Methods for endometrial preparation in frozen-thawed embryo transfer cycles

A randomized clinical trial of transdermal (gel) versus oral estrogen for endometrial preparation in frozen embryo transfer cycle

OBJECTIVE

The aim of this study was to compare endometrial thickness with the use of transdermal estrogen (gel) versus oral estrogen (pills) for endometrial preparation in the frozen embryo transfer cycle and serum estrogen concentrations during the preparation cycle, side effects, and chemical and clinical pregnancy rates.

METHODS

This was a prospective, randomized controlled trial of women undergoing endometrial preparation for cryopreserved blastocyst transfer. A total of 88 women were randomized, of which 82 completed the study protocol. Of this group, 44 received 6 mg/day of estradiol valerate orally (pills group) and 38 received 4.5 mg/day of estradiol hemihydrate transdermally (gel group). Endometrial thickness was measured using transvaginal ultrasound between the 7 and 10th day of the cycle. Serum estradiol concentrations were measured on the day of initiating the cycle, on control transvaginal ultrasounds, and on the day of embryo transfer. Side effects were documented at each study visit. p<0.05 were adopted as statistically significant. The groups were compared using Student's t-test for continuous variables and chi-square or Fisher's exact test for categorical variables.

RESULTS

There were no significant group differences (p>0.05) in endometrial thickness, biochemical and clinical pregnancy rates, miscarriage rate, blood estradiol concentrations, duration of estradiol administration, or cycle cancellation rates.

CONCLUSION

Endometrial preparation with transdermal estrogen yielded similar reproductive outcomes to oral estrogen with fewer side effects.

Comparing the success rate of natural cycle and modified natural cycle protocols for frozen-thawed embryo transfer

Objective: The aim of the present study is to compare the effects of Natural Cycle and modified Natural Cycle protocols for frozen-thawed embryo transfer on clinical pregnancy rate and live birth rate. Methods: This prospective randomized controlled trial comprised 145 patients scheduled for frozen-thawed embryo transfer and was conducted at a university hospital between 2019 and 2021. The Natural Cycle protocol was administered to 73 patients and the modified Natural Cycle protocol to 72 patients and the clinical outcome was compared between the groups. The main outcome measure was live birth rate. Results: Baseline characteristics and cycle parameters were similar in both groups. There was no difference in clinical pregnancy rate (58.9% and 54.2%, respectively; p = .565) and live birth rate between the Natural Cycle and modified Natural Cycle groups (49.3% and 48.6% respectively; p = .932). Conclusion: This study established that clinical pregnancy and live birth rates were not affected by natural cycle ovulation being spontaneous or hCG-triggered among patients undergoing frozen-thawed embryo transfer. Thus, the protocol for natural cycle frozen-thawed embryo transfers should be chosen according to the priorities of the patient and the physician.

A Comparative Study to Assess the Efficacy of Two Different Estradiol Formulations during In Vitro Fertilization

Improvements in stimulation protocols, introduction of vitrification, and changes in clinical practices have contributed to improved efficacy and safety of assisted reproductive technology (ART) procedures. This has also led to a concomitant increase in number of cycles requiring hormone replacement therapy (HRT) protocol for performing an embryo transfer. Successful implantation is dependent on endometrial thickness which in turn is regulated by temporal regulation of hormones. Careful control of estrogen levels determines uterine receptivity. One of the most used drugs for achieving appropriate endometrial lining of >7 mm in HRT is estradiol valerate. Although different estrogen formulations with varying physicochemical properties exist, there is not enough literature to support if the differences translate into a discernible clinical outcome in an in vitro fertilization (IVF) setting. Objective and Method. In this study, retrospective in nature, we compare the efficacy of oral estradiol hemihydrate with estradiol valerate in HRT cycles in 2,529 Indian women, undergoing treatment at a center in India between Jan 2017 and May 2019. Results. Our results primarily indicate that between the estradiol valerate and estradiol hemihydrate treatment groups, the implantation rate (IR) was 47.42% and 49.07%, respectively (P value 0.284), and the endometrial thickness (mean ± SEM in mm) that was achieved was 9.25 ± 0.038 mm and 9.57 ± 0.058 mm (P value < 0.001), respectively. There were no significant differences observed in the secondary outcome measures including clinical pregnancy rate, abortion rate, ectopic pregnancy, and live birth rate. Conclusions. Hence, this study concludes that oral estradiol hemihydrate and estradiol valerate are therapeutically equivalent and provide similar clinical outcomes in an IVF setting.

Subcutaneous progesterone versus vaginal progesterone for luteal-phase support in frozen-thawed embryo transfer: A cross-sectional study

Background

Luteal-phase support is a complex and controversial issue in the field of reproductive management.

