The importance of the length of uterine cavity, the position of the tip of the inner catheter and the distance between the fundal endometrial surface and the air bubbles as determinants of the pregnancy rate in IVF cycles

Ultrasound Evaluation of Uterine Cavity Changes After Stimulation for In Vitro Fertilization

OBJECTIVES

Mock embryo transfer (ET) before in vitro fertilization (IVF) allows for the clinical determination of uterine cavity length (UCL) to optimize embryo placement during clinical ET. Most studies have shown that optimal pregnancy rates occur with clinical ET at a depth of 15 mm from the uterine fundus. In our study, we sought to determine the effect of ovarian stimulation and endometrial preparation on UCL using 2D transabdominal ultrasound.

METHODS

We performed a retrospective cohort study comparing documented 2D transabdominal ultrasound measurements of UCL at the time of mock ET and clinical ET. Statistical analyses were performed with SPSS v. 26 with paired sample t-test and significance determined with P < .05.

RESULTS

Seventy patients who underwent 91 IVF-ET cycles between 2015 and 2018 at our academic center met inclusion criteria. Patient's demographics include a median age of 34 (interquartile range [IQR]: 31, 37), gravida 1 (IQR: 0, 2), parity 0 (IQR: 0, 0), and body mass index 25.87 (IQR: 21.78, 30.01). There was a statistically significant increase in UCL by 11.9 mm after IVF stimulation (P < .001), compared to mock ET. Mean UCL at the time of mock ET was 7.66 cm (±0.98 cm) and at clinical ET was 8.85 cm (±0.98 cm).

CONCLUSIONS

The uterine cavity undergoes a significant length change during ovarian stimulation and endometrial preparation. These findings confirm the remarkable uterine plasticity in response to hormonal stimulation even before pregnancy ensues. These changes in UCL should be considered during ultrasound-guided clinical ET to ensure optimal embryo placement.

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.

Uterine factors modify the association between embryo transfer depth and clinical pregnancy

The embryo transfer depth may affect the chance of pregnancy. However, embryo dislodging caused by uterine contraction may occur after the transfer. The aim of the retrospective study was to investigate whether the factors associated with uterine contractilities, such as endometrial thickness and progesterone elevation, affect the association between transfer depth and implantation. A total of 7849 fresh transfer cycles on conventional stimulation in a single in vitro fertilization (IVF) center during the period 2013–2015 was reviewed. Patients were categorized according to quartiles of embryo transfer depth (≤ 9 mm, n = 1735, 9.1–11 mm, n = 2557, 11.1–14 mm, n = 1933, ≥ 1.4 mm, n = 1624, respectively). Adjusted for confounding factors, the adjusted odds ratio (aOR) (95% confidence interval, CI) for clinical pregnancy was 0.90 (0.79–1.02), 0.86 (0.74–0.99), and 0.70 (0.60–0.82) respectively in quartiles 2 through 4, comparing with quartile 1. However, the aORs were significantly increased when the endometrial thickness was < 8 mm. In comparison with that in the cycles with a normal endometrial thickness (8–11 mm), the aORs comparing quartiles 2 through 4 with quartile 1 in the cycles with an endometrial thickness < 8 mm increased from 0.78 (95% CI 0.65–0.93), 0.79 (95% CI 0.65–0.97), and 0.64 (95% CI 0.51–0.81) to 1.73 (95% CI 1.21–2.47), 1.04 (95% CI 0.69–1.56), and 1.45 (95% CI 0.91–2.31), respectively. In the cycles with elevated progesterone and blastocyst stage transfer, the aORs comparing quartiles 4 with quartile 1 decreased from 0.73 (95% CI 0.62–0.87) and 0.74 (95% CI 0.63–0.87) to 0.58 (95% CI 0.40–0.84) and 0.42 (95% CI 0.25–0.73) than those in the cycles without. However, only blastocyst transfer showed a significant interaction with transfer depth (p = 0.043). Our data suggested that endometrial thickness and blastocyst transfer significantly affect the association between embryo transfer depth and clinical pregnancy.

Resveratrol and Reproductive Health

Resveratrol (RSV), a plant-derived polyphenol, demonstrates broad-spectrum health benefits, including anti-proliferative, anti-inflammatory, antidiabetic, anti-ischemic and antioxidant effects. The aim of this review is to give an important heads-up regarding the influence of RSV as a phytoestrogen, RSV effects on most common pregnancy-related complications, as well as its impact on the embryogenesis, spermatogenesis, and women’s reproductive health. Considering the important implications of RSV on human reproductive health, this overview could provide a groundwork, encouraging more detailed research at the clinical level.

