Embryo Day Research Articles

Hormone-free versus FSH-primed infertility treatment of women with polycystic ovary syndrome using biphasic in vitro maturation: a randomized controlled trial

To compare oocyte maturation rates and pregnancy outcomes in women with polycystic ovary syndrome (PCOS) undergoing biphasic in vitro maturation (capacitation [CAPA]-IVM) with versus without follicle-stimulating hormone (FSH) priming. Randomized, controlled, assessor-blinded trial SUBJECTS: Women aged 18-37 years with PCOS and an indication for CAPA-IVM. Participants were randomized (1:1) to undergo CAPA-IVM with or without FSH priming. The FSH priming group had two days of FSH injections before oocyte pick-up; no FSH was given in the non-FSH group. After CAPA-IVM, day-5 embryos were vitrified for transfer in a subsequent cycle. The primary endpoint was number of matured oocytes. Secondary outcomes included rates of live birth, implantation, clinical pregnancy, ongoing pregnancy, pregnancy complications, obstetric and perinatal complications, and neonatal complications. The number [interquartile range] of matured oocytes did not differ significantly in the non-FSH versus FSH group (13 [9-18] vs. 14 [7-8]; absolute difference -1 [95% confidence interval (CI) -5, 4]); other oocyte and embryology outcomes did not differ between groups. Rates of ongoing pregnancy and live birth were both 38.3% in the non-FSH group and both 31.7% in the FSH group (risk ratio for both outcomes: 1.21, 95% CI 0.74-1.98). Maternal complications were infrequent and occurred at a similar rate in the two groups; there were no preterm deliveries before 32 weeks' gestation. These findings open the possibility of a new, hormone-free approach to infertility treatment of women with PCOS.

Factors Associated with Clinical Pregnancy following Assisted Reproductive Technology: A Comparative Cross-Sectional Study

Abstract Background: Over the years, the numbers of centres performing assisted reproductive technology (ART) have increased in urban regions of Africa. We reviewed a 10-year record of ART in a public hospital in a bid to determine the pregnancy rate and identify factors associated with achieving clinical pregnancy. Materials and Methods: This was a retrospective, analytical, cross-sectional study of 604 women who had undergone in vitro fertilisation (IVF) or IVF/intra-cytoplasmic sperm injection, over a 10-year period, at the [Institute of Fertility Medicine, Lagos State University Teaching Hospital]. Data were obtained from the medical records of couples who had undergone IVF at the study location and analysed using relevant descriptive and inferential statistics. Regression analysis was used to determine possible predictors of clinical pregnancy outcomes at 95% confidence level and significant P value of <0.05. Results: The clinical pregnancy rate observed was 23.7%. Women aged ≥35 years of age had 2.9 odds of achieving pregnancy compared to women <35 years of age. The quality of embryo and dose of the follicle-stimulating hormone used were not significantly different when compared in pregnant and non-pregnant women (P = 0.612 vs 0.881). Endometrial preparation techniques, number of embryos transferred, types of embryos transferred, sperm quality, and source of gametes used were not significantly different in pregnant and non-pregnant women. There was a 0.77 odds of achieving pregnancy when a day-5 embryo was used compared to a day-3 embryo (P = 0.008). Conclusion: Overall, these results emphasise the multifaceted nature of IVF outcomes, urging further research to elucidate the intricate factors influencing success rates in assisted reproduction.

Analysis of assisted reproductive outcomes for gynecologic cancer survivors: a retrospective study

