Number Of Cycles Research Articles

P-712 A national survey of women’s perspectives and experiences of pursuing donor eggs

Abstract Study question What are the experiences of women who consider a donor egg, and the outcomes of those who receive donor eggs for conception? Summary answer Of 255 respondents, 59 women (23.1%) were formally placed on a donor egg waitlist, despite 80.6% respondents considering donor eggs with an IVF clinic (166/206). What is known already There is a shortage of donor eggs worldwide. Oocyte donation is a treatment option that is increasingly used for infertile women, as seen through the percentage of patients undergoing IVF who are over 40 years. Previous international studies report oocyte donation recipients to be predominantly aged 34-40 years, white, nulliparous, well-educated, married and financially secure. Although there are records in Australia for the number of donor and recipient cycles undertaken, there is no published data on the number of patients considering a donor oocyte, or on oocyte donor waitlists. In Australia egg donation is altruistic, non-commercial and not anonymous. Study design, size, duration A 52-point online survey was distributed via social media to women in Australia who had ever considered or pursued donor eggs, or come to the end of their own IVF treatment. The survey was sent to all clinical members of the Fertility Society of Australia and New Zealand (FSANZ) and available on the Victorian Assisted Reproductive Technology Authority (VARTA) website. The survey was open from 1 February to 30 April 2023. Hospital ethics approved. Participants/materials, setting, methods A cross-sectional, anonymous, online survey of women in Australia who were potential egg donor recipients. Survey questions included demographics, potential donor egg recipient preferences, IVF clinic experiences, barriers, any impact of the COVID-19 pandemic, attitudes around the reimbursement for donor eggs, and fertility costs already incurred. Responses were collected via the Qualtrics XM platform. Statistical analysis for quantitative data was analysed using Microsoft 365 Excel. Qualitative coding performed on the commentary in free text fields. Main results and the role of chance This study identified a large gap between those who considered a donor egg (80.6%), pursue a donor egg on an IVF clinic waitlist (23.1%), and those who actually received a donor egg. Of the 59/255 women who were placed on an oocyte donor waitlist at an IVF clinic in Australia, less than a quarter (23.1%) received a donor egg (13/58), with a pregnancy and live birth rate of 76.9% and 61.5%, respectively. Thus, of those that were on an Australian waitlist, one quarter received donor eggs, with over half of these recipients having a live birth. ‘Women preferred donor eggs from Australia than overseas, preferred an unknown donor from an IVF clinic program, and wished to know source information for themselves and children in the future. Attitudes towards financial reimbursement were generally positive towards compensation. Barriers to pursuing donor eggs included grief of loss of own fertility, cost, availability and time. When on an Australian donor egg list, many respondents still looked at other sources of donor eggs in Australia and overseas. Reasons women came off an Australian donor egg waitlist included receiving donor eggs and donor embryos elsewhere, including from overseas, as well as advancing age and expense. Limitations, reasons for caution Risk of respondent selection bias of those who chose to response to a public survey, with incomplete data for some respondents. Given survey in English, may have underrepresentation of some cultural groups and sampling a limited range of women from diverse social, economic and religious settings. Wider implications of the findings In this first paper of potential egg recipients’ preferences in the Asia-Pacific region, we have identified a gap where demand for donor eggs exceeds local supply. A majority of potential recipients would support financial reimbursement for eggs already cryopreserved by women initially freezing for own elective purposes. Trial registration number not applicable

P-706 The pregnancy rates in a large cohort of patients with thin endometrium when stratified according to estradiol levels on the day of triggering

Abstract Study question Is there any difference in ongoing pregnancy rate in women with thin endometrium (<8 mm) when scrutinized based on estradiol levels on triggering day? Summary answer Either with a low, moderate, or high estradiol level on the day of triggering, ongoing pregnancy rates do not change in patients with thin endometrium. What is known already Endometrial thickness has been argued to be one of the proxy determinants of endometrial receptivity. In that context, although the optimal thickness has been widely stated to be between 8-14 mm, the negative effect of thin endometrium on pregnancy outcome is still controversial in in-vitro-fertilization (IVF) cycles. Nevertheless, particularly lack of large sample size of women with thin endometrium among the available literature, is the leading factors that avoids to solid conclusion.Furthermore, it might be hypothesized that patients with thin endometrium and accompanying low estradiol might be distinct from women with thin endometrium despite relatively high estradiol level. Study design, size, duration A retrospective cohort study was designed among patients that has undergone in-vitro fertilization (IVF) treatment between January-2018 and June-2023 in Bahceci Health Group. Only patients having an endometrial thickness <8 mm on the day of triggering were recruited. Other inclusion criteria was having at least one blastocyst to be transferred. All frozen-thawed embryo transfer cycles were excluded. Female age and body mass index were not considered as an exclusion criterion. Participants/materials, setting, methods During the study period, a total of 3076 IVF cycles with fresh ET were employed. Of them, 814 had an endometrial thickness of < 8 mm on the day of triggering. Among 814 IVF cycles, 25th, 50th and 75th quartiles of estradiol levels on the day of triggering referred to 322.8, 755.7 and 1310.5 pg/ml, respectively. The number of IVF-ET cycles in the 1st, 2nd, 3th and 4th quartiles were 203, 204, 204 and 203. Main results and the role of chance The mean (SD) age of women recruited in the final analyses was 36.5 (5.5) years and endometrial thickness was 7.2 (0.8) mm. The pregnancy rates per ET with regard to 1st, 2nd, 3th and 4th quartiles were 37.6%, 33.0%, 37.3% and 44.3%, respectively without any statistical significance (p = 0.134). However, the respective ongoing pregnancy rates were 26.1%, 18.1%, 22.1%, 31.0 % and the highest quartile had a statistically superior ongoing pregnancy rates than the second (p = 0.003) and third quartiles (p = 0.022). When binary logistic regression analysis was performed by inserting the female age, body-mass index, duration of infertility and quartiles of estradiol levels on the day of triggering, only female age remained as an independent factor for the prediction of an ongoing pregnancy (RR: 0.92 CI95%: 0.87 to 0.98, p = 0.008). Utilization of estradiol level as a continuous variable in the same model also failed to present the independent validity of it to predict an ongoing pregnancy. Notably, the lowest thickness of a positive pregnancy resulting with an ongoing pregnancy was 4.7 mm. Limitations, reasons for caution The inherent risks cannot be excluded due to the retrospective nature of the current study, which had been efforted to overcome with regression analysis. Wider implications of the findings The current study includes one of the largest numbers of experience particularly with thin endometrium on the day of triggering. However, having a thin endometrium despite low or relatively high estradiol level does yield any prediction for the pregnancy outcome. Trial registration number Not Applicable

O-123 Trends and challenges in the practice of ART in China

Abstract China is a large country with a population of over 1.4 billion. In 1988, the first in-vitro fertilization-embryo transfer (IVF-ET) baby was born in Peking University Third Hospital. In the following 3 decades, assisted reproductive technology (ART) has developed rapidly in China, and the availability and accessibility of the ART service have improved markedly. In 2004 totally, only 37 institutions had passed the administrative licensing procedure to carry out ART. While in 2020, 536 institutions obtained the ART license. Since 2016, the total number of ART service cycles(Artificial insemination included)has exceeded 1 million, and the number of babies born has exceeded 300,000, accounting for about 2% of the total live births in China in 2016. At present, assisted reproductive technology has become one of the important medical interventions for the treatment of infertility in China, which has brought good news to infertile couples and their families, and has made great contributions to social harmony and family happiness. Cycles per million population (C/M) in 2009 was 120. In 2020, it has increased to 668, with more and more infertile couples having access to this technique in China. The success rate of assisted reproductive technology remained stable. In 2020, the clinical pregnancy rates (CPR)of conventional IVF and ICSI fresh embryo transfer cycles reached 52.4% and 49.4%, respectively, and the live birth rates were 43.0% and 40.6%, respectively. The clinical pregnancy rate and live birth rate of frozen-thawed embryo cycle were 51.3% and 40.5% per transfer. With the widespread application of embryo freezing technology, the cumulative live birth rate was estimated to reach 49.5% (CLBR estimate) in 2020. The safety monitoring indicators of assisted reproductive technology showed that since 2015, the multiple pregnancy rates of conventional IVF, ICSI and FET have decreased year by year, and have dropped to 22.4%, 21.4% and 17.6% in 2020, respectively. The incidence of moderate-severe ovarian hyper-stimulation syndrome (OHSS) and severe bleeding were also under control, within a reasonable range. Assisted reproductive technology, which involves many medical, social, ethical and legal issues, is a special clinical technology with limit application for medical indication. The Chinese government attaches great importance to the quality and safety management of assisted reproductive technology. A series of management documents such as the Administrative Measures for Human Assisted Reproductive Technology, the Regulations for Human Assisted Reproductive Technology and so forth, have been issued since 2001. Further improvement of key performance indicators (KPIs) correlated with ART quality and safety control is of the top priority and also challenging. In addition, the ART surveillance data in China is still aggregated data, which does not include important indicators such as age stratification, infertile factors or indications and delivery gestational age, maternal and infant outcomes, with some limitations for surveillance. Continuous improvement of data quality, and initiation of cycle-based data collection and security measures of case information are also challenging for the next step.

P-749 Maternal and obstetric outcomes following the transfer of embryos warmed with fatty acid supplemented solutions

Abstract Study question Does fatty acid (FA) supplementation into warming solutions influence maternal and obstetric outcomes after single vitrified-warmed cleavage stage embryo transfer (SVCT)? Summary answer FA-supplemented warming solutions improve the live birth rate after SVCTs without exerting any adverse effects on maternal and obstetric outcomes. What is known already Vitrification procedures decrease the intracellular lipid content and impair developmental competence. Adding fatty acids (FAs) to the warming solution has been shown to recover the lipid content of the cytoplasm and improve developmental competence and clinical pregnancy by stimulating the beta-oxidation pathway in warmed embryos. Recently, the FA-supplemented warming solutions have been commercially released. However, influence of the FA-supplemented supplementation on live birth rate after embryo transfers and perinatal outcomes remains unknown. Study design, size, duration The clinical records of 701 treatment cycles in 701 women who underwent SVCTs were retrospectively analysed. Vitrified embryos were warmed using solutions (from April 2022 to June 2022, control group, n = 340) or FA-supplemented solutions (from July 2022 to September 2022, FA group, n = 361). All pregnant women were invited to respond to the questionnaire at 9 weeks of gestation and after delivery. Maternal and obstetric outcomes were obtained from a self-reported questionnaire completed by the patients. Participants/materials, setting, methods The embryos in the FA group were warmed with the FA-supplemented solutions (VT526, Kitazato Corporation) while the embryos in the control group were warmed with the non-supplemented solutions (VT506, Kitazato Corporation). SVCTs were performed on day 2 after ovulation in natural cycles. The live birth rate, incidence of pregnancy complications, and neonatal outcomes were compared between the control and FA groups. Main results and the role of chance The live birth rate was higher in the FA group than in the control group (P = 0.0399). The miscarriage rates were comparable between the groups. Multivariate logistic regression analysis also demonstrated a higher probability of live births in the FA group than in the control group (adjusted odds ratio, 1.46; P = 0.0404). Patients were stratified by median maternal age for further analysis (37 years). This subgroup analysis showed that the live birth rate was significantly higher in the FA group than in the control group in women younger than 37 years of age. However, the live birth rate was comparable between the two groups for women aged 37 years or older. The incidence and types of pregnancy complications were comparable between the control and FA groups. Furthermore, caesarean section rates were similar between the groups. The average gestational age and incidence of preterm delivery were comparable between the groups. Birth length and weight, incidence of low birth weight, incidence of small for gestational age and large for gestational age, and infant sex were comparable between the groups. The incidence of birth defects was similar between the groups. Multivariate logistic regression analysis revealed a similar trend. Limitations, reasons for caution The single-centre retrospective study limits the strength of the study, necessitating further multicentre studies to ascertain the generalizability of these findings to other clinics with different protocols and/or patient demographics. Furthermore, the number of perinatal cycles was low. Wider implications of the findings The FA-supplemented warming solutions improved the live birth rates after SVCTs, particularly in young patients. Furthermore, the incidence of pregnancy complications and infant health was not affected by the FA-supplemented solutions. Therefore, FA-supplemented solutions can be considered safe and effective at improving clinical outcomes and reducing the patient burden. Trial registration number not applicable

O-216 The impact of maternal age on cumulative life birth rates after single euploid embryo transfer: differences between autologous and donor oocyte cycles

Abstract Study question How much of an impact has the maternal age on cumulative life births after euploid Single Embryo Transfer (SET) in autologous and donor oocyte cycles? Summary answer A maternal age ≥ 42 years old affects negatively the cumulative Life Birth Rates (cLBRs) even after euploid SET, but only in the autologous cycles. What is known already Despite the improvements in assisted reproduction technologies (ART) in the last decades, the LBRs remain suboptimal, especially when advanced maternal age is considered. Although several factors could explain these outcomes (i.e. infertility history; uterine pathologies/surgery; advanced paternal age), maternal age-related aneuploidies remain the most limiting factor for a favorable clinical outcome. Thus, the Genetic Testing for Aneuploidies (PGT-A) has been integrated into ART as a strategy to evaluate chromosomal status before transfer. Interestingly, recent studies show that, even after the transfer of euploid blastocyst, the maternal age negatively influences the LBRs. Study design, size, duration This study, carried out in Villa Mafalda Reproductive Medicine Department (Italy), included 568 euploid SET: 542 from autologous cycles (divided in four subgroups according to maternal age: ≤ 34 y.o. (n = 207); 35-38 y.o. (n = 193); 39-41 y.o. (n = 106); ≥ 42 y.o. (n = 36)) and 26 from oocyte donation (OD) cycles (average recipient age is 44.2). All cycles were performed from May 2020 to February 2023. PGT for Monogenic disorders (PGT-M) cycles were excluded. Participants/materials, setting, methods All blastocysts included in this study were analyzed by Next Generation Sequencing (NGS) after a day 5/6 trophectoderm biopsy. For each subgroup was annotated the embryo morphology- divided into good (AA-AB-BA); average (BB-BC-CB) and poor (CC) according to Gardner/Schoolcraft blastocyst grading system- and the day of expanded blastocyst formation (grade 4 of Gardner/Schoolcraft blastocyst grading system). Primary analysis included the cumulative LBRs. Secondarily, blastocyst morphology and blastocyst expansion were examined for all embryo categories considered. Main results and the role of chance The pairwise comparison between groups was performed by Chi-square analysis and p < 0.05 was considered statistically significant. The cLBRs for each subgroup were respectively: ≤ 34 (63.09%); 35-38 (58.47%); 39-41 (56.84%); ≥ 42 (48.57%); OD (69.23%). Data showed that cLBRs decreased with the increase of maternal age, although statistical significance was observed only among women ≤ 34 y.o. and ≥ 42 y.o. (P=0.029). Notably, there was no statistical significance in cLBRs comparing women ≤ 34 y.o. and OD patients (P=0.086). The good-quality blastocyst rate was respectively: ≤ 34 y.o. (54.58%); 35-38 y.o. (47.66%); 39-41 y.o. (60.37%); ≥ 42 y.o. (50%); OD (59.37%). The pairwise comparison showed no significant difference between groups. Furthermore, there was not found significant difference about the day of expanded blastocyst formation: ≤ 34 y.o. (D5: 78.92%; D6 21.07%); 35-38 y.o. (D5: 78.49%; D6: 21.50%); 39-41 y.o. (D5:75.70%;D6: 24.29%); ≥ 42 y.o. (D5:69.44%; D6: 30.55%); OD (D5: 87.5%; D6: 12.5%). Data showed that maternal age ≥ 42 y.o. affects negatively cLBRs even after euploid SET, suggesting that other factors age-related, rather than aneuploidies, influence implantation. Interestingly, these factors do not affect OD recipients, with advanced maternal age, who, instead, reach successful LBRs like patients ≤ 34. Limitations, reasons for caution These results should be evaluated carefully because of the small sample size of the OD patients. A greater number of OD cycles are needed to verify the results obtained. Wider implications of the findings Our findings suggest that embryonic age-related factors - changes in gene expression, metabolism or epigenetics - could influence the embryo capability to, successfully, support implantation other than the ploidy status. This thesis was supported by the OD recipient’s behavior, who had cLBRs comparable to young autologous patients. Trial registration number Not Applicable

P-702 New era in donor programs. Is it time to leave behind the antagonist for a progestin-primed ovarian stimulation protocol? Retrospective cohort analysis of 711 cycles

Abstract Study question Are GnRH-antagonist and progestin-primed ovarian (PPOS) stimulation protocols comparable in terms of effectiveness and efficiency in an egg donor program? Summary answer The PPOS protocol would have similar efficacy to the antagonist protocol, despite a slightly lower rate of useful blastocyst, without impact on recipient’s clinical results. What is known already There are numerous studies based on the comparison of oral progestin (P) vs. subcutaneous GnRH-antagonist (A) as pituitary suppressors during ovarian stimulation with gonadotropins, showing similar results in terms of ovarian response and reproductive outcomes in IVF cycles. Limited data are available on the comparison of both protocols in egg donor programs to evaluate their effectiveness and efficiency. Study design, size, duration Retrospective and observational cohort study with 711 oocyte donor cycles included over 18 months (July 2022-Dec 2023). As pituitary suppressors during ovarian stimulation, Ganirelix was used in 394 cycles and Medroxyprogesterone in 317. We obtained 626 reception cycles (369 from A group and 257 from P group). 499 egg-recipients underwent an embryo transfer (309 form A group and 190 from P group). Live birth rates were calculated only over the 192 informative embryo transfer cycles. Participants/materials, setting, methods Variables such as duration of the ovarian stimulation, number of mature oocytes (MII), maturation rate, fertilization rate, useful blastocysts (uBL) rate and their quality (>3BB/≤3BB), clinical pregnancy and live birth rate, have been evaluated. An economic analysis has been conducted for both protocols. Statistical analysis was performed using T-Student and Chi-Square tests. Main results and the role of chance There were no significant differences between groups A and P in terms of: average stimulation days (11.44±1.45 vs. 11.39±1.38, p = 0.62), average number of MII (15.69±7.46 vs. 15.12±7.12, p = 0.30), maturation rate (78.97% vs. 80.01%, p = 0.13), and fertilization rate (68.6% vs. 70.1%, p = 0.15). However, a statistically significant difference was observed in the rate of viable blastocyst formation (uBL/2PN) between groups A and P (70.4% vs. 66.8%, p < 0.05), although there were no differences in embryo qualities obtained (>3BB: 89.4% vs. 90.6%, ≤3BB: 10.6% vs. 9.1%, p = 0.083). Regarding obstetric outcomes, no differences have been found in live birth rates between the two groups (52,4% vs 64,5%, p = 0,11). The cost of the antagonist protocol was significantly higher being 8.48% more expensive than the oral progestin protocol (p < 0.05). Limitations, reasons for caution A regulated randomization has not been used to assign donors to both treatments. The population size, although enough to provide significant differences, could be wider. The number of cycles performed with P are smaller compared to A. Most clinical pregnancy are still ongoing so these data are lacking Wider implications of the findings Besides being more donor-friendly, the progestin-primed ovarian stimulation offers a significant economic advantage. Both protocols have proven similar efficacy. Clinical data are necessary to evaluate the impact of the lower BLu rate on the reproductive outcomes. Trial registration number Not applicable

P-020 Clinical outcomes of 583 treatment cycles with fresh and cryopreserved testicular sperm in cases without karyotype abnormalities and Y chromosome microdeletions needing testicular sperm extraction

Abstract Study question What are the embryological, clinical and newborn outcomes using fresh and cryopreserved testicular sperm in non-obstructive azoospermia patients? Are the differences between both techniques significant? Summary answer In this population there was a high live birth delivery rate with no significant differences observed in the outcomes using fresh and cryopreserved testicular sperm. What is known already The use of cryopreserved testicular sperm has been considered of lower quality due to freezing/thawing consequences (1). Nevertheless, cryopreserved testicular sperm presents the advantages of avoiding female stimulation in cases of failed testicular sperm retrieval, or multiple testicular biopsies (2). However, the majority of the studies evidenced no significant differences in the clinical outcomes between the use of cryopreserved and fresh sperm (3). As only a few studies are dedicated to compare both techniques (4) we expanded the number of cycles and provided full demographic, stimulation, embryological, clinical and newborn outcomes.

O-243 Promoting family building strategies - a global call to action

Promoting family building strategies - a global call to action Study question Are there any strategies that can be improved or implemented to promote family building and slow down the global decline in fertility rates? Summary answer Fertility rates are dangerously decreasing worldwide, therefore current strategies need to be improved and new ones should be developed to face present-day challenges. What is known already Although to different extent, almost half of the countries in the world are below replacement level due to generalized fertility decline. Through the years, many of them have put in place policies to promote natality, with variable results depending on the kind of strategy adopted, on socio-cultural factors and on other local peculiarities. Most commonly used policies include prevention and education, plans aimed at allowing couples to have children (ensuring work stability, financial stability, housing stability), benefits and incentives for families and implementation of childcare services and facilities. Assisted Reproduction Techniques (ART) have also been considered a potential tool to boost fertility rates. Main results and role of chance Quite surprisingly, however, even countries who have been adopting high-quality family-friendly policies are experiencing a decline in fertility rates (e.g. Finland) and strategies that have been effective in the past century may be even counterproductive nowadays. In fact, cultural, psychological, biological and cognitive factors should also be taken into consideration (alongside social and economical ones) and it should not be forgotten that attitude towards having children is not stable and may be subject to sudden, unpredictable changes (e.g. war in Ukraine and Middle East). With specific reference to ART, it has been undergoing tremendous scientific and technical development in the last few decades, fueling the unrealistic expectation that it might solve all fertility problems and allow people to have children at any age. Actually, however, ART success rates are relatively low, especially in specific categories of patients. On the other hand, costs of these treatments are particularly high, which also affect accessibility for some of the patients in need. Financial, physical and emotional toll even of a single ART cycle can be burdensome for most couples, who tend to give up after a couple failed attempts. However, data in literature show that in specific categories of patients, repetition of up to 5-6 cycle can importantly increase success rates. Based on this assumption, the scientific community worldwide should start considering an ART treatment not as a single cycle, but a succession of more cycles, as deemed appropriate based on the patients’ characteristics. Number of cycles offered, planning and pricing should of course be adjusted accordingly. This paradigm shift might be difficult to instill in both professionals’ and patients’ minds, but it might turn out to be tremendously useful for ones as well as the others. Limitation, reasons for caution Although a global intervention in favour of family building is required, individual countries should design multidisciplinary strategies taking into account local and regional peculiarities. The above mentioned paradigm shift might initially encounter resistance from couples and professionals until its benefits are clearly documented. Wider implications of the findings Data show that it is essential that policymakers, healthcare professionals and other institutional stakeholders team up to raise awareness on infertility and to develop long term plans aimed at inverting this insidious trend that is already affecting all society and is destined to get even worse if not immediately tackled in a determined and cooperative way.

Influence of Hydrogen on the Failure Mechanism of Standard Duplex Stainless Steel X2CrNiMoN22-5-3 Exposed to Corrosion Fatigue

IIn a geothermal environment, cathodic protection is employed to improve resistance against corrosion fatigue. However, during the cathodic reactions under applied potential, hydrogen is generated and assimilated, leading to a reduced lifetime expectancy of high-alloyed steels. The corrosion fatigue mechanism of a standard duplex stainless steel X2CrNiMoN22-5-3 (1.4462) specimen loaded with hydrogen was studied in a corrosion chamber specifically designed for the purpose, surrounded by the electrolyte of the Northern German Basin at 369 K. The microstructural reactions resulting in hydrogen incorporation significantly decrease the number of cycles to failure of the specimen. This reduction is attributed to hydrogen enhancing crack propagation and causing early failure, primarily due to the deterioration of the mechanical properties of the ferritic phase rather than corrosion reactions or corrosive degradation.

P-535 Effect of advanced female age (AFA) on the ratio of patients receiving mosaic embryo transfers

Abstract Study question How does female age affect ratio of patients with at least one euploid embryo (≥1EE) and at least one mosaic embryo without any euploid ones(≥1ME)? Summary answer Percentage of patients receiving mosaic embryo transfers increases with female age. What is known already Introduction of Next Generation Sequencing (NGS) to the area of Preimplantation Genetic Testing for Aneuploidy (PGT-A) has enabled detection of mosaicism in human embryos. Studies reporting the birth of healthy babies after the transfer of embryos with a chromosomal mosaic result on PGT-A have been published (Greco et al., 2015; Kahraman et al., 2020; Viotti et al., 2021 and 2023). Data suggested lower implantation rates and higher miscarriage rates when mosaics were compared with euploid embryo transfers. The percentage of mosaic embryos in overall tested embryos decreases with increased maternal age, similar to euploid embryos’ decline (Sanders et al., 2023). Study design, size, duration This retrospective study includes 7287 cycles with PGT-A performed between January 2017 and December 2023. Number of biopsied blastocysts was 21,277 and all were tested with NGS. All PGT-A testing was conducted on Ion Torrent S5 (Thermo Fisher Scientific) according to the manufacturer guidelines. The mosaic embryo reporting thresholds were determined as 20 to 80%. Participants/materials, setting, methods Euploidy ratio (ER) was defined as (euploid embryos (n)/ all tested embryos(n)). Mosaicism ratio (MR) was defined as (mosaic embryos (n)/all tested embryos(n)). Alternative mosaicism ratio (AMR) was defined as the number of mosaic embryos divided by the sum of euploid embryos and mosaic embryos. In other words, AMR can be defined as the number of mosaic embryos divided by non-aneuploid embryos. Female ages were divided into five categories: FAG1:<35, FAG2:35-37, FAG3:38-40, FAG4:41-42, FAG5:>42. Main results and the role of chance The number of cycles, total number and average biopsied embryos with standard deviations were highest in FA1 and declined with AFA: FAG1:2537, 9298, 3.7±2.2; FAG2:1348, 4140, 3.1±1.7; FAG3:1701, 4298, 2.5±1.6; FAG4: 958,2116, 2.2±1.5; FAG5:738, 2407, 1.9±1.2. ER and MR were observed to decrease with AFA: FAG1:%48.4, %15.2; FAG2:%39.0, %12.7; FAG3:%26.5, %10.5; FAG4:%14.9, %6.0; FAG5:%5.0, %2.6. This decrease was statistically significant (p < 0.0001, Chi-Square Test). However, when AMR was calculated among age groups, AMR was increasing with AFA: FAG1:%23.9; FAG2:%24.6; FAG3:%28.5;FAG4:%28.7; FAG5:%34.5 and this was also statistically significant (p = 0.0002, Chi-Square Test). Correlation of MR and AMR with female age groups were tested with Pearson correlation coefficient and MR was found to be negatively correlated with AFA whereas AMR was positively correlated (r=-0.19, p < 0.0001; r = 0.07, p < 0.0001, respectively). The ratio of patients with ≥1EE and ≥1ME was found to be decreasing with AFA when compared to overall tested cycles: FAG1: %83%, %7; FAG2: %69, %9; FAG3: %47, %11; FAG4: %28, %9; FAG5: %9, %4. However, the ratio of ≥ 1ME in cycles with transferrable embryos significantly increased with AFA consisting of more than one fourth of embryo transfer cycles above 38 years of age: FAG1: %7; FAG2: %12; FAG3: %19; FAG4: %24; FAG5: 31%. Limitations, reasons for caution These are the results of a single ART and Reproductive Genetics Center with its strictly defined standard operating procedures for PGT-A testing and ovarian stimulation protocols. Although not expected, different PGT-A testing methodologies or stimulation protocols may influence the above-mentioned outcomes. Wider implications of the findings The alternative mosaicism ratio defined here is generally overlooked but impacts the treatment strategies of ART patients, specifically for the advanced maternal age groups. Trial registration number not applicable

P-189 Can artificial intelligence outperform traditional non-invasive assessments in prioritizing euploid blastocysts for transfer? A retrospective intra-cohort analysis of 786 PGT-A cycles

Abstract Study question Are Artificial Intelligence (AI)-powered tools more efficient than traditional non-invasive assessments to prioritize euploid blastocysts for transfer? Summary answer Only one third of cycles yielded ≥3 blastocysts with different diagnoses. In these cycles, AI and traditional grading prioritized euploid embryos with comparable performance. What is known already While embryo morphology and developmental pace to blastocyst are associated with chromosomal and reproductive competence, their evaluation remains subjective and lacks reproducibility. The introduction of Time-lapse technology (TLT) in IVF has provided valuable insights into preimplantation development but has not enhanced embryologists’ reproducibility. Recently, AI models integrated with TLT offered the potential for automating and standardizing assessments. Whole-chromosome testing for uniform aneuploidies still is the strongest predictor of embryo (in)competence. In fact, if transferred, >98% of aneuploid blastocysts fail to result in a live-birth. AI tools strive to non-invasively predict blastocyst (an)euploidy, yet their clinical utility requires intra-cohort testing. Study design, size, duration Retrospective blinded analysis of 786 PGT-A cycles (maternal-age:38.9; years:2013-2020; 2184 blastocysts). For static assessment, 3 embryologists used Gardner’s grading at the time of biopsy (t-biopsy). For morphodynamic assessment, time of blastocyst-expansion (tEB) and embryo-area (embA at tEB) were also annotated. For AI assessment, scores were generated with three commercially-available models. All approaches were compared for their effectiveness in ranking euploid blastocyst(s) as top-quality among cohorts with ≥3 blastocysts and ≥1 euploid and ≥1 aneuploid (N = 279/786,35.5%). Participants/materials, setting, methods Embryologists ranked AA-blastocysts as top-quality (score=1), CC-blastocysts as worst-quality (score=9), prioritizing trophectoderm over ICM, with t-biopsy as third criterion. Morphodynamic assessments followed the same hierarchy but using tEB and embA in place of t-biopsy. For AI, higher scores corresponded to higher priority. For all assessments, coefficients of variation (CV=SD/mean) were calculated to assess data dispersion within cohorts with ≥3 blastocysts (N = 363/786,46.2%). Intra-cohort CVs were tested for their association with the likelihood of prioritizing euploid blastocysts. Main results and the role of chance Intra-cohort CVs were 0.71±0.35, 0.28±0.14, 0.58±0.26, and 0.56±0.34 for Gardner’s score, AI model-1, -2, and -3, respectively. Spearman’s correlations between Gardner’s score and AI model-1, -2, and -3 Intra-cohort CVs were 0.32, 0.34, and 0.14, respectively. AI model-1 and -2 were strongly correlated (0.63), but poorly with model-3 (0.21 and 0.22). Euploid blastocysts were prioritized in 163 cohorts by static assessments (N = 163/279,58.4%), 179 (64.2%) by morphodynamic, 174 (62.4%), 190 (68.1%), and 145 (52%) by AI model-1, -2, and -3. A maternal age-adjusted 0.1-larger Gardner’s grading intra-cohort CV correlated with higher likelihood of prioritizing euploid over aneuploid blastocysts (multivariate-OR:1.1, 95%CI:1.03-1.19, adjusted-p=0.005). No association was reported with AI models intra-cohort CVs. Notably, blastocysts affected from aneuploidies compatible with implantation were prioritized over euploid in 59 cohorts (N = 59/279,21.1%) by static assessment, 54 (19.4%) by morphodynamic, 52 (18.6%), 48 (17.2%), and 54 (19.4%) by AI model-1, -2, and -3. A maternal age-adjusted 0.1-larger Gardner’s grading intra-cohort CV correlated with lower likelihood of prioritizing aneuploid blastocysts compatible with implantation over euploid (multivariate-OR:0.9, 95%CI:0.83-0.98, adjusted-p=0.010). No association was reported with AI models intra-cohort CVs. Limitations, reasons for caution While representing the real-life scenario of a large PGT-A program, this study is a single center retrospective analysis in advanced maternal age women with a limited number of cycles with ≥3 blastocysts showing both euploid and aneuploid. Other AI-powered models exist, some specifically trained to predict euploidy. Wider implications of the findings Trophectoderm biopsy and testing aim to prevent the transfer of chromosomally-abnormal blastocysts. Although traditional/AI-based grading correlate with euploidy, their goal is prioritizing embryos for transfer, irrespective of the IVF setting (with or without PGT-A). Future research should concentrate on emphasizing live-birth prediction over misleadingly considering them as non-invasive PGT-A surrogates. Trial registration number None

O-250 Never a lost cause: can artificial intelligence (AI)-powered ranking help decrease time to pregnancy when only poor-quality embryos are available?

Abstract Study question Can an objectively trained AI system complement embryologists in their ranking of embryos and minimize time to pregnancy, when only poor-quality embryos are available? Summary answer An objective AI algorithm could have decreased cycle to pregnancy by 18% in cohorts of embryos where only poor-quality embryos were available. What is known already Morphokinetics is a key criterion for embryologists to rank embryos as good, fair, or poor quality, with the latter frequently being discarded. Although poor-quality embryos can still lead to a pregnancy, selection of a viable embryo remains challenging to embryologists due to their depleted morphological characteristics. Unlike embryologists, an AI can be trained to see beyond embryo morphological quality, on data that includes many poor-quality embryos that resulted in a pregnancy. As such, AI has the potential to recognize viable poor-quality embryos, which becomes especially crucial in cases where good or fair embryos are unavailable from the embryo pool. Study design, size, duration Data from a French center was acquired through a MIRI® (ESCO) time-lapse system and uploaded on EMBRYOLY, between January 2022 and March 2023. For a total of 204 patients (women’s average age 35 y.o.), embryologists were faced with having to choose an embryo to transfer among 4.3 ± 1.7 poor-quality embryos either because the cohort was composed of only poor-quality embryos or because higher quality embryos had already been transferred. Participants/materials, setting, methods A previously described deep learning algorithm trained on videos of developing embryos with known pregnancy outcome was used to score embryos according to their chances of leading to a clinical pregnancy (fetal heartbeat between 6-9 weeks). A 2D ResNet model was trained, validated and tested on 8138 images of day 5 embryos annotated by senior embryologists to identify those of poor-quality (Gardner grade ICM and/or TE = C, corresponding to 44.7% of the dataset). Main results and the role of chance The association between video predictions and pregnancy was assessed with a logistic regression. A McNemar test was used to compare cycle to pregnancy (CTP) with and without EMBRYOLY’s hypothetical impact. EMBRYOLY’s AI was able to rank poor-quality embryos, as illustrated by a 2-7% relative increase in likelihood of clinical pregnancy observed with an increase in the video score (logistic regression with unit level +0.02, OR = 1.04, 95CI = [1.02-1.07], N = 261 transferred embryos, p < 0.05). EMBRYOLY’s first choice was concordant with the embryologists’ first choice in 74% of the cases that led to a pregnancy (N = 42 embryos). For patients who had two poor-quality embryos transferred with at least one pregnancy (N = 14 cycles), the results show that if the embryologist had first transferred the highest EMBRYOLY-ranked embryo, the number of cycles to pregnancy would have been reduced by 18% (from 1.7 to 1.4, McNemar, p < 0.05), corresponding to a median of 2.3 months. Limitations, reasons for caution The endpoint used was clinical pregnancy as measured by fetal heartbeat, and does not indicate the probability of live birth. The current investigation was performed with retrospective data from a single center. In the future, a multi-centre evaluation should be performed to generalize our findings. Wider implications of the findings Our findings support that an objectively trained AI can help embryologists not miss out on poor-quality embryos that can lead to a pregnancy, which is all the more important to target when good or fair embryos are unavailable from the embryo pool. Trial registration number not applicable

P-329 Evaluating Implansera, autologous platelet-derived growth factors, to improve clinical pregnancy and live birth rates in frozen embryo transfer for women with recurrent implantation failure

Abstract Study question Can Implansera, Autologous Platelet-Derived Growth Factors, serve as a promising adjuvant therapy in assisted reproductive techniques to enhance endometrial thickness and implantation rates? Summary answer Use of Implansera significantly increased clinical pregnancy and Live Birth Rate In Patients With repeated implantation failure during FET cycles. What is known already Insufficient endometrial thickness and receptivity contribute to Recurrent Implantation Failure (RIF), prompting consideration of surrogacy. Despite global rise in Frozen Embryo Transfer (FET), quest for an optimal implantation protocol persists. Recent research highlights platelet-rich plasma (PRP) as promising solution for thin endometrium and RIF cases, attributing positive outcomes to PRP’s high growth factor concentration. Recognizing the need for precise platelet and growth factor concentrations, Implansera—a specialized platelet-derived growth factor concentrate—was developed. This innovation addresses the challenge of unresponsive endometrium, offering tailored solution to maximize therapeutic efficacy and improve pregnancy outcomes for patients facing RIF issues. Study design, size, duration Conducted from May 2021 to December 2023, this prospective interventional self-controlled study focused on 21 women (aged 30-48) experiencing recurrent IVF failure due to stubborn thin endometrium. Selected after negative hysteroscopic and bacteriologic screenings, and unsuccessful pregnancies despite multiple immune therapy regimens, such as intralipid and granulocyte colony-stimulating factor infusions, steroids, and endometrial scratching. The subjects underwent Implansera treatment, aiming to address refractory thin endometrium and potentially enhance their chances of successful conception. Participants/materials, setting, methods After obtaining informed consent women with at least two previous unexplained RIF, who were candidates for frozen-thawed embryo transfer were treated with intrauterine infusion of 0.8 ml of Implansera was infused into uterine cavity in addition to standard HRT protocols 2 days before ET. Clinical pregnancy was determined by positive serum β-HCG, 2weeks after ET and presence of fetal heart beat in trans-vaginal ultrasound 5weeks after ET. Main results and the role of chance Among 21 women, 10 achieved pregnancy (47.6%), while 11 did not conceive (52.4%). Clinical outcomes varied: 1 woman (4.8%) experienced chemical pregnancy, 3 (14.3%) miscarried before 6-12 weeks, 3 (14.3%) delivered healthy full-term babies, and 3 (14.3%) are in the 24th week of uneventful gestation accounts for 28.6% cumulative successful pregnancy outcomes. Implansera treatment yielded no reported adverse effects.Implansera, prepared through a patented proprietary process, standardized to contain 6-9 times higher growth factors than peripheral blood, particularly implantation-friendly and anti-inflammatory cytokines, addresses the crucial angiogenic and anti-inflammatory requirements for successful implantation. Tailored for the cyclical demands of endometrial proliferation, secretion, and implantation phases, it efficiently restores impaired uterine environments.Beyond efficacy, Implansera’s safety, reproducibility, and effectiveness in emulating natural tissue repair and regeneration processes are noteworthy. Studies underscore the significance of creating an environment conducive to successful implantation, and Implansera’s composition aligns with these requirements. Its capacity to mimic natural processes positions it as a promising solution, offering a comprehensive approach to enhancing endometrial receptivity, thus optimizing conditions for successful pregnancies. Limitations, reasons for caution This self-controlled prospective study, albeit with small sample size and lacking randomized control group, aligns with published data in demonstrating Implansera’s benefits. Proposing larger studies, particularly with unexplained RIF, to establish Implansera as routine IVF adjuvant. Further investigations aim to identify active molecules influencing implantation and suggest targeted recommendations. Wider implications of the findings Implansera improved implantation, pregnancy, and live birth rates (LBR) in unexplained RIF patients which indicates clearly endometrial thickness and receptivity improvement and motivated us to plan randomized controlled studies to confirm the results and provide opportunity for women with unexplained RIF to conceive and deliver in lesser number of cycles. Trial registration number Not applicable

P-185 Shortening the time from ovulation trigger to insemination is effective in reducing multiple pronuclei formation in anti-centromere antibody-positive patients

Abstract Study question Does shortening the time from ovulation trigger to insemination reduce multiple pronuclei formation (MPF) and improve the outcome after fertilization? Summary answer Shortening the time from ovulation trigger to insemination increased the normal fertilization rate and increased the number of cycles in which good embryos were obtained. What is known already When anti-centromere antibody (ACA)-positive patients undergo IVF, low oocyte maturation rates and MPF may be observed, which tend to occur when ACA antibody titers are high. In this case, the patient tends to present with poor embryonic development. There is currently no effective treatment for ACA-positive patients. It has been reported that MPF is caused by chromosome dispersion due to significant abnormal spindle deformation. In such cases, it has been reported that the oocyte spindle is often not visualized by polarized light microscopy. The oocyte is affected by ACA during the meiosis, but the mechanism is not well understood. Study design, size, duration A retrospective study was conducted on 764 mature oocytes from 174 cycles in 45 patients who underwent oocyte retrieval and inseminated by intra-cytoplasmic sperm injection (ICSI) with consent from 2009 to 2022. Patients were limited to those who tested positive for ACA by blood antinuclear antibody testing and whose oocytes occurred MPF. Participants/materials, setting, methods Oocyte retrieval was performed 36 hours after ovulation trigger. After ICSI, embryos were cultured until day 3 or blastocyst. The group was divided into two groups: the time reduced from ovulation trigger to ICSI (S group, n = 95) and the normal protocol (N group, n = 79). The normal fertilization rate, MPF rate, the rate of good embryo on day 3, the percentage of IVF cycles with good embryo, and clinical pregnancy rate per transfer were compared. Main results and the role of chance The mean time from maturation trigger to insemination was shorter in the S group than in the N group (38.2h vs. 41.8h, P < 0.01). The normal fertilization rate was significantly increased in the S group compared to the N group (49.9 vs. 40.7, P < 0.01) and the MPF rate was significantly decreased (39.1 vs. 28.3, P < 0.01). The rate of transferable embryo on day 3 tended to increase in the S group compared to the N group (70.6 vs. 61.9, P = 0.09). In addition, the percentage of IVF cycles with good embryo was significantly increased in the S group compared to the N group (57.4 vs. 28.4, P < 0.01). There was no difference in pregnancy rate per embryo transfer. There was no difference in the age of the wife at the time of oocyte retrieval. Limitations, reasons for caution The data were conducted from a single facility. and the limited number of cases, resulting in a small sample size. The process of visualizing the oocyte spindle was not performed in this study because it is time consuming and increases the time from ovulation trigger to insemination. Wider implications of the findings Shortening the time from maturation trigger to insemination was decreased MPF, suggesting that the oocyte spindle is affected by ACA in a time-dependent manner. It is recommended that ICSI be performed as soon as possible after oocyte retrieval. Trial registration number not applicable

P-597 Pain intensity of oocyte retrieval of low and moderate number of oocytes is only mild, questioning the need of anesthesia and analgesia

Abstract Study question What is the pain intensity of oocyte retrieval (oocyte pick-up, OPU) without anesthesia and analgesia in women with low or medium number of follicles? Summary answer Pain intensity is only mild and is only slightly different in cycles with up to 5 aspirated oocytes and in repeated In-Vitro-Fertilisation (IVF) cycles. What is known already OPU is usually performed with anesthesia. However, OPU with anesthesia requires more treatment time and is more expensive. Previous studies have assessed the pain of OPUs without anesthesia in conventionally stimulated IVF using 15 to 19 gauge (G) aspiration needles and found high pain scores. Therefore, anesthesia is usually used in such IVF treatments. In contrast, in Natural cycle IVF (NC-IVF) OPU is commonly performed without anesthesia. The pain intensity of such OPUs and of OPUs of medium number of follicles has never been systematically analysed. Study design, size, duration A prospective, cross-sectional, multi-center observational study analyzing IVF cycles without anesthesia and analgesia was performed in seven IVF centers in Germany and Switzerland between January 2022 and March 2023. Women who performed one to ten NC-IVF or minimal stimulation IVF treatment cycles were enrolled. 518 aspirations were performed with 17G needles and 1772 with 19G or 20G needles. In total, 2290 cycles from 1039 patients were recorded. Participants/materials, setting, methods Pain score was assessed using a Visual Analogue Scale (VAS), graded 0 to 10 (0 = no pain; 10 = worst pain possible). Information about ovarian stimulation, number of collected oocytes, needle size, aspiration pressure and complications were recorded. A descriptive analysis was performed first, followed by a statistical evaluation using a linear mixed model to analyze the effect of the number of oocytes retrieved and of the number of cycles on the pain score. Main results and the role of chance The number of oocytes retrieved varied from 0 to 16 (interquartile range 1-2). The pain score varied from 0 to 10 with a median pain score of 3.0 (interquartile range 2-4), defined as “mild” pain. Compared to a reference value of aspirations with 1 oocyte, the pain score increased slightly by 0.5 points if no oocyte was retrieved, by 0.42 points if 2-5 oocytes were retrieved and by 1.14 points if ≥ 6 oocytes were retrieved (p < 0.001). Pain decreased slightly with repeated aspirations (-0.05 points per cycle) (p = 0.028). Needle size did not affect the pain scores. Seventeen vaginal and abdominal bleedings were recorded, two requiring hospitalization (<0.1%). Limitations, reasons for caution As only NC-IVF and minimal stimulation IVF cycles were analysed using mainly 19G and 20G needles, the results cannot be extrapolated to cycles with a high ovarian response and to aspirations using larger volume needles. Wider implications of the findings In case of one or few follicles OPU can be offered without anesthesia and analgesia to reduce aspiration time and cost. Trial registration number NCT05125497

P-046 Ejaculatory abstinence: is there any association with embryo developmental competence? A Retrospective Study in time-lapse incubators

Abstract Study question Is ejaculatory abstinence (EA) associated with fertilization and blastocyst development in ICSI cycles with embryo culture in time-lapse incubators? Summary answer There is no association between length of EA and fertilization, blastocyst development or morphology. What is known already Semen analysis is pivotal in medically assisted reproduction (MAR), serving as a significant indicator of male partners’ health. The period of EA is a relevant factor that can affect sperm quality. Numerous studies described EA association with clinical outcomes, while its impact on embryological results remains inconclusive. Recent meta-analyses, despite a conflicting literature, highlighted positive effects of shorter abstinence periods. A recent study suggested that prolonged abstinence might reduce fertilization rate in ICSI cycles without time-lapse imaging, thereby reducing usable zygotes’ rate Study design, size, duration Retrospective study including all oocytes (N = 7164) from 1148 ICSI cycles (N = 902 couples) cultured in time-lapse incubators at a single IVF center between January 2020 and December 2022. Only non-donor fresh gametes were included (Mean Maternal age: 38.5±4 years; Paternal Age: 41±5.6 years). The primary embryological outcomes were fertilization rate and type, and blastocyst development per inseminated oocyte and per 2PN-zygote. Secondary outcomes were euploidy, day of blastocyst development and Gardner’s morphology. Participants/materials, setting, methods Semen analysis was conducted according to WHO. All oocytes were cultured up to day7 in EmbryoScope or GERI incubators with continuous media and refresh in day5 (if needed). If requested, PGT-A was performed to assess full-chromosome uniform aneuploidies. Univariate and multivariate logistic regressions were conducted. Possible confounders were assessed among ovarian stimulation, maternal, paternal, sperm, and IVF cycles characteristics. Associations were confirmed with Generalized estimating equations (GEE) to account for repeated measurements among oocytes’ cohort. Main results and the role of chance Logistic regressions and GEE were conducted to assess associations between possible confounders and blastocyst development per inseminated metaphase-II oocyte. Maternal age, sperm concentration, and motility A+B were associated. The same confounders were reported on blastocyst development among 2PN-zygotes. The days of EA (1-8 days) did not show any association with fertilization (p = 0.198) or blastocyst development per metaphase-II oocyte (p = 0.495). No association was reported with abnormal fertilization, neither combining all abnormalities in a single group, nor clustering them as 1PN, 3PN, 3.1PN, and multi-PN. An increasing trend was reported in blastocyst development among 2PN-zygotes according to the length of EA (1-day: 17/37,45.9%; 2-days: 190/424,44.8%; 3-days: 1405/2574,54.6%; 4-day: 746/1410,52.9%; 5-days: 450/827,54.4%; 6-days: 70/133,52.6%; 7-days: 46/101,45.5%; 8-days: 85/162,52.5%), but this was not significant in a multivariate logistic regression (p = 0.887). Length of EA showed no association with euploidy (p = 0.424), nor with day of development (p = 0.966) and Gardner’s inner cell mass (p = 0.204) or trophectoderm (p = 0.428) morphology. Limitations, reasons for caution This study is inherently limited by its retrospective design. The limited number of cycles included was balanced using time-lapse incubators to improve the accuracy of fertilization check and benefit from an undisturbed embryo culture environment. Artificial Intelligence will be implemented to automate developmental timings’ annotation and objectify embryo quality assessment. Wider implications of the findings The length of EA seems not associated with embryological outcomes, adding to the controversy on this topic. Here, we included only ICSI cycles with blastocyst culture conducted in time-lapse to enhance the quality of the evidence. Larger datasets and diverse settings are now required, especially enriched with poor prognosis patients. Trial registration number not applicable

P-178 Putrescine supplementation enhances embryonic development in patients with Recurrent Implantation Failure (RIF)

Abstract Study question Does putrescine, a type of polyamine, affect embryonic development in patients with recurrent implantation failure (RIF)? Summary answer Putrescine supplementation on cumulus-oocyte complexes (COCs) was associated with better embryologic development from fertilization to blastulation in patients with RIF. What is known already Putrescine, a type of polyamine, plays a role in cell growth and proliferation. Several animal studies suggest the potential impacts of putrescine on embryo development, but its effects on human IVF have yet to be extensively studied. Study design, size, duration This retrospective study analyzed 442 patients who have undergone IVF cycles three or more times from January to December 2023. The average IVF cycle number of RIF patients was 7.4 times. A total of 1356 oocytes from the putrescine group and 1391 oocytes from the control group underwent aspiration and ICSI. Further analysis was conducted by classifying RIF patients into two groups: patients under 40 years of age and patients over 40 years of age. Participants/materials, setting, methods COCs were cultured for 4 hours in a culture medium supplemented with 0.5mM putrescine. 2 hours after oocyte collection, cumulus cells were denuded, and ICSI was performed. Embryonic development was evaluated based on fertilized oocytes (2PN), good quality embryos (GQE) on day 3, and blastulation rates on day 5/6. Group differences were analyzed using t-tests and chi-square tests (p < 0.05). Main results and the role of chance When maternal age was ≥40, the fertilization rate in the putrescine group was significantly higher than that in the control group (86.6% vs. 80.5%, p=0.002). The putrescine group had a numerically higher proportion of embryos with top-grade morphology on day 3 (47.8%, compared with 53.3% for control; p=0.057), without statistical significance. Additionally, the rate of blastulation on day 5 indicated a significant difference between the two groups (14.5% vs. 6.1%, p=0.0001). Further analysis was conducted in younger patients (<40 years old), and it also showed a significantly higher fertilization rate (89.7% vs. 71.1 p=0.0001) and blastocyst development rates on the day 5 in the putrescine group (22.3% vs. 11.1%, p=0.0001), respectively. This study suggests that putrescine supplementation can be utilized to improve embryo quality and facilitate blastocyst formation in IVF procedures for patients with RIF, irrespective of age. Limitations, reasons for caution Putrescine supplementation in IVF showed improved fertilization and blastulation rates, but caution is needed due to the small sample size used. Therefore, a larger sample size will help improve the robustness of the conclusions drawn with respect to the embryologic development in patients with RIF. Wider implications of the findings The study’s findings suggest that putrescine supplementation in IVF may enhance outcomes for patients with RIF, potentially leading to personalized treatments. Trial registration number not applicable

