Freeze-all Cycles Research Articles

“Try until the last?”—the relevance of fresh embryo transfer outcomes for subsequent same-cohort vitrified–warmed cycles

PurposeTaking into consideration earlier attempts at assisted reproduction and previous pregnancies allows a more differentiated approach when counseling couples regarding their chances in assisted reproductive treatments. The aim of this study was to investigate whether the outcome of fresh embryo transfers affects subsequent same-cohort vitrified–warmed cycles.MethodsThis retrospective cohort study analyzes the outcome of all fresh and frozen embryo transfers (n = 8118) between January 1, 2011, and December 31, 2022. All women who received fresh or frozen embryo transfers at Kepler University Hospital Linz were included. The use of donor eggs, previously cryopreserved oocytes, and freeze-all cycles were excluded from the analysis.ResultsPositive serum βhCG after a fresh cycle has a significant impact on the chances of positive βhCG in a subsequent vitrified–warmed cycle (36.3% [33.2%, 39.5%]; P = 0.002). Negative βhCG after a fresh cycle does not predict the outcome of the following same-cohort embryo transfer (33.1% [30.7%, 35.7%], P = 0.726). Pregnancy rates of the first, second, third, and fourth same-cohort vitrified–warmed embryo transfer remain continuously high, with 32.8%, 30.8%, 28.9%, and 27.1%, respectively.ConclusionsPositive serum βhCG after a fresh embryo transfer has a positive predictive value for the outcome of a subsequent vitrified–warmed embryo transfer. Couples with a negative fresh cycle should not be discouraged from continuing fertility treatment using same-cohort frozen embryos.Trial registrationThis study was prospectively registered at the German Clinical Trials Register on September 5, 2023 (DRKS00032552).

Significance of FSHR and LHCGR gene polymorphisms on clinical outcomes in gonadotropin-releasing hormone antagonist protocol with freeze-all strategy: A case-control study.

Follicle-stimulating hormone receptor (FSHR) and luteinizing hormone/choriogonadotropin receptor (LHCGR) are integral to ovarian function, facilitating follicle development and maturation through their respective hormonal interactions. The influence of receptor polymorphisms on the outcomes of freeze-all cycles remains unclear. This study investigates the impact of FSHR N680S and LHCGR N312S polymorphisms on clinical outcomes in freeze-all cycles. Women undergoing controlled ovarian stimulation for assisted reproductive technology participated in this study. They were administered a gonadotropin-releasing hormone antagonist protocol, with recombinant follicle-stimulating hormone (rFSH) dosages adjusted according to age, body mass index, antral follicle count, and individual hormonal responses. Additionally, human menopausal gonadotropin dosages were tailored based on the LHCGR N312S genetic variant. Analysis revealed no significant differences in age, body mass index, antral follicle count, or marital status across the genotypes of FSHR N680S and LHCGR N312S. However, notable differences were observed in the rFSH dosage required daily and in total among the FSHR polymorphism genotypes. Genotypes of the LHCGR polymorphism correlated with fewer stimulation days. A significant interaction was observed between the 2 polymorphisms concerning total rFSH dosage. The presence of serine in the FSHR polymorphism was associated with higher rFSH dosage requirements. Both FSHR N680S and LHCGR N312S polymorphisms significantly influenced clinical pregnancy and live birth outcomes in freeze-all cycles, underscoring the potential of a pharmacogenomic approach to optimize hormone supplementation in controlled ovarian stimulation protocols during assisted reproductive technology treatments.

Success Rates with Preimplantation Genetic Testing for Aneuploidy (PGT-A) in Good Prognosis Patients is Dependent on Age.

To evaluate cumulative live birth following preimplantation genetic testing for aneuploidy (PGT-A) with next generation sequencing (NGS) compared to morphology alone among patients aged 21-40 years undergoing single blastocyst transfer. Retrospective cohort study SUBJECTS: Patients aged 21 to 40 years undergoing first, autologous retrieval cycles resulting in ≥ 5 fertilized oocytes, with subsequent single blastocyst transfer in SART clinics from 2016 to 2019. PGT-A using NGS MAIN OUTCOME MEASURES: The primary outcome was cumulative live birth per retrieval. Secondary outcomes included clinical pregnancy, miscarriage, and live birth per transfer. A total of 56,469 retrieval cycles were included in the analysis. Retrieval cycles were stratified based on age (< 35, 35-37, and 38-40 years) and exposure to PGT-A with NGS. Modified Poisson regression modeling was used to evaluate the association between PGT-A and cumulative live birth per retrieval while controlling for covariates. In this cohort, most cycles did not utilize PGT-A (n=49,608; 88%). After adjusting for covariates, the use of PGT-A was associated with a slightly lower cumulative live birth in individuals aged <35 years (risk ratio [RR] 0.96; 95% CI: 0.93, 0.99) compared with no PGT, but higher cumulative live birth in ages 35-37 years (RR 1.04; 95% CI: 1.00, 1.08), and 38-40 years (RR 1.14; 95% CI: 1.07, 1.20). A subgroup analysis limited to freeze-all cycles (n=29,041) showed that PGT-A was associated with higher cumulative live birth in individuals aged ≥ 35 years and was similar to no PGT in individuals aged < 35 years. Miscarriage was significantly less likely in individuals aged ≥ 35 years utilizing PGT-A compared with no PGT-A. In this large national database study, success rates in cycles utilizing PGT-A were dependent on age. Cumulative live birth was observed to be significantly less likely in PGT-A cycles among individuals aged < 35 years and more likely among individuals aged 38 to 40 years, compared to no PGT-A. In individuals with no fresh transfer, results were similar. Moreover, miscarriage was significantly less likely with PGT-A among individuals aged 35-40 years in a subgroup analysis of freeze-all cycles.

