Among women undergoing embryo transfer, is the probability of pregnancy and live birth improved with ultrasound guidance over clinical touch alone? A systemic review and meta-analysis of prospective randomized trials

Sonographer-guided frozen embryo transfer vs ultrasound-assisted frozen embryo transfer - A randomised controlled study

BACKGROUND

The use of ultrasound to guide placement of the embryo during in vitro fertilisation (IVF) is important, but there are times where a good image cannot be obtained. Having a trained sonographer perform the ultrasound may therefore improve the success of embryo transfer.

AIM

To determine whether the routine use of a sonographer to guide embryo transfer is superior to standard care.

MATERIALS AND METHODS

Randomised, controlled, prospective clinical study in a private infertility clinic. There were 113 women aged <38 years undergoing frozen embryo transfer (donor egg/embryo excluded) who were randomised to sonographer-guided embryo transfer or standard care (the doctor performs an ultrasound prior to embryo transfer and the patient holds the ultrasound probe). The primary outcome was visualisation of the air bubble, and secondary outcomes were distance of the air bubble from the fundal endometrium, pregnancy rate (gestational sac on ultrasound at seven weeks) and live birth rate.

RESULTS

The bubble was visualised in 100% of embryo transfers with a sonographer compared to 83% in the ultrasound-assisted group, and this was statistically significant (P < 0.01). No statistically significant differences were found in terms of distance from the fundal endometrium or in pregnancy rate and live birth rate.

CONCLUSION

Sonographer-guided embryo transfer leads to statistically higher rates of visualisation of the air bubble compared to ultrasound-assisted transfer.

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.

Efficacy of a modified transvaginal ultrasound-guided fresh embryo transfer procedure

OBJECTIVE

To present a modified transvaginal ultrasound (TVUS) guided embryo transfer (ET) procedure and analyze its efficacy in comparison with conventional transabdominal ultrasound (TAUS) guided ET in an unselected population of Brazilian women.

METHODS

This retrospective observational case-control study involved 447 fresh ET cycles, 221 guided by TVUS (Group 1), conducted between June 2016 and February 2019, and 226 by TAUS (Group 2), conducted between July 2012 and December 2015. Pregnancy rate was the main endpoint. Groups were compared using the Z test at a level of significance of 95% (p≤0.05).

RESULTS

Patient age ranged from 21 and 48 years; mean age was 37.7 years in Group 1 and 38 years in Group 2. Overall, patients that underwent TVUS-guided fresh ET demonstrated significantly higher pregnancy rates than their counterparts that underwent TAUS-guided fresh ET (p=0.0107). TVUS-guided fresh ET also yielded significantly higher pregnancy rates in the subgroups of women aged 36-39 years (p=0.0037) and ≥ 40 years (p=0.0025). However, no significant pregnancy rate difference was observed in women aged ≤ 35 years (p=0.0905).

CONCLUSIONS

The results suggested that TVUS-guided fresh ET was at least as effective as TAUS-guided fresh ET in the studied sample. Pending further prospective studies to better ascertain the effect of TVUS-guided ET, the technique presented deserves consideration since it can offer better visualization, more comfort to patients, and requires only one operator, without negatively affecting pregnancy results.

The Role of Transvaginal Ultrasound Guided Embryo Transfer to Improve Pregnancy Rate in Obese Patients Undergoing Intracytoplasmic Sperm Injection

OBJECTIVE

To evaluate the effectiveness of transvaginal ultrasound (TVUS) versus the transabdominal ultrasound (TAUS) guided embryo transfer (ET) in obese patients undergoing Intracytoplasmic sperm injection (ICSI).

DESIGN

A prospective randomized controlled trial.

SETTING

University hospital.

PATIENTS

Eight hundred participants with BMI ≥30 received the long agonist protocol. They were randomized into 2 equal groups of 400 patients. Each group had either TAUS guided ET or TVUS guided ET.

