A postal survey of embryo transfer practice in the UK

National Survey Highlights the Urgent Need for Standardisation of Embryo Transfer Techniques in the UK

Embryo transfer (ET) is one of the vital steps in the in vitro fertilisation (IVF) process, yet there is wide variation in ET technique throughout the UK, without a nationally approved standardised approach. The aim of this study was to gain contemporaneous information regarding the current clinical ET practice in the UK.

METHOD

A 38-question electronic survey was distributed to the 79 UK Human Fertilisation and Embryology Authority (HFEA) registered clinics performing ETs.

RESULTS

In total, 59% (47/79) of units responded, 83% (39/47) performing ultrasound-guided transfers, with 42% (20/47) of units using a tenaculum; 22% (10/45) would proceed with transfer regardless of fluid in the endometrial cavity. In 91% (43/47) of units, embryos were deposited in the upper/middle portion of the uterine cavity, but interpretation of this area ranged from 0.5 to >2 cm from the fundus, with 68% (32/47) allowing patients to mobilise immediately after transfer. In 60% (27/45) of clinics, success rates were based on clinical pregnancy rates (CPR).

CONCLUSION

Within the UK there is a wide range of variability in ET techniques, with >70% of discordance in survey-responses between clinics. Whilst there are areas of good practice, some disadvantageous techniques continue to persist. This survey emphasises the importance of developing a standardised, evidence-based approach to improve ET success rates.

Is the clinician an independent variable in embryo transfer outcomes under standardized direct and indirect supervision? A 5-year observational cohort study

Objective: To compare the cumulative pregnancy rate (CPR) for experienced clinicians and trainees naive to the skill of embryo transfer (ET) during an assisted reproductive treatment (ART) cycle. To establish the minimum number of procedures required to achieve consistent outcomes. Method: A non-interventional retrospective observational cohort study looking at all consecutive ETs undertaken over a 5-year study period. The CPR was determined by a self-reported urinary home pregnancy test undertaken 16 days after oocyte retrieval. Results: The CPR did not differ between an experienced clinician (39%) and trainee (45%) for the first 50 (p=0.41) and last 50 (40.7% versus 42.7%) (p=0.81) ET procedures. The CPR for the individuals remained consistent with their peaks and troughs mirroring the overall success rate of the unit. This pattern continued when the data was further stratified for co-variables (age [≤37 years of age], catheter type [soft] and embryo quality [expanded blastocyst of grade ≥2]): CPRs for experienced clinicians was 65.7% (first 50 transfers) and 40.9% (last 50 transfers); CPR for trainees was 66.7% (first 50 transfers) and 53.6% (last 50 transfers); p=0.95 and p=0.37, respectively. The trainees, however, were more likely to use a stylet catheter with a 2-step transfer technique, with a cost over clinical implication. Furthermore, patients expressed a preference for an experienced clinician to perform their procedure, despite being informed that the grade of the clinician had no impact on the cycle outcome after an analysis of the unit's data. Conclusion: The clinician's grade and duration of service have not been shown to significantly impact the outcome of the ART cycle. The findings, however, should be interpreted with caution, as they reflect the culture of training in the unit, where there is a strong emphasis on adequate direct and indirect supervision. Furthermore, the relationship between the volume of work and outcomes is established in postgraduate medical education, with the exact number required to achieve clinical competence being dependent on the procedure and intensity of the workload.

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.

The Impact of the Depth of Embryo Replacement into the Uterine Cavity under Transabdominal Ultrasound Guidance on In Vitro Fertilization and Embryo Transfer Outcome

Aim: The aim of the present study was to determine the importance of the depth of embryo replacement into the uterine cavity (upper or lower half endometrial cavity) on the implantation clinical pregnancy rates.Material and Methods: In this prospective observational were included 160 patients underwent controlled ovarian hyperstimulation followed by IVF/ICSI and embryo transfer. On the day of embryo transfer under direct transabdominal ultrasound guidance, the transfer catheter was advanced to a defined distance from the uterine fundus, up to the point estimated for transfer: 10 ± 2.5 mm (Group A) and 15 ± 2.5 mm (Group B).Results: In total, 160 patients, aged 24-42 years were included in the study. Overall clinical pregnancy rate were 41.2%. Analysis of our results demonstrated that pregnancy rate is significantly influenced by transfer distance from the fundus where the  pregnancy rate decreases from 48.7% in group B to 34.5%  in group A (p<0.05). There was not significantly difference in abortion rate between the two groups.Conclusion: In conclusion, our results suggest that depth of embryo replacement inside the uterine cavity may influence the pregnancy rates and should be considered as an important factor to improve the success of IVF cycles.

