Improvement of pregnancy rate by modification of embryo transfer technique: a randomized clinical trial

Interventions to optimize embryo transfer in women undergoing assisted conception: a comprehensive systematic review and meta-analyses

BACKGROUND

Several interventions and techniques are suggested to improve the outcome of embryo transfer (ET) in assisted conception. However, there remains no consensus on the optimal practice, with high variations among fertility specialists.

OBJECTIVE AND RATIONALE

We conducted a comprehensive systematic review and meta-analyses of randomized controlled trials (RCTs) aiming to identify effective interventions that could be introduced around the time of ET to improve reproductive outcomes.

SEARCH METHODS

We searched the electronic databases (MEDLINE, EMBASE and Cochrane CENTRAL) from inception until March 2021 using a multi-stage search strategy of MeSH terms and keywords, and included all RCTs that evaluated an intervention in the 24-h period before/after ET in women undergoing IVF/ICSI. Our primary outcome was clinical pregnancy rate post-ET confirmed as viable pregnancy on ultrasound scan. We assessed the risk of bias in included trials and extracted data in duplicate. We pooled data using a random-effect meta-analysis and reported using risk ratio (RR) with 95% CI. We explored publication bias and effect modifiers using subgroup analyses.

OUTCOMES

Our search yielded 3685 citations of which we included 188 RCTs (38 interventions, 59 530 participants) with a median sample size of 200 (range 26-1761). The quality of included RCTs was moderate with most showing a low risk of bias for randomization (118/188, 62.8%) and attrition (105/188, 55.8%) but there was a significant risk of publication bias (Egger's test P = 0.001). Performing ET with ultrasound guidance versus clinical touch (n = 24, RR 1.265, 95% CI 1.151-1.391, I2 = 38.53%), hyaluronic acid versus routine care (n = 9, RR 1.457, 95% CI 1.197-1.261, I2 = 46.48%) and the use of a soft versus hard catheter (n = 27, RR 1.122, 95% CI 1.028-1.224, I2 = 57.66%) led to higher clinical pregnancy rates. Other pharmacological add-ons also showed a beneficial effect including granulocyte colony-stimulating factor (G-CSF: n = 4, RR 1.774, 95% CI 1.252-2.512, I2 = 0), Atosiban (n = 7, RR 1.493, 95% CI 1.184-1.882, I2 = 68.27%) and hCG (n = 17, RR 1.232, 95% CI 1.099-1.382, I2 = 57.76%). Bed rest following ET was associated with a reduction in clinical pregnancy (n = 6, RR 0.857, 95% CI 0.741-0.991, I2 = 0.01%). Other commonly used interventions, such as non-steroidal anti-inflammatory drugs, prophylactic antibiotics, acupuncture and cervical mucus removal, did not show a significant benefit on reproductive outcomes. Our effect estimates for other important outcomes, including miscarriage and live birth, were limited by the varied reporting across included RCTs.

WIDER IMPLICATIONS

Using ultrasound guidance, soft catheters and hyaluronic acid at the time of ET appears to increase clinical pregnancy rates. The use of Atosiban, G-CSF and hCG showed a trend towards increased clinical pregnancy rate, but larger trials are required before adopting these interventions in clinical practice. Bed rest post-ET was associated with a reduction in clinical pregnancy and should not be recommended.

A fine tuning of embryo loading technique by eliminating the air bubble in the outer sheath of embryo catheter among women undergoing IVF treatment

OBJECTIVES

The role of air bubbles in bracketing the embryo-containing medium in inner catheter during embryo transfer (ET) has already been established. However, the role of air bubbles in outer catheter (OC) during implantation is yet to be determined. This study aimed to compare the implantation rates between women who have undergone ET with or without ASP (Vitrolife^®; Sweden), a medium use for oocyte retrieval and rinsing in OC embryo catheter. The purpose of introducing the ASP medium to the OC was to eliminate air bubbles in that space during implantation.

METHODS

A total of 312 women were randomly divided into two groups with 156 participants each group. In Group A, ASP medium was used during ET, whereas in Group B, no ASP medium was utilized. Positive implantation was defined as serum beta-hCG level >5 mIU/mL taken on the 7th day following ET.