ObjectiveTo examine the reproductive outcomes of assisted reproductive technology (ART) in gynecologic cancer patients and to assess maternal and neonatal complications.MethodsWomen diagnosed with gynecologic cancer who underwent their first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment between 2013 and 2021 at Shanghai Ji Ai Genetics and IVF Institute were included in this study. Infertile women without any history of cancer were matched to the cancer group. The primary outcome was the cumulative live birth rate. Baseline and follow-up data were compared between groups using Student’s t-tests for normally distributed variables and with Chi-square test for categorical variables. A propensity score-based patient-matching approach was adopted to ensure comparability between individuals with and without specific cancer type.ResultsA total of 136 patients with a history of gynecologic cancer and 241 healthy infertile controls were included in this study. Endometrial cancer constituted 50.70% of the cases and cervical cancer constituted 34.60% of the cases. The cancer group exhibited significantly shorter duration of stimulation, lower levels of estradiol, lower number of retrieved oocytes, day-3 embryos, and blastocysts compared to the control group (P < 0.05). The cumulative live birth rate of the gynecologic cancer group was significantly lower than that of the control group (36.10% vs. 60.50%, P < 0.001). Maternal and neonatal complications did not significantly differ between the groups (P > 0.05). The endometrial cancer and cervical cancer groups showed significantly lower cumulative live birth rates than their matched controls (38.60% vs. 64.50%, P = 0.011 and 24.20% vs. 68.60%, P < 0.001, respectively).ConclusionsThese findings highlight the decreased occurrence of pregnancy and live birth in female gynecologic cancer patients undergoing ART, particularly in endometrial cancers and cervical cancers. These findings have important implications for counseling and managing gynecologic cancer patients undergoing ART.

Day 3 embryo assessment does not provide a reliable prediction for blastocyst formation and designation: a retrospective cohort study.

Although many Fertility Centers have adopted day 5 or 6 embryo transfer policy, yet, 30% of embryo transfers in the US are performed on day 3. This is mainly due to concerns related to longer embryo culture effect and higher rates of embryo transfer cancellation on day 5, with no effect on cumulative pregnancy rate. We conducted a retrospective cohort study comparing individual embryo transfer order rank, best embryo for fresh transfer and intention to freeze, of day-3 and day-5 embryos based on their morphology score. Day-3 embryos of each patient were ranked by embryologists for the order of transfer and intention to freeze, based on morphological score, blinded to actual blastulation outcome. The corresponding blastocysts were similarly ranked for the order of transfer and vitrification intention. Ranking was compared to test the predictive value of day-3 morphological assessment. Sixty patients with 784 day-3 embryos were included. There was only a moderate positive significant correlation between ranks on day-3 and ranks on day-5 [r = 0.662 95% CI (0.611-0.706, p < 0.001)]. Only 25% of the best embryos for transfer on day 3 (rank = 1) were chosen for fresh transfer on day 5. A total of 441 embryos were intended to be frozen on day 3. Of those, 201 were not transferred nor vitrified on day 5-6 (45%), 3.35 embryos per patient. No significant difference was found between average day-3 rank of embryos ranked 1, 2 (3.12 vs 4.12, p = 0.074) and 3 (3.12 vs 4.08, p = 0.082) on day-5-6. To conclude, this study brings a different perspective to the comparison of day 3 and day 5 by following each embryo's putative and actual designation. Day-3 ranking of embryo morphology did not provide a reliable prediction for blastocyst formation, transfer order and vitrification intention, and may support transfer or cryopreservation of blastocysts over cleavage stage embryos.

P-511 Euploidy potential of day 7 embryos and the relevance in Assisted Human Reproduction treatments