Factors affecting pregnancy in IVF: age and duration of embryo transfer

The aim of this retrospective study was to investigate factors affecting clinical pregnancy rates, especially age and duration of embryo transfer, in IVF/intracytoplasmic sperm injection cycles (1313 embryo transfers). Overall clinical pregnancy rate was 30.0% (n=394). Clinical pregnancy rates were found to be 31.6% for the <44 s interval, 25.9% for the 45-59 s interval and 23.6% for the > or = 60 s interval (P=0.020). In the <35 year age group, clinical pregnancy rates were 35.1%, 29.9% and 30.6%, and in the > or = 35 year age group, they were 26.9%, 21.0% and 13.4% (P=0.013), respectively. According to logistic regression analyses, the odds of failed pregnancy increased by 1.61 times [95% confidence interval (CI) 1.07-2.41] for embryo transfer durations longer than 60 s and odds ratios of a failed pregnancy were 1.53 (95% CI 1.18-1.99) in the > or = 35 year age group, 1.49 (95% CI 1.05-2.12) for fewer than five oocytes and 3.38 (95% CI 2.10-5.43) for fewer than two transferred embryos. In conclusion, to increase the likelihood of a successful pregnancy in women over 35 years of age, the duration of embryo transfer must be kept below 60 s. The number of oocytes obtained and the number of transferred embryos also play a role in the success of pregnancy.

What is the best site for embryo deposition? A systematic review and meta-analysis using direct and adjusted indirect comparisons

The site of embryo replacement has been postulated as being important to the success of IVF/ICSI. In order to determine the best site for embryo deposition during embryo transfer, a meta-analysis of randomized trials comparing different uterine deposition sites was undertaken. Electronic (e.g. PubMed, EMBASE, Cochrane Library, LILACS) and hand searches were performed to locate trials. Outcomes measures were the live-birth (LBR), ongoing pregnancy (OPR), and clinical pregnancy rates (CPR). Assessments of the endometrial cavity length (ECL) and the distance from the fundus to the tip of the catheter (DTC) were utilized. Six studies were identified, of which three were excluded. Meta-analysis was conducted with the Mantel-Haenszel method, utilizing the fixed-effects model. The LBR and OPR showed an increasing trend when transfers were performed to the lower half of the uterine cavity. For the DTC, all rates were significantly higher for the approximately 20 mm versus approximately 10 mm distance from the uterine fundus, supporting the results of the ECL analysis. The results of this systematic review show that there is limited evidence of the superiority of lower cavity transfers (e.g. approximately 20 mm) compared with the traditional high cavity (e.g. approximately 10 mm) transfers. More well-designed and powered randomized trials are needed to confirm this conclusion.

The impact of the depth of embryo replacement on IVF outcome

PURPOSE

To evaluate the effect of the depth of embryo transfer replacement on clinical pregnancy rate.

METHODS

Data from a total of 104 consecutive embryo transfers performed on 104 women aged 26-37 years were prospectively collected for this study. All patients underwent a standard down regulation protocol for ovarian stimulation. Oocytes retrieval were performed at 36 h after hCG administration. Embryo transfer took place at 48 h after insemination. The patients were matched in two groups according to the distance between the tip of the catheter and the uterine fundus at transfer (group A > 10 < 15 mm and group B < or = 10 mm). The same method of loading embryos into the embryo transfer catheter was used.

RESULTS

Clinical pregnancy rates varied significantly (p < or = 0.05) between the two groups: 27.7% in group A and 14% in group B. The number and quality of embryos transferred did not differ between the groups.

CONCLUSIONS

The results suggest that the depth of embryo replacement may be an important variable in embryo transfer technique.