Objective

To compare the safety and efficacy of low-dose subcutaneous progesterone with the vaginal progesterone for luteal-phase support in patients undergoing rozen-thawed embryo transfer.

Materials and Methods

In this cross-sectional study, information related to 77 women that had frozen-thawed embryo transfer was reviewed. The patients were divided into two groups based on the route of progesterone administration used as a luteal-phase support. When the endometrial thickness reached ≥ 8 mm, in one group progesterone (Prolutex) 25 mg/ daily subcutaneous and in another group, vaginal progesterone (CyclogestⓇ) 400 mg twice or (EndometrinⓇ) 100 mg thrice daily, were administrated and continued until menstruation or in case of clinical pregnancy for 8 wk after the embryo transfer when the fetal heart activity was detected by ultrasonography.

Results

The patient's characteristics were matched and there was no significant difference. The chemical and clinical pregnancy rate was higher in the vaginal progesterone group compared to the prolutex group, but statistically unnoticeable, (40% vs. 29.6%, p = 0.367) and (28% vs. 22.2%, p = 0.581), respectively.

Conclusion

The findings of this study demonstrate that the new subcutaneous progesterone can be a good alternative for intramuscular progesterone in women that dislike and do not accept vaginal formulations as luteal-phase support in assisted reproductive technology.

Relationship between temporal changes of endometrial blood flow impedance during natural and hormone replacement cycles and prediction of pregnancy during vitrified-warmed embryo transfer

AIM

This study aimed to examine the relationship between the temporal changes in endometrial blood flow impedance during natural and hormone replacement therapy (HRT) cycles and clinical outcomes of vitrified-warmed embryo transfer (ET).

METHODS

This retrospective observational cohort study included 60 women, 28 with natural, and 32 with HRT cycles, who underwent vitrified-warmed ET. Uterine radial artery resistance index (RA-RI) was measured during the natural and HRT cycles at the following time points: early follicular phase, day of the human chorionic gonadotropin injection during a natural cycle or day of progesterone administration during an HRT cycle, and day of ET.

RESULTS

The clinical pregnancy rates of the natural and HRT cycles were 32.1% and 34.4%, respectively. The RA-RI at the early follicular phase was significantly lower in the pregnant group than in the nonpregnant group with natural but not HRT cycles (p = 0.04). The odds ratio for pregnancy was 0.70 (95% confidence interval [CI], 0.52-0.95) when the RA-RI value at the early follicular phase was increased by 0.01 in the natural cycle. With the natural cycle, the area under the receiver-operating characteristic curves for the RA-RI at the early follicular phase with a threshold of 0.68 was 0.75 (95% CI, 0.57-0.93), and the positive and negative predictive values were 0.53 (95% CI, 0.37-0.59) and 0.92 (0.74-0.99), respectively.

CONCLUSION

RA-RI at the early follicular phase might be an effective and useful tool for deciding between natural or HRT cycles for vitrified-warmed ET.

Endometrial Liquid Biopsy Provides a miRNA Roadmap of the Secretory Phase of the Human Endometrium

CONTEXT

Endometrial liquid biopsy (ELB) is a minimally invasive alternative for research and diagnosis in endometrial biology.

OBJECTIVE

We sought to establish an endometrial micro ribonucleic acid (miRNA) roadmap based on ELB during the secretory phase of the menstrual cycle in both natural and hormonal replacement therapy (HRT) cycles.

DESIGN

Human ELB samples (n = 58) were obtained from healthy ovum donors undergoing a natural and an HRT cycle consecutively. miRNA profiles were identified using next-generation sequencing (NGS). For functional analysis, messenger ribonucleic acid targets were chosen among those reported in the endometrial receptivity analysis.

RESULTS

The human endometrial secretory phase is characterized by a dynamic miRNA secretion pattern that varies from the prereceptive to the receptive stages. No differences in miRNA profiles were found among natural versus HRT cycles in the same women, reinforcing the similarities in functional and clinical outcomes in natural versus medicated cycles. Bioinformatic analysis revealed 62 validated interactions and 81 predicted interactions of miRNAs differentially expressed in the HRT cycle. Annotation of these genes linked them to 51 different pathways involved in endometrial receptivity.

CONCLUSION

This NGS-based study describes the miRNA signature in human ELB during the secretory phase of natural and HRT cycles. A consistent endometrial miRNA signature was observed in the acquisition of endometrial receptivity. Interestingly, no significant differences in miRNA expression were found in natural versus HRT cycles reinforcing the functional clinical similarities between both approaches.