Abstract Study question Is it worth waiting embryos with late blastulation (Day 7) for preimplantation genetic analysis? Summary answer Embryo biopsy on Day 7 (D7) benefits cases of ovarian insufficiency and severe male factor with a euploidy rate of 15.1%. What is known already New technologies and improvements in IVF laboratories has allowed the extended cultivation of blastocysts to increase the pool of embryos per IVF cycle, resulting in greater chances, especially in cases of low blastulation rate, blastocysts with low quality or with few cells at Day 5(D5) and Day 6(D6). The variation in the time of the compaction stage depends on many factors, which may take more time, leading some embryos to reach the blastocyst stage only on D7 of development. These embryos have a lower euploidy rate, but there is embryonic competence and these embryos can be eligible for embryo transfer. Study design, size, duration Retrospective study that evaluated the chromosomal status (by Next Generation Screening - NGS) of 33 blastocysts biopsied on day 7 of development, between 2016 and 2023. Subsequently, it was compared the rate of euploidy and mosaicism with 295 blastocysts biopsied at D5 and D6, biopsied from January to October 2023. D7 embryos were originated from IVF cycles of couples with female age between 26 and 44 years, and males age between 29 and 56 years. Participants/materials, setting, methods D7 blastocysts from fresh and own oocytes fertilized by ICSI. The euploidy and mosaicism rates was compared, as well as the morphology of the ICM and trophectoderm (A-C; by Gardner Blastocyst Grade), the day which biopsy was performed and the respective infertility factors, in the groups: Group 1: D7 euploid and Group 2: D7 aneuploid. Subsequently, the rate of euploidy and mosaicism was compared between D7 embryos (Group 3) and D5/D6 embryos (Group 4). Main results and the role of chance There was no difference (p &amp;gt; 0.05) between maternal age for group D7 euploid (38.4 years) vs group D7 aneuploid (37.9 years) and group 3 (38.4 years) vs group 4 (38.2 years). Embryonic morphological evaluation of D7 embryos showed that ICM was classified as B (18.2%) or C (81.8%) and trophectoderm as A (6.1%), B (24.2%) or C (69.7%). Comparisons of ICM and trophectoderm classifications between euploid (group 1) and aneuploid (group 2) in D7 blastocysts showed no difference (p &amp;gt; 0.05). There was a predominance of 5CC embryos in both groups (Group 1: 40.0% vs Group 2: 42.4%), with no difference between them (p &amp;gt; 0.05). In most cases, the biopsy was performed on two days (D5+D7 – 39.3%; D6+D7 – 35.7%), while in 10.7% of cases only on Day 7, when the infertility factor was 100% ovarian insufficiency. In cases of biopsy within 3 days (D5+D6+D7), we observed that 100% of cases were related to severe male factor. When comparing the euploidy rate of D7 embryos – group 3 (15.1%) with that of D5/D6 – group 4 (34.2%), we observed a statistical difference (p &amp;lt; 0.05), while, for in mosaicism rates, D7 embryos represented 6.1% and D5/D6 embryos 9.1%, with no statistical difference (p &amp;gt; 0.05). Limitations, reasons for caution The retrospective nature of our study may lead to bias derived from clinical practices and variability in relation to patient age, embryonic quality and infertility factor. Wider implications of the findings Extended culture and biopsy on D7 benefits cases of ovarian insufficiency and severe male factor by optimizing the IVF cycle. Although the euploidy rate in D7 embryos is lower than D5/D6 embryos, 15% of D7 embryos are euploid, demonstrating that the slower development is not caused exclusively by aneuploidy Trial registration number NA

P-196 Early blastocyst formation on day 4 is associated with improved clinical outcome and advocates for embryo quailty assessment on day 4

Abstract Study question Is early cavitation on day 4 associated with improved clinical outcome? Summary answer Early blastulation on day 4 is a positive predictor of implantation after single blastocyst transfer on day 5. What is known already In order to select the blastocyst with the highest implantation potential for transfer or freezing, several morphological and/or morphokinetic parameters have been proposed. For instance, early compaction on day 3 (D3) or blastocyst expansion on day 5 (D5) have been reported to be relevant when selecting embryos for transfer. However, day 4 has often been overlooked and very few studies focused on early blastulation on day 4 (D4). Indeed, data on early blastulation on day 4 is scarce. It was however recently demonstrated that embryos transferred on day 4 could provide acceptable pregnancy rates. Study design, size, duration This monocentric retrospective cohort study was conducted in all consecutive couples undergoing IVF cycles in 2017-2022 with single blastocyst transfer and observation on day 4. Participants/materials, setting, methods Morphological and morphokinetic assessment was performed by 2 operators at 93±2h, 116±2h (and 140±2h) post insemination, on day 4, 5 (and 6) respectively. A total of 26 507 D4 embryos were included in this study and grouped according to the observation of early cavitation or not : 23 244 were in the D4 control group (absence of early cavitation on D4) and 3263 were in the D4 blastocyst group (observation of early cavitation on D4). Main results and the role of chance The proportion of embryos used clinically for either transfer or freezing on day 5 or 6 was significantly higher in the D4 blastocyst group than in D4 control group (86.7% vs 50.1% respectively, p &amp;lt; 0.05). Concerning pregnancy rate, cinical pregnancy rate was significantly higher in the D4 blastocyst group than in D4 control group (p &amp;lt; 0.05). In the D4 control group, 5051 embryos were transferred and clinical pregnancy rate is 28.7%. In the D4 blastocyst group, 1286 embryos were transferred (fresh or frozen) and clinical pregnancy rate is 40.2%. Limitations, reasons for caution The retrospective and monocentric design calls for caution when considering the generalizability of our findings. Wider implications of the findings We postulate that D4 embryo quality assessment should be widely implemented in any blastocyst program in order to improve embryo quality assessment and subsequently clinical outcome. Trial registration number not applicable