O-121 Assisted Reproductive Technology (ART) in Europe 2021 and development of a strategy of vigilance: Preliminary results generated from European registers by the ESHRE EIM Consortium

Study question What are the reported data on cycles in ART, IUI and fertility preservation interventions in 2021 as compared to previous years and what are the main trends over the years? Summary answer The 25th ESHRE report on ART and IUI shows a progressive increase in reported treatment cycle numbers in Europe, a small decrease in the number of transfers (IVF + ICSI) with more than one embryo with a trend to decreasing multiple delivery rates, outcomes for IUI cycles are similar to previous years. What is known already Since 1997, ART aggregated data generated by national registries, clinics or professional societies have been collected, analyzed by the European IVF-monitoring Consortium (EIM) and reported in 23 manuscripts published in Human Reproduction and Human Reproduction Open. Study design, size, duration Yearly collection of European medically assisted reproduction (MAR) data by EIM for ESHRE. The data on treatments performed between January 1 and December 31, 2021, in 34 European countries were provided by either National Registries or registries based on personal initiatives of medical associations and scientific organizations. Participants/materials, setting, methods In all 1155 clinics offering ART services in 34 countries reported a total of 910 470 treatment cycles, involving 115 567 with IVF, 346 183 with ICSI, 311 487 with frozen embryo replacement (FET), 62 694 with preimplantation genetic testing (PGT), 69 883 with egg donation (ED), 246 with IVM of oocytes and 4410 cycles with frozen oocyte replacement (FOR). European data on IUI using husband/partner’s semen (IUI-H) and donor semen (IUI-D) were reported from 1242 institutions offering IUI in 29 and 21 countries, respectively. A total of 139 350 treatments with IUI-H and 45 532 treatments with IUI-D were included. A total of 28 692 fertility preservation (FP) interventions from 15 countries including oocyte, ovarian tissue, semen and testicular tissue banking in pre-and post-pubertal patients were reported. Main results and the role of chance In total, 1155 IVF clinics participated (81.4% of registered clinics in the participating countries). Next to these also 1242 IUI units reported their data. In the 34 reporting countries, after IVF the clinical pregnancy rates (PR) per aspiration and per transfer in 2021 were similar to those observed in 2020 (26.2% and 43.3% versus 25.4% and 40.9%, respectively). After ICSI the corresponding rates were also similar to those achieved in 2020 (23.9% en 45.7% versus 25.2% and 45.3%). Also after FET with own embryos, the PR per thawing is stabilizing, 35.0% in 2020 and 36.2% in 2021. After ED the PR per fresh embryo transfer was slightly increased to 53.1% (51.3% in 2020) and per FOR 45.5% (43.9% in 2020). In IVF and ICSI together, the trend towards the transfer of fewer embryos continues with the transfer of 1, 2, 3 and ≥4 embryos in 60.2%, 34.8%, 1.8% and 0.2% of all treatments, respectively (corresponding to 57.9%, 37.5%, 2.1% and 0.2% in 2020). This resulted in a proportion of singleton, twin and triplet DRs of 90.4%, 9.5% and 0.1%, respectively (compared to 88.9%, 10.9% and 0.2%, respectively in 2020). Treatments with FER in 2021 resulted in twin and triplet DR of 7.0% and 0.1%, respectively (versus 7.9% and 0.1% in 2020). After IUI, the DRs remained similar at 9.2% after IUI-H (8.8% in 2020) and at 14.0% after IUI-D (12.5% in 2020). Twin and triplet DRs after IUI-H were 7.4% and 0.2%, respectively (in 2020: 7.9% and 0.4%) and 5.9% and 0.2% after IUI-D (in 2020: 5.7% and 0.1%). The majority of FP interventions included the cryopreservation of oocytes (n= 11 966 from 15 countries) and of ejaculated sperm (n=14 688 from 15 countries). Limitations, reasons for caution As the methods of data collection and levels of completeness of reported data vary among European countries, the results should be interpreted with caution. For this abstract, some countries were not able to provide adequate data about the number of centers and initiated cycles and deliveries. Wider implications of the findings The 25th ESHRE report on ART and IUI shows a continuous increase of reported treatment numbers and MAR-derived live births in Europe. Being already the largest data collection on MAR in Europe, continuous efforts to stimulate data collection and reporting strive for future quality control and completeness of the data and offer higher transparency and vigilance in the field of reproductive medicine.

The effects of age, mature oocyte number, and cycle number on cumulative live birth rates after planned oocyte cryopreservation.

To examine the effects of age, mature oocyte number, and cycle number on cumulative live birth rates after planned oocyte cryopreservation (OC), with the goal of developing a patient counselling tool. We performed a retrospective cohort study of all patients with ≥ 1 autologous oocyte thaw at our university-affiliated fertility center before 12/31/2023. Patients were included if they (1) had a live birth or ongoing pregnancy > 12weeks from OC, or (2) used all oocytes and euploid/untested embryos from OC. Primary outcome was cumulative live birth / ongoing pregnancy rate (CLBR). 527 patients with 1 OC cycle, 149 patients with 2 OC cycles, and 55 patients with ≥ 3 OC cycles were included. Overall CLBR was 43%. CLBR was > 70% among patients who thawed ≥ 20 mature oocytes that were cryopreserved at age < 38years. Multiple logistic regression showed that age at first OC and total number of mature oocytes thawed independently predicted CLBR, but number of OC cycles did not. Patients must be counselled that younger age at OC and more mature oocytes improve CLBR. However, additional OC cycles do not independently improve CLBR. Our results can help patients decide whether to pursue additional OC cycles to obtain more oocytes.

Stable SnAgCu solder joints reinforced by nickel-coated carbon fiber for electronic packaging

Today’s 3D electronic packaging is characterized by smaller size and higher functional density, which generally require multiple reflow cycles. However, due to the Ostwald ripening process of the interfacial intermetallic compound (IMC), the solder joint’s strength would decrease as the number of reflow cycles increases. To address this, we developed a novel composite solder by incorporating nickel-coated carbon fiber (Ni@CF) into the Sn–3.0Ag–0.5Cu (SAC305) solder connection. The study showed that Ni@CF effectively enhanced the stability and reliability of solder joints during multiple reflow processes. Compared with Ni@CF-free equivalents, Ni@CFs promoted the nucleation of interfacial IMC during the solid–liquid reaction and inhibited Ostwald ripening, leading to a refinement of the interfacial IMC grains. As a result, the interface was strengthened, and the shift of shear fracture to the brittle interface seen in the SAC305 solder joint with multiple reflows did not occur in the composite solder joint. Furthermore, carbon fiber strengthened the solder matrix through the load transfer and shear-off mechanisms, depending on its inclination angle with the shear plane. Consequently, the Ni@CFs-reinforced solder joints maintained a shear strength of over 42 MPa throughout ten reflow cycles, while the pristine SAC305 solder joint exhibited decreased shear strength to 33 MPa. This study provides new insights into composite solder joints’ stability and reinforcement characteristics when subjected to multiple reflows.