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.

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.

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.

Soft versus firm embryo transfer catheters for assisted reproduction: a systematic review and meta-analysis*

BACKGROUND

The true impact of the embryo transfer catheter choice on an IVF programme has not been fully examined. We therefore decided to systematically review the evidence provided in the literature so that we may evaluate a single variable in relation to a successful transfer, the firmness of the embryo transfer catheter.

METHODS

An extensive computerized search was conducted for all relevant articles published as full text, or abstracts, and critically appraised. In addition, a hand search was undertaken to locate any further trials.

RESULTS

A total of 23 randomized controlled trials (RCT) evaluating the types of embryo transfer catheters were identified. Only ten of these trials, including 4141 embryo transfers, compared soft versus firm embryo catheters. Pooling of the results demonstrated a statistically significantly increased chance of clinical pregnancy following embryo transfer using the soft (643/2109) versus firm (488/2032) catheters [P = 0.01; odds ratio (OR) = 1.39, 95% confidence interval (CI) = 1.08-1.79]. When only the truly RCT were analysed, the results were again still in favour of using the soft embryo transfer catheters [soft (432/1403) versus firm (330/1402)], but with a greater significance (P < 0.00001; OR = 1.49, 95% CI = 1.26-1.77).

CONCLUSION

Using soft embryo transfer catheters for embryo transfer results in a significantly higher pregnancy rate as compared to firm catheters.

Immediate ambulation after embryo transfer: A prospective study

OBJECTIVE

To assess whether bed rest following the embryo transfer (ET) procedure contributes to the implantation process and pregnancy rate.

DESIGN

A prospective (patient-influenced) study.

SETTING

An in vitro fertilization (IVF) unit of an academic medical center.

PATIENT(S)

Four hundred six patients undergoing controlled ovarian hyperstimulation and IVF.

INTERVENTION(S)

All women undergoing in vitro fertilization-embryo transfer (IVF-ET) cycles in our unit were given a special individual counseling session before the ET procedure in which they were informed that our previous experience showed no advantage for bed rest over immediate ambulation after ET. The women were allowed to select the practice of their choice, and they were assured that their decision would have no influence on their further treatment.

MAIN OUTCOME MEASURE(S)

The stimulation pattern and cycle outcome were compared between the two groups (bed rest and immediate ambulation).

RESULT(S)

Of the 406 patients counseled during the study period, 167 preferred immediate ambulation and 239 opted to stay in the unit for 1 hour's bed rest. There were no significant differences between the groups in mean patient age, number of embryos transferred, and other variables of the assisted reproductive technique cycles. Pregnancy rates did not differ between the groups: 41 out of 167 (24.55%) in the immediate-ambulation group and 51 out of 239 (21.34%) in the bed-rest group.

CONCLUSION(S)

Immediate ambulation following the ET procedure has no adverse influence on the ability to conceive.

Air in the transfer catheter does not affect the success of embryo transfer

OBJECTIVE

To investigate the effect on embryo transfer (ET) success of air loaded into the transfer catheter to bracket the embryo-containing medium.

DESIGN

Prospective, randomized study.

SETTING

University teaching hospital.

PATIENT(S)

One hundred two consecutive patients undergoing ET after IVF.

INTERVENTION(S)

In group 1 (n = 52), embryos were loaded as follows: 200 microL of air in the syringe, 100-125 microL of air in the proximal part of the catheter, 20-25 microL of medium containing the embryos to be transferred, and 10 microL of air at the tip of the catheter. In group 2 (n = 50), the syringe and the entire catheter were filled with medium and the embryo-containing medium (20-25 microL) was aspirated without being bracketed by air spaces.

MAIN OUTCOME MEASURE(S)

Implantation and pregnancy rates.

RESULT(S)

No differences were found between groups 1 and 2 with respect to implantation and pregnancy rates.

CONCLUSION(S)

The air loaded into the transfer catheter to bracket the embryo-containing medium has no negative effect on ET success.

