Preparation of endometrium for frozen embryo replacement cycles: a systematic review and meta-analysis

Serum progesterone levels greater than 32.5 ng/ml on the day of embryo transfer are associated with lower live birth rate after artificial endometrial preparation: a prospective study

BACKGROUND

Previous observational studies have highlighted the negative effects of serum hormone levels at the minimum threshold during frozen embryo transfer (FET) cycles. However, still the questions regarding the maximum threshold level, and the highest allowed dosage of hormonal medications remain unresolved. The present study was conducted to determine whether there is any relationship between the serum progesterone and estradiol levels on the day of ET, and live birth rate (LBR) in patients receiving HRT in FET cycles.

METHODS

In this prospective cohort study, eligible women who were undergoing their first or second FET cycles with the top graded blastocyst stage embryos were included. All patients received the same HRT regimen. FET was scheduled 5 days after administration of the first dosage of progesterone. On the morning of ET, 4-6 h after the last dose of progesterone supplementation, the serum progesterone (P4, ng/ml) and estradiol (E2, pg/ml) levels were measured.

RESULTS

Amongst the 258 eligible women that were evaluated, the overall LBR was 34.1 % (88/258). The serum P4 and E2 values were divided into four quartiles. The means of women's age and BMI were similar between the four quartiles groups. Regarding both P4 and E2 values, it was found that the LBR was significantly lower in the highest quartile group (Q4) compared with the others, (P = 0.002 and P = 0.042, respectively). The analysis of the multivariable logistic regression showed that the serum level of P4 on ET day, was the only significant predictive variable for LBR. The ROC curve revealed a significant predictive value of serum P4 levels on the day of ET for LBR, with an AUC = 0.61 (95 % CI: 0.54-0.68, P = 0.002). The optimum level of serum P4, with 70 % sensitivity and 50 %specificity for LBR, was 32.5 ng/ml.

CONCLUSIONS

The present study suggests that a serum P4 value at the maximum threshold on the day of FET is associated with reduced LBR following blastocyst transfer. Therefore, measuring and monitoring of P4 levels during FET cycles might be necessary. However, the results regarding the necessity for the screening of serum E2 levels before ET, are still controversial, and further prospective studies are required.

Optimising Follicular Development, Pituitary Suppression, Triggering and Luteal Phase Support During Assisted Reproductive Technology: A Delphi Consensus

BACKGROUND

A Delphi consensus was conducted to evaluate global expert opinions on key aspects of assisted reproductive technology (ART) treatment.

METHODS

Ten experts plus the Scientific Coordinator discussed and amended statements plus supporting references proposed by the Scientific Coordinator. The statements were distributed via an online survey to 35 experts, who voted on their level of agreement or disagreement with each statement. Consensus was reached if the proportion of participants agreeing or disagreeing with a statement was >66%.

RESULTS

Eighteen statements were developed. All statements reached consensus and the most relevant are summarised here. (1) Follicular development and stimulation with gonadotropins (n = 9 statements): Recombinant human follicle stimulating hormone (r-hFSH) alone is sufficient for follicular development in normogonadotropic patients aged <35 years. Oocyte number and live birth rate are strongly correlated; there is a positive linear correlation with cumulative live birth rate. Different r-hFSH preparations have identical polypeptide chains but different glycosylation patterns, affecting the biospecific activity of r-hFSH. r-hFSH plus recombinant human LH (r-hFSH:r-hLH) demonstrates improved pregnancy rates and cost efficacy versus human menopausal gonadotropin (hMG) in patients with severe FSH and LH deficiency. (2) Pituitary suppression (n = 2 statements): Gonadotropin releasing hormone (GnRH) antagonists are associated with lower rates of any grade ovarian hyperstimulation syndrome (OHSS) and cycle cancellation versus GnRH agonists. (3) Final oocyte maturation triggering (n=4 statements): Human chorionic gonadotropin (hCG) represents the gold standard in fresh cycles. The efficacy of hCG triggering for frozen transfers in modified natural cycles is controversial compared with LH peak monitoring. Current evidence supports significantly higher pregnancy rates with hCG + GnRH agonist versus hCG alone, but further evidence is needed. GnRH agonist trigger, in GnRH antagonist protocol, is recommended for final oocyte maturation in women at risk of OHSS. (4) Luteal-phase support (n = 3 statements): Vaginal progesterone therapy represents the gold standard for luteal-phase support.

CONCLUSIONS

This Delphi consensus provides a real-world clinical perspective on the specific approaches during the key steps of ART treatment from a diverse group of international experts. Additional guidance from clinicians on ART strategies could complement guidelines and policies, and may help to further improve treatment outcomes.

Letrozole for Female Infertility

Letrozole, an aromatase inhibitor that blocks estrogen synthesis by inhibiting the final step of the estrogen biosynthetic pathway, has been used in the applications of a wide range of infertility settings. It has been more than 20 years since the initial clinical trial of letrozole for ovulation induction. In light of the accumulating clinical and basic evidence, the efficacy and safety of letrozole have been identified. This mini review focuses on our current knowledge of the applications and mechanisms of letrozole for female infertility and various questions are put forward about how letrozole could be more effectively used.

Retrospective analysis of the endometrial preparation protocols for frozen-thawed embryo transfers in women with endometrial polyps

We aimed to explore the clinical effects of the endometrial preparation protocol for frozen-thawed embryo transfer (FET) in women with endometrial polyps. This retrospective study was performed at the Reproductive Medicine Centre of the First Affiliated Hospital of Sun Yat-sen University between January 2015 and May 2018 involving women diagnosed with endometrial polyps by hysteroscopy. The freeze-all strategy was performed in controlled ovarian stimulation cycles followed by FET cycles. Endometrial preparation protocols included: (i) gonadotropin-releasing hormone agonist-hormone replacement therapy (GnRHa-HRT); (ii) hormone replacement therapy (HRT); (iii) natural cycle (NC); and (iv) ovulation induction (OI). Recurrence rate of polyps and clinical results were compared among the four groups. If polyp recurrence was found in ultrasound scans during the FET cycles, the embryo transfers were cancelled. The recurrence rate of polyps was lower in the GnRHa-HRT protocol [2.13% (2/94)] than in the other three protocols [6.15% (26/423), 6.7% (28/418), and 4% (1/25) in the HRT, NC, and OI, respectively; p = 0.038], showing statistically significant difference. Pregnancy, early pregnancy loss, and live birth rates among the four protocols were similar (p = 0.922, p = 0.171, and p = 0.072, respectively). The GnRHa-HRT protocol used for FET in women with endometrial polyps could reduce the recurrence rate of the polyps. In addition, we found that it did not decrease pregnancy or live birth rates.

Clinical Outcomes of Frozen-Thawed Embryo Transfer in Natural Cycles with Spontaneous or Induced Ovulation: a Retrospective Cohort Study from 1937 Cycles

Our objective was to assess whether there is a difference in the pregnancy outcomes in the natural cycle (NC) with spontaneous LH rise compared with modified natural cycle controlled by hCG for final oocyte maturation and ovulation after frozen-thawed embryo transfer (FET). In this retrospective cohort study, we analyzed the clinical outcomes of a total of 1937 patients undergoing FET followed by endometrial preparation with the natural cycle and modified natural cycle. The primary outcome was live birth, and secondary outcomes included miscarriage rate, clinical pregnancy rate, preterm birth rate, and ectopic pregnancy rate. The type of endometrial preparation did not impact live birth (adjusted odds ratio [aOR] 0.92; 95% confidence interval [CI], 0.69-1.23), miscarriage (aOR 0.83; 95%CI, 0.50-1.39), clinical pregnancy (aOR 0.88; 95%CI, 0.66-1.18), preterm birth (aOR 0.91; 95%CI, 0.56-1.50), or ectopic pregnancy (aOR 1.06; 95%CI, 0.29-3.94). In conclusion, in women undergoing FET, natural cycles and modified natural cycles resulted in comparable clinical outcomes.

Maternal and Neonatal Complications After Natural vs. Hormone Replacement Therapy Cycle Regimen for Frozen Single Blastocyst Transfer

Objective: To evaluate the maternal and neonatal complications after frozen-thawed blastocyst transfer cycles utilizing different endometrial preparation regimens.

Design: This is a retrospective cohort study and a secondary analysis of a multicenter, randomized, controlled trial comparing live birth rate after fresh vs. frozen single blastocyst transfer (Frefro-blastocyst).

Setting: Reproductive medicine centers.

Patient(s): A total of 800 women with regular menstrual cycles undergoing their first cycle of in-vitro fertilization after frozen-thawed single blastocyst transfer.

Intervention(s): Endometrium preparation was performed with a natural cycle regimen or hormone replacement therapy (HRT) cycle regimen, at the discretion of local investigators. All pregnancies were followed up until delivery.

Main Outcome Measure(s): Maternal and neonatal complications.

Result(s): 513 infertile patients who underwent natural cycles regimen and 287 who underwent HRT cycles regimen were analyzed. The incidences of maternal and neonatal complications were comparable between the natural cycle and HRT cycle regimen. Regarding the risk of gestational diabetes, gestational hypertension, pre-eclampsia, preterm delivery, small for gestational age and large for gestational age, the HRT cycle was still not a significant risk factor after adjusting for potential confounders. The natural cycle regimen yielded an insignificant higher total live birth rate [59.45 vs. 50.17%, P = 0.001, adjusted odds ratio (AOR) 1.366, 95% confidence interval (CI) 0.975–1.913], clinical pregnancy rate (68.23 vs. 58.89%, P = 0.008, AOR 1.406, 95% CI 0.992–1.991) and ongoing pregnancy rate (62.18 vs. 52.61%, P = 0.008, AOR 1.387, 95% CI 0.988–1.948) than did the HRT cycle regimen. However, compared to natural cycles, HRT cycles were associated with a significantly higher risk of biochemical miscarriage (6.86 vs. 18.18%, P < 0.001, AOR 0.328, 95% CI, 0.176–0.611).

Conclusion(s): The incidence of maternal and neonatal complications in natural cycle and HRT cycle regimens after frozen single blastocyst transfer were comparable. Frozen-thawed single blastocyst transfer in a natural cycle was associated with lower biomedical miscarriage than the use of the HRT cycle.

Clinical Trial Registration Number: Frefro-blastocyst was registered at Chinese Clinical Trial Registry, ChiCTR-IOR-14005405.

The effect of intrauterine insemination preceding frozen-thawed elective single embryo transfer in couples with unexplained subfertility

Introduction

This prospective randomized controlled trial aimed to evaluate the effect of intrauterine insemination (IUI) before frozen-thawed elective single embryo transfer (FT-eSET).

Material and methods

A total of 200 couples with unexplained subfertility underwent in-vitro fertilization (IVF) treatment. Patients were randomly assigned to either FT-eSET or IUI preceding FT-eSET. Both groups were composed of 100 women. IUI was timed 6 days before FT-eSET in the IUI preceding FT-eSET group. Implantation rates (IR), biochemical and clinical abortion rates (AR), clinical pregnancy rates (PR), ongoing pregnancy rates (PRs), and live birth rates were measured in this study.

Results

The IUI preceding FT-eSET group was associated with higher rates of clinical pregnancy, 54% vs. 42%, but not significantly. Similarly, IR, PR and live birth rate were higher in the IUI preceding FT-eSET group but not significantly. In the IUI preceding FT-eSET group, the biochemical and clinical abortion rates were lower than in the control group (9.5% vs. 14.2% and 5.5% vs. 5.2%, respectively). However, no statistically significant difference was found between the two groups, either.

Conclusions

This is the first study showing that IUI may precede FT-eSET to improve PR in couples with unexplained subfertility. Also, performing IUI before FT-eSET may decrease biochemical and clinical abortion rates.

Modified natural protocol seems superior to natural and artificial protocols for preparing the endometrium in frozen embryo transfer cycles

BACKGROUND

Although several studies claim higher success rates in natural cycle (NC) and modified natural cycle (mNC) protocols, currently, there is no consensus on the most effective method of endometrium preparation prior to frozen embryo transfer (FET) cycles. We aimed to find out the best protocol by comparing three different protocols for preparing the endometrium in FET cycles.

METHODS

This retrospective cohort study was conducted at a private in-vitro fertilization (IVF) center. Medical records of all patients enrolled in frozen embryo transfer cycles between November 2017 and February 2019 were reviewed. Group I (N.=94) included patients who underwent artificial endometrial preparation (AC), group II (N.=23) confined patients enrolled in mNC and group III (N.=12) included patients who had NC protocol. Main outcome parameters were clinical pregnancy rates, implantation rates and miscarriage rates.

RESULTS

There was a tendency towards higher clinical pregnancy rate in mNC group. Clinical pregnancy rates of the three groups were 54.3%, 65.2% and 33.3% respectively (P=0.199). Implantation rate was significantly higher in group II (34%, 50% and 12% respectively, P=0.006). Miscarriage rates were similar for the three groups.

CONCLUSIONS

Although not reaching a statistically significant level, there is a tendency towards higher implantation rate and pregnancy rate in mNC protocol compared to true NC and AC protocols.

Endometrial preparation using gonadotropin-releasing hormone agonist prior to frozen-thawed embryo transfer in women with repeated implantation failure: An RCT

Background

Preparation of endometrial thickness in frozen-thawed embryo transfer (FET) is extremely important, particularly in repeated implantation failure (RIF) patients.

Objective

This study aimed to investigate the clinical outcomes of FET cycles among RIF women, based on the effects of administering gonadotropin-releasing hormone (GnRH) agonist prior to estrogen-progesterone preparation of the endometrium.

Materials and Methods

In this randomized clinical trial, 67 infertile women who were candidates for FET were divided into two groups: A) case group (n = 34), treated with GnRH agonist prior to endometrial preparation and B) control group (n = 33), which received the routine protocol. (6 mg daily estradiol started from second day) The clinical outcomes) including chemical and clinical pregnancy, in addition to implantation rates, were compared between the two groups.

Results

The results showed no significant differences in women's age (p = 0.558), duration (p = 0.540), type (p = 0.562), and cause of infertility (p = 0.699). Regarding pregnancy and implantation rates, there was a trend toward an increase in the case group; however, differences were not statistically significant.

Conclusion

Although our results showed no significant differences between groups. Because there are trends to better results in case group larger sample size may show significant difference.

Live birth after frozen-thawed embryo transfer: which endometrial preparation protocol is better?

OBJECTIVE

To compare the clinical outcomes of modified natural cycle (mNC) and artificial cycle (AC) protocols for frozen embryo transfers.

MATERIAL AND METHODS

A total of 490 frozen-thawed autologous embryo transfer cycles, performed in a single tertiary IVF center, between January 2015 and September 2017, were retrospectively analyzed. Of these, 214 cycles were performed after mNC and 276 cycles were performed after gonadotrophin-releasing hormone (GnRH) agonist plus sequential estrogen and progestin priming protocol. The primary outcome was live birth and secondary outcomes were clinical pregnancy, implantation and miscarriage rates. Multivariate regression analysis was used to adjust covariates on clinical outcome.

RESULTS

The rates of live birth (33.6 % vs. 29.3 %, respectively), clinical pregnancy (40.2 % vs. 36.6 %, respectively), implantation (32.3 % vs. 28.5 %, respectively), and miscarriage (5.1 % vs. 6.9 %, respectively) were not different between the mNC and AC groups. Multivariate analysis also showed that the method for endometrial preparation had no significant effect on clinical pregnancy and live birth. The adjusted odds ratios (OR) of live births and clinical pregnancies were 0.97 (95 % CI 0.64-1.48) and 0.98 (95 % CI 0.65-1.46) for the AC compared to mNC group. However, there was a significant difference between mNC and AC in cycles in which double embryo transfer was performed. The live birth (48 % vs. 31.4 %P= 0.01) and clinical pregnancy rates (53.9 % vs. 38.8 %, P= 0.02) were significantly higher in the mNC group than the AC group for double embryo transfers.

CONCLUSION

The live birth and clinical pregnancy rates are comparable between mNC and AC with GnRH agonists in frozen thawed embryo transfer cycles. In ovulatory patients with planned double embryo transfer, mNC can be considered. Further well-designed prospective studies are needed to confirm our results.

Subcutaneous versus vaginal progesterone for vitrified-warmed blastocyst transfer in artificial cycles

RESEARCH QUESTION

Does subcutaneous progesterone provide similar live birth or ongoing pregnancy rates as vaginal progesterone in frozen embryo transfer (FET) cycles?

DESIGN

Retrospective cohort study (n = 214 women), consisting of 107 women who received subcutaneous progesterone for FET in artificial cycles and 107 women receiving vaginal progesterone who were matched for age and treatment cycle rank acted as controls. All embryos were transferred in an artificial cycle with 6 mg per day oral oestradiol valerate starting on the second or third day of the menstrual cycle. Patients underwent transvaginal ultrasound on the 10th day of priming, and subcutaneous progesterone (50 mg/day) or vaginal progesterone (180 mg/day) was started if the endometrium had a trilinear pattern regardless of its thickness. Embryo transfer was carried out on the sixth day of progesterone administration. Oestradiol and progesterone were continued until a negative pregnancy test, 10 days after the transfer, or until the completion of 10th gestational week. Main outcome measures were live birth or ongoing pregnancy rates.

RESULTS

Baseline characteristics were similar between the groups. Positive pregnancy test rates (64.5% versus 58.9%; P = 0.40; RR 1.1; 95% CI 0.89 to 1.35), live birth or ongoing pregnancy rates (39.3% versus 35.5%; P = 0.57; RR 1.11; 95% CI 0.78 to 1.56) and miscarriage rates (29% versus 25.5%; P = 0.68; RR 1.08; 95% CI 0.76 to 1.55) were similar in the subcutaneous progesterone and vaginal progesterone groups, respectively.

CONCLUSIONS

Subcutaneous progesterone seems to be an effective alternative to vaginal progesterone in patients undergoing FET. Randomized controlled trials comparing it with different progesterone preparations, routes and protocols are needed to better define its role.

Maternal and perinatal outcomes in programmed versus natural vitrified-warmed blastocyst transfer cycles

RESEARCH QUESTION

Do maternal and perinatal outcomes differ between natural and programmed frozen embryo transfer (FET) cycles?

DESIGN

Retrospective cohort study at a university-affiliated fertility centre including 775 patients who underwent programmed or natural FET cycles resulting in a singleton live birth using blastocysts vitrified between 2013 and 2018.

RESULTS

A total of 384 natural and 391 programmed FET singleton pregnancies were analysed. Programmed FET resulted in higher overall maternal complications (32.2% [126/391] versus 18.8% [72/384]; P < 0.01), including higher probability of hypertensive disorders of pregnancy (HDP) (15.3% [60/391] versus 6.3% [24/384]; P < 0.01), preterm premature rupture of membranes (2.6% [10/391] versus 0.3% [1/384]; P = 0.02) and caesarean delivery (53.2% [206/387] versus 42.8% [163/381]; P = 0.03) compared with natural FET. After controlling for potential confounders, including age, body mass index, parity, smoking status, history of diabetes or chronic hypertension, infertility diagnosis, number of embryos transferred and use of preimplantation genetic testing, the adjusted odds ratio for HDP was 2.39 (95% CI 1.37 to 4.17) and for overall maternal complications was 2.21 (95% CI 1.51 to 3.22) comparing programmed with natural FET groups. The groups did not significantly differ for any perinatal outcomes analysed, including birth weight (3357.9 ± 671.6 g versus 3318.4 ± 616.2 g; P = 0.40) or rate of birth defects (1.5% [6/391] versus 2.1% [8/384]; P = 0.57), respectively.

CONCLUSION

Vitrified-warmed blastocyst transfer in a programmed cycle resulted in a twofold higher probability of HDP compared with transfer in a natural cycle. Natural FET cycle should, therefore, be recommended as first line for all eligible patients undergoing FET to reduce the risk of HDP.

Comparison of letrozole with gonadotropin-releasing hormone agonist in frozen embryo transfer after recurrent implantation failure: An RCT

Background

The use of frozen embryo transfer (FET) is increasing worldwide in the treatment of infertility by in vitro fertilization. Different methods of endometrial preparation for FET have been suggested.

Objective

The aim of this study was to compare the pregnancy outcomes after treatment with letrozole and those after treatment with the combination of gonadotropin-releasing hormone (GnRH) agonist and estradiol in FET.

Materials and Methods

This randomized controlled trial study was conducted on 142 infertile women with a history of previous FET failure. Participants were randomly assigned to two groups (n = 71 each). The GnRH group received 500 µg of buserelin plus 4mg estradiol (which increased to 8 mg if endometrial thickness was less than 5 mm), and the letrozole group received 5 mg of letrozole plus 75 IU of recombinant human follicle-stimulating hormone). At least two high-quality embryos were transferred to each subject in both groups. The outcome measures were clinical pregnancy rate and fetal heart rate detection.

Results

Subjects in the study groups had similar demographic characteristics and baseline clinical condition. Mean endometrial thickness in the letrozole and GnRH agonist groups were 8.90 ± 0.88 mm and 8.99 ± 0.85 mm, respectively (p = 0.57). The number of positive results of the beta human chorionic gonadotropin test and detection of fetal heartbeat were not significantly different between the groups (p > 0.05).

Conclusion

The administration of letrozole and GnRH may produce similar pregnancy outcomes in FET.

Addition of intramuscular progesterone to vaginal progesterone in hormone replacement therapy in vitrified-warmed blastocyst transfer cycles

RESEARCH QUESTION

Does intramuscular progesterone supplementation ensure ongoing pregnancy rates (OPR) comparable with vaginal progesterone only in hormone replacement therapy cycles for vitrified-warmed embryo transfer; and is there a window of serum progesterone concentration out of which reproductive outcomes may be negatively affected?

DESIGN

Retrospective longitudinal cohort study carried out at a single IVF clinic. In total, 475 consecutive, day-5 to day-6 vitrified-warmed embryo transfer cycles using hormone replacement therapy regimen were included. Vaginal progesterone only was given to 143 patients; supplementation of vaginal progesterone only with intramuscular progesterone supplementation every third day was given to 332 patients. On the sixth day of progesterone administration, immediately before frozen-thawed embryo transfer, circulating progesterone levels were measured. Main outcome measure was OPR.

RESULTS

The baseline demographic features and embryological data of the vaginal progesterone only and intramuscular progesterone supplementation groups were comparable. The OPR were 48.3% and 51.8%, respectively (P = 0.477). Neither the circulating progesterone level nor the type of progesterone administration were independent predictors of OPR. The effect of serum progesterone levels on OPR was evaluated by percentiles (<10%, 10-49%, 50-90% and >90%), taking 50-90% as the reference sub-group. All percentiles in the intramuscular progesterone supplementation group and in the vaginal progesterone only group had similar OPR.

CONCLUSIONS

Intramuscular progesterone supplementation every third day, overall, does not enhance OPR compared with vaginal progesterone only.

Endometrial preparation for frozen-thawed embryo transfer in an artificial cycle: transdermal versus vaginal estrogen

The objective was to compare the endometrial thickness (ET) in a frozen embryo transfer (FET) cycle between transdermal and vaginal estrogen. Our secondary objectives were to compare the patient satisfaction and the pregnancy outcomes. Prospective monocentric cohort study between 01/2017 and 12/2017 at a single institution. Choice of administration was left to the patient. 119 cycles had transdermal estrogen (T-group) and 199 had vaginal estrogen (V-group). The ET at 10 ± 1 days of treatment was significantly higher in the T-group compared to the V-group (9.9 vs 9.3 mm, p = 0.03). In the T-group, the mean duration of treatment was shorter (13.6 vs 15.5 days, p < 0.001). The rate of cycle cancelation was comparable between the two groups (12.6% vs 8.5%, p = 0.24). Serum estradiol levels were significantly lower (268 vs 1332 pg/ml, p < 0.001), and serum LH levels were significantly higher (12.1 ± 16.5 vs 5 ± 7.5 mIU/ml, p < 0.001) in the T-group. Patient satisfaction was higher in the T-group (p = 0.04) and 85.7% (36/42) of women who had received both treatments preferred the transdermal over the vaginal route. Live birth rates were comparable between the two groups (18% vs 19%, p = 0.1). Transdermal estrogen in artificial FET cycles was associated with higher ET, shorter treatment duration and better tolerance.

Seven Years of Vitrified Blastocyst Transfers: Comparison of 3 Preparation Protocols at a Single ART Center

Introduction: Frozen-thawed embryo transfers (FET) have become a standard practice to increase cumulative pregnancy rates, however, the choice of the best preparation protocol remains a matter of debate. Design: Retrospective analysis of clinical pregnancy (CPR) and live birth rate (LBR) of FET in natural cycles (NC-FET), modified natural cycles with hCG-triggered ovulation (mNC-FET), and hormonal artificial replacement (AR-FET). Materials and Methods: For natural cycles, patients were monitored by ultrasound to evaluate the dominant follicle and by urinary LH kits (NC-FET). When the endometrial thickness reached at least 7 mm and the dominant follicle 16-20 mm, hCG was administered in absence of urinary LH surge (mNC-FET). Embryo thawing and transfer was planned 7 days after LH surge or hCG administration. For the AR-FET, oral estradiol valerate was administered from day 2 of menstrual cycle until endometrial thickness reached at least 7 mm and transfer was planned after 5 days of vaginal progesterone start. Only single vitrified blastocyst transfers were included. Results: In total 2,895 transfers were performed of which 561 (19.4%) carried out with NC-FET, 1,749 (60.4%) with mNC-FET and 585 (20.2%) with AR-FET. CPRs were 32.62, 43.05, and 37.26%, respectively. LBR were 24.06, 33.56, and 25.81%, respectively. A statistically significant (p < 0.001) higher LBR for mNC-FET vs. NC-FET (OR 0.49-0.78) and AR-FET (OR 0.47-0.74) was observed. A higher ectopic pregnancy rate (p = 0.002) was observed in NC-FET (3.28%) than in AR-FET (1.83%) and mNC-FET (0.40%). A higher abortion rate (p = 0.031) in pregnancies <12 weeks was observed in AR-FET (27.52%) than in NC-FET (19.67%) and in mNC-FET (19.39%). At Post hoc analysis only female age (OR 0.91-0.95), antimullerian hormone (AMH) (OR 1.01-1.07) and mNC-FET (OR 1.39-1.98) were statically significant prognostic factors for LBRs. Conclusions: These results demonstrate a superior CPR and LBR following FET in hCG-triggered ovulation cycles compared to NC and AR-FET, a higher ectopic pregnancy rate in NC-FET and a higher abortion rate in pregnancies <12 weeks in AR-FET. However, these data need to be confirmed in randomized and prospective studies before definitive conclusions can be drawn. Clinicaltrials.gov ID: NCT03581422.

[Progesterone and frozen-thawed embryo transfer after hormonal replacement therapy for endometrial preparation: An update on medical practices]

Frozen-thawed embryo transfer (FET) has recently become the most frequently performed ART procedure. Many protocols for endometrial preparation are used, without any evidence-based superiority of one protocol above the others. Most French fertility centers mainly use hormonal replacement treatment (HRT) for endometrial preparation for organizational reasons. According to some studies, early pregnancy losses rate is higher with HRT endometrial preparation for FET than with other protocols, leading to new insights in improving outcomes into ART centers. There is a lack of consensual guidelines regarding the use of HRT for FET: there are various protocols, with different dosages, duration and routes for progesterone (PG) prescription. To date, the vaginal route is the most popular around the world as it gives higher intra-uterine concentration of PG because of the first uterine pass. However, recent scientific publications have pointed the importance of PG measurement in order to detect a lack of PG supplementation. Whatever the route of administration, it seems that a significant proportion of patients do not reach adequate PG concentrations for successful implantation and ongoing pregnancy. Timing of the measurement and ideal serum PG rate to reach are yet to be defined. What treatment strategy to adopt according to the results is still under investigation. Individualization of PG doses and routes of administration could lead to a decrease in miscarriages and better outcome.

Measuring the serum progesterone level on the day of transfer can be an additional tool to maximize ongoing pregnancies in single euploid frozen blastocyst transfers

BACKGROUND

Endometrial preparation with hormone replacement therapy (HRT) is the preferred regimen for clinicians due to the opportunity to schedule the day of embryo transfer and for patients due to the requirement of fewer visits for frozen-warmed embryo transfers (FET). The increasing number of FETs raises the question of the serum P levels required to optimize the pregnancy outcome on the embryo transfer day.

METHODS

This prospective cohort study includes patients who underwent single euploid FET. All patients received HRT with oestradiol valerate (EV) and 100 mg of intramuscular (IM) progesterone (P). FET was scheduled 117-120 h after the first IM administration of 100 mg P. The serum P level was analyzed 1 h before the embryo transfer (ET). In all cycles, only embryos that were biopsied on day 5 were utilized for FET. Next generation sequencing (NGS) was used for comprehensive chromosomal analysis.

RESULTS

Overall, the ongoing pregnancy rate (OPR) was 58.9% (99/168). Data were then categorized according to the presence (Group I; n = 99) or the absence (Group II; n = 69) of an ongoing pregnancy. No significant differences regarding, female age, body mass index (BMI), number of previous miscarriages, number of previous live birth, sperm concentration, number of oocytes retrieved, number of mature oocytes (MII), rate of fertilized oocytes with two pronuclei (2PN), trophectoderm score, inner cell mass (ICM) score, endometrial thickness (mm), oestrodiol (E₂) and P levels prior to IM P administration were found between two groups. The P levels on the day of ET (ng/ml) were significantly higher in Group I (28 (5.6-76.4) vs 16.4 (7.4-60) p = 0.039). The P level on the day of ET was a predictor of a higher OPR (p < 0.001 OR: 1.033 95%CI [1.009-1.056]) after multivariate analysis. The ROC curve showed a significant predictive value of serum P levels on the day of ET for OPR, with an AUC (95%CI) = 0.716 (0.637-0.795). The optimal cut-off value for prediction of the OPR was a P level of 20.6 ng/ml (71.7% sensitivity, 56.5% specificity).

CONCLUSIONS

The present study suggests a minimum threshold of the serum P value on the day of ET that needs to be reached in HRT cycles to optimize the clinical outcome. Individualization of the P dosage should be evaluated in further studies.

Higher live birth rate with stimulated rather than artificial cycle for frozen-thawed embryo transfer

OBJECTIVE

To study which endometrial preparation allows a better ongoing pregnancy rates (OPR) and live birth rate (LBR) after frozen-thawed embryo transfer (FET) between mild gonadotropin ovarian stimulation (OS) and artificial cycles (AC).

STUDY DESIGN

Retrospective follow-up study including all FET performed in one fertility center from 2013 to 2016. In the OS group, gonadotropins were followed by r-hCG triggering. Vaginal micronized progesterone (200 mg/day) was given systematically. In the AC group, estradiol (E2) was started on Day 1. Vaginal micronized progesterone (600 mg/d) was added to E2 for 12 weeks. Data were analyzed using a multiple regression model.

RESULTS

Among 1021 FETs, 35% underwent OS preparation, 65% had an AC. As expected, patients in the AC group suffered more from endometriosis (18.5% vs. 12.9%; p = .021) and polycystic ovarian syndrome (21.7% vs. 10.9%; p < .0001) than patients in the OS group. There was no difference between groups with respect to endometrial thickness, number of embryos transferred, development stage at FET, cryopreservation technique. Despite a similar clinical pregnancy rate (CPR) (24.4% vs. 20.8%; p = .189), the OPR was significantly higher in the OS than in the AC group (17.9% vs. 11%; p = .002), leading to an increased LBR (17.1% vs. 9.8%; p < .001). After adjusting for parameters usually linked to early pregnancy losses or potential bias (patient age at freezing, smoking status, PCOS, endometriosis, rank of transfer and previous miscarriages), the results remained significant.

CONCLUSION

Despite a similar CPR, LBR was significantly higher with mild OS than with the AC preparation, even after adjusting for potential confounders. In light of these results, the first-line endometrial preparation could be OS instead of an AC. In an AC, a potential defect of the luteal phase may exist, treatment could be optimized to avoid pregnancy losses. A randomized controlled trial should be undertaken to assess the role of OS and ACs in FET.

Modified natural-cycle cryopreserved embryo transfer: is a washout period needed after a failed fresh cycle?

RESEARCH QUESTION

Are the characteristics of the natural cycle or modified natural cycle (mNC), or live birth rates (LBR), affected by delaying frozen embryo transfer (FET) after a failed fresh IVF cycle?

DESIGN

In a retrospective study, conducted at a university-affiliated tertiary centre, 198 women aged 18-45 years undergoing their first FET cycle after a failed fresh embryo transfer attempt using an mNC were evaluated. Cycles were divided according to the time interval between oocyte retrieval and the start of the FET cycle into the immediate FET group (<22 days) and the delayed FET group (≥22 days). The main outcome measures were ovulation day and LBR.

RESULTS

The mean interval between oocyte retrieval and the start of the FET cycle was 15.6 ± 3.2 days in the immediate FET group and 84.8 ± 73.7 days in the delayed FET group (P < 0.001). Ovulation day was significantly delayed in the immediate FET group (day 17.1 ± 4.4 versus day 15.4 ± 3.7; P = 0.004). There was no difference between the immediate and delayed FET groups in terms of clinical pregnancy rate (CPR) (25.4% and 25.0%, respectively) or LBR (21.2% and 20.0%, respectively).

CONCLUSIONS

Natural-cycle characteristics are similar in immediate and delayed cycles, except for a slight delay in ovulation day. Deferring mNC-FET after a failed fresh IVF cycle does not improve the reproductive outcome. These results should encourage patients and clinicians who want to proceed with FET immediately after failure of fresh IVF.

Low serum progesterone the day prior to frozen embryo transfer of euploid embryos is associated with significant reduction in live birth rates

A retrospective cohort study was performed to examine whether, in artificial endometrial preparation for frozen embryo transfer (FET) cycles, progesterone (P) levels the day prior to embryo transfer of euploid embryos have an impact on pregnancy outcomes. In a private university clinic, 244 FETs between January 2016 and June 2017 were analyzed. Endometrial preparation was achieved with estradiol valerate and vaginal micronized progesterone. Serum P and estradiol levels the day prior to embryo transfer were measured. A multivariable analysis to assess the relationship between serum P level and pregnancy outcomes was performed, adjusted for confounding variables. Mean P value was 11.3 ± 5.1 ng/ml. Progesterone levels were split in quartiles: Q1: ≤ 8.06 ng/ml; Q2: 8.07-10.64 ng/ml; Q3: 10.65-13.13 ng/ml; Q4: > 13.13 ng/ml. Patients included in the lower P quartile had a significantly higher miscarriage rate and significantly lower live birth rate (LBR) compared to the higher ones. A low serum P level (≤ 10.64 ng/ml) one day before FET is associated with a lower pregnancy and LBR following FET of euploid embryos.

Innovations in assisted reproductive technologies: impact on contemporary donor egg practice and future advances

Innovations in assisted reproductive technologies (ART) have driven progress in the donor egg field since the birth of the first baby derived from a donor egg in 1983. Over time, donor oocytes have become an increasingly used option for patients unable to conceive with autologous oocytes. In donor egg, the unique separation of the oocyte source and recipient uterus has created a model that has propelled advances in ART. Progressive ART innovations that have optimized the oocyte donor and resulting embryo include the following: evaluation of ovarian reserve, controlled ovarian hyperstimulation regimens that reduce the risk of ovarian hyperstimulation syndrome, blastocyst culture, oocyte cryopreservation, and preimplantation genetic testing. For donor egg recipients, methods to optimize the endometrium to maximize implantation include endometrial receptivity testing, immunologic donor-recipient matching, and increased understanding of the uterine microbiome.

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.

Endogenous progesterone levels could predict reproductive outcome in frozen embryo replacement cycles supplemented with synthetic progestogens: A retrospective cohort study

PURPOSE

A retrospective, cohort study was conducted between 2009 and 2017 in a private infertility center to determine the predictive value of endogenous estrogen (E2) and progesterone (P4) levels in hormone-replacement frozen embryo replacement (FER) treatment cycles.

METHODS

A total of 120 consecutive, infertile patients who became pregnant after FER cycles were analyzed (age: 37.4 ± 4.4 years). Electively vitrified blastocysts were created during natural cycle IVF or mild ovarian stimulation treatments and subsequently transferred through delayed vitrified-thawed blastocyst transfer cycles supplemented with estrogens and a combination of synthetic progestogens. Serum E2 and progesterone P4 levels were intensively monitored every five days (from the day after embryo transfer until 9w1d of pregnancy) and compared among patients with a subsequent live birth (n = 76) or first-trimester pregnancy loss (n = 44).

RESULTS

Endogenous placental activity started as early as 5-6th pregnancy week differing significantly according to pregnancy outcome. For P4, the exponential rise from 6w2d onwards allowed distinguishing between failing and successful conceptions. For P4, lower quartiles of the live birth group did not intersect with upper quartiles of the miscarriage group.

CONCLUSIONS

Innovative FER protocols incorporating synthetic progestogens allow the correct measurement of endogenous placental activity and could help to monitor early first-trimester ART pregnancies.

Impact of method of endometrial preparation for frozen blastocyst transfer on pregnancy outcome: a retrospective cohort study

OBJECTIVE

To determine whether live birth rates differ by type of endometrial preparation in frozen embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

Academic fertility center.

PATIENT(S)

Reproductive-aged women undergoing autologous vitrified-warmed blastocyst FETs.

INTERVENTION(S)

Comparison of two methods of endometrial preparation: programmed FET (known as group A: luteal phase GnRH agonist suppression, oral E2, and IM P starting 5 days before ET) versus unstimulated FET (known as group B: hormone and ultrasound monitoring for follicle collapse to time transfer).

MAIN OUTCOME MEASURE(S)

Live birth rates in group A and group B.

RESULT(S)

Group A consisted of 923 cycles, and group B consisted of 105. When stratified by age at transfer, there was no difference in any of the measured outcomes, including live birth rates in adjusted models (adjusted odds ratio 1.0, 95% confidence interval 0.6-1.5), except in patients older than 40 years. These patients in group B had a 100% failure rate (n = 6).

CONCLUSION(S)

In most women, unstimulated endometrial preparation with luteal support before FET has similar success compared with exogenous hormone preparation. Women older than 40 years may benefit from programmed FETs owing to the challenges of increased cycle variability expected in that age group.

Double Stimulation in the Same Ovarian Cycle (DuoStim) to Maximize the Number of Oocytes Retrieved From Poor Prognosis Patients: A Multicenter Experience and SWOT Analysis

A panel of experts known as the POSEIDON group has recently redefined the spectrum of poor responder patients and introduced the concept of suboptimal response. Since an ideal management for these patients is still missing, they highlighted the importance of tailoring the ovarian stimulation based on the chance of each woman to obtain an euploid blastocyst. Interestingly, a novel pattern of follicle recruitment has been defined: multiple waves may arise during a single ovarian cycle. This evidence opened important clinical implications for the treatment of poor responders. For instance, double stimulation in the follicular (FPS) and luteal phase (LPS) of the same ovarian cycle (DuoStim) is an intriguing option to perform two oocyte retrievals in the shortest possible time. Here, we reported our 2-year experience of DuoStim application in four private IVF centers. To date, 310 poor prognosis patients completed a DuoStim protocol and underwent IVF with blastocyst-stage preimplantation-genetic-testing. LPS resulted into a higher mean number of oocytes collected than FPS; however, their competence (i.e., fertilization, blastocyst, euploidy rates, and clinical outcomes after euploid single-embryo-transfer) was comparable. Importantly, the rate of patients obtaining at least one euploid blastocyst increased from 42.3% (n = 131/310) after FPS to 65.5% (n = 203/310) with the contribution of LPS. A summary of the putative advantages and disadvantages of DuoStim was reported here through a Strengths-Weaknesses-Opportunities-Threats analysis. The strengths of this approach make it very promising. However, more studies are needed in the future to limit its weaknesses, shed light on its putative threats, and realize its opportunities.

[Natural cycle for frozen-thawed embryo transfer: Spontaneous ovulation or triggering by HCG]

OBJECTIVE

To compare frozen-thawed embryo transfer (FET) outcomes in natural cycles according to ovulation induction: spontaneous versus recombinant human chorionic gonadotrophin (r-hCG) triggering.

METHODS

This retrospective study included all patients monitored for natural cycle FET during one year. When serial monitoring were performed until spontaneous LH rise, patients were included in group A (n=38) whereas those receiving r-hCG for ovulation triggering formed group B (n=43). All embryos had been cryopreserved by a vitrification method following a previous IVF cycle. No luteal phase support had been given. We compared outcomes between the 2 groups.

RESULTS

After checking groups comparability, we didn't find significant difference for the implantation rate, clinical pregnancy rate and live birth (31% vs 45%, 32% vs 51% et 21% vs 32%, respectively for group A and B). The number of monitoring was significantly lower in group B (1,9±0,8 versus 2,5±1, P=0,006).

DISCUSSION

Although no consensus has been yet established, natural cycle seems indicated for normo-ovulating patients but the question of ovulation induction is still debated. In our study, triggering ovulation by r-hCG, respecting strict criteria, seems provide good results while reducing both protocol's constraints and cost.

Artificial cryopreserved embryo transfer cycle success depends on blastocyst developmental rate and progesterone timing

This retrospective cohort analysis compared the developmental competence of cryopreserved day-4 and 5 blastocysts, and investigated the effect of progesterone administration duration on the success of artificial frozen embryo transfers. Between October 2015 and March 2016, 868 intracytoplasmic sperm injection blastocyst cryo-all cycles were carried out, with 586 subsequently undergoing frozen embryo transfer. Of these, 243 were day-5 single blastocyst transfers (SBT) and 152 were day-4 SBT. Day-4 blastocysts were transferred on day-5 progesterone (day-4 group) and day-5 blastocysts were transferred on day-5 (short-protocol day-5 sub-group, n = 104) or day-6 (standard-protocol day-5 sub-group, n = 139) progesterone. Although more blastocysts were transferred in the standard-protocol day-5 sub-group (P = 0.009), pregnancy, clinical pregnancy and live birth rates were similar to those of the day-4 group, but were significantly lower in the short-protocol day-5 sub-group (P = 0.004, P = 0.008 and P = 0.02 respectively). For optimal outcomes, day-4 blastulating embryos should be prioritized for transfer on day 5 of progesterone and for day-5 blastocysts, transfer should be delayed by 1 day. The retrospective analysis and lack of adjustment for all known confounding variables limit the study.

Frozen embryo transfer: a review on the optimal endometrial preparation and timing

STUDY QUESTION

What is the optimal endometrial preparation protocol for a frozen embryo transfer (FET)?

SUMMARY ANSWER

Although the optimal endometrial preparation protocol for FET needs further research and is yet to be determined, we propose a standardized timing strategy based on the current available evidence which could assist in the harmonization and comparability of clinic practice and future trials.

WHAT IS KNOWN ALREADY

Amid a continuous increase in the number of FET cycles, determining the optimal endometrial preparation protocol has become paramount to maximize ART success. In current daily practice, different FET preparation methods and timing strategies are used.

STUDY DESIGN, SIZE, DURATION

This is a review of the current literature on FET preparation methods, with special attention to the timing of the embryo transfer.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Literature on the topic was retrieved in PubMed and references from relevant articles were investigated until June 2017.

MAIN RESULTS AND THE ROLE OF CHANCE

The number of high quality randomized controlled trials (RCTs) is scarce and, hence, the evidence for the best protocol for FET is poor. Future research should compare both the pregnancy and neonatal outcomes between HRT and true natural cycle (NC) FET. In terms of embryo transfer timing, we propose to start progesterone intake on the theoretical day of oocyte retrieval in HRT and to perform blastocyst transfer at hCG + 7 or LH + 6 in modified or true NC, respectively.

LIMITATIONS REASONS FOR CAUTION

As only a few high quality RCTs on the optimal preparation for FET are available in the existing literature, no definitive conclusion for benefit of one protocol over the other can be drawn so far.

WIDER IMPLICATIONS OF THE FINDINGS

Caution when using HRT for FET is warranted since the rate of early pregnancy loss is alarmingly high in some reports.

STUDY FUNDING/COMPETING INTEREST(S)

S.M. is funded by the Research Fund of Flanders (FWO). H.T. and C.B. report grants from Merck, Goodlife, Besins and Abbott during the conduct of the study.

TRIAL REGISTRATION NUMBER

Not applicable.

Can letrozole plus HMG protocol improve pregnancy outcomes in frozen-thawed embryo transfer? An RCT

BACKGROUND

There are different methods in endometrial preparation for frozen-thawed embryo transfer (FET).

OBJECTIVE

The purpose of this study was to compare the live birth rate in the artificial FET protocol (estradiol/ progesterone with GnRH-agonist) with stimulated cycle FET protocol (letrozole plus HMG).

MATERIALS AND METHODS

This randomized clinical trial included 100 women (18-42 years) randomly assigned to two groups based on Bernoulli distribution. Group I received GnRH agonist [Bucerelin, 500μg subcutaneously] from the previous midlutea lcycle, Then estradiol valerat [2 mg/ daily orally] was started on the second day and was increased until the observation of 8mm endometrial thickness. Finally progesterone [Cyclogest, 800 mg, vaginally] was started. Group II received letrozole on the second day of the cycle for five days, then HMG 75 IU was injected on the7^th day. After observing [18 mm folliclhCG10000 IU was injected for ovulation induction. Trans cervical embryo transfer was performed in two groups. The main outcome was the live birth rate. The rate of live birth, implantation, chemical, and clinical pregnancy, abortion, cancellation and endometrial thickness were compared between two groups.

RESULTS

Implantation rate was significantly higher in group I. Live birth rate was slightly increased in group I without significant difference (30% vs. 26%). The rate of chemical and clinical pregnancy was similar in two groups. The abortion rate was lower in letrozole protocol but the difference was not statistically significant. The mean endometrial thickness was not different between two groups.

CONCLUSION

Letrozole plus HMG method cannot improve pregnancy outcomes in frozen-thawed embryo transfer but it has only one injection compare to daily injections in artificial method.