AQP2 is regulated by estradiol in human endometrium and is associated with spheroid attachment in vitro

17β‑estradiol (E2) and aquaporin 2 (AQP2) are associated with endometrial receptivity, and E2 directly regulates AQP2 expression in endometrial cancer cells. The present study aimed to investigate the role of AQP2 in embryo implantation. Normal endometrial samples were collected at the Women's Hospital (Hangzhou, China) from women seeking in vitro fertilization and embryo transfer; women with endometrial abnormalities were excluded from the study. Samples were categorized into early‑mid proliferative, late proliferative, early secretory, mid‑secretory and late secretory phase groups, according to the menstrual cycle. The mRNA and protein expression levels of AQP2 were assessed in normal human endometrium in response to E2 via reverse transcription‑quantitative polymerase chain reaction and western blotting, respectively. The effects of AQP2 on spheroid attachment were assessed using an in vitro co‑culture assay with small interfering (si)RNA against AQP2. The highest expression levels of AQP2 were observed in the late proliferative and mid‑secretory phases, with the lowest levels detected in the early proliferative and late secretory phases. In addition, treatment with 10‑9 or 10‑7 M E2 for 24 h upregulated AQP2 in the cultured endometrium. Knockdown of AQP2 by siRNA significantly decreased JAr spheroid attachment; however, this effect was significantly reversed when AQP2 siRNA‑transfected cells were treated with 10‑7 M E2. The results of the present study suggested that AQP2 expression levels in human endometrium may be mediated by estrogen, and low AQP2 expression levels may be a potential cause of impaired uterine receptivity.

Systematic and standardized hysteroscopic endometrial injury for treatment of recurrent implantation failure

RESEARCH QUESTION

To investigate the effect of hysteroscopic endometrial injury for treatment of recurrent implantation failure (RIF).

DESIGN

This prospective and randomized controlled trial included 239 patients who had failed to achieve a clinical pregnancy after the transfer of at least four good-quality embryos in a minimum of three fresh or frozen-thawed embryo transfer cycles and were under the age of 40 years, who were randomized into two groups. The injury group (n = 124) received endometrial injury during their hysteroscopic procedure, whereas the control group (n = 115) did not. Patients who had endometrial pathologies were excluded from the study.

RESULTS

There were no statistically significant differences in duration of gonadotrophin use (8.23 versus 8.30 days), total dose of gonadotrophins (2330 versus 2338 IU), number of oocytes (7.03 versus 8.21), number of mature oocytes (5.27 versus 6.02), number of fertilized oocytes (4.19 versus 4.55), number of good-quality embryos (2.07 versus 2.43), number of embryos transferred (1.97 versus 1.93) or endometrial thickness (9.04 versus 9.35 mm) between the injury group and control group, respectively. Clinical pregnancy rates (25.8% versus 15.6%, P = 0.047), live birth rates (21.8% versus 12.2%, P = 0.049) and implantation rates (14.2% versus 8.8%, P = 0.036) were significantly different, favouring the injury group.

CONCLUSION

This study suggests that endometrial injury is beneficial in RIF patients to increase the odds of implantation, clinical pregnancy and live birth.

A Comparison of the Miscarriage and Live Birth Rate for Frozen Embryo Transfer According to Two Endometrial Preparations: Natural or Primed with Estrogens

Objective The primary objective is to compare miscarriage rates in frozen-thawed embryo transfer (FET) cycles, according to the endometrial preparation used either artificial through the administration of exogenous estrogen and progesterone or natural without any treatment, during a spontaneous ovulatory cycle. The secondary objective is to compare the live birth rates between the two endometrial preparations.

Study design This is a retrospective study done at KK Women’s and Children’s Hospital Singapore. We included women who underwent FET cycles either with hormone replacement treatment (HRT) or no treatment (natural) for the endometrial preparation, regardless of their cycle number, from 1 January 2011 till 31 December 2015.

Results A total of 2,752 FET cycles were included in our analysis. The natural cycle followed by vaginal progesterone support was used in 1,221 cycles and the HRT cycle with estrogen and vaginal progesterone was used in 1,531 cycles. There is a significantly higher miscarriage rate in the HRT group (38.4%) compared with the natural group (22.3%). The live birth rate is significantly higher in the natural group (22.8%) compared with the HRT group (17.3%). The multivariate analysis further shows that the HRT therapy is independently associated with an increased risk of miscarriage (adjusted odds ratio 2.05; 95% confidence interval 1.45–2.90; [Formula: see text] <0.001) and hence lower odds of live birth (adjusted odds ratio 0.69; 95% confidence interval 0.56–0.84; [Formula: see text] <0.001) after adjusting for the patient’s age at which the embryo was cryopreserved, race, body mass index, main indications for in vitro fertilization, number of embryos transferred and type of embryo transferred.

Conclusion We have shown in this study that the miscarriage rate is higher in the HRT FET group and that this increased miscarriage rate translates into a lower live birth rate in the HRT group. Thus, we conclude that patients with regular menstrual cycles should be offered a natural FET cycle to achieve better outcomes in terms of live birth rate and reducing the miscarriage rate.

Natural cycle versus hormone replacement therapy cycle in frozen-thawed embryo transfer

OBJECTIVES

To compare implantation rates, clinical pregnancy rates and live birth rates associated with natural and hormone replacement therapy (HRT) methods of endometrial preparation in frozen-thawed embryo transfer (FET) cycles.  Methods: The results of 108 natural cycles and 224 HRT cycles of FET transfers performed in a private in vitro fertilization (IVF) center between June 2013 and August 2015 were  retrospectively compared with respect to implantation rate, clinical pregnancy rate, and live birth rate. Results: A total of 144 embryos were transferred in 108 natural cycles and 357 embryos were  transferred in 224 HRT cycles. No statistically significant differences were found in the implantation rate (p=0.796), clinical pregnancy rate per cycle (p=0.900), clinical pregnancy rate per transferred embryo (p=0.283), live birth rate per cycle (p=0.821), or live birth rate per transferred embryo (p=0.481) between the 2 groups.  Conclusion: This study showed no difference between the implantation rate, clinical pregnancy rate or live birth rate between the natural cycle group and HRT cycle group. These results may provide clinicians with more freedom to individualize patient treatment, particularly with respect to the selection of the endometrial preparation method, if these results are supported by large randomized controlled studies in the future.

Endometrial Preparation for Women Undergoing Embryo Transfer Frozen-Thawed Embryo Transfer With and Without Pretreatment With Gonadotropin Releasing Hormone Agonists

Objective: To evaluate the efficacy of endometrial preparation by exogenous steroids, with and without pretreatment by the use of GnRH agonist. Materials and methods: This randomized interventional study was conducted on 100 women who underwent a FTET that were randomly assigned to receive GnRH agonist (buserelin) in the luteal phase or no receive this medication. In both groups endometrial preparation was achieved by the use of estradiol valerate pill started from the second day of the menstruation and used every day, with an initial dose of 2mg/d and every 3 days increased to 4 mg/d and 6 mg/d, respectively. Endometrial thickness was evaluated by vaginal ultrasound. Forty eight hours after beginning of progesterone administration 2 to 3 embryos surviving in freezing procedure were transferred. Results: the two groups were similar in mean age, body mass index, duration of infertility, type of infertility, number of embryos transferred and endometrial thickness on the day of beginning progesterone therapy. Comparing outcome of FTET between the two groups scheduled for receiving GnRH agonist showed no significant difference in the rate of implantation (6.7% versus 10.0%), the rate of chemical pregnancy (21.7% versus 22.5%), clinical pregnancy rate (15.0% versus 17.5%), and also ongoing pregnancy (13.3% versus 12.5%). Conclusion: Endometrial preparation for FTET using GnRH agonists appears to be as effective as FTET without administrating these agonists.

[Pregnancy and obstetric outcomes of fresh embryo transfer versus frozen-thawed embryo transfer in women below 35 years of age]

OBJECTIVE

To compare the obstetric and perinatal outcomes between fresh embryo transfer (ET) and frozen-thawed ET (the "freeze-all" strategy) and evaluate the benefits of the "freeze-all" embryo strategy for young patients.

METHODS

We reviewed a total of 2091 ET cycles performed between January, 2011 and December, 2015 in women aged 20-35 years, including 1295 fresh ET cycles and 796 frozen-thawed ET cycles. The demographic characteristics, ovarian stimulation syndrome, clinical pregnancy rates, live birth rate and the obstetric outcomes (gestational age, preterm delivery rate and mean birth weight) were compared between the two groups.

RESULTS

The mean age of the patients receiving frozen-thawed ET cycles had a significantly younger age than those having fresh ET cycles (29.5 vs 30.2 years, P<0.05); the patients undergoing frozen-thawed ET cycles also had significantly higher estradiol level on the day of trigger (12 973 pmol/L vs 8673 pmol/L) and a greater oocyte number retrieved (12.7 vs 8.7). The incidence of severe ovarian hyperstimulation syndrome was significantly lower in patients with frozen ET than those with fresh ET (P<0.05). No significant differences were found in the pregnancy rate (59.5% vs 56.0%; P>0.05), live birth rate (50.3% vs 47.0%; P>0.05), mean birth weight or gestational age between the two groups.

CONCLUSIONS

The freeze-all policy produces similar pregnancy and obstetric outcomes with those of fresh ET. Our results support the hypothesis that the freeze-all strategy help to prevent OHSS with a good pregnancy rate.