Impact des techniques de transfert sur l’implantation

Embryo transfer is an important step in the success of IVF treatment. All efforts should be made to avoid difficult embryo transfers provoking bleeding or uterine contractions. Evaluation before IVF treatment, including a trial transfer and a uterine ultrasonography, should allow one to evaluate the transfer step, anticipate problems, and thus improve treatment. An hysteroscopy can be useful for uterine cavity exploration. It is also important to remove cervical mucus before introduce the transfer catheter. It is essential to deposit embryos as gently as possible during IVF, avoiding manoeuvres that might trigger uterine contractions which could adversely affect the results of this treatment. Soft catheters perform better, and ultrasound-guidance facilitates embryo transfer. Progesterone administration starting on the day of oocyte retrieval induces a decrease in uterine contraction frequency on the day of ET (embryo transfer). Both Wallace and CDD catheters perform similarly. Trial catheterization on the day of ET could prevent most of the unanticipated procedural difficulties during the transfer.

Influence of embryo transfer depth on in vitro fertilization and embryo transfer outcomes

OBJECTIVE

To investigate the influence of transfer distance from the fundus (TDF) on clinical pregnancy rate (PR) and ectopic pregnancy rate.

DESIGN

Retrospective cohort. Between January 2000 and December 2001, 699 ultrasound (US)-guided embryo transfers were conducted. Mock transfer was performed to measure uterine cavity depth 1 month before treatment. Cavity depth was measured by abdominal US before the transfer, from the vaginal stripe to the fundus. Transfers were performed with a Wallace embryo transfer catheter (Cooper Surgical, Shelton, CT) using US and physician's judgment of cavity depth. Transfer distance from the fundus was calculated by subtracting the depth of catheter insertion from the cavity depth, as determined by US or by mock transfer. Statistical analyses were performed by building a multivariable logistic regression model to calculate odds ratios and 95% confidence intervals (CI).

SETTING

Women aged 23 to 43 years who are in a university-affiliated, community-based IVF program in Springfield, Massachusetts.

PATIENT(S)

All patients enrolled in IVF program undergoing embryo transfer.

INTERVENTION(S)

No patient received any additional procedure or intervention. All of the measurements obtained with the embryo catheter and the transvaginal ultrasound were part of the program's protocol for the embryo transfer.

MAIN OUTCOME MEASURE(S)

Odds ratio examining relationship between embryo transfer depth and PR.Clinical, implantation, and ectopic PR were 37%, 20%, and 2.1%. Cavity depth by US differed from cavity depth by mock by at least 10 mm in >30% of cases. The TDF by US was highly predictive of PR; TDF by mock was not predictive of PR. Increasing the TDF by US resulted in significantly increased PR as well as lower ectopic rates. Using regression analysis, the odds ratio for TDF by US was 1.11 (95% CI: 1.07-1.14). This suggests that for every additional millimeter embryos are deposited away from the fundus, the odds of clinical pregnancy increased by 11%.

CONCLUSION(S)

After controlling for potential confounders, the clinical PR is significantly influenced by the transfer distance from the fundus. Cavity depth by US is clinically useful to determine the depth beyond which catheter insertion should not occur.

The transfer point is a novel measure of embryo placement

OBJECTIVE

To study the relationship between IVF-ET pregnancy outcomes and measures of embryo placement.

DESIGN

Case-control study.

SETTING

Tertiary care center.

PATIENT(S)

Twenty-three patients who underwent two ultrasonography-guided ETs, of which one resulted in a clinical pregnancy and the other did not.

MAIN OUTCOME MEASURES

Point of embryo placement normalized to the endometrial cavity length (the transfer point), distance from the point of embryo placement to the uterine fundus, time required for ET, contact with the uterine fundus, and evidence of trauma. Videotaped ETs were quantitatively analyzed.

RESULT(S)

From February 1, 2000, to March 31, 2001, videotaped ETs from 23 pairs of pregnant and nonpregnant cycles were identified. Embryo placement was more shallow in pregnancy cycles than in nonpregnancy cycles. The groups did not differ in the absolute distance of embryo placement to the fundus, ovarian stimulation, or other features of the ET.

CONCLUSION(S)

The transfer point may serve as a better marker of embryo position than does the absolute distance to the uterine fundus.

