Impact of technical difficulties, choice of catheter, and the presence of blood on the success of embryo transfer--experience from a single provider

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.

Optimizing embryological aspects of oocyte retrieval, oocyte denudation, and embryo loading for transfer: a state of the art review

Oocyte retrieval, oocyte denudation, and embryo transfer are crucial processes during assisted reproduction (ART). Air quality in the ART laboratory, temperature, pH of the media used and the time interval between oocyte retrieval and insemination are all critical factors. Anesthesia is required for oocyte retrieval, however evidence regarding the potential impact of different methods (general anesthesia, conscious sedation, and local anesthesia) on the clinical outcomes is unclear. The optimal timing of oocyte denudation following retrieval has not been established. Regarding the mechanical denudation process, there is a lack of evidence to demonstrate the safest minimum inner diameter of denuding pipettes used to complete the removal of granulosa cells surrounding the oocytes. During embryo transfer, many clinics worldwide flush the catheter before embryo loading, in an attempt to potentially rinse off any toxic agents; however, there is insufficient evidence to show that flushing the embryo transfer catheter before loading increases the success of ART outcome. Considering the serious gaps in knowledge in ART practice, the aim of this review is to provide an updated overview of the current knowledge regarding the various steps and techniques involved in oocyte retrieval, oocyte denudation, and embryo loading for transfer.

The effect of embryo transfer technique on pregnancy rates in in vitro fertilization-intracytoplasmic sperm injection cycles: A prospective cohort study

Objective:

To investigate whether embryo transfer affects pregnancy rates in in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) treatment.

Materials and Methods:

A total of 2,257 patients who underwent IVF-ICSI treatment between 2012 and 2017 were included in this study. Subjects were categorized according to the embryo transfer technique that was required: group 1 (n=1,657) underwent easy transfer with a soft catheter; group 2 (n=548) received external guidance transfers; and group 3 (n=52) experienced difficult transfers with a stylet. Basal parameters, clinical and laboratory IVF-ICSI outcomes, and clinical pregnancy rates (CPR) were compared between the groups.

Results:

There were no differences between the groups in terms of age, body mass index, smoking status, duration and etiology of infertility, baseline folliclestimulating hormone, luteinizing hormone, estradiol (E₂), thyroid-stimulating hormone, prolactin levels, antral follicle count, duration of stimulation, stimulation protocol, total gonadotropin dose required, peak E₂ levels, progesterone levels, and endometrial thickness on human chorionic gonadotropin administration and transfer days (p>0.05). The numbers of oocytes retrieved, MII and 2PN, fertilization rate, day of embryo transfer, and CPRs were also comparable between the groups (p>0.05).

Conclusion:

Our data suggest that embryo transfer has no impact on pregnancy rates in patients who undergo IVF-ICSI treatment. Further studies with more participants are required to elucidate this situation.

Does the Presence of Blood in the Catheter or the Degree of Difficulty of Embryo Transfer Affect Live Birth?

The technique used for embryo transfer (ET) can affect implantation. Prior research that evaluated the effect of postprocedural blood of the transfer catheter tip have yielded mixed results, and it is unclear whether this is actually a marker of difficulty of the transfer. Our objective was to estimate the effect of blood at the time of ET and the difficulty of ET on live birth rates (LBR). This retrospective cohort study utilized generalized estimating equations (GEEs) with nesting for repeated cycles for all analyses. Univariate modeling was performed and a final multivariate (adjusted) GEE model accounted for all significant confounders. Embryo transfers were subjectively graded (easy, medium, or hard) by a physician at the time of transfer. The presence of blood at ET was associated with more difficult ETs, retained embryos, and presence of mucous in the catheter. In the univariate analysis, ET with blood was not associated with live birth, while the degree of difficulty for ET had a negative impact on LBR. In the final multivariate GEE model, which accounts for repeated cycles from a patient, the only factors associated with an increased LBR were the degree of difficulty of the ET, female age, and blastocyst transfer. After controlling for confounding variables, the presence of blood in the transfer catheter was not associated with the likelihood of pregnancy and thus was not an independent predictor of cycle outcome. This indicates that the difficulty of the transfer itself was a strong negative predictor of pregnancy.

Effect of the afterloaded external guidance embryo transfer technique on pregnancy rates in single embryo transfer cycles

OBJECTIVE

To investigate effect of the afterloaded external guidance embryo transfer technique on pregnancy rates in single embryo transfer intracytoplasmic sperm injection (ICSI) cycles.

MATERIAL AND METHODS

This retrospective study was performed at the Dr. Zekai Tahir Burak Women's Health Research and Education Hospital. Three hundred and thirteen women who underwent ICSI were included in the study. Subjects were categorized according to the embryo transfer technique; Group 1 (n: 232): easy transfer with a soft catheter, Group 2 (n: 45): after external guidance transfer, and Group 3 (n: 36): difficult transfer with a stylet. Basal parameters, clinical and laboratory IVF outcomes and pregnancy rates were studied.