MAIN OUTCOME MEASURES

Our primary outcomes were clinical pregnancy rate, degree of patient pain assessed by visual analogue scale (VAS). The secondary outcomes were live birth rate, implantation rate, miscarriage and chemical pregnancy rates, duration of ET.

RESULTS

Our results showed a significant higher chemical and clinical pregnancy rates in the TVUS group in comparison to TAUS group (45.3% vs. 38.3%, p=0.045) and (37.8% vs. 30.8%, p=0.044) respectively. There was tendency for increased live birth rates in the TVUS group however it did not reach statistical significance (50.2% vs. 44.8%). The VAS of the pain was significantly less in TVUS group in comparison to the TAUS group (2.1 ±0.7 vs. 4.5 ±1.3), also abdominal discomfort was significantly less in TVUS group in comparison to the TAUS group (13% vs. 58%) p= value 0.0001.

CONCLUSIONS

This study showed superior role of TVUS guided ET over TAUS regarding less pain and better pregnancy and live birth rates in obese participants.

CLINICAL TRIAL REGISTRATION NUMBER

Clinical trial. Gov identifier NCT03473028.

Evaluation of a strategy for difficult embryo transfers from a prospective series of 2,046 transfers

OBJECTIVE

To evaluate an embryo transfer strategy for difficult transfers (DiTs).

DESIGN

Prospective, nonrandomized, observational, cohort study.

SETTING

A hospital fertility center in France.

PATIENTS

Data were collected on all embryo transfers conducted using the strategy between February 2014 and February 2020.

INTERVENTIONS

Anatomical characteristics that could cause DiT were identified by transvaginal ultrasound and the catheter was adapted accordingly. Transfer was guided by transvaginal ultrasound. After passage through the cervix, a rest period was introduced to allow any contractions to stop before embryo deposition in the uterus.

MAIN OUTCOME MEASURES

The primary criterion was the percentage of pregnancies per transfer (P/T) after an easy transfer (EaT) or a DiT. The secondary criteria included the anatomical causes of DiT and the patients' levels of discomfort.

RESULTS

Of 2,046 transfers, 257 (12%) were DiTs: minor difficulties (n = 152; 7.4%), major difficulties (n = 96; 4.7%), very significant difficulties (n = 7; 0.3%), or impossible (n = 2; 0.1%). The most common causes of DiTs were endocervical crypts (54%), tortuous cervical canal (36%), and marked uterine anteversions (30%). Several causes were often responsible for DiTs. There was no statistically significant difference in the P/T between the EaTs (n = 1,789, 41%) and all degrees of DiT (n = 257, 37%). In addition, there was no statistically significant difference between the level of patient-reported discomfort in the EaT and DiT groups.

CONCLUSIONS

This study demonstrated that an adapted embryo transfer strategy, monitored by transvaginal ultrasound, led to similar pregnancy rates regardless of whether the transfer was easy or difficult.

Embryo location in the uterus during embryo transfer: An in vitro simulation

OBJECTIVE

To evaluate the location of transferred embryos under various parameters during embryo transfer in in vitro fertilization (IVF) by applying an in vitro experimental model for embryo transfer (ET).

METHODS

Mock ET simulations were conducted with a laboratory model of the uterine cavity. The transfer catheter was loaded with a sequence of air and liquid volumes, including development-arrested embryos donated by patients. The transfer procedure was recorded using a digital video camera. An orthogonal design, including three independent variables (uterine orientation, distance of the catheter tip to the fundus, and injection speed) and one dependent variable (final embryo position), was applied.

RESULTS

The uterine cavity was divided into six regions. The distribution of the transferred matter within the uterine cavity varied according to the uterine orientation. Medium speed-injected embryos were mostly found in the static region while fast- and slow-speed injected embryos were mostly found in the fundal region and the cervical-left region, respectively. The possibility of embryo separation from the air bubble increased from 11.1% in slow injection cases to 29.6% and 48.1% in medium and fast injection cases, respectively.

CONCLUSION

The experimental model provides a new method for investigating ET procedures. Fast injection of embryos into a retroverted uterus may be more likely to result in embryo separation from the air bubble.

Embryo flash migration in fresh and frozen embryo transfers for day 3 and day 5 embryos

OBJECTIVE

The aim of this study is to evaluate the embryo flash migration after 60 min from embryo transfer in fresh and frozen cycles.

DESIGN

80 fresh and 81 frozen embryo transfers implemented Ondokuz Mayıs University between December 2017 and May 2018 were included in this prospective study. The fresh transfers performed at day 3 embryos as the frozen transfers were day 5 embryos. The distance between the embryo and the fundus was measured in the sagittal plane within 1 min of the transfer. After 60 min of bed rest the distance between the air bubble and the fundus was measured. The transfers were divided into three groups based on the migration of the embryos after the transfer. Embryos were classified as static if they were within 15 mm of their initial position. If they moved more than 15 mm towards the cervix or more than 15 mm towards the fundus, it was classified as cervical and fundal, respectively.

RESULTS

There was a statistically significant difference in embryo flash movements between frozen and fresh transfers (p < 0.05). In fresh transfers 48 patients (%60.0) were cervical, 14 patients (%17.5) were static and 18 patients (22.5%) were fundal. In frozen embryo transfers 31 patients (38.3%) were cervical, 31 patients (38.3%) were fundal and 19 (23.5%) patients were static.

CONCLUSION

We found that cervical migration is lower in frozen transfers than in fresh transfers. This result may be related with the day of embryo or the endometrium in fresh or frozen cycles. Because in this study the embryos transferred were day 3 in fresh cycle and day 5 in frozen cycle. In frozen transfers there was not any significant difference in embryo position between pregnant and non-pregnant group. But in fresh transfers the cervical migration was significantly high in non-pregnant patients (p < 0.05).

Correlation between Ovarian Reserve and Incidence of Ectopic Pregnancy after In Vitro Fertilization and Embryo Transfer

PURPOSE

To elucidate the correlation between ovarian reserve and the incidence of ectopic pregnancy (EP) following in vitro fertilization and embryo transfer (IVF/ET) cycles.

MATERIALS AND METHODS

In this observational study, 430 fresh IVF/ET cycles were examined from patient data of two university hospital infertility clinics. All included patients were positive for β-human chorionic gonadotropin (hCG) at 2 weeks after oocyte retrieval via controlled ovarian stimulation. For each cycle, information on age, duration of infertility, basal follicle stimulating hormone (FSH), anti-Müllerian hormone (AMH), days of ovarian stimulation, numbers of retrieved oocytes and transferred embryos, and pregnancy outcomes was collected. Patients with AMH lower than 1.0 ng/dL or basal FSH higher than 10 mIU/mL were classified into the decreased ovarian reserve (DOR) group, and the remaining patients were classified into the normal ovarian reserve (NOR) group.

RESULTS

In total, 355 cycles showed NOR, and 75 cycles DOR. There were no significant differences between the DOR and NOR groups regarding intrauterine (74.7% vs. 83.4%, respectively) or chemical (14.7% vs. 14.1%, respectively) pregnancies. The DOR group had a higher EP than that of NOR group [10.7% (8/75) vs. 2.5% (9/355), p=0.004]. In both univariate [odds ratio (OR) 5.6, 95% confidence interval (CI) 1.4-9.6, p=0.011] and multivariate (adjusted OR 5.1, 95 % CI 1.1-18.7, p=0.012) analysis, DOR was associated with a higher risk of EP.

CONCLUSION

DOR may be associated with a higher risk of EP in IVF/ET cycles with controlled ovarian stimulation. More careful monitoring may be necessary for pregnant women with DOR.

Accuracy and efficacy of embryo transfer based on the previous measurement of cervical length and total uterine length

PURPOSE

Aim of the study was to examine the accuracy of embryo transfer based on the previous measurement of cervical length and total uterine length.

METHODS

The study has taken place in an academic-assisted reproduction clinic. 248 patients with infertility requiring IVF/ICSI treatment have been included. All patients underwent IVF/ICSI cycles with antagonist protocol and were treated with controlled ovarian stimulation using recombinant FSH (100-400 IU/day). On the day of oocyte retrieval, all patients were given vaginally natural micronized progesterone in a dose of 200 mg/tds. All patients had transvaginal ultrasound measurement of cervical length and endometrial cavity length prior to embryo transfer and measurement of embryo distance (intrauterine air bubbles) from fundal surface of uterine cavity and internal cervical os immediately after embryo transfer. Embryo transfer was performed on days 2-3. Primary outcome was to estimate the accuracy of embryo transfer based on the measurement of the embryo distance from middle of uterine cavity after embryo transfer and secondary outcome was to assess the effect of embryo distance from uterine fundus and internal cervical os to clinical pregnancy rate.

RESULTS

The clinical pregnancy rate was 42.7%. The mean embryo distance from the middle of endometrial cavity was 0.48 ± 0.02 cm, the mean embryo distance from the uterine fundus was 0.88 ± 0.32 cm, and from the internal cervical os was 1.67 ± 0.45 cm. Multiple regression analysis showed that the embryo distance from middle of cavity was related to endometrial cavity length and to the embryo distance from the fundus and it was not related to Cx length, total uterine length, embryo distance from internal Cx os, and embryo transfer length.

CONCLUSIONS

Embryo transfer with the previous measurement of total uterine length and estimation of embryo transfer length can be performed with very good accuracy by a single operator.

Establishment of a trans-vaginal ultrasound-guided pinpoint transfer method

Purpose

Through the use of the trans‐vaginal ultrasound‐guided pinpoint transfer method, the aim was to ensure the safety of the embryo being transferred in cases of difficult cervixes. It also was aimed to be able to stop embryo transfers in difficult cases and to be able to restart the process under anesthesia or cryopreservation.

Methods

A new type of transfer catheter was developed. With this method, after reaching the internal os, the embryologist begins the loading of the embryo into the inner catheter. Then, the embryo transfer begins. Under the guidance of the trans‐vaginal ultrasonography, the optimal position for implantation is selected.

Results

Out of 666 cases, 14 were difficult cervixes. This transfer method enabled 221 of the 666 patients to become pregnant successfully, which was a success rate of 33.2%.

Conclusion

From start to finish, this method takes only 2 min. It is simple, fast, and reliable, with a high satisfaction rate amongst patients.

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.

Large randomized trial comparing transabdominal ultrasound-guided embryo transfer with a technique based on uterine length measurement before embryo transfer

OBJECTIVE

To compare in a randomized, non-inferiority trial the embryo transfer (ET) technique based on uterine length measurement before transfer (ULMbET) with transabdominal ultrasound-guided embryo transfer (TA-UGET) in a large population of patients undergoing in-vitro fertilization (IVF).

METHODS

Patients undergoing IVF with ET with cleaving fresh embryos were randomized to receive ULMbET or TA-UGET. The transfer of one to three embryos on day 2-3 of culture was performed using a soft catheter either under transabdominal ultrasound guidance (TA-UGET group) or after measurement of the uterine cavity by transvaginal ultrasound and calculation of the discharge site (ULMbET group). The primary outcome measures were clinical pregnancy rate, ongoing pregnancy rate and implantation rate, and secondary outcomes included patient discomfort during ET.

RESULTS

A total of 1648 patients undergoing IVF were randomized to receive ULMbET (n = 828) or TA-UGET (n = 820) and were included in the analysis. Comparable clinical pregnancy rate (38.2% vs 38.9%), implantation rate (24.8% vs 25.2%) and ongoing pregnancy rate (33.1% vs 34.8%) were observed in ULMbET and TA-UGET groups. The discomfort intensity score and the proportion of patients with moderate-to-severe discomfort during ET were significantly higher in the TA-UGET group (2.6 vs 1.5 visual analog scale points and 19.8% vs 1.2%; P = 0.045 and P = 0.003, respectively).

CONCLUSION

The ULMbET technique leads to IVF results comparable to those obtained with UGET, but is better tolerated than is TA-UGET and is technically easier to perform for a single operator. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

How often does the embryo implant at the location to which it was transferred?

OBJECTIVE

To determine how often the embryo implants exactly at the site of transfer and what additional factors may affect the eventual site of implantation in assisted reproductive technology (ART) cycles.

METHODS

This was a prospective observational study of women undergoing ART treatment in a tertiary university unit. Several factors inherent to the embryo transfer (ET), such as the location of the air bubbles and uterine contractility at 1 and at 60 min after ET were assessed with two-dimensional and three-dimensional (3D) ultrasound. In women in whom there was a resulting pregnancy, the position of the gestational sac (i.e. right, left, center or low) was subsequently assessed using 3D ultrasound, and predictors of its location were evaluated.

RESULTS

Of 239 recruited women with visualization of air bubbles at ET, 71 singleton gestational sacs were subsequently observed on 3D ultrasound. Overall, 40.8% (29/71) of embryos implanted at the location where the air bubbles were visualized at 1 min after ET, and 50.7% (36/71) implanted where the air bubbles were visualized at 60 min after ET (Cohen's kappa coefficients 0.21 and 0.37, respectively; comparison of agreement values: P = 0.28). Specifically, at 1 min the correspondence between the location of the air bubble and embryo implantation was 37.5% (6/16), 57.1% (8/14), 36.8% (7/19) and 36.4% (8/22) for right, left, central and lower uterus, respectively (4 × 4 contingency table, P < 0.01); at 60 min, the correspondence was 72.2% (13/18), 50.0% (9/18), 33.3% (8/24) and 85.7% (6/7), respectively (5 × 4 contingency table, P < 0.001). In addition, higher vs lower frequency of uterine contractions at 60 min was associated with different sites of implantation (5.6% (1/18), 11.1% (2/18), 27.8% (5/18) and 55.6% (10/18) vs 34.0% (18/53), 24.5% (13/53), 13.2% (7/53) and 28.3% (15/53) for right, left, central and lower uterus, respectively, P < 0.05). In particular, a high uterine contraction frequency following ET was associated with a twofold increased chance of the pregnancy implanting in the lower part of the uterine cavity (relative risk, 1.96 (95% CI, 1.08-3.56), P < 0.05).

CONCLUSIONS

The position of the air bubbles within the first 60 min of ET appears to predict the site of implantation in approximately half of cases, denoting an overall poor agreement. This implies significant embryo migration, and has important clinical implications, as it demonstrates that other factors such as uterine contractility may dictate where the embryo will eventually implant following transfer. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

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.

Absolute position versus relative position in embryo transfer: a randomized controlled trial

BACKGROUND

Meta-analysis revealed that embryo placement 20 mm from the fundal endometrial surface resulted in higher pregnancy rate, ongoing pregnancy rate, and live birth rate compared with placement 10 mm from the fundal endometrial surface. Pregnancy and implantation rates according to relative position were higher when the catheter tip was positioned close to the middle of the endometrial cavity. The aim of the current study is to evaluate differences in implantation and pregnancy rates if the site of embryo transfer is 2 cm distance from the fundal endometrium (DFE) compared to the midpoint of the endometrial cavity length (ECL).

METHODS

Patients were randomized to one of two groups: in group A (n = 98, 98 IVF-ET cycles), the embryo transfer catheter tip was positioned 2 cm DFE, while that in group B (n = 97, 97 IVF-ET cycles) was positioned at the midpoint of the ECL. We compared pregnancy outcomes of implantation rate, chemical pregnancy rate, clinical pregnancy rate, ongoing pregnancy rate, ectopic pregnancy rate, and miscarriage rate in the two groups.

RESULTS

Analysis of implantation rate (19.5 ± 27.7 vs. 21.7 ± 32.6; p = 0.6), chemical pregnancy rate (51 % vs. 50.5 %; p = 0.94), clinical pregnancy rate (35.7 % vs. 38.1 %; p = 0.73), ongoing pregnancy rate (31.6 % vs. 30.9 %; p = 0.92), ectopic pregnancy rate (8.6 % vs. 2.7 %; p = 0.35), and miscarriage rate (11.4 % vs. 16.2 %; 0.74) revealed comparable results for both groups.

CONCLUSIONS

Implantation and pregnancy rates were not influenced by the site of the ET catheter tip being 2 cm DFE compared to at the midpoint of the ECL.

ISRCTN

ISRCTN15972342.

Risk of ectopic pregnancy associated with assisted reproductive technology in the United States, 2001-2011

OBJECTIVE

To assess national trends in ectopic pregnancy incidence among assisted reproductive technology users and identify risk factors associated with ectopic pregnancy.

METHODS

We identified 553,577 pregnancies reported to the National ART Surveillance System between 2001 and 2011. Of those, 9,480 were ectopic, of which 485 were heterotopic. As a result of small numbers, ectopic and heterotopic pregnancies were combined for analysis. We assessed temporal trends in annual ectopic pregnancy rates using Poisson regression. We used log-binomial regression models with generalized estimating equations for correlated outcomes within clinics to calculate unadjusted and adjusted risk ratios for the association between ectopic pregnancy and selected patient characteristics and treatment factors.

RESULTS

The rate of ectopic pregnancy declined from 2.0% (n=735, 95% confidence interval [CI] 1.9-2.2) in 2001 to 1.6% (n=968, 95% CI 1.5-1.7) in 2011 (P for trend <.001). The ectopic pregnancy rate ranged from 2.0% (n=7,469, 95% CI 1.9-2.0) for fresh, nondonor cycles to 1.0% (n=641, 95% CI 0.9-1.1) for fresh, donor cycles. Among fresh, nondonor cycles, the rate of ectopic pregnancy was 1.6% (95% CI 1.4-1.7) when one embryo was transferred compared with 1.7% (95% CI 1.7-1.8), 2.2% (95% CI 2.1-2.3), and 2.5% (95% CI 2.4-2.6) when two, three, or four or more embryos were transferred, respectively (adjusted risk ratios 1.11, 95% CI 0.94-0.30; 1.33, 95% CI 1.12-1.56; and 1.49, 95% CI 1.25-1.78).

CONCLUSION

Ectopic pregnancy incidence after assisted reproductive technology has decreased over time, but factors such as multiple embryo transfer increase the risk of ectopic pregnancy.

LEVEL OF EVIDENCE

II.

Post-embryo transfer interventions for assisted reproduction technology cycles

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Embryo transfer

Embryo transfer is a critical step in the overall success of in vitro fertilization (IVF). Despite its apparent simplicity, it is an integral part of the IVF cycle that can be difficult to teach and perform well. In this chapter we describe the procedure of embryo transfer and discuss various modifications that have been evaluated in an effort to improve the probability of embryo implantation including ultrasound guidance, catheter design, transfer technique, as well as enrichment of the embryo transfer media.

Assessment of pregnancy-associated, within-woman change in uterine length

OBJECTIVE

To evaluate how absolute uterine length changes as a result of pregnancy.

METHODS

Longitudinal repeated-measures study of all women presenting to a university-affiliated clinic for uterine sounding prior to in vitro fertilization (IVF) who went on to deliver at term and return for repeat measurement from 2002 to 2012. Change in uterine length was assessed by the Wilcoxon signed-rank test.

RESULTS

Among 495 women, mean pregnancy-associated change in uterine length was 0.0 cm (SD ± 0.7, p = 0.84), with 31% of women experiencing no change and 75% of women experiencing a change ≤0.5 cm. Mean uterine lengths at pre-cycle and repeat measurement were 7.2 cm (SD ± 0.7) and 7.2 cm (SD ± 0.7) with medians of 7.0 cm (IQR 7.0-7.5) and 7.0 cm (IQR 6.8-7.8), respectively. Change in uterine length did not vary by gestational number or within time interval between measurements (all p > 0.5).

CONCLUSIONS

There was no difference in uterine length before and after term pregnancy. The finding of minimal variation in uterine length both across and within women suggests uterine length may be relatively stable such that patients undergoing IVF after term IVF pregnancy may not require repeat measurement. Future studies might assess pregnancy-associated sonographic changes in uterine volume and the relationship between uterine length and IVF outcomes.

Intraoperative imaging

Intraoperative image is a rapidly expanding field encompassing many applications that use a multitude of technologies. Some of the these applications have been in use for many years and are firmly embedded in, and indispensable to, clinical practice (e.g. the use of X-ray to locate foreign bodies during surgery or oocyte retrieval under ultrasound guidance. In others, the application may have been in use in one discipline but not yet fully explored in another. Examples include the use of intraoperative ultrasound with or without contrast enhancement for the detection of hepatic metastases not identified preoperatively, and the effect of such additional information on the ultimate operative procedure. Intraoperative identification of sentinel lymph nodes has been explored in many specialties to a varying extent, with the aim of fine tuning and avoiding unnecessary surgery. In both these instances, we do not know the long-term effect of these interventions on patient survival or quality of life. In this chapter, we will explore the available evidence on these applications and current advances in the new technology in general, with a specific focus on gynaecology.

The use of ultrasound during intrauterine insemination in unexplained infertility may improve pregnancy outcomes

OBJECTIVE

To investigate the role of ultrasound guidance in intrauterine insemination (IUI).

MATERIALS AND METHODS

A retrospective study was conducted. The data was collected from the records of 197 couples with unexplained infertility who underwent IUI with a total of 267 IUI cycles in the in vitro fertilization center of our hospital between January 2009 and December 2010.

RESULTS

Of the 267 IUI cycles, 145 were carried out as US-guided, while 122 cycles IUI were performed with a blind procedure. In the US-guided IUI and blinded IUI groups, the pregnancy rates were 23.4 and 13.9%, respectively. The difference between the groups was statistically significant (p = 0.049), thereby indicating that US guidance improves pregnancy rates. In the US-guided IUI group, 9.7% of the cases were difficult, while in the blinded IUI group, 26.2% were difficult and the difference between the groups was also statistically significant (p < 0.001).

CONCLUSION

US guidance in IUI improves pregnancy rates and reduces the frequency of difficult IUI.

[Quality of transfer. Biologist and clinician's point of view]

Embryonic transfer is one of the briefest procedures in the long-lasting chain of events occurring during an infertility treatment. Embryo transfer is, however, one of the most crucial steps in assisted reproductive technologies. The realization of this ultimate gesture involves the control of numerous parameters that exert an impact on its success. These various influential factors engage the multidisciplinary team: biologist, clinician... to permanently search for ways to optimize embryo transfer outcome.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

[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.

Firm versus soft embryo transfer catheters under ultrasound guidance: Does catheter choice really influence the pregnancy rates?

In contrast to the previously published evidence, under ultrasound guidance, individual catheter choice does not statistically significantly affect the clinical pregnancy rate in a modern clinical IVF practice. This may be as a result of decreasing the incidence of difficult transfers and endometrial injury with ET under ultrasound guidance.