P-650 Cumulative live birth rate after use of capacitation in vitro maturation in women with predicted excessive response to ovarian stimulation: an analysis of 1,563 cycles

Abstract Study question What is the cumulative live birth rate in biphasic (capacitation) in vitro maturation (CAPA-IVM) cycles in women with predicted excessive response? Summary answer The cumulative live birth rate achieved after CAPA-IVM in women with predicted excessive response was 37.8%. What is known already In vitro maturation (IVM) is an alternative infertility treatment for women at high risk of complications during conventional in vitro fertilisation with ovarian stimulation. There is debate about the merits of a newer biphasic approach (capacitation [CAPA]-IVM) versus standard IVM. At centres where it is used, CAPA-IVM has increased the maturation rate, and therefore the number of embryos available for transfer. However, there is a lack of data from large numbers of CAPA-IVM cycles, especially cumulative outcomes. Study design, size, duration This analysis included data from 1,563 individuals who underwent CAPA-IVM at a tertiary IVF center in Ho Chi Minh City, Vietnam from January 2016 to December 2023. Participants/materials, setting, methods All CAPA-IVM cycles in women with predicted excessive response (polycystic ovary syndrome or high antral follicle count) were included. Mean age was 29.6±3.5 years. Median duration of infertility was 3.3±2.5 years. CAPA-IVM was the first assisted reproductive technology in 90.5% of participants. Cumulative live birth rate was defined as the number of live births after using all embryos generated from a CAPA-IVM cycle. Main results and the role of chance Cumulative rates of clinical pregnancy, ongoing pregnancy and live birth were 54.9%, 44.4% and 37.8%, respectively. The median proportion of mature oocytes per cumulus-oocyte complex was 61.3% (IQR 50.0–73.3) and the median proportion of fertilized oocytes per cumulus-oocyte complex was 72.2% (IQR 55.6-85.7). The median total number of day-3 embryos per patient was 4.0 [IQR 3.0–7.0] and the total number of good day-3 embryos per patient was 3.0 [IQR 2.0–5.0]. The proportion of patients with no embryo was 5.2%. The number of frozen embryo transfer cycles was 1 (53.6% of patients), 2 (24.9%), 3 (7.0%), 4 (0.8%) or 5 (0.3%); 7.9% of patients had not undergone transfer of day-3 embryos at the time of analysis. Median [IQR] number of embryos and good embryos transferred was 2.0 [2.0–4.0] and 2.0 [1.0–2.0], respectively. No case of ovarian hyperstimulation syndrome recorded. Limitations, reasons for caution The characteristics of the study population (relatively young, lean women from Vietnam with predicted excessive response to ovarian stimulation) limit the external generalisability of the findings. Wider implications of the findings The cumulative live birth rate from all CAPA-IVM cycles performed in women with predicted excessive response at our centre was comparable to that of IVF. CAPA-IVM could be an alternative for this selected group of patients to avoid ovarian hyperstimulation. Trial registration number not applicable

P-582 Analysis of assisted reproductive outcomes for gynecologic cancer survivors: a retrospective study