RESULTS

Infertility etiology, basal follicle stimulating hormone (FSH) levels, antral follicle count, duration of stimulation, total dose of gonadotropin, peak estradiol levels, endometrial thickness, oocyte number, 2 PN, and fertilization rate were similar between the three groups (p>0.05). Despite the decreased pregnancy rate in Group 3, there were no differences in clinical pregnancy rates among the groups (p=0.204).

CONCLUSION

Embryo transfer is one of the critical steps in assisted reproduction procedures. Using the afterloaded external guidance embryo transfer technique did not improve pregnancy rates.

Correlation of technical difficulty during embryo transfer with rate of clinical pregnancy

AIM

To correlate the ease or difficulty of embryo transfer and blood at catheter tip with pregnancy rate when embryo transfer (ET) was performed by the same operator using soft catheter.

MATERIALS AND METHODS

A retrospective analysis of 342 patients who underwent in vitro fertilization or ICSI cycle from January 2008 to December 2010 in a single centre was done. The type of transfer was divided into two groups: 'easy' or 'difficult'. Transfer was considered difficult when additional instrumentation was required or firmer catheter was used or required changing of catheter. Patients undergoing cryo-preserved ET were excluded from the study.

RESULTS

On the day of transfer in 284 (83%) patients, ET was easy and difficulty was encountered in 58 (17%) patients. Blood at catheter was seen in 101 (29.53%) patients. In the group of 58 difficult transfers, 10 pregnancies resulted with a clinical pregnancy rate of 17.2%, while 67 pregnancies resulted in 284 cycles of easy transfer with clinical pregnancy rate of 23.6% (P value = 0.045). While no significant difference was seen in pregnancies with blood on outer catheter and blood less transfer, there was significant reduction in pregnancy rate when blood was present on catheter tip compared to bloodless transfer (13.3% v/s 24.1; P value = 0.032).

CONCLUSION

Reduction in clinical pregnancy rate is seen with difficult ETs, more when blood is present at the catheter tip.

Quality Management Issues in the Assisted Reproduction Laboratory

In the United States, the Clinical Laboratory Improvement Act (CLIA) of 1988 describes requirements and guidelines for implementing a quality control/quality assurance (QC/QA) program for moderate and high complexity laboratories. These requirements and guidelines apply to Assisted Reproductive Technology (ART) laboratories as well. The general topic of QC and QA as it pertains to in vitro fertilization (IVF) and embryo transfer (ET) is extensively reviewed. This review summarizes many of the QC and QA events that contribute to the advancement of knowledge in this biotechnological field. These events include control of the culture environment inside and outside of the incubator, as well as factors that affect culture media. This review also discusses, in considerable detail, the QC and the QA that pertain to equipment used within the laboratory and how to control for potential contaminants, which reside within the laboratory. This review provides evidence to indicate the need for laboratory personnel to monitor quality improvement issues on a continuous basis. Personnel must be willing to change as improvements in technology occur in order to meet the ever-evolving demands of a more difficult patient population. Suggestions for meeting these demands are offered.

[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.

Prospective randomized comparison of Wallace and Labotect embryo transfer catheters

The aim of this study was to compare the clinical performance of Wallace and Labotect embryo transfer catheters in a single assisted reproduction centre. A total of 260 women undergoing embryo transfer were randomized between Wallace and Labotect catheters. When both catheters failed to negotiate the cervical canal, the transfer was accomplished with a stiff catheter. Intention to treat analysis revealed that Wallace and Labotect embryo transfer catheters yielded statistically similar clinical pregnancy (44.6 versus 34.6%), implantation (23.2 versus 18.9%) and ongoing pregnancy (38.5 versus 27.7%) rates. As treated analysis revealed clinical pregnancy rates of 42.5 versus 35.4%, implantation rates of 22.3 versus 20.6% and ongoing pregnancy rates of 36.8 versus 28.3% with Wallace and Labotect catheters respectively. Catheter change due to unsuccessful negotiation of the internal cervical os was significantly more frequently necessary when embryo transfer was first intended with the Wallace than the Labotect catheter (P < 0.001; 33 and 2% respectively). Although not being statistically significant, the observed differences may be regarded as clinically important and may reach statistical significance in larger trials. More trials are necessary before reaching a definitive conclusion regarding the performance of the Labotect embryo transfer catheter.