The usefulness of ultrasound guidance in frozen-thawed embryo transfer: a prospective randomized clinical trial

BACKGROUND

Recent randomized controlled trials have shown that implantation and pregnancy rates were improved with ultrasound-guided embryo transfer compared with clinical touch in fresh IVF cycles associated with supraphysiological ovarian steroid levels. However, the usefulness of ultrasound guidance in frozen-thawed embryo transfer where potential hormonal influences are lacking has not been appropriately investigated.

METHODS

A total of 184 consecutive patients undergoing thawed embryo transfer cycles with hormone replacement under pituitary suppression were randomized by computer-generated randomization table to two study groups: 93 had ultrasound-guided (group 1) and 91 had clinical touch (group 2) embryo transfer.

RESULTS

There was equal distribution between the two study groups with respect to the main demographic and baseline characteristics of the patients as well as the characteristics of both prior IVF cycles from which embryos were generated and cryopreserved-thawed embryo transfer cycles. However, both pregnancy and implantation rates in group 1 (34.4 and 19.8% respectively) were significantly higher than the corresponding values (19.7 and 11.9%) in group 2.

CONCLUSIONS

Ultrasound guidance in frozen-thawed embryo transfer significantly increases pregnancy and implantation rates.

Ultrasound-guided embryo transfer improves pregnancy rates and increases the frequency of easy transfers

BACKGROUND

Recent reports have suggested that ultrasound (US) guidance during embryo transfer might improve pregnancy rates.

METHODS

A prospective randomized (computer-generated random table) trial was performed to compare embryo transfer under abdominal US guidance (n = 255 women) with clinical touch embryo transfer (n = 260).

RESULTS

The clinical pregnancy rate was 26.3% (67/255) in the US-guided transfer group compared with 18.1% (47/260) in the clinical touch transfer group (P < 0.05). The implantation rate was 11.1% (100/903) in the US group compared with 7.5% (66/884) in the clinical touch group (P < 0.05). US-guided transfer was associated with a decrease in the difficulty of the transfers: 97% of transfers were easy in the US-guided group compared with 81% in the clinical touch group (P < 0.05).

CONCLUSIONS

US-guided embryo transfer increased pregnancy and implantation rates in IVF cycles, as well as the frequency of easy transfers. It is suggested that the decrease in cervical and uterine trauma can play a role in the increase in pregnancy rates associated with US-guided transfer. It is recommended that embryo transfer should be performed under US guidance.

Ultrasound measurement of the uterocervical angle before embryo transfer: a prospective controlled study

BACKGROUND

The study aim was to determine whether moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound could improve pregnancy and implantation rates.

METHODS

Patients were alternately allocated to one of two groups. In the ultrasound-guided group (n = 320), the catheter was moulded according to the uterocervical angle measured by abdominal ultrasound. In controls (n = 320), embryo transfer was performed using the "clinical feel" method.

RESULTS

Moulding the embryo transfer catheter according to the uterocervical angle significantly increased clinical pregnancy [(OR = 1.57, 95% CI (1.08-2.27)] and implantation rates [(OR = 1.47, 95% CI (1.10-1.96)] compared with the "clinical feel" method. It also significantly reduced difficult transfers [(OR = 0.25, 95% CI (0.16-0.40)] and blood during transfers [OR = 0.71, 95% CI (0.50-0.99)]. Patients with large angles (>60 degrees ) had significantly lower pregnancy rates compared with those with no angle [OR = 0.36, 95% CI (0.16-0.52)].

CONCLUSIONS

Moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound increases clinical pregnancy and implantation rates and diminishes the incidence of difficult and bloody transfers.

A randomized controlled trial of a soft double lumen embryo transfer catheter versus a firm single lumen catheter: significant improvements in pregnancy rates

BACKGROUND

Embryo transfer has changed little since originally described in 1978. Clinicians rate the type of catheter used as the third most important variable in embryo transfer, but there are no adequately powered randomized trials. We compared the clinical pregnancy rates with the single lumen catheter (TCC) and the double lumen catheter (CC) in a randomized single blind trial.