Abstract Study question Do women diagnosed with gynecologic cancer have worse pregnancy and neonatal outcomes of assisted reproductive technology (ART) ? Summary answer Decreased live birth rate was observed in female gynecologic cancer patients undergoing ART, particularly in endometrial cancers and cervical cancers. What is known already Gynecologic malignancies comprise approximately 13% of female cancer diagnoses, and oncological treatments such as surgery, chemotherapy, abdominal or pelvic radiotherapy, and hormonotherapy may induce infertility, premature ovarian failure, or early menopause, resulting in a loss of reproductive potential. ART has emerged as an important option for cancer patients undergoing treatment, but the reproductive outcomes of ART among cancer survivors remain poorly understood. Limited research exists regarding the impact of a history of gynecologic cancer on reproductive outcomes of ART. Study design, size, duration 136 women diagnosed with gynecologic cancer who underwent their first IVF/ICSI treatment between 2013 and 2021 were retrospectively enrolled in this study. 241 infertile women without any history of cancer were matched to the cancer group. Participants/materials, setting, methods Women diagnosed with gynecologic cancer who underwent their first IVF/ICSI treatment between 2013 and 2021 were included. Infertile women without any history of cancer were matched to the cancer group. The primary outcome was the cumulative live birth rate. A propensity score-based patient-matching approach was adopted to ensure comparability between individuals with and without specific cancer type. Main results and the role of chance A total of 136 patients with a history of gynecologic cancer and 241 healthy infertile controls were included in this study. Endometrial cancer constituted 50.70% of the cases and cervical cancer constituted 34.60% of the cases. The cancer group exhibited significant shorter duration of stimulation, lower levels of estradiol, lower number of retrieved oocytes, day-3 embryos, and blastocysts compared to the control group (P &amp;lt; 0.05). The cumulative live birth rate of the gynecologic cancer group was significantly lower than that of the control group (36.10% vs. 60.50%, P &amp;lt; 0.001). Maternal and neonatal complications did not significantly differ between the groups (P &amp;gt; 0.05). The endometrial cancer and cervical cancer groups showed significantly lower cumulative live birth rates than their matched controls (38.60% vs. 64.50%, P = 0.011 and 24.20% vs. 68.60%, P &amp;lt; 0.001, respectively). Limitations, reasons for caution Our study was limited by the retrospective design in nature and small sample size of its patient cohort. In addition, the effect of cancer treatments was not evaluated specifically in the current study due to the limited number of patients and possible inconsistency in surgical operations. Wider implications of the findings Our study provides data support for further exploration of the effects of endometrial cancer, cervical cancer, and other gynecologic cancers on fertility. Comprehensive ovarian function assessment, detailed counseling, individualized fertility guidance, and close follow-up after ART therapy are recommended for patients with gynecologic malignancy history. Trial registration number Not applicable

P-043 Preliminary clinical outcome using the Q300™ device in a reproductive laboratory environment

Abstract Study question How does the Q300™ Device impact clinical outcomes in a reproductive laboratory environment compared to established standards? Summary answer The device showed favorable clinical outcomes and was user-friendly. More research is needed to identify the patient subgroups that can benefit the most from system What is known already Embryologists struggle with accurately assessing sperm morphology without staining, prompting interest in emerging technologies like AI. These methods evaluate motility parameters, offering non-invasive sperm selection. A previous study comparing Q300 to manual staining methods showed high agreement and repeatability, indicating Q300’s accuracy in measuring live sperm cells. It aids in selecting cells per WHO2021 guidelines without staining, potentially revolutionizing sperm assessment. Study design, size, duration The study is an open-label, non-randomized study. Semen samples intended for ICSI were imaged by the Q300™ device before micro-injection to aid in selecting morphologically compliant sperm cells. The data collected was compared to the Key Performance Indicators (KPI) for ART laboratories according to the Vienna Consensus. Up to 5 sites will be enrolled in the study, with up to 100 couples in total from all sites. Study duration: 18 months Participants/materials, setting, methods The Q300™ device is an optical system using quantitative phase microscopy and holographic imaging to analyze human semen morphology. The device aids embryologists in selecting live and motile sperm cells for ICSI by providing automatic, objective analysis. Couples meeting inclusion criteria, including female age ≤40 and availability of motile sperm, were recruited for ICSI procedures. There were no restrictions on previous IVF/ICSI cycles. Endpoints: fertilization, day-3 embryo development, good blastocyst development rates, and implantation rates. Main results and the role of chance 14 couples were recruited from Barzilay Medical Center’s IVF unit in Ashkelon, Israel. The average fertilization rate is 79.1% (Vienna consensus competency is ≥ 65%), the day 3 embryo development rate is 55% (Vienna consensus competency is ≥ 45%), and the good blastocyst development rate is 42.5% (Vienna consensus competency is ≥ 30%). The implantation rate (day 3+day5) is 36.8% (Vienna consensus competency is ≥ 25% for day 3 embryo transfers and ≥ 35% for blastocyst transfers). The intended users performed the procedures with no reported malfunctions. 270 sperm imaging procedures were performed using the Q300 device to select 109 morphologically suitable cells for ICSI. The utilization of the product resulted in approximately a 40% yield of correct selections by the embryologist. Consequently, out of every 10 cells deemed compliant by the embryologist, only 4 were confirmed by the device, with roughly 3 falling within a margin of 10% around the WHO measurement range. Moreover, only about 1 of these selections fell within the boundaries defined by the WHO standards. This observation offers insights into the characteristics of cells routinely chosen for injection into oocytes. Limitations, reasons for caution The study recruited 14 couples from a single site; it is important to validate and statistically power the outcome measures and compare them with clinical control groups in the future. In the next generation of the product, incorporating an objective selection based on sperm motility can further improve its functionality. Wider implications of the findings The findings offer insights into optimizing sperm selection processes, potentially improving fertilization, embryo development, and implantation rates in couples undergoing ICSI. Moreover, the study highlights the importance of continued research and refinement of technological innovations in ART to better serve patient needs and improve treatment outcomes. Trial registration number NCT06232720