Firm embryo transfer catheters for assisted reproduction: a systematic review and meta-analysis using direct and adjusted indirect comparisons

A systematic review of published evidence on firm embryo transfer catheters is presented. Extensive searches were conducted for full-text manuscripts, abstracts, ongoing and unpublished trials. Direct and adjusted indirect comparisons were undertaken, where appropriate. Twenty-six randomized controlled trials comparing embryo transfer catheters were identified. Only two trials (314 transfers) compared different firm embryo catheters. Using direct comparison, both the Tom Cat and Tefcat catheters demonstrated statistically significant increased chances of clinical pregnancy compared with the Tight Difficult Transfer (TDT) catheter (P=0.007; OR=3.67, 95% CI=1.48-9.10 and P<0.0001; OR=4.71, 95% CI=2.34-9.48 respectively). The implantation rates were also higher with the Tom Cat and Tefcat catheters than the TDT catheter (P=0.005; OR=3.67, 95% CI=1.48-9.10 and P<0.00001; OR=4.29, 95% CI=2.45-7.50 respectively). Using adjusted indirect comparison, Tom Cat and Tefcat catheters were compared, and shown to have similar pregnancy and implantation rates (OR=0.99; 95% CI=-0.87-1.79 and OR=0.86; 95% CI=-0.77-1.35). In conclusion, both Tom Cat and Tefcat catheters give better outcomes than the TDT catheter, but are similar to each other.

A review and meta-analysis of prospective trials comparing different catheters used for embryo transfer

OBJECTIVE

To determine the relative efficacy of different types of embryo transfer (ET) catheters.

DESIGN

Systematic review and meta-analysis of prospective randomized, controlled trials comparing at least two different ET catheters.

SETTING

Infertility centers providing treatment with in vitro fertilization/embryo transfer (IVF-ET).

PATIENT(S)

Women undergoing ET.

INTERVENTION(S)

Embryo transfer with soft or hard catheters.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate.

RESULT(S)

A total of seven prospective trials were identified that compared soft (Cook or Wallace) catheters with hard (TDT, Frydman, Tomcat, Rocket) catheters. The meta-analysis demonstrated an increased chance of clinical pregnancy when soft ET catheters were used. The TDT catheter was compared against both soft catheters and other hard catheters, showing decreased chance of clinical pregnancy when the TDT catheter was used. Six more prospective trials were identified comparing the Cook and Wallace soft catheters, and the meta-analysis of these data showed no demonstrable difference in clinical pregnancy rates.

CONCLUSION(S)

An increased chance of clinical pregnancy is achieved when soft ET catheters are used. There appears to be little difference between the Cook and Wallace soft catheters.

Embryo transfer: factors involved in optimizing the success

PURPOSE OF REVIEW

Embryo transfer is arguably the most critical step in assisted reproduction. The purpose of this article is to review the different aspects of the procedure in the light of recent evidence.

RECENT FINDINGS

Randomized trials have shown that significantly higher pregnancy rates are obtained when embryo transfer is performed under ultrasound guidance, the embryos are deposited in the middle part of the uterine cavity, an atraumatic technique is used and when low-dose aspirin is routinely administered following the procedure. Blood in the catheter and leaving the embryos inside it for more than 120 s diminish the pregnancy rate significantly. Air in the catheter, immediate removal of the catheter, performing two transfers in the same cycle, prolonged bed rest, sexual intercourse after embryo transfer or the use of sildenafil do not affect the results. Based on currently available evidence, Cochrane reviews have concluded that the live birth rate is not increased by delaying embryo transfer from day two to three or to the blastocyst stage, and that single embryo transfer leads to lower live birth rates than the transfer of two embryos. The value of a mock transfer a few days before the actual procedure has been challenged as the position of the uterus may change. The effect of holding the cervix with a volsellum, routinely administering antibiotics and the superiority of one catheter over the others is still to be determined.

SUMMARY

Recent studies confirm the importance of the various aspects of embryo transfer. More randomized studies are needed to further evaluate them.

Cannulation of a resistant internal os with the malleable outer sheath of a coaxial soft embryo transfer catheter does not affect in vitro fertilization–embryo transfer outcome

OBJECTIVE

To assess the impact of cannulation of a resistant cervical os with the outer malleable sheath of a double-lumen, soft ET catheter on IVF-ET outcomes.

DESIGN

Retrospective cohort study.

SETTING

University-based IVF center.

PATIENT(S)

One hundred forty-two patients undergoing 142 ETs.

INTERVENTION(S)

Trial ultrasound-guided ET at all transfers, leaving the malleable outer sheath in situ when the soft inner catheter could not negotiate the internal os.

MAIN OUTCOME MEASURE(S)

Implantation rate and clinical pregnancy rate.

RESULT(S)

In 102 ETs (71.8%), the soft inner sheath easily negotiated the internal os (group 1). Forty ETs (28.2%) required cannulation of resistant internal ora with the outer sheath of the trial catheter (group 2). Implantation rates (35% vs. 32% in groups 1 and 2, respectively) and clinical pregnancy rates (50% vs. 45%) were not significantly different between groups. Blood was present on the transfer catheter after ET more frequently in group 2 than in group 1 (55% vs. 15%); however, neither the implantation rate nor the clinical pregnancy rate were affected by the presence of blood.

CONCLUSION(S)

Cannulation of a resistant internal os by the malleable outer sheath and blood on the transfer catheter after ET do not have an adverse effect on implantation rate or clinical pregnancy rate.