proceedings were also hand searched (ASRM, ESHRE and FIGO).

SELECTION CRITERIA

Only randomised controlled trials were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility and quality of trials and extracted data from those selected.

MAIN RESULTS

Thirteen out of fifteen identified studies were eligible for analysis. No study reported live births, however, personal communication resulted in data relating to this outcome being obtained in two of the studies. Six studies reported on ongoing pregnancies. The live birth/ ongoing pregnancies per woman randomised associated with UGET (452/1376) was significantly higher than for clinical touch (353/1338) OR 1.40, 95%CI 1.18 to 1.66, P<0.0001). This means, for example, that for a population of women with a 25% chance of pregnancy using clinical touch this would be increased to 32% (28% to 46%) by using UGET. There were no statistically significant differences in the incidence of adverse events between the two comparison groups with the exception of blood on the catheter.

AUTHORS' CONCLUSIONS

The studies are limited by their quality with only one of the thirteen studies reporting details of both computerised randomisation techniques and adequate allocation concealment. Ultrasound guidance does appear to improve the chances of live/ongoing and clinical pregnancies compared with clinical touch methods. The quality of future studies should be improved with adequate reporting of randomisation, allocation concealment, and power calculations. The primary outcome measure of future studies should be the reporting of live births per woman randomised.

Use of phenazopyridine for reducing discomfort during embryo transfer

OBJECTIVE

The embryo transfer is a critical part of in vitro fertilization. When performed under abdominal ultrasound guidance, the embryo transfer procedure requires a full bladder. Patients often state that the discomfort of the distended bladder causes more pain than the actual transfer procedure. Phenazopyridine HCl is a bladder analgesic. The objective of this study was to determine if a single dose of phenazopyridine prior to embryo transfer reduces patient discomfort during that procedure.

DESIGN

Prospective randomized double-blinded clinical trial.

SETTING

University-based Reproductive Medicine practice.

PATIENT(S)

Eighty-five reproductive age infertile women undergoing in vitro fertilization.

INTERVENTION(S)

Phenazopyridine (200 mg) or placebo taken 1 hour prior to embryo transfer utilizing transabdominal sonography.

MAIN OUTCOME MEASURE(S)

Pain as assessed by visual analogue pain scale and physician and nurse assessment of patient discomfort.

RESULT(S)

Study groups were similar in their demographic background. Mean pain score as assessed by a visual analogue pain scale during the procedure was 2.95 +/- 2.4 in the placebo group, and 3.03 +/- 2.6 in the active medication group (NS). There were also no significant differences in the observations of pain assessments.

CONCLUSION(S)

Phenazopyridine used in a single dose prior to embryo transfer does not alleviate patient discomfort.

Is what we clearly see really so obvious? Ultrasonography and transcervical embryo transfer—a review

OBJECTIVE

To critically review the role of ultrasound-guided embryo transfer (ET) and its influence on the outcome of in vitro fertilization (IVF).

DESIGN

Medline review of published manuscripts.

RESULT(S)

Studies evaluating the role of ultrasound-assisted ET have had mixed results, and although meta-analysis of prospective trials suggests an improvement in outcome, limitations in study design may overstate the effect of ultrasonography. Other ET techniques may eliminate the advantages provided by ultrasonography, limiting its benefit to specific clinical scenarios. However, because no trial has demonstrated an adverse effect and because cases that may benefit from its use often cannot be predicted reliably, the routine application of ultrasonography can be justified.