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.

Shallow artificial networks with morphokinetic time‐lapse parameters coupled to ART data allow to predict live birth

Purpose

The purpose of this work was to construct shallow neural networks (SNN) using time‐lapse technology (TLT) from morphokinetic parameters coupled to assisted reproductive technology (ART) parameters in order to assist the choice of embryo(s) to be transferred with the highest probability of achieving a live birth (LB).

Methods

A retrospective observational single‐center study was performed, 654 cycles were included. Three SNN: multilayers perceptron (MLP), simple recurrent neuronal network (simple RNN) and long short term memory RNN (LSTM‐RNN) were trained with K‐fold cross‐validation to avoid sampling bias. The predictive power of SNNs was measured using performance scores as AUC (area under curve), accuracy, precision, Recall and F1 score.

Results

In the training data group, MLP and simple RNN provide the best performance scores; however, all AUCs were above 0.8. In the validating data group, all networks were equivalent with no performance scores difference and all AUC values were above 0.8.

Conclusion

Coupling morphokinetic parameters with ART parameters allows to SNNs to predict the probability of LB, and all SNNs seems to be efficient according to the performance scores. An automatic time recognition system coupled to one of these SNNs could allow a complete automation to choose the blastocyst(s) to be transferred.

Estimation of embryo transfer media viscosity and consideration of its effect on media and uterine fluid interactions

RESEARCH QUESTION

What are the viscosities of media used for human embryo transfer and what is the possible effect of viscosity as it relates to interactions between transfer media and uterine fluid.

DESIGN

Chamber slide filling times, in seconds, were used to calculate viscosity for each commercial and in-house modified medium, with 12 or 24 replicates per medium under standard operating procedure temperature and gas equilibration conditions used for embryo transfer. Means, standard deviations and coefficients of variation were calculated, and each viscosity was estimated using a regression equation; viscosities for each medium were presented for comparative purposes.

RESULTS

Complete culture media (G1-Plus, G2-Plus, G-TL, 1-Step, Global Total, Global Total HEPES, and Sperm Wash Medium) had viscosity estimates of 1.65 cP, 1.77 cP, 1.68 cP, 1.29cP, 1.18 cP, 1.15 cP, and 1.20 cP, respectively. Complete transfer media (EmbryoGlue, UTM), had viscosity estimates of 3.59 cP and 1.28 cP, respectively. Global HEPES medium with 10%, 20%, 30%, and 50% synthetic serum substitute (SSS) volume per volume had viscosity estimates 1.16 cP, 1.23 cP, 1.25 cP, and 1.34 cP, respectively. For reference, water had a viscosity estimate of 1.06 cP.

CONCLUSIONS

A relatively narrow distribution of viscosities was observed across several transfer media despite the various commercial or in-house modifications. These data demonstrate the vast difference between viscosities of embryo transfer media and the assumed viscosity of uterine fluid (1000 cP). Contemporary embryo transfer media may be well-suited for IVF, but evaluation of all variables, e.g. media viscosity in the context of embryo transfer, adds to the knowledge base that should be available to practitioners.

Embryo transfer techniques

Embryo transfer is the final and rate-limiting step of the assisted reproductive technique. Few advances have occurred in the last few decades with regard to this procedure. Studies conducted thus far have focused on factors and interventions taking place before, during and after this procedure. These factors are highly varied and range from methods to improve the psychological state of the patients to methods aimed at reducing uterine contractility and methods aimed at optimising the precise transfer of the embryo. The key question is which factors and interventions have thus far been proven to increase pregnancy rates and live birth rates. This paper aims to review the evidence relating to embryo transfer techniques in a systematic manner with a view to provide practical recommendations to practitioners involved in the procedure.

Improving the safety of the embryo and the patient during in vitro fertilization procedures

In vitro fertilization (IVF) is a method of treatment for infertility in selected indications. Recent years have brought dynamic development of technologies related to IVF. This article presents problems pertaining to the safety of technology with respect to the patient, as well as the embryo, based on an analysis of scientific reports and our own experience. Invasiveness of the IVF procedure for the woman and the embryo varies on an individual basis. Minimization of the invasiveness of IVF requires experience of the staff performing the procedure, especially with respect to the assessment of risk for an individual patient. Technologies related to IVF are constantly being improved, and the effectiveness of the selected individual treatment methods is not always scientifically confirmed.