P-130 Comparing head-first and tail-first injection techniques in guiding new embryologists for human oocyte Piezo-ICSI

Abstract Study question Which technique is more effective for new embryologists in human oocyte Piezo-ICSI: Head-first or tail-first injection? Summary answer Tail-first injection is superior as it significantly increases fertilization rates without adversely affecting embryo development compared to head-first injection in Piezo-ICSI. What is known already ICSI is an essential technique in assisted reproductive technology. Recently, some researchers have reported that Piezo-ICSI is clinically more useful than Standard-ICSI. In most papers, Piezo-ICSI has shown significantly higher fertilization rates than Standard-ICSI. This is because, in Piezo-ICSI, it eliminates the need to aspirate the cytoplasm into the ICSI needle upon membrane breakage. After membrane breakage, the sperm is injected into the cytoplasm. A few papers evaluated the effect of sperm injection direction (head-first or tail-first) on ICSI results for human oocytes. However, little information is available to guide new embryologists on whether to use head-first or tail-first injection. Study design, size, duration During their Piezo-ICSI training, new embryologists were taught either head-first or tail-first injection techniques before commencing clinical procedures. Only the head part of the sperm was injected into the cytoplasm in the head-first group, and half of the whole sperm was injected in the tail-first group. This study divided the new embryologists into two groups (head-first or tail-first) and collected and retrospectively analyzed their first 200 oocyte ICSI results between January 2017 and November 2023. Participants/materials, setting, methods This study involved five new embryologists and a total of 1,000 oocytes. Two embryologists performed head-first injection for 400 oocytes, and three performed tail-first injection for 600 oocytes. The rates of degeneration, 2PN, 0PN, 1PN, ≥3PN, good quality day-3 embryo (≥7cell, ≤15%fragmemtation) per 2PN, blastocyst, and good quality blastocyst (better than BB with Gardner criteria) were compared. Statistical analysis was performed using either a t-test, Welch’s t-test, or Fisher’s exact test as appropriate. Main results and the role of chance The average ages of women and their husbands in the head-first and tail-first injection groups were 37.8 vs. 37.2 and 40.1 vs. 39.2, respectively, with average total motile sperm counts of 52.2 x106 vs. 52.6 x106. No significant difference was observed in these comparison items between the groups. Theoretical injected medium volume into the cytoplasm with sperm of the head-first and tail-first injection groups was 104μm3 vs. 520μm3. The 2PN rate of the tail-first injection group (88.3%; 530/600) was significantly higher (P = 0.0151) than head-first (82.8%; 331/400). The 0PN rate of the tail-first group (4.0%; 24/600) was significantly lower (P = 0.0007) than the head-first (9.5%; 38/400). The degeneration rates, 1PN rates, and ≥3PN rates of head-first and tail-first injection groups were 1.5% (6/400) vs. 1.3% (8/600), 3.5% (14/400) vs. 2.3% (14/600), and 2.8% (11/400) vs. 4.0% (24/600). No significant difference was observed in these comparison items between the groups. The good quality day-3 embryo per 2PN rates, blastocyst rates, and good quality blastocyst rates of head-first and tail-first injection groups were 64.7% (214/331) vs. 64.3% (341/530), 62.1% (192/309) vs. 62.7% (289/461), 35.3% (109/309) vs. 35.6% (164/461). No significant difference was observed in these comparison items between the groups. Limitations, reasons for caution The estimated volumes of medium injected into the cytoplasm for both head-first and tail-first injections were theoretical. We calculated the length of the sperm head and whole sperm as 6μm and 60μm. Some day-3 embryos were transferred or cryopreserved, so the blastocyst and good-quality blastocyst rