Modified natural cycle for embryo transfer using frozen-thawed blastocysts: A satisfactory option

Pretreatment with a long-acting GnRH agonist for frozen-thawed embryo transfer cycles: how to improve live birth?

BACKGROUND

Whether pretreatment with gonadotropin-releasing hormone agonist (GnRHa) can improve the pregnancy outcomes in frozen-thawed embryo transfer (FET) cycles is controversial. The inconsistencies in the results of different studies would be related to the characteristics of the included patients and the protocol of GnRHa use. In this study, we investigated the efficacy of pretreatment with a long-acting GnRH agonist in the early follicular phase of FET cycles and determined which population was suitable for the protocol.

RESULTS

We retrospectively included 630 and 1141 patients in the GnRHa FET and hormone replacement treatment (HRT) FET without GnRHa groups respectively, between October 2017 and March 2019 at a university-affiliated in vitro fertilization center. On the second or third day of menstruation, 3.75 mg of leuprorelin was administered. After 14 days, HRT was initiated for endometrial preparation. No significant differences were observed between the two groups in terms of patient characteristics. However, the GnRHa FET group showed a higher percentage of endometrium with a triple line pattern (94.8% vs 89.6%, p < 0.001) on the day of progesterone administration, with increased implantation (35.6% vs 29.8%, p = 0.005), clinical pregnancy (49.8% vs 43.3%, p = 0.008), and live birth rate (39.4% vs 33.7%, p = 0.016), than the HRT FET cycles with similar endometrial thickness, ectopic pregnancy and early miscarriage rates. Binary logistic regression analysis showed the GnRHa FET group to be associated with an increased chance of clinical pregnancy (P=0.028, odds ratio [OR] 1.32, 95% confidence interval [CI] 1.03-1.70) and live birth (P=0.013, odds ratio [OR] 1.34, 95% confidence interval [CI] 1.06-1.70) compared to the HRT FET without GnRHa group. After subgroup analysis, we found that the GnRHa FET group showed a significantly higher live birth rate in the subgroups of age < 40 years, primary infertility, with polycystic ovary syndrome (PCOS), and irregular menstruation.

CONCLUSIONS

Pretreatment with a long-acting GnRHa during the early follicular phase improved the live birth rate in FET cycles. Age < 40 years, primary infertility, PCOS, and irregular menstruation are effective indications for endometrial preparation with GnRHa pretreatment in FET cycles. However, further randomized controlled trials are required to verify these results.

Natural cycle frozen embryo transfer: a survey of current assisted reproductive technology practices in the U.S

PURPOSE

Emerging data suggests improved obstetric outcomes with frozen embryo transfer (FET) in an ovulatory or natural cycle (NC-FETs), as compared to programmed endometrial preparation. The objective of this study is to better understand practice patterns and provider attitudes regarding the use of NC-FETs in the United States (U.S.).

METHODS

In this cross-sectional study, an anonymous 22-question survey was emailed to 441 U.S. Assisted Reproductive Technology (ART) clinics to assess the utilization of NC endometrial preparation for FET, protocols used, restrictions to offering NC-FET, and providers' perspectives on advantages and disadvantages of NC-FET. Descriptive statistics were used to analyze survey responses.

RESULT(S)

The survey response rate was 49% (216/441). Seventeen percent of responding clinics did not offer NC-FET. Of the clinics that did not offer NC-FET, 65% had only 1-2 physicians in their practice. Common reasons for not offering NC-FET included "lack of timing predictability for transfer" (81%) and "increased burden on staff/laboratory personnel on holidays and weekends" (54%). Of clinics offering NC-FET, 76% reported < 25% of cycles used the NC for endometrial preparation. Over half (52%) of clinics that offered NC-FET reported having eligibility restrictions for NC-FET. Reported benefits of NC-FET were "patient satisfaction" (18%), "decreased cost of medications" (18%), and "avoidance of intramuscular progesterone" (17%). The attitude towards NC-FET in their clinics was reported as positive by 65% of respondents.

CONCLUSION

NC-FETs are offered by most U.S. ART clinics but are used only in the minority of FET cycles for endometrial preparation, and use is often restricted.

Treatment outcomes of blastocysts thaw cycles, comparing the presence and absence of a corpus luteum: a systematic review and meta-analysis

PURPOSE

This study aims to review the literature and perform a meta-analysis to determine if the presence of a corpus luteum has an impact on treatment outcomes in thaw cycles, where blastocyst embryos are transferred.

METHOD

PUBMED, EMBASE, CENTRAL and CINAHL were searched for papers published between January 2017 and 27 July 2020. Additional articles were selected from the reference list of the results and previous reviews. Three reviewers independently reviewed and extracted data. The meta-analysis was conducted though RevMan V.5.4.1. Studies were quality assessed with the Cochrane risk of bias tool and the Newcastle-Ottawa Scale.