METHODS

A total of 650 cycles of women from the Adelaide University reproductive medicine units in Australia were included in this trial. Patients were <40 years of age undertaking IVF and embryo transfer. Exclusion criteria were: known uterine abnormality, day 3 FSH >10 IU/l, previous difficult embryo transfer and pre-implantation genetic diagnosis. Cycles were randomized from numbered sealed envelopes immediately prior to embryo transfer with stratification for fresh or frozen cycles.

RESULTS

There was a significantly higher pregnancy rate in the group treated with the CC compared with the TCC catheter [29.6 versus 20.5% per embryo transfer, odds ratio (OR) = 1.63 (95% confidence interval: 1.14-2.30), P = 0.0076]. The point estimate for the OR was similar for fresh and frozen cycles.

CONCLUSIONS

The pregnancy rate was increased by 50% and this justifies the increased cost of the soft double lumen catheter and the training of clinical staff required.

A prospective randomized comparison of the Wallace catheter and the Cook Echo-Tip catheter for ultrasound-guided embryo transfer

OBJECTIVES

To compare the performance of a new coaxial catheter system with an echo-dense tip (Cook Echo-Tip catheter) with a Wallace catheter during ultrasound-guided ET.

DESIGN

Prospective, randomized study.

SETTING

Private academically affiliated infertility center.

PATIENT(S)

Two hundred fifty-one patients undergoing IVF-ET.

INTERVENTION(S)

The patients underwent ultrasound-guided ET by a single physician with a standardized technique alternately using one of the two catheters.

MAIN OUTCOME MEASURE(S)

Implantation rates, pregnancy rates, ease of transfer, visualization, and status of catheter tip.

RESULT(S)

The echo-dense tip of the Cook Echo-Tip catheter was consistently seen with ultrasound guidance, minimizing the need for catheter movement to identify the tip. Implantation rate (30% vs. 35%), clinical pregnancy rate (57% vs. 55%), and ongoing pregnancy rate (49% vs. 47%) were similar in both groups.

CONCLUSION(S)

The Cook Echo-Tip catheter with its echogenic tip simplifies ultrasound-guided ET, but pregnancy success rates are similar to those obtained when a Wallace catheter is used.

A Wallace malleable stylet for difficult embryo transfer in an in vitro fertilization program: a case-control study

BACKGROUND

The aim of the study was to evaluate the impact of using a Wallace malleable stylet in combination with an Edwards-Wallace embryo replacement catheter in case of difficult embryo transfer (ET).

METHODS

A retrospective case-control study was used. The standard ET procedure at the clinic was to use a single tooth tenaculum, and a speculum to straighten the cervical canal prior to inserting the Edwards-Wallace embryo replacement catheter. In 205 of 2041 (10%) fresh ET difficulties were experienced during ET and a Wallace malleable stylet was used to place the outer catheter sheath correctly. This stylet transfer group was compared with a control transfer group of 410 ET performed just before and after each stylet transfer.

RESULTS

No differences in number of transferred embryos, cleavage stage, or embryo morphology score were found between the two groups. We found no differences in implantation rates (20.7 and 19.2% [95% confidence interval (CI) 0.8-1.5]) or delivery rates (29.3 and 25.4% [CI 0.8-1.8]) between the study and control group.

CONCLUSION

Using a Wallace malleable stylet in combination with an Edwards-Wallace embryo replacement catheter in case of difficult ET has no negative impact on implantation and delivery rates.

The effect of ease of transfer and type of catheter used on pregnancy and implantation rates in an IVF program

PURPOSE

To test the effects of type of embryo transfer catheter, transfer difficulty, and observations after the transfer procedure on pregnancy and implantation rates in an IVF programme.

METHODS

Patients were prepared for IVF using standard protocols. Embryo transfer was performed using either Edwards-Wallace or TDT catheter. The difficulty of transfer was graded by a clinician and biologist. Blood observed inside the catheter after the transfer procedure was scored as endometrial damage. Pregnancy and implantation rates were scored.

RESULTS

Type of embryo transfer catheter and the observation of blood did not significantly affect pregnancy and implantation rates when transfer was performed by a single operator.

CONCLUSIONS

In the hands of experienced, skilled operators, neither choice of transfer catheter and difficulty of transfer nor observations of blood on the transfer catheter caused any significant reduction in outcome to the patient.