RESULTS

The average age of the majority of the participants was 30-39 years and had at least 4-5 years of subfertility. The unexplained subfertility was the prominent cause of ET failure in both groups. In most of the participants in both groups, ET was done using fresh embryo cycles with good to excellent embryo grades. After the ASP medium was manipulated in the OC in both groups, the positive implantation rate was not different in both groups (p>0.05).

CONCLUSIONS

The elimination of air bubbles in OC by using the ASP medium during ET did not confer an additional benefit nor exert a negative impact on implantation rate.

The Effect of Vaginal Sildenafil on The Outcome of Assisted Reproductive Technology Cycles in Patients with Repeated Implantation Failures: A Randomized Placebo-Controlled Trial

Background

The aim of this study was to investigate the effects of vaginal sildenafil on the outcome of patients with at least two unsuccessful in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) attempts.

Materials and Methods

In this randomized placebo-controlled trial study, a total of 66 infertile women aged ≤38 years, with a history of normal ovarian reserve, two prior consecutive failed IVF/ICSI attempts, human chorionic gonadotropin (hCG) day endometrial thickness <7 mm in all prior IVF/ICSI cycles, normal endometrial appear- ance by either hysteroscopy, hysterosonography, or hysterosalpingography enrolled in this study. The conventional gonadotropin-releasing hormone (GnRH) protocol was used for ovarian stimulation. The patients were randomly divided into three groups: vaginal sildenafil (suppository-100 mg/daily), vaginal placebo/sildenafil (suppository-100 mg/daily), and vaginal placebo (suppository). Each patient underwent colour Doppler ultrasound on day 14 of their previous cycle to investigate any abnormalities in the uterus and adnexa. Endometrial thickness, echo pattern, uterine artery resistance, and pulsatility indices were recorded pre- and post-treatment. The primary outcome measures were implantation, chemical and clinical pregnancy rates. For data analysis, SPSS version 20 software was used. In all tests, the significance level was considered less than 0.05.

Results

There was no significant difference between three groups in endometrial thickness on the hCG injection day. The chemical pregnancy in women who received sildenafil (alone or in combination with placebo) showed a two-fold increase in comparison to the placebo group. This increase was clinically meaningful, but according to sample size, it was statistically non-significant. The results of our study showed that the implantation was higher in women who received placebo/sildenafil compared to the other groups. The abortion rate was not statistically significant among the groups.

Conclusion

Vaginal sildenafil may conceivably improve chemical pregnancy rates in repeated IVF failure patients. Further randomized clinical trials using oral or vaginal sildenafil with higher sample size are recommended (Registra- tion number: NCT03192709).

Does low-dose aspirin improve pregnancy rate in women undergoing frozen-thawed embryo transfer cycle? A pilot double-blind, randomized placebo-controlled trial

AIM

To evaluate the effect of adjuvant low-dose aspirin therapy on clinical pregnancy rate and uterine perfusion in women undergoing frozen-thawed embryo transfer (FET) cycles.

METHODS

This study was performed as a pilot randomized, double-blind placebo-controlled trial, from May 2012 to February 2015. Overall, 60 available eligible women who were candidates for FET were randomly assigned to two groups receiving either 100 mg oral aspirin (n =30) or placebo (n =30). The primary outcome measure was clinical pregnancy rate. Secondary outcome measures were pulsatility index (PI), resistance index (RI), implantation rate, live birth rate and miscarriage rate.

RESULTS

There was no significant difference in endometrial thickness, PI and RI. However, the study group had higher rates of clinical pregnancy, implantation, live birth (P = 0.042, P = 0.031 and P = 0.007, respectively) and lower rate of miscarriage (P = 0.020) as compared to the control group. Twin birth rate was comparable between the two groups.

CONCLUSION

Our pilot study demonstrated that administration of low-dose aspirin in FET cycles results in better pregnancy, implantation and live birth rates without changing the uterine hemodynamics or endometrial thickness. However, further randomized clinical studies in larger populations are needed to confirm these findings.

Prospective Randomized Trial Comparing Embryo Transfers of Cases with and without Catheter Rotation during Its Withdrawal

OBJECTIVE

To compare embryo transfer (ET) technique based on catheter rotation during its withdrawal in cases with unexplained infertility in a prospective, randomized trial (NCT03097042).

METHODS

Two hundred intracytoplasmic sperm injection (ICSI) patients undergoing ET with cleaving or blastocyst-stage fresh embryos were randomized into 2 groups: cases with (n = 100), and without (n = 100) catheter rotation during its withdrawal. Groups were matched for age and some clinical parameters. A soft catheter was used to transfer a single embryo with catheter rotation during its withdrawal in the study group and without rotation in the control. The use of a stiff catheter or tenaculum was not needed in any case. Groups were compared in terms of cycle characteristics and clinical pregnancy rates.

RESULTS

Pregnancy rate was significantly higher in the study group (41 vs. 26%, p = 0.04). Clinical pregnancy rate was also significantly higher in the study group (39 vs. 25%, OR 1.9 [1.1-3.5], p = 0.05). On the other hand, the ongoing pregnancy rate was similar between the 2 groups (33 vs. 23%, p = 0.2).

CONCLUSION

Catheter rotation during its withdrawal may be associated with increased pregnancy and clinical pregnancy rates; however, the difference in ongoing pregnancy rates did not reach statistical significance.

Intrauterine air impairs embryonic postimplantation development in mice

OBJECTIVE

Although most embryologists load air bubbles into the catheter along with embryos during embryo transfer, the effects of these air bubbles on embryo transfer success rate are not clear.

STUDY DESIGN

Air bubbles were nonsurgically injected into unilateral uterine horns of mice to demonstrate the negative effects of intrauterine air bubbles on embryonic development.

RESULTS

Our data showed that when air bubbles are nonsurgically injected into unilateral uterine horns of pregnant 4days mice the litter size is significantly decreased. Four days after the introduction of air, abnormal decidua and dead conceptuses were detected in the uterine horns receiving the air bubbles. In addition, intrauterine air also significantly impaired murine embryo transfer success rates, and induced an increase in endometrial capillary permeability and decidualization in mice on day 4 of pseudopregnancy. These results strongly indicated that the air bubbles loaded into embryo transfer catheters to bracket the embryo-containing medium may have negative effect on embryonic implantation and development.

CONCLUSIONS

Intrauterine air impaired murine embryonic postimplantation development, and this provided some clues for improving embryo transfer techniques in human.

How do laboratory embryo transfer techniques affect IVF outcomes? A review of current literature

Over the last few years, many studies have focused on embryo selection methods, whereas little attention has been given to the standardization of the procedure of embryo transfer. In this review, several parameters of the embryo transfer procedure are examined, such as the: (i) culture medium volume and loading technique; (ii) syringe and catheters used for embryo transfer; (iii) viscosity and composition of the embryo transfer medium; (iv) environment of embryo culture; (v) timing of embryo transfer; (vi) and standardization of the embryo transfer techniques. The aim of this manuscript is to review these factors and compare the existing embryo transfer techniques and highlight the need for better embryo transfer standardization.

Use of Versapoint to refashion the cervical canal to overcome unusually difficult embryo transfers and improve in-vitro fertilization-embryo transfer outcome: A case series

BACKGROUND

Smooth atraumatic embryo transfer is paramount for the success of in-vitro fertilization (IVF). In difficult cases, cervical canal manipulation may be required.

AIM

To see if surgical correction of the cervical canal or cervical canal refashioning could improve ease of embryo transfer.

SETTING

Private infertility and IVF hospital.

DESIGN

Prospective study.

MATERIALS AND METHODS

PATIENTS

11 women with failed 1-3 IVF cycles with history of extremely difficult embryo transfers (ETs) despite undergoing cervical dilatation in the cycle prior to IVF.

INTERVENTIONS

Operative hysteroscopy using Versapoint for refashioning of the cervical canal.

MAIN OUTCOME MEASURES

Ease of ET in the subsequent IVF cycle. Secondary outcome measure was to assess reproductive outcome.

RESULTS

Easy and atraumatic ET in the IVF cycle after procedure in 100% patients. PR was 46.5%.

CONCLUSIONS

Use of Versapoint for refashioning the cervical canal can improve the quality of ET and PR.