Fresh vs. frozen: pregnancy outcomes and treatment efficacy between fresh embryo transfer vs. untested freeze-all cycles

Fresh vs. frozen: pregnancy outcomes and treatment efficacy between fresh embryo transfer vs. untested freeze-all cycles

P-608 Cumulative live birth rates after 3 consecutive embryo transfers in freeze-all cycles following gonadotropin-releasing hormone antagonist protocol versus progesterone-primed ovarian stimulation

Abstract Study question Do cumulative live birth rates in freeze-all cycles differ between gonadotropin-releasing hormone (GnRH) antagonist protocol and progesterone-primed ovarian stimulation (PPOS)? Summary answer GnRH antagonist and PPOS protocols have similar cumulative live birth rates in freeze-all cycles. What is known already GnRH antagonists and progesterone have been used for pituitary suppression in ovarian stimulation cycles. While PPOS protocol has the advantage of oral usage and lower cost, data regarding the laboratory and clinical outcome is limited and confounding. Freeze-all cycles might provide a better model to assess the impact of PPOS protocol and GnRH antagonist protocol on laboratory, clinical outcomes and cumulative live birth rates. Study design, size, duration A retrospective cohort study on IVF cycles performed (n = 568) between January 2020 and May 2022.The entire cohort of embryos were cryopreserved at the blastocyst stage.Inclusion criteria were 18-42 years of age,ICSI for severe male factor infertility.Exclusion criteria were PGD and severe endometriosis.Indications for cryopreservation in the antagonist group were high ovarian response (n:102),endometrial polyps (n:34),high follicular phase P4(n:48) and elective purposes(n:260).PPOS was used due to a transient shortage of GnRH antagonist in the market (n:124). Participants/materials, setting, methods 568 women (GnRH antagonist:444; PPOS:124) were included in the analysis.The primary outcome was the cumulative live birth rate (CLBR) after 3 consecutive embryo transfer cycle, and the secondary outcome parameters were the number of M-II oocytes, fertilization rate and blastocyst utilization rate. Student’s t-test was used for normally distributed continuous data and Fisher’s exact tests for categorical data were used. A generalized estimating equation model and logistic regression analysis were performed to adjust for confounding factors. Main results and the role of chance The mean age of the GnRH antagonist group was 34.1 ± 5.3 and 34.5 ± 5.7 years in PPOS group (p = 0.38). The baseline characteristics including BMI, serum AMH levels, duration of infertility, duration of stimulation and gonadotropin ampules used were similar in both groups. Estradiol and progesterone levels at the time of ovulation trigger were higher in GnRH antagonist cycles (2383.5 ± 1375.4 vs 2034.5 ± 1218.3, p = 0.02 and 0.7 ± 0.6 vs 0.5 ± 0.4, p = 0.01, respectively) The mean number of cumulus-oophorus complexes (12.9 ± 7.4 vs 11.5± 10.0, p = 0.61), M-II oocytes (10.0± 6.1 vs 9.1± 6.1, p = 0.14), frozen blastocysts (4.8± 3.5 vs 4.7± 3.6, p = 0.71) were similar between GnRH antagonist and PPOS groups, respectively. Fertilization rates (84.4% vs 87.2%, p = 0.12) and blastocyst utilization rates (63.4% vs 65.9%, p = 0.34) were also similar between GnRH antagonist and PPOS groups, respectively. The number of transferred embryos and the number of unused blastocysts were similar between groups. The CLBRs after one IVF cycle and 3 consecutive frozen-thawed blastocyst transfers were comparable in GnRH antagonist and PPOS cycles (56.8% and 53.2%, p = 0.37, respectively). Limitations, reasons for caution This was a retrospective study with relatively small sample size performed at a single fertility center, which may limit the generalizability of our findings. Wider implications of the findings If the fresh embryo transfer is not intended, PPOS protocol can be used in all patient types with cost-effective and patient-friendly manner. Trial registration number 2024.013.IRB2.012

P-121 Post-warming morphokinetics as a predictive tool for embryo implantation

Abstract Study question Does frozen-thawed blastocyst morphokinetics observed using time-lapse imaging provide an indicator for implantation in intracytoplasmic sperm injection (ICSI) cycles with deferred embryo transfers? Summary answer The blastocyst morphokinetic behavior after warming may provide an indicator for implantation in ICSI cycles. What is known already Embryo cryopreservation has become a pivotal component in assisted reproduction, applicable both to surplus embryos and in freeze-all cycles. Throughout vitrification and warming processes, embryos face considerable challenges. Historically, the evaluation of fresh blastocysts has relied on the examination of morphological features and the assessment of blastocoel expansion, trophectoderm, and inner cell mass. However, for vitrified and warmed blastocysts, traditional evaluation may not suffice to predict implantation. The emergence of a TLI culture system has facilitated a comprehensive examination of embryo development. Hence, post-warming culture in TLI incubators may provide a more precise assessment of vitrified and warmed blastocyst behavior. Study design, size, duration From January to October 2022, an observational cohort study was conducted at a private university-affiliated IVF centre. This included 411 vitrified/warmed blastocysts, from freeze-all cycles, with known implantation data (no implantation and full implantation per transfer), which were evaluated by TLI. Blastocyst morphological dynamics variables after warming were recorded, and their potential association with clinical pregnancy was investigated using Generalized linear models (GzLM) adjusted for oocyte age, followed by Bonferroni post hoc test. Participants/materials, setting, methods After warming, the recorded factors were: (i) initial blastocyst area (IBA); (ii) maximum blastocyst area (MBA); (iii) Blastocyst area delta (DBA); (iv) initial ZP thickness (IZP); (v) minimum ZP thickness (MZP); (v) ZP thickness delta (delta ZP area); and (iv) blastocyst expansion (BE). Embryos received a final score from 0 to 9, according to the sum of the scores from each parameter and were grouped as: Low total-score, medium total-score), and high total-score. Main results and the role of chance No significant difference was observed when maternal age (37.8 ± 5.3, 37.2 ± 5.2, and 37.4 ± 5.7, for low, medium and high total-score groups respectively, p = 0.743) and oocyte age (34.9 ± 4.9, 34.1 ± 4.7, and 33.7± 5.2, for low, medium and high total-score groups respectively, p = 0.229) were compared between the score groups. A significant increase in the implantation rate was noted among embryos presenting higher scores, followed by those with median scores, while embryos with lower scores presented the lowest implantation rate (34.8 ± 5.3, 35.9 ± 5.2, and 39.7 ± 5.2, for low, medium and high total-score groups respectively, p &amp;lt; 0.001). No significant differences in the miscarriage rate were observed between the three score groups (10.0 ± 4.2, 13.2 ± 4.1, and 5.1 ± 2.9, for low, medium and high total-score groups respectively, p = 0.239.) The logistic regression analysis showed that embryos in the low total-score group presented a 12.3% decreased chance of implantation when compared with embryos in the high total-score group (OR: 0.877, CI: 0.843-0.912, p &amp;lt; 0.001), while embryos in the medium total-score group presented a 9.6% decreased implantation chance when compared with embryos in the high total-score group (OR: 0.904, CI: 0.870-0.939, p &amp;lt; 0.001). Limitations, reasons for caution The use of historical cohort groups is a drawback. Wider implications of the findings The behavior of blastocysts after warming, as indicated by blastocyst area, ZP thickness, re-expansion, along with the pre-vitrification embryo classification, may provide crucial information for selecting the optimal embryo for transfer and managing patient expectations. Trial registration number N/A