Evaluation of embryo transfer through a scoring system: ETSS (Embryo transfer scoring system)

INTRODUCTION

To create a scoring system by including all of the factors that are recommended for an ideal ET and to investigate its correlation with the Β-HCG results.

MATERIALS AND METHODS

This study was conducted as a retrospective trial between January 2009 and December 2018. Women who had a single ET between the specified dates were included in the study. The embryo grade, ET day, distance between the fundus to embryo transfer site measured via ultrasonography, endometrial thickness on ET day, and presence of mucus and blood in the catheter after transfer were the variables evaluated. Each one of the five variables that constituted the scoring system were rated separately.

RESULTS

Overall, 1652 patients participated in this research. Antral follicle count (13,3 ± 8 vs. 14,6 ± 8,2, p: 0,001), endometrial thickness on the ET day (9.9 ± 2 vs.10.3 ± 2, p = 0.006) and number of mature oocytes (8.6 ± 6 vs. 9 ± 5.1, p: 0.003) were significantly higher in patients with positive Β-HCG values. The total score in the Β-HCG positive group was 9.8 ± 1.4 versus 8.9 ± 1.4 in the Β-HCG negative group (p < 0.001). The best ETSS cut-off value for predicting Β-HCG positivity was 9.5, with 82% sensitivity and 67% specificity (AUC:0.808).

CONCLUSION

Our scoring system is an important step toward standardization, as it offers a new, practical, cost-free, and applicable scoring system based on pre- and post-ET measurements and laboratory data.

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.

Patient(s)

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 Measure(s)

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.

Result(s)

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.

Conclusion(s)

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.

The position of the euploid blastocyst in the uterine cavity influences implantation

RESEARCH QUESTION

Does the position of the euploid blastocyst in the uterine cavity upon transfer, measured as distance in millimetres (mm) from the fundus (DFF) to the air bubble, influence implantation potential?

DESIGN

A total of 507 single/double euploid frozen embryo transfer (FET) cycles at blastocyst stage were included retrospectively between March 2017 and November 2018 at a single centre. The patients were on average 33.3 years old. The FET were performed in natural cycles (n = 151) or hormone replacement therapy cycles (n = 356).

RESULTS

Of the 507 transfers, 370 (73.0%) resulted in a pregnancy, defined as human chorionic gonadotrophin concentration over 15 mIU/ml, and 341 (67.3%) in a clinical pregnancy, with an implantation rate of 62.0% and ongoing pregnancy rate of 59.6% (302/507). When comparing the number of embryos transferred, the pregnancy rate, clinical pregnancy rate and ongoing pregnancy rate were significantly higher after double-embryo transfer (DET) (P = 0.002: P < 0.001 and P = 0.002). The quality of the blastocyst in the single-embryo transfer group had a positive effect on the pregnancy rate (A versus B, P = 0.016; A versus C, P = 0.003) and clinical pregnancy rate (A versus C, P = 0.013). After performing a multivariate logistic regression analysis to consider the effect of all explanatory variables, a negative effect between DFF and pregnancy (P = 0.001), clinical pregnancy (P = 0.001) and ongoing pregnancy (P = 0.030) was found. When all variables remained constant, an increase of 1 mm of DFF changed the odds of pregnancy by 0.882, of clinical pregnancy by 0.891 and of ongoing pregnancy by 0.925. No significant effect of DFF was found on the miscarriage outcome (P = 0.089).

CONCLUSIONS

The depth of blastocyst replacement inside the uterine cavity may influence the pregnancy, clinical pregnancy and ongoing pregnancy rates and should be considered as an important factor to improve the success of IVF cycles.

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.

Logistic regression analyses of factors affecting fertility of intrauterine adhesions patients

Background

Intrauterine adhesion (IUA) prevalence is difficult to measure, but appears to have increased over the last few decades. The reproductive outcomes following hysteroscopic adhesiolysis (HA) for moderate-severe IUAs were unsatisfactory, and few studies have analyzed the clinical characteristics pre-, intra- and post-HA to determine the main risk factors for infertility in patients with IUAs.

Methods

This retrospective observational study included 406 patients, desiring fertility, who had undergone HA between January 1st, 2016 to May 31st, 2017, and had moderate-to-severe IUA [5-12 on the American Fertility Society (AFS) classification scale]. Logistic regression was performed to analyze the data of the clinical characteristics associated with IUA.

Results

A total of 406 IUA patients were initially collected. Twenty-six [26] were lost during follow-up or excluded by other criteria; 380 were included in the study with a follow-up period ranging from 2 to 3 years. There were 215 patients (56.6%) that became pregnant, of whom 18 spontaneously miscarried, 5 birthed prematurely (31-36 gestational weeks), 182 delivered at term, and 10 were pregnant at the end of the study. A bivariate and binary logistic regression analysis showed that an age of >30 years, cohesive IUA, lack of increased menstrual volume, and more than 2 times undergoing HA procedure were the risk factors for infertility in IUA patients (P<0.05).

Conclusions

Age, severity of IUA, increased menstrual volume, and HA procedures were the dominant factors affecting reproductive outcomes and may be regarded as potential predictors for evaluating IUA prognosis.

Embryo placement in IVF and reproductive outcomes: a cohort analysis and review

Objective:

The objective of the present study was to determine the influence of the embryo placement depth on the endometrial cavity in relation to the reproductive outcomes, after frozen-thawed embryo transfer performed under transabdominal ultrasound guidance.

Methods:

Retrospective cohort study that evaluated the influence of the embryo placement depth in the endometrial cavity in relation to the reproductive outcomes of patients submitted to cryotransfer cycles at a private assisted reproduction clinic, from 2012 to 2017. The patients were classified according to three variables: <10mm, 10 to 15mm and >15mm. The primary outcome was clinical pregnancy, and the secondary outcomes were miscarriage, ongoing pregnancy and live birth. The data was summarized as relative risk, with a 95%CI.

Results:

Clinical and ongoing pregnancy rates were higher in the 10-15mm and >15mm Groups, when compared to the <10mm Group; there was no statistical difference between the groups in terms of miscarriage and live birth rates. We performed a subsequent analysis, using the same sample of patients, comparing only the <10mm and ≥10mm variables. The ≥10mm Group had better reproductive outcomes, with higher clinical and ongoing pregnancy rates.

Conclusion:

Pregnancy rates are influenced by embryo transfer site, and better results can be achieved when the tip of the catheter is placed in the central area of the endometrial cavity, especially when the distance from the endometrial fundus is >10mm.

Analysis of the reproductive outcomes and the size of the unicornuate uterus measured by magnetic resonance imaging and their relationship

PURPOSE

To evaluate the relationship between the uterine size measured by pelvic magnetic resonance and reproductive outcome in women with a unicornuate uterus.

METHODS

This was a retrospective study including 140 patients affiliated with unicornuate uterus diagnosed by the pelvic MR prior to their first pregnancy in the Obstetrics and Gynecology Hospital of Fudan University from April 2010 to December 2017. All the length of the unicornuate uterus were re-measured and recorded by skilled radiologists during the study period. We divided all the 140 participants with complete pelvic MR imaging into four groups by the best reproductive outcomes, which refers to Group 1 (primary infertility, n = 21), Group 2 ( < 24 weeks' gestation, n = 34), Group 3 (preterm delivery, 24-35 weeks' gestation, n = 13), Group 4 ( ≥ 35 weeks' gestation, n = 72), followed them up and then analyzed the data.

RESULTS

Measurements of 140 patients with hemi-uteri were retrieved for analysis. The mean length of the uterine was 4.90  ± 0.56 cm. There were no significant differences in the uterine cavity length, cervical length, endometrial thickness and uterine wall thickness between the four groups while the uterine length (P = 0.001) was statistically significant. Women with uterine lengths  ≥  4.5 cm were more likely to experience full-term delivery compared with the other group (P = 0.001). Ordinal multiple logistic regression analysis showed that the uterine length [OR = 9.03 (95% CI: 2.90-28.13)] and uterine cavity length [OR = 0.32 (95% CI: 0.06-2.04)] were independent protective factors for better obstetric outcomes CONCLUSION: The uterine length is a reliable prognostic factor for the gestational week of delivery and an appropriate antenatal surveillance factor of women with unicornuate uterus.

Embryo transfer techniques

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

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.

