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

Clinical and laboratory parameters associated with pregnancy outcomes in patients undergoing frozen euploid blastocyst transfer

RESEARCH QUESTION

Which factors impact on clinical pregnancy rate (CPR) and live birth rates (LBR) in euploid frozen embryo transfer (eFET) cycles?

DESIGN

Retrospective observational study including 1660 eFET cycles with 2439 euploid blastocysts, from November 2016 to December 2020. The impact of clinical and laboratory parameters on CPR, biochemical miscarriage rate (BMR), clinical miscarriage rate (CMR) and LBR was evaluated.

RESULTS

CPR per transfer was 63.4%, LBR per transfer 51.6%. CPR and LBR were significantly higher when double embryo transfer (DET) was performed (71.6% versus 57.7%, P < 0.001; 55.2% versus 49.1%, P = 0.016, respectively). However, pregnancy loss was significantly higher in the DET group (28.8% versus 22.8%, P = 0.02). When patients were classified by body mass index (BMI), no differences were observed for CPR, but CMR was lower (P < 0.001) and LBR higher (p = 0.031) for the normal BMI group. The natural cycle protocol revealed lower CMR (P < 0.001) and lower pregnancy loss (P < 0.001); subsequently, higher LBR (57.6%, 48.8%, 45.0%, P = 0.001) compared with hormonal replacement protocol and stimulated cycle. Day of trophectoderm biopsy affected CPR (P < 0.001) and LBR (P < 0.001), yet no differences were observed for BMR, CMR or pregnancy loss. The multivariate analysis showed that day 6/7 embryos had lower probabilities for pregnancy; overweight and obesity had a negative impact on LBR, and natural cycle improved LBR (adjusted odds ratio 1.445, 95% confidence interval 0.519-0.806).

CONCLUSIONS

Day of biopsy affected CPR, while BMI and endometrial preparation protocol were associated with LBR in eFET. DET should be discouraged as it will increase the risk of pregnancy loss. Women with higher BMI should be aware of the higher risk of pregnancy loss and lower LBR even though a euploid blastocyst is transferred.

Management of a uterine serosal heterotopic pregnancy after in vitro fertilization in a woman with bilateral salpingectomy: A case report and literature review

RATIONALE

Heterotopic pregnancy (HP) is defined as the simultaneous presence of intrauterine pregnancy and ectopic pregnancy (EP). HP after bilateral salpingectomy is extremely rare and may lead to serious complications if it is misdiagnosed and untreated timely. Here, we presented the first reported case of uterine serosal HP in a woman after assisted reproductive technology with bilateral salpingectomy because of bilateral tubal ectopic pregnancy.

PATIENT CONCERNS

A 27-years-old pregnant woman after in vitro fertilization with bilateral salpingectomy complained of a sudden onset of unprovoked abdominal pain, which was persistent and dull. She denied vaginal bleeding.

DIAGNOSES

Serum beta-human chorionic gonadotropin levels are difficult to predict HP. Transvaginal ultrasonography demonstrated 1 gestational sac in the uterine cavity and 1 thick-walled cystic mass over the upper of the uterus, with a large amount of fluid in the Pouch of Douglas. Emergency laparotomy revealed a uterine serosal pregnancy combined with intrauterine pregnancy.

INTERVENTIONS

This patient was successfully managed via emergency laparotomy to remove residual tissue and repair the rupture of the uterine serosal pregnancy.

OUTCOMES

At postoperative 4 days, repeat transvaginal ultrosonography presented 1 intrauterine gestational sac with a visible fetal bud and cardiac tube pulsation. Now the patient recover well and is in an ongoing pregnancy.

LESSONS

It is noteworthy that HP/ectopic pregnancy is still not prevented after bilateral salpingectomy. In cases of multiple embryo transfer, even if intrauterine pregnancy has been established, it is important to rule out HP/ectopic pregnancy in time. Early diagnosis and early management can significantly improve clinical outcomes.

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.