P-391 Association between meteorological season at the time of embryo transfer and pregnancy outcomes in freeze-all cycles: lessons from seasonal reproductive mammals

Abstract Study question Is there any effect of meteorological season at the time of embryo transfer on clinical outcomes of freeze-all cycles? Summary answer Optimal conditions for implantation appear to be associated with spring and summer. Embryo transfers performed in autumn or winter are associated with reduced ongoing pregnancy. What is known already Extensive research has consistently shown that most mammals are seasonal breeders, and as day length increases, gonadotropin secretion increases, to anticipate reproduction in the spring and summer months. There is intriguing evidence that there is a seasonal variance in human reproduction, but the data are inconclusive. Therefore, the goal for the present study was to evaluate the effect the meteorological season at the time of embryo transfer on clinical outcomes of freeze-all cycles. Study design, size, duration This historical cohort study was performed in a private university-affiliated IVF center between February 2018 and December 2022. A total of 4952 frozen-thawed embryos transferred to 3725 cycles in a single clinic were analyzed. Participants/materials, setting, methods Both vitrification and the warming procedures were performed using the Cryotop method. Embryos survival and clinical outcomes were analyzed by the season, at the time of embryo transfer, using generalized linear models adjusted for potential confounders. Main results and the role of chance The mean maternal age was 37.0 ± 4.7 years. Embryos were cryopreserved for a mean of 8.1 ± 17.3 months. Autumn was designated as the reference season for all analyses. No significant differences were observed in embryo survival rates when the seasons were compared, however, lowest implantation and pregnancy rates were observed when embryo transfers occurred in autumn (44.6%), followed by winter (45.8%, OR: 1.049, CI: 0.876 – 1.257, p = 0.603) and summer (49.0%, OR: 1.196, CI: 1.010 – 1.415, p = 0.038), while spring embryo transfers had a 30% increased odds of pregnancy (51.2%, OR: 1.302, CI: 1.100 – 1.541, p = 0.002). An increased miscarriage rate was observed when embryo transfers occurred in autumn (13.9%), followed by winter (11.4%, OR: 0.510, CI: 0.323 – 0.805, p = 0.004) and summer (10.4%, OR: 0.461, CI: 0.292 – 0.727, p = 0.001), while spring embryo transfers had a 63% decreased odds of miscarriage (5.6%, OR: 0.369, CI: 0.230 – 0.592, p &amp;lt; 0.001). Limitations, reasons for caution The use of historical cohort groups is a drawback. Despite the eligibility criteria for inclusion in the analysis, potential differences in the baseline characteristics cannot be ruled out. Wider implications of the findings In seasonal breeding mammals, melatonin increases the gonadotropins’ release during the transition period. Melatonin rise favors embryo implantation and protects offspring by increasing progesterone levels. Our evidence suggests that human reproductive potential may be influenced by climatic variations. Trial registration number N/A

P-278 The impact of previous pituitary suppression protocols on IVF outcomes in patients with endometriosis undergoing freeze-all approach

Abstract Study question Do embryological parameters and live birth rates differ in patients with endometriosis undergoing freeze-all approach when GnRH-antagonist protocol or progestin primed pituitary suppression(PPOS) was preferred? Summary answer When comparing the GnRH antagonist protocol, the PPOS protocol was associated with more usable cleavage stage embryos but with a similar live birth rate. What is known already Optimal COH protocol for patients with endometriosis is still controversial. Initially, the GnRH agonist protocol was hypothesized to be superior because it was assumed to increase pregnancy rates by improving the inflammatory process of endometriosis. However, available data represented similar pregnancy rates in GnRH antagonist and GnRH agonist protocols. Recently, progestins have been used for suppression of endogenous LH surge instead of GnRH analogs in COH for various indications. Since, recent data indicates that utilization of progestins for more than eight days can reduce the inflammatory process of endometriosis, PPOS protocol might be employed in this patient group. Study design, size, duration This retrospective cohort study conducted at Bahçeci Health Group between January 2021-January 2023. Inclusion criteria were female age between 20-44 years, patients with endometrioma diagnosed by transvaginal ultrasonography and freeze-all cycles. Exclusion criteria were pre-implantation genetic testing (PGT) cycles, patients with uterine myoma distorting the endometrial cavity, congenital uterine anomaly and presence of hydrosalpinx.Each patient was included only once. A total of 607 patients;407 in GnRH antagonist group and 200 in PPOS group were recruited. Participants/materials, setting, methods The study analyzed the embryological parameters and live birth rates undergoing freeze-all cycles. COH was performed with recombinant FSH or HMG at a starting dose 150-300 IU depending on ovarian reserve and body mass index (BMI). LH surge was controlled by a flexible GnRH antagonist or fixed PPOS protocol. Primary outcome for embryological parameters were usable cleavage embryo after OS and live birth after the first frozen embryo transfer (FET) cycles. Main results and the role of chance Female age in PPOS group was older than GnRH antagonist group (33.3±4.9 vs.32.4±4.8,p=0,02).Other demograhic characteristics were similar among two groups.Total gonadotrophin dose and duration of stimulation in PPOS group were lower than antagonist group (2602.3±1083.5 vs.2866.9±1147.9 IU, p = 0,002 and 10.86±1.77 vs. 11.59±1.82 days, p &amp;lt; 0.001). No significant difference regarding endocrinological parameters of OS and number of oocytes retrieved, mature oocyte, maturation and fertilization rates was found in two groups. However, the number of day 3 usable embryos were higher in the PPOS group than GnRH antagonist group (4.66±4.38 vs. 3.84±3.72 p = 0.04). There was no difference in the cancellation rates. A total of 478 FET cycles of 607 were evaluated; 323 in GnRH antagonist and 255 in PPOS group. No significant difference in FET cycle and embryological characteristics was found in two groups. The clinical pregnancy rate, miscarriage rate, live birth rate and multiple pregnancy rates per transfer were comparable between the two groups [59.1% (191/323) vs. 59.4% ( 92/155) p = 0,963;17.3%(33/191) vs 0.9%(10/92) p = 0,16; 48.6%(157/323) vs. 52.9% (82/155) p = 0,379; 7.3%(14/191) vs.10.9% (10/92) p = 0317, respectively].Multivariate binary regression analysis revealed that female age, embryo day embryo quality.number of embryos transferred were significant independent factors for live birth but not the PPOS vs GnRH antagonist. Limitations, reasons for caution Although we used regression models to adjust all possible confounders, it was a retrospective study with its intrinsic limitations. Further prospective RCTs are warranted. Wider implications of the findings Although cleavage stage usable embryo was significantly higher in PPOS group,the pregnancy outcomes were comparable between groups.Those results suggest that theoretical advantages of progestin in preceding OS does not seem to present a significant difference on live birth,but should be confirmed with prospective trials within cohort of women with endometriosis. Trial registration number not applicable ( retrospective study)

O-303 What is the ideal dose of daily FSH after corifollitropin-alfa? A multicentre-randomized control trial

Abstract Study question Does the mean serum trigger-progesterone levels show significant variation based on the administered rFSH dose from day 8 onwards during ovarian stimulation using corifollitropin-alfa? Summary answer Lower rFSH doses from day 8 of ovarian stimulation onwards are linked to reduced serum progesterone (P4) levels without impact on cumulus-oocyte complexes. What is known already Progesterone elevation during ovulation trigger prompts a non-elective freeze-all strategy, given the lower live birth rates in fresh embryo transfers. Ongoing research explores methods to mitigate late follicular phase P4 rise to allow a fresh embryo transfer. Granulosa cells’ progesterone production is an FSH-driven and dose-dependent process, and FSH dose is furthermore pivotal for a good ovarian response. Balancing FSH dose is crucial for both optimal ovarian response and preventing undesirable P4 elevation while maintaining an adequate number of retrieved oocytes and allowing a fresh embryo transfer. Study design, size, duration This study is an interim-analysis of a randomized-controlled multi-center clinical-trial comparing three ovarian-stimulation-protocols: (A) corifollitropin alfa (CFA) followed by rFSH 50 IU/day; (B) CFA followed by rFSH 150 IU/day; (C) CFA followed by rFSH 250 IU/day.The primary outcome is the serum-progesterone-level on the day of hCG among the study groups, secondary outcomes included number of oocytes, clinical pregnancy rates and freeze-all cycles. 167 women (of 261) were randomized between July 2019-November 2023, with a 1:1allocation. Participants/materials, setting, methods Young (&amp;lt;40 years old), normo-ovulatory cycle (25-35 days), with AFC&amp;gt;7 and &amp;lt;20, and a BMI&amp;lt;29 Kg/m2 patients were recruited in the fertility clinic of three different tertiary university hospitals. On day 8 of ovarian stimulation (OS) following CFA administration, patients who needed additional rFSH were randomized into 3 groups (A-B-C). The OS was performed in a GnRH-antagonist protocol and the ovulation triggered with hCG. A fresh embryo-transfer was performed on day 5 following oocyte retrieval. Main results and the role of chance Overall, 167 patients were randomized, 60 in group A, 55 in group B and 52 in group C. The mean age and BMI were comparable between the groups. Mean AMH was respectively 2.2, 2.1 and 2.2 ng/mL, for group A, B and C (p = 0.95). Group A resulted in a significantly lower P4 level at trigger as compared with group B and C (respectively, 0.4ng/mL, 0.9 ng/mL and 1.4 ng/mL; p &amp;lt; 0.001). The mean number of retrieved oocytes was 10.7, 11 and 12.1 for group A, B and C, respectively (p = 0.47), while the mean number of mature oocytes was 7.3, 6.9 and 7.8 for group A, B and C, respectively (p = 0.7). A freeze-all approach was decided for 27%, 29% and 46% for group A, B and C respectively (p = 0.057). No significant differences were found for fresh-embryo-transfer outcomes (chemical pregnancy rates: 33%, 31% and 29%, respectively for A, B and C (p = 0.12).Of interest, comparisons between serum FSH at trigger showed a mean of 12.5, 17 and 20.5 IU/L for group A, B and C, respectively (p &amp;lt; 0.001) while the serum estradiol levels on day of trigger were comparable among the groups (1659, 2092 and 2098 ng/L for group A, B and C, respectively (p = 0.091). Limitations, reasons for caution This is an interim analysis planned to detect the mean difference in COC between groups. Therefore, the mean differences of the primary outcome should be interpreted as exploratory findings which warrant future investigation. Wider implications of the findings Administering a lower rFSH dose from day 8 onward during ovarian stimulation results in comparable numbers of COC but also leads to significantly lower serum P4 levels. Consequently, this finding has the potential to reduce the overall consumption of rFSH, thereby possibly increasing the likelihood of a fresh embryo transfer. Trial registration number NCT03686852

P-208 To assess or not to assess: reconsidering day 3 embryo quality in planned freeze-all blastocyst cycles

Abstract Study question Should day 3 embryo quality assessment be consider in planned freeze-all blastocyst cycles? Summary answer Day 3 embryo assessment may be unnecessary in planned freeze-all blastocyst cycles. What is known already Day 3 embryo quality is a predictor of in vitro fertilizastion (IVF) success rates in cleavage stage embryo transfer. However, the association between day 3 embryo quality and live birth in blastocyst transfer policy is largely unknown. Study design, size, duration This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfer between January 2019 to December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariate logistic regression. We applied factor analysis of mixed data to reduce potential collinearity between covariates used in the model. Participants/materials, setting, methods All blastocysts included in this study were obtained from first ICSI freeze-all cycles. Cleavage stage and blastocyst evaluation were performed according to the Istanbul consensus. Cleavage and blastocysts stage were assessed between 67±0.5 (day-3), 115±0.5 (day-5) and 139±0.5 (day-6) hours post-insemination (hpi), respectively. Exclusion criteria were: i) ICSI-cycles performed with surgically retrieved or frozen sperm, (ii) gamete donation cycles, (iii) cryopreserved-thawed oocyte cycles, (iv) preimplantation genetic testing. The primary outcome was live birth rate. Main results and the role of chance After adjusting for the day of transfer (day 5 or day 6) and several confounding variables, no statistical differences in live birth were observed among same quality blastocysts derived from different day 3 embryo quality groups (top=A, good=B and poor=C). The analysis was stratified for different blastocyst quality groups: 1) top quality blastocyst [day 3 quality A =reference group; day 3 quality B= OR 1.04 95% CI (0.62 – 1.74), p value=0.871; day 3 quality C= OR 0.67 95% CI (0.34 – 1.33), p value= 0.254] 2) good quality blastocyst [A =reference group; B= OR 0.80 95% CI (0.49 – 1.30), p value=0.361; C= OR 0.74 95% CI (0.44 – 1.27), p value= 0.276] 3) poor quality blastocyst [A =reference group; B= OR 0.78 95% CI (0.29 – 2.10), p value=0.622; C= OR 0.80 95% CI (0.31 – 2.07), p value= 0.650]. Limitations, reasons for caution The study is limited by its retrospective design. Embryo assessment without time-lapse technology, to assess the blastocysts at the same developmental time-frame, is another limitation; although the static observation time very close and restricted to the Istanbul consensus guidelines may mitigate such a weakness. Wider implications of the findings Our findings showed that day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles. In the context of static embryo assessment, this can reduce the stress on embryos by avoiding unnecessary retrievals from incubators. Trial registration number not applicable

P-713 Proposal of model to calculate the trend in the cumulative live birth rate in IVF cycles using Spanish National Register data from 2009 to 2021

Abstract Study question Is it possible to estimate the trend in the cumulative rate of live births in IVF over 12 years, using data from the Spanish Registry? Summary answer With the proposed formula, a constant increase of 1.7% in the cumulative live birth rate is verified throughout the 12 years of study. What is known already The progressive increase in elective freeze-all cycles no longer allows the use of live birth data by fresh transfer, especially in time series. Cumulative live birth rate (CLBR) has been proposed as an appropriate way of reporting success of an IVF program, incorporating both, fresh and frozen embryos. Nevertheless, views on the most appropriate parameters required to calculate such an outcome have been inconsistent and difficult for national aggregate registries. Furthermore, there is not unanimous definition for its calculation and although IVF Register is mandatory in Spain, an analysis of the CLBR has not been carried out. Study design, size, duration Data from the Spanish National Register of Assisted Reproduction including 456302 women undergoing IVF/ICSI (563000 ovarian stimulation cycles started, 359587 fresh transfers, and 36400 cryotransfer) using autologous gametes performed in Spain from 2009 to 2021 were analyzed. Oocyte donation and PGT-a cycles were excluded. Participants/materials, setting, methods The main outcomes of present study were live birth rate per cycle (LBR) and cumulative live birth rate (CLBR). To obtain the CLBR, the probability of achieving at least one live birth for each cycle started was calculated. This includes both live births after fresh transfer and those achieved after cryotransfer of the embryos obtained from each cycle until they have run out, or a full-term pregnancy is obtained. Main results and the role of chance The live birth rate (LBR) per fresh transfer remains steady (around 24%) throughout the period analyzed. However, LBR for started cycle, which remains constant (17%) until 2013, shows a marked decline since then at a rate of 1% per year. In this same period was observed: a progressive increase in the percentage of cycles with frozen embryos (from 29% to 48%), a greater number of cryopreserved embryos (from 0.9 to 1.6 embryos per started cycle), and a constant decrease in the number of embryos in each cryotransfer (from 2.39 to 1.42). LBR after cryotransfer per started cycle has increased exponentially from 4% to 24%. It was also found a steady increase of the percentage of births after a cryotransfer cycle (from 19 to 70%), surpassing since 2017 those obtained after fresh transfer. To calculate the cumulative live birth rate (CLBR), an algorithm has been developed including all pregnancies that can be achieved with the use of all the embryos obtained after each cycle started until alive child is born. CLBR shows a constant increase in the cumulative delivery rate of 1.7% annually since 2012, rising from 22 % to 35% of births per cycle started. Limitations, reasons for caution One of the main weaknesses of the study is that some patients have not attempted a second or third cryotransfer during the timeframe (for unknown reasons), though they had supernumerary embryos available. However, this model reflects the potential capacity to have at least one living child for each cycle started. Wider implications of the findings The LBR per cycle based only on fresh transfers is not useful for a historical analysis of the effectiveness of the technique. Only the calculation of the CLBR per cycle allows us to understand the real progress of IVF effectiveness in recent years. Trial registration number not applicable

O-009 Comparison of the flexible Progestin-Primed Ovarian Stimulation with the GnRH antagonist protocol in predicted suboptimal responders: a freeze-all randomized controlled trial

Abstract Study question Is the Flexible Progestin-Primed Ovarian Stimulation (fPPOS) non-inferior to GnRH antagonist regarding fertility outcomes in women with a suboptimal response scheduled for freeze-all cycles? Summary answer In predicted suboptimal responders, who do not contemplate a fresh embryo transfer, the ongoing pregnancy outcomes of fPPOS was comparable to that of GnRH-antagonist protocol. What is known already Recent retrospective cohort studies involving donor cycles have demonstrated that Medroxyprogesterone Acetate (MPA) can be effectively and flexibly employed during the mid-follicular phase of the PPOS protocol. This approach prevents premature ovulation without compromising oocyte yields. Given its lesser degree of pituitary suppression, the fPPOS protocol may be particularly relevant for women predicted to have a suboptimal response (defined as AFC &amp;lt; 10) where accumulation of more oocytes could enhance cumulative success rates. Study design, size, duration This is a open-label RCT, performed in a single IVF centre Between July 2019 and June 2023. A total of 484 women scheduled for freeze-all strategy were randomly assigned to fPPOS or GnRH-antagonist protocol. The primary outcome was live birth per woman starting stimulation following18 months of randomization. In this abstract, we present fertility outcomes following the initial frozen embryo transfer (FET) and ongoing pregnancy rates per women within a period of 6 months. Participants/materials, setting, methods Women (AFC&amp;lt;10) referred for IVF/ICSI and did not intend to undergo a fresh transfer, were recruited for this study. MPA (10 mg/day) and Cetrotide (0.25 mg/day) were initiated either when the leading follicle reached 14 mm or on the sixth day of stimulation, whichever occurred first. Due to the COVID-19 pandemic, 22 women withdrew from the study at the stimulation commencement, resulting in 462 women included in the analysis. Data underwent intention-to-treat and per-protocol analyses. Main results and the role of chance No significant difference was observed between the two groups in terms of serum endocrine profiles and stimulation parameters, including the consumption of gonadotropins. Within the 6-month period, 79.5% of women in the fPPOS group and 84.02% in the GnRH antagonist group had undergone at least one cycle of FET (P = 0.234).The ongoing pregnancy rates per women were 48.20% (107/222) in the fPPOS group versus 52.92% (127/240) in the GnRH-anta group (RR: 0.91, 95%CI, 0.76 to 1.09, P = 0.311). There are 62 women who are ongoing pregnancy but do not reached live birth during the follow-up period. Regarding the outcomes of the initial FET cycle, there was no difference in the ongoing pregnancy rate between the two groups (49.01% vs 48.37%, RR: 1.03, 95% CI, 0.81 to 1.26, P = 0.908). Other outcomes including biochemical pregnancy rate (62.25% vs 63.59%), clinical pregnancy rate (60.26% vs 57.61%), and miscarriage rate per pregnancy (16.48% vs 15.09%), also exhibited no significant differences. The number of oocytes retrieved, two-pronuclear oocytes, viable and high-quality embryos, as well as the total number of embryos cryopreserved were also similar between groups. There was one case of premature ovulation in the fPPOS group and none in the GnRH-ant group. Limitations, reasons for caution Due to the distinct administration routes of the medications, blinding was not feasible in this open-label trial, which may affect the assessment of outcomes. All participants were recruited in a single center from one country, limiting the generalizability. In this abstract, we only report on the ongoing pregnancy outcomes. Wider implications of the findings This is the first freeze-all RCT comparing the long-term outcomes of fPPOS and GnRH antagonist in autologous ovarian stimulation cycles. Eliminating the variability of fresh and frozen transfers, the fPPOS seems an efficacious alternative for women with predicted suboptimal response, when a GnRH antagonist would have been the preferred regimen. Trial registration number ChiCTR2000030356

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles.

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality, or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariable logistic regression. We applied a Factorial Analysis of Mixed Data (FAMD) to reduce the potential collinearity between the covariates used in the model. All the blastocysts included in this study were obtained from the first ICSI freeze-all cycles. The cleavage and blastocysts stages were assessed between 67 ± 0.5 (day 3), 115 ± 0.5 (day 5), and 139 ± 0.5 (day 6) hours post-insemination (hpi), respectively. After adjusting for the day of transfer (day 5 or day 6) and FAMD dimensions, no statistical differences in a β-HCG, clinical pregnancy, and live birth were observed among the same-quality blastocysts derived from different day 3 embryo quality groups (top = A, good = B, and poor = C). Our findings showed that a day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles.

Fresh or frozen day 6 blastocyst transfer: is there still a question?

BackgroundThe Live Birth Rate (LBR) after day 5 (D5) blastocyst transfer is significantly higher than that with D6 embryos in both fresh and frozen-vitrified embryo transfer cycles, according to the most recently published meta-analyses. Therefore, for women obtaining only D6 blastocysts, the chances of pregnancy may be lower but nonetheless sufficient to warrant transferring such embryos. The best strategy for transfer (i.e., in fresh versus frozen cycles) remains unclear and there is a paucity of data on this subject.MethodsA total of 896 couples with D6 single blastocyst transfers were retrospectively analyzed: patients receiving a fresh D6 embryo transfer (Fresh D6 transfer group, n = 109) versus those receiving a frozen-thawed D6 embryo transfer (Frozen D6 transfer group, n = 787). A subgroup comprising a freeze-all cycle without any previous fresh or frozen D5 embryo transfers (Elective frozen D6, n = 77) was considered and also compared with the Fresh D6 transfer group. We compared LBR between these two groups. Correlation between D6 blastocyst morphology according to Gardner’s classification and live birth occurrence was also evaluated. Statistical analysis was carried out using univariate and multivariate logistic regression models.ResultsThe LBR was significantly lower after a fresh D6 blastocyst transfer compared to the LBR with a frozen-thawed D6 blastocyst transfer [5.5% (6/109) vs. 12.5% (98/787), p = 0.034]. Comparison between LBR after Elective frozen D6 group to the Fresh D6 blastocyst transfers confirmed the superiority of frozen D6 blastocyst transfers. Statistical analysis of the blastocyst morphology parameters showed that both trophectoderm (TE) and inner cell mass (ICM) grades were significantly associated with the LBR after D6 embryo transfer (p < 0.001, p = 0.037). Multiple logistic regression revealed that frozen D6 thawed transfer was independently associated with a higher LBR compared with fresh D6 transfer (OR = 2.54; 95% CI: [1.05–6.17]; p = 0.038). Our results also show that transferring a good or top-quality D6 blastocyst increased the chances of a live birth by more than threefold.ConclusionsOur results indicate that transferring D6 blastocysts in frozen cycles improves the LBR, making it the best embryo transfer strategy for these slow-growing embryos.Clinical trial numberNot applicable.

GnRH agonist trigger in poor prognosis patients undergoing a multicycle approach through DuoStim or consecutive stimulations: a SWOT analysis.

Identify the most recent and significant evidence regarding the ovulation trigger within the framework of a multicycle approach through DuoStim, providing valuable insights for improving treatment strategies in patients with a poor prognosis. The trigger method plays a pivotal role in optimizing in-vitro fertilization (IVF) stimulation, influencing oocyte retrieval and maturation rates, as well as follicle recruitment in consecutive ovarian stimulations such as double stimulation. Decision-making involves multiple factors and, while guidelines exist for conventional stimulation, specific recommendations for the multicycle approach are not well established. The different methods for inducing oocyte maturation underscore the need for personalization of IVF protocols. The GnRH agonist trigger induces rapid luteolysis and establishes favorable hormonal conditions that do not adversely affect the recruitment of consecutive follicular waves in the context of DuoStim. It serves as a valid alternative to hCG in freeze-all cycles. This strategy might enhance the safety and flexibility of ovarian stimulations with no impact on oocyte competence and IVF efficacy.

Embryo long-term storage does not affect assisted reproductive technologies outcome: analysis of 58,001 vitrified blastocysts over 11 years

BackgroundRecently the potential detrimental effect that the duration of storage time may have on vitrified samples has raised some concern, especially when some studies found an association between cryo-storage length and decreased clinical results. ObjectiveThis study aimed to evaluate the effects of the storage time length of day-5 vitrified blastocysts in two study groups: freeze-all cycles and non elective frozen embryo transfers (FET). Study designThis was a retrospective study including 58001 vitrified/warmed day-5 blastocysts from two different populations according to the reason for FET. Elective FET comprised freeze-all cycles (N=16615 blastocysts and 16615 patients) where only single embryo transfers (SET) and only the first FET were included. The non elective FET group included 41386 embryos from 25571 patients where FET took place using supernumerary embryos after fresh embryo transfer. All the possible FETs were included. Both SET and double embryo transfers (DET) were included. Donor and autologous oocytes were used. The period covered by this study was 11 years. The blastocysts sample was clustered into deciles which provided specific storage duration categories. Main outcome was live birth rate (LBR) and secondary outcomes were embryo survival, miscarriage, clinical and ongoing pregnancy rates according to storage duration. The impact of storage time was assessed by univariable analyses in both groups. The comparison was made between each decile to the last one. A multivariable logistic regression analysis was conducted including the variables with significant association found in the univariate analysis. Student's t-test and Chi squared tests, or an analysis of variance were used wherever appropriate. P < 0.05 was considered statistically significant. ResultsThere were statistical differences in baseline characteristics of patients included in the study groups. Storage durations ranged from ≤ 0.67 to ≥ 4.34 and from ≤ 1.8 to ≥ 34.81 months in freeze-all and non elective FET respectively. Embryo survival did not show statistical differences across the categories of storage time in freeze-all and non elective FET groups. Statistical differences were found for the LBR across some, but not all the subgroups of storage duration. The multivariable analysis showed no association between storage time and the LBR in both groups (NS). Blastocyst quality, body mass index (BMI), number of retrieved oocytes, endometrial preparation, male factor and uterine factor were related to the drop in the LBR in the freeze-all group (p<0.05). In the non elective FET group the variables that showed significant association with the LBR were, age at retrieval and at FET, type of FET (SET or DET), number of retrieved oocytes, BMI, endometrial preparation, origin of sperm sample and female factor. ConclusiónThis large study demonstrated no association between storage time and clinical outcome. Other variables such as patient's age, embryo quality, BMI and etiology, are somewhat responsible for impacting outcome. This provides evidence for the safety of embryo vitrification, even after long storage periods. This is reassuring for both IVF practitioners and the patients undergoing FET of either elective or non elective embryos.

Progesterone-primed cycles result in slower embryos without compromising implantation potential and with the advantages of oral administration and potential cost reduction

To study the impact of the use of progesterone on embryo morphokinetics and on the outcomes of intracytoplasmic sperm injection cycles. Cohort study. Private university-affiliated invitro fertilization center. This study included 236 freeze-all intracytoplasmic sperm injection cycles and the resultant 2,768 injected oocytes cultured in a time-lapse imaging incubation system. Patients were matched by age and divided into groups depending on the protocol used to prevent the luteinizing hormone surge: progestin-primed (144 cycles and 1,360 embryos) and gonadotropin hormone-releasing hormone (GnRH) antagonist (144 cycles and 1,408 embryos) groups. The kinetic recorded markers were time to pronuclear appearance and fading, time to 2-8 cells, time to morulation, time to start of blastulation, and time to blastulation. The durations of cell cycles and time to complete synchronous divisions were calculated. The Known Implantation Data Score ranking was recorded. Morphokinetics and clinical outcomes were compared between the groups. Embryo morphokinetics and clinical outcomes. Slower time to pronuclear appearance, time to 2 cells, time to 7 cells, time to start of blastulation, and time to blastulation were observed in embryos derived from progestin-primed cycles than in those from the GnRH antagonist group. No significant differences were noted in any other morphokinetic milestone. Significantly higher cancellation and implantation rates were observed in the progestin-primed group. However, no significant differences were noted in the pregnancy and miscarriage rates. The expenses for treatment using premature GnRH antagonist and progestins were US$318.18 and US$11.05, respectively. Exogenous progesterone replaces the GnRH antagonist for the prevention of premature luteinizing hormone surge, in freeze-all cycles, with the advantage of oral administration and potential cost reduction.

ART in Europe, 2019: results generated from European registries by ESHRE†.

What are the data and trends on ART and IUI cycle numbers and their outcomes, and on fertility preservation (FP) interventions, reported in 2019 as compared to previous years? The 23rd ESHRE report highlights the rising ART treatment cycles and children born, alongside a decline in twin deliveries owing to decreasing multiple embryo transfers; fresh IVF or ICSI cycles exhibited higher delivery rates, whereas frozen embryo transfers (FET) showed higher pregnancy rates (PRs), and reported IUI cycles decreased while maintaining stable outcomes. ART aggregated data generated by national registries, clinics, or professional societies have been gathered and analyzed by the European IVF-Monitoring (EIM) Consortium since 1997 and reported in a total of 22 manuscripts published in Human Reproduction and Human Reproduction Open. Data on medically assisted reproduction (MAR) from European countries are collected by EIM for ESHRE each year. The data on treatment cycles performed between 1 January and 31 December 2019 were provided by either national registries or registries based on initiatives of medical associations and scientific organizations or committed persons in one of the 44 countries that are members of the EIM Consortium. Overall, 1487 clinics offering ART services in 40 countries reported, for the second time, a total of more than 1 million (1077813) treatment cycles, including 160782 with IVF, 427980 with ICSI, 335744 with FET, 64089 with preimplantation genetic testing (PGT), 82373 with egg donation (ED), 546 with IVM of oocytes, and 6299 cycles with frozen oocyte replacement (FOR). A total of 1169 institutions reported data on IUI cycles using either husband/partner's semen (IUI-H; n = 147711) or donor semen (IUI-D; n = 51651) in 33 and 24 countries, respectively. Eighteen countries reported 24139 interventions in pre- and post-pubertal patients for FP, including oocyte, ovarian tissue, semen, and testicular tissue banking. In 21 countries (21 in 2018) in which all ART clinics reported to the registry 476760 treatment cycles were registered for a total population of approximately 300 million inhabitants, allowing the best estimate of a mean of 1581 cycles performed per million inhabitants (range: 437-3621). Among the reporting countries, for IVF the clinical PRs per aspiration slightly decreased while they remained similar per transfer compared to 2018 (21.8% and 34.6% versus 25.5% and 34.1%, respectively). In ICSI, the corresponding PRs showed similar trends compared to 2018 (20.2% and 33.5%, versus 22.5% and 32.1%) When freeze-all cycles were not considered for the calculations, the clinical PRs per aspiration were 28.5% (28.8% in 2018) and 26.2% (27.3% in 2018) for IVF and ICSI, respectively. After FET with embryos originating from own eggs, the PR per thawing was at 35.1% (versus 33.4% in 2018), and with embryos originating from donated eggs at 43.0% (41.8% in 2018). After ED, the PR per fresh embryo transfer was 50.5% (49.6% in 2018) and per FOR 44.8% (44.9% in 2018). In IVF and ICSI together, the trend toward the transfer of fewer embryos continues with the transfer of 1, 2, 3, and ≥4 embryos in 55.4%, 39.9%, 2.6%, and 0.2% of all treatments, respectively (corresponding to 50.7%, 45.1%, 3.9%, and 0.3% in 2018). This resulted in a reduced proportion of twin delivery rates (DRs) of 11.9% (12.4% in 2018) and a similar triplet DR of 0.3%. Treatments with FET in 2019 resulted in twin and triplet DR of 8.9% and 0.1%, respectively (versus 9.4% and 0.1% in 2018). After IUI, the DRs remained similar at 8.7% after IUI-H (8.8% in 2018) and at 12.1% after IUI-D (12.6% in 2018). Twin and triplet DRs after IUI-H were 8.7% and 0.4% (in 2018: 8.4% and 0.3%) and 6.2% and 0.2% after IUI-D (in 2018: 6.4% and 0.2%), respectively. Eighteen countries (16 in 2018) provided data on FP in a total number of 24139 interventions (20994 in 2018). Cryopreservation of ejaculated sperm (n = 11592 versus n = 10503 in 2018) and cryopreservation of oocytes (n = 10784 versus n = 9123 in 2018) were most frequently reported. Caution with the interpretation of results should remain as data collection systems and completeness of reporting vary among European countries. Some countries were unable to deliver data about the number of initiated cycles and/or deliveries. The 23rd ESHRE data collection on ART, IUI, and FP interventions shows a continuous increase of reported treatment numbers and MAR-derived livebirths in Europe. Although it is the largest data collection on MAR in Europe, further efforts toward optimization of both the collection and the reporting, from the perspective of improving surveillance and vigilance in the field of reproductive medicine, are awaited. The study has received no external funding and all costs are covered by ESHRE. There are no competing interests.

Free your patients and yourself from day 2–3: start ovarian stimulation any time in freeze-all cycles

Ovarian stimulation for assisted reproductive technology is traditionally started in the early follicular phase. The essential rationale is to allow timely follicle growth and oocyte retrieval to ensure synchronization of the in-vitro cultured embryos with the receptive period of the endometrium in a fresh transfer cycle. In addition, conventional thought suggested that follicle recruitment happened only once, around menstruation. A deeper understanding of folliculogenesis, advances in cryobiology and an increasing proportion of freeze-all cycles provide a unique opportunity here. Experience from oncofertility patients as well as infertile women and oocyte donors who underwent ovarian stimulation in different phases of the menstrual cycle, dubbed ‘random start’ cycles, suggests that the number of oocytes collected and their reproductive potential do not depend on the time of starting ovarian stimulation, although the duration of stimulation and gonadotrophin consumption can vary slightly. It may be time to free both patients and clinics from the obsession with starting ovarian stimulation in the early follicular phase in planned freeze-all cycles. The flexibility provided by random start cycles is one aspect of individualizing treatment to patients’ needs.

The effect of peak serum estradiol level during ovarian stimulation on cumulative live birth and obstetric outcomes in freeze-all cycles.

To determine whether the peak serum estradiol (E2) level during ovarian stimulation affects the cumulative live birth rate (CLBR) and obstetric outcomes in freeze-all cycles. This retrospective cohort study involved patients who underwent their first cycle of in vitro fertilization followed by a freeze-all strategy and frozen embryo transfer cycles between January 2014 and June 2019 at a tertiary care center. Patients were categorized into four groups according to quartiles of peak serum E2 levels during ovarian stimulation (Q1-Q4). The primary outcome was CLBR. Secondary outcomes included obstetric and neonatal outcomes of singleton and twin pregnancies. Poisson or logistic regression was applied to control for potential confounders for outcome measures, as appropriate. Generalized estimating equations were used to account for multiple cycles from the same patient for the outcome of CLBR. A total of 11237 patients were included in the analysis. Cumulatively, live births occurred in 8410 women (74.8%). The live birth rate (LBR) and CLBR improved as quartiles of peak E2 levels increased (49.7%, 52.1%, 54.9%, and 56.4% for LBR; 65.1%, 74.3%, 78.4%, and 81.6% for CLBR, from the lowest to the highest quartile of estradiol levels, respectively, P<0.001). Such association remained significant for CLBR after accounting for potential confounders in multivariable regression models, whereas the relationship between LBR and peak E2 levels did not reach statistical significance. In addition, no significant differences were noticed in adverse obstetric and neonatal outcomes (gestational diabetes mellitus, pregnancy-induced hypertension, preeclampsia, placental disorders, preterm birth, low birthweight, and small for gestational age) amongst E2 quartiles for either singleton or twin live births, both before and after adjustment. In freeze-all cycles, higher peak serum E2 levels during ovarian stimulation were associated with increased CLBR, without increasing the risks of adverse obstetric and neonatal outcomes.