Ideal embryo transfer position and endometrial thickness in IVF embryo transfer treatment

OBJECTIVE

To establish an ideal transfer strategy by investigating the relationships among embryo transfer (ET) depth, endometrial thickness, and subsequent in vitro fertilization treatment clinical pregnancy outcomes.

METHODS

In the present retrospective analysis, data from in vitro fertilization-ET treatment cycles conducted at a fertility center in Shanghai, China, between October 2014 and March 2015 were analyzed. Women were divided into groups 1-4 according to transfer depth (<10; 10-15, 15-20, and >20 mm, respectively), as measured by air bubbles. Additionally, 391 women were divided into groups A-C according to endometrial thickness (<7, 1-12, and >12 mm, respectively). Clinical pregnancy outcomes were assessed by group.

RESULTS

Data from 501 cycles were included. Clinical pregnancy and live delivery rates were significantly higher in group 2 (P=0.009 and P=0.002, respectively) and group 3 (P=0.008 and P=0.001, respectively) than in group 4. Among the 394 patients with endometrial thickness data available, clinical pregnancy and live delivery rates were higher in group B (P=0.028 and P=0.015, respectively) and group (P=0.013 and P=0.013, respectively) than in group A.

CONCLUSION

Correct transfer depth and endometrial thickness can increase the rates of clinical pregnancy, implantation, and live delivery. Placing the embryos at 10-20 mm from the fundus and at an endometrial thickness of more than 7 mm is recommended for optimal clinical pregnancy outcomes.

Effect of air bubbles localization and migration after embryo transfer on assisted reproductive technology outcome

OBJECTIVE

To evaluate the effect of embryo flash position and movement of the air bubbles at 1 and 60 minutes after ET on clinical pregnancy rates (PRs).

DESIGN

Prospective clinical trial.

SETTING

University fertility clinic.

PATIENT(S)

A total of 230 fresh ultrasound-guided ETs performed by a single physician (C.F.) at the IVF center of Yeditepe University Hospital between September 2016 and February 2017 were included.

INTERVENTION(S)

Transabdominal ultrasonographic guidance at ET.

MAIN OUTCOME MEASURE(S)

Clinical PRs.

RESULT(S)

There was no significant difference in terms of clinical PRs between women with embryo flash located >15 mm and <15 mm from the fundus at 1 or 60 minutes (P=.6 and P=.7, respectively). The PRs in women with embryo flash located <15 mm and >15 mm from the fundus were 47% and 60%, respectively (P=.6). The clinical intrauterine PRs were 69.5%, 38.5%, and 19.1% in fundal, static, and cervical, respectively. The highest PR was in fundal when compared with others (P<.01). The clinical PR appears to be associated with the embryo flash movement/migration and the PR was dramatically reduced when the embryo migrated from its original position toward the cervix at 60 minutes.

CONCLUSION(S)

We concluded that clinical PR appears to be associated with the embryo flash movement/migration at 60 minutes after ET and embryo flash movement toward the fundus is associated with higher clinical PRs. Further well-designed randomized controlled trials are required to optimize ET technique in the future.

Transvaginal ultrasound-guided embryo transfer in IVF

OBJECTIVES

To determine whether transvaginal ultrasound-guided embryo transfer is a technique that can be used routinely, whether it improves IVF outcomes and whether it makes difficult transfers easier and more successful.

MATERIAL AND METHOD

Non-randomized retrospective study conducted between 2012 and 2016 in the fertility center of the Diaconesses-Croix St-Simon hospital group. The outcomes of 3910 transfers, performed by 5 senior operators, under transabdominal ultrasound guidance are compared with those of 800 transfers, performed by 1 senior operator under transvaginal ultrasound guidance. The criteria studied are the feasibility of the technique and the percentage of pregnancies per transfer in the two populations described, as well as in the difficult and very difficult transfer populations.

RESULTS

All the transfers were feasible under transvaginal ultrasound guidance without the use of forceps or additional instruments. The percentage of pregnancies per transfer is significantly increased, when the transfer is performed under transvaginal ultrasound guidance compared with that performed under transabdominal ultrasound guidance, in the general population (38%, n=800 vs 30%, n=3910; P 0.0004) and in the reference population characterized by age <38 years and >6 oocytes collected per puncture (45%, n=490 vs 36%, n=1968; P 0.002). The percentage of pregnancies per transfer (P/T) is not significantly different in the populations of easy transfers (n 695, 38% P/T), difficult transfers (n 58, 46% P/T; P=ns) and very difficult transfers (n 47, 34% P/T; P=ns).

CONCLUSIONS

Embryo transfer is a key stage in IVF, in which the quality of performance determines the outcome. In this study, transvaginal ultrasound guidance of the transfer, which is the reference procedure in gynaecological imaging, significantly increases the percentage of pregnancies per transfer, both in the general population and in the reference population, compared with transfers performed under transabdominal ultrasound guidance. Transvaginal ultrasound facilitates the performance of difficult transfers and in particular achieves outcomes in these situations that are not significantly different from those of easy transfers. Visual monitoring of transcervical passage, which is rendered more precise and less traumatic and precision of embryo deposition are the factors that probably account for the improvement in outcomes.

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.

Ectopic pregnancy secondary to in vitro fertilisation-embryo transfer: pathogenic mechanisms and management strategies

BACKGROUND

Ectopic pregnancy (EP) is the leading cause of maternal morbidity and mortality during the first trimester and the incidence increases dramatically with in vitro fertilisation and embryo transfer (IVF-ET). The co-existence of an EP with a viable intrauterine pregnancy (IUP) is known as heterotopic pregnancy (HP) affecting about 1% of patients during assisted conception. EP/HP can cause significant morbidity and occasional mortality and represent diagnostic and therapeutic challenges, particularly during fertility treatment. Many risk factors related to IVF-ET techniques and the cause of infertility have been documented. The combination of transvaginal ultrasound (TVS) and serum human chorionic gonadotrophin (hCG) is the most reliable diagnostic tool, with early diagnosis of EP/HP permitting conservative management. This review describes the risk factors, diagnostic modalities and treatment approaches of EP/HP during IVF-ET and also their impact on subsequent fertility treatment.

METHODS

The scientific literature was searched for studies investigating EP/HP during IVF-ET. Publications in English and within the past 6 years were mostly selected.

RESULTS

A history of tubal infertility, pelvic inflammatory disease and specific aspects of embryo transfer technique are the most significant risk factors for later EP. Early measurement of serum hCG and performance of TVS by an expert operator as early as gestational week 5 can identify cases of possible EP. These women should be closely monitored with repeated ultrasound and hCG measurement until a diagnosis is reached. Treatment must be customised to the clinical condition and future fertility requirements of the patient. In cases of HP, the viable IUP can be preserved in the majority of cases but requires early detection of HP. No apparent negative impact of the different treatment approaches for EP/HP on subsequent IVF-ET, except for risk of recurrence.

CONCLUSIONS

EP/HP are tragic events in a couple's reproductive life, and the earlier the diagnosis the better the prognosis. Due to the increase incidence following IVF-ET, there is a compelling need to develop a diagnostic biomarker/algorithm that can predict pregnancy outcome with high sensitivity and specificity before IVF-ET to prevent and/or properly manage those who are at higher risk of EP/HP.

Embryo catheter loading and embryo culture techniques: results of a worldwide Web-based survey

PURPOSE

To identify trends in embryo catheter loading and embryo culture techniques performed worldwide.

METHODS

A retrospective evaluation using the results of a web-based survey, (IVF Worldwide ( www.IVF-worldwide.com ), was performed.

RESULTS

Responses from 265 centers in 71 countries were obtained. Most centers (97 %) preferred a catheter with its orifice on top, with only 3 % preferring a catheter with the orifice on its side; 41 % preferred a catheter marked for clear ultrasound view. The most commonly-reported methods of embryo loading were medium-air-embryo-air-medium (42 %), medium in catheter with embryo at end (20 %) and medium-air-embryo (15 %). In 68 % of centers the final volume of the catheter was up to 0.3 ml, with only 19 % using 0.3-0.5 ml and 1 % using 0.5-0.7 ml. Using reduced oxygen concentrations for embryo culture was divided between those who used it in combination with the two-gas system (34 %) and those who did not use it at all (39 %); 24 % reported using a three-gas system. Most clinics using reduced oxygen concentrations used it throughout the entire culture period. Half of centers (51 %) reported using reduced oxygen concentrations for the entire IVF population while 6 % reserved it only for blastocyst transfer. The use of sequential media was highly dominant with 40 % reporting its use.