The influence of abdominal ultrasound-guided embryo transfer on pregnancy rate: a preliminary report

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.

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.

Ultrasound guidance during embryo transfer: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To summarize the current evidence on the effect of using ultrasound (US) guidance during embryo transfer (ET).

METHODS

In this systematic review, we included randomized controlled trials examining the effect of the use of US guidance during ET; data from studies using the same catheter type in study arms were not pooled with the results from studies that used different catheter types.

RESULTS

Twenty-one studies were included in the quantitative analysis: 18 compared 'US guidance' with 'clinical touch', of which one was subsequently excluded from the quantitative meta-analysis owing to a lack of available data, three studies compared transvaginal US guidance with transabdominal US guidance, and one study compared 'hysterosonometry before ET' with US guidance. Comparison of the use of US guidance with clinical touch, in studies that used the same catheter type in the study arms, indicated a benefit of using US guidance during ET on the rates of live birth (relative risk (RR), 1.48 (95% CI, 1.16-1.87)), based on two studies involving 888 women with moderate-quality evidence, and on the rates of clinical pregnancy (RR, 1.32 (95% CI, 1.18-1.46)), based on 13 studies involving 3641 women with high-quality evidence. However, when comparing the use of US guidance with clinical touch in studies that used different catheter types, the results suggest that using US guidance during ET has no effect on the rates of reproductive outcome: live birth (RR, 0.99 (95% CI, 0.83-1.19)), based on one study involving 1649 women with moderate-quality evidence; clinical pregnancy (RR, 1.04 (95% CI, 0.89-1.21)), based on five studies involving 2949 women with moderate-quality evidence. The estimates for the rate of miscarriage and for the other identified comparisons were imprecise.

CONCLUSIONS

The available evidence suggests that there is a benefit of using US guidance during ET. However, both US-guided transfer and clinical touch should be considered acceptable, as the benefit of US is not large and should be balanced against the increased cost and need to change the catheter type. More studies are required before conclusions can be drawn regarding the effect of other techniques on reproductive outcome.

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 a more effective technique of embryo transfer. This review evaluates the effectiveness of ultrasound guided embryo transfer (UGET) compared with 'clinical touch' (CTET) the traditional method of embryo transfer.

OBJECTIVES

To determine whether ultrasound guidance influences treatment outcomes in women undergoing embryo transfer (ET) during assisted reproductive technology (ART) cycles.

SEARCH STRATEGY

Electronic databases were searched in November 2009. We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched November 2009), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2009), MEDLINE (1970-2009), EMBASE (1985-2009), BIO Extracts (1980-2009). Relevant conference proceedings were also hand searched (ASRM, ESHRE and FIGO).

SELECTION CRITERIA

Only randomised controlled trials were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility and quality of trials and extracted data from those selected.

MAIN RESULTS

This update identified 59 potential trials of which 42 were excluded. Data for analysis was available in seventeen studies. One study reported live births and personal communication resulted in data relating to this outcome being obtained in two additional studies. There is no evidence of a significant difference in the outcome of live birth (OR 1.14 (95%CI0.93 to 1.39; P=0.02) although heterogeneity was high (64%) and the results should be interpreted with caution. Seven studies reported on ongoing pregnancies. The ongoing pregnancies per woman randomised associated with UGET (441/1254) was significantly higher than for clinical touch (350/1218) OR 1.38, 95%CI 1.16 to 1.64, P<0.0003). No statistically significant differences in the incidence of adverse events were identified between the comparison groups. These events are relatively rare and sample sizes limit the ability to detect such differences.

AUTHORS' CONCLUSIONS

The studies are limited by their quality with only two studies reporting details of both computerised randomisation techniques and adequate allocation concealment. Ultrasound guidance does appear to improve the chances of live/ongoing and clinical pregnancies compared with clinical touch methods. The quality of future studies should be improved with adequate reporting of randomisation, allocation concealment, and power calculations. The primary outcome measure of future studies should be the reporting of live births per woman randomised.