RESULTS

Nine publications were included for data extraction and subsequent meta-analysis. Two studies were randomised controlled trials, and seven were cohort studies. Subgroup analysis of the different study designs was performed. While the rates of positive human chorionic gonadotropin results (relative risk, RR 1.0, 95% CI 0.95 to 1.05) and clinical pregnancies (RR 1.06, 95% CI 0.96 to 1.18) were comparable between the two groups, the rates of live births were higher in thaw cycles with a corpus luteum (RR 1.14, 95% CI 1.06 to 1.22). Analysis of pregnancy losses demonstrated that both biochemical pregnancy (early miscarriage) (RR 0.71, 95% CI 0.62 to 0.82) and miscarriages (RR 0.72, 95% CI 0.62 to 0.83) were increased in cycles without a corpus luteum.

CONCLUSION

Where clinically appropriate, the use of cycle types that have a functional corpus luteum should be favoured. There were several limitations to this study, including the quality of studies and the inherent bias of retrospective cohort studies. Further, high-quality research, particularly randomised controlled trials with blastocysts embryos, is required to further explore these findings.

PROSPERO REGISTRATION NUMBER

CRD42020209583.

Effect of Oral versus Vaginal Administration of Estradiol and Dydrogesterone on the Proliferative and Secretory Transformation of Endometrium in Patients with Premature Ovarian Failure and Preparing for Assisted Reproductive Technology

Purpose

This study aimed to assess the efficacy of vaginally versus orally administered estradiol (E₂) and dydrogesterone (DG) on the proliferative and secretory transformation of endometrium in patients with premature ovarian failure (POF) and preparing for assisted reproductive technology.

Methods

Twenty patients with POF who were awaiting oocyte donation were included in the study; they were randomly assigned to two groups to receive E₂ and DG either orally or vaginally. Treatment efficacy was compared between the two groups regarding blood E₂ concentrations, endometrial thickness, histology using hematoxylin and eosin staining, immunohistochemical analysis of ER expression, and PR and pinopodes morphology using scanning electron microscopy.

Results

E₂ concentrations differed significantly between oral and vaginal E₂ and DG administration for 14 days (82.3 vs 1015.6 pg/mL; P < 0.001) and 21 days (85.0 vs 809.8 pg/mL; P < 0.001). Endometrial thickening was more pronounced in the vaginal treatment group, and also ER staining was stronger on days 14 and 21 in the vaginal treatment group. PR staining in the endometrium appeared more intense in the oral treatment group, which was, however, not significant. The abundance of developing pinopodes was higher in the vaginal treatment group (P = 0.04).

Conclusion

Vaginal administration of E₂ and DG is more effective than oral administration regarding proliferative and secretory transformation of the endometrium in POF patients and preparing for assisted reproductive technology.

The ART of frozen embryo transfer: back to nature!

The implementation of cryopreservation-techniques in the IVF laboratory and the improved survival rates of oocytes, cleavage and blastocyst stage embryos have led to a significant increase in the number of frozen-thawed embryo transfer cycles (FET). FETs can be planned either in a 'pure' natural cycle, a modified natural cycle, a stimulated cycle or a hormonal replacement therapy cycle and the optimal means to prepare the endometrium for frozen embryo transfer is a topic of ongoing controversy. Recent findings report an increased risk of hypertensive disorders if pregnancy is achieved in a frozen embryo transfer cycle without an existing corpus luteum. Therefore, the question of how to prepare the endometrium has gained even more importance and taken on a new dimension as it should not simply be reduced to the basic question of 'which approach will result in superior pregnancy rates?' but instead 'which approach will result in the best pregnancy rates and the safest outcome for mother and baby?'. The aim of this review is to summarize and critically appraise the existing data on the different approaches of endometrial preparation for frozen embryo transfer with a special focus on the 'pure' natural cycle.

Natural cycle versus artificial cycle in frozen-thawed embryo transfer: A randomized prospective trial

Objective:

To investigate whether there was a difference in pregnancy outcomes between modified natural cycle frozen-thawed embryo transfer (NC-FET) cycles and artificial cycles (AC)-FET in women who all had regular menstrual cycles.

Materials and Methods:

One hundred seventy patients who met the inclusion criteria and had at least two cryopreserved embryos were included in a prospective randomized controlled trial. Eighty-five patients were randomized based on Bernoulli distribution into the following two groups: 1) Modified NC-FET using human chorionic gonadotropin for ovulation induction and 2) AC-FET, in which endometrial timing was programmed with estrogen and progesterone. The main studied outcome measure was the clinical pregnancy rate per cycle.

Results:

No significant differences were found between the two groups with regard to the chemical, clinical, and ongoing pregnancy rates (48.2% vs 45.9%, p>0.05; 38.9% vs 35.3%, p>0.05; and 37.6% vs 34.1%, p>0.05, respectively), as well as the live birth or miscarriage rates per cycle (35.3% vs 31.8%, p>0.05; and 1.2% vs 1.2%, p>0.05, respectively).

Conclusion:

These findings suggest that although both FET protocols are equally effective in terms of pregnancy outcomes in women with regular menstrual cycles, NC-FET is more favorable because it requires no medication, has no adverse events, and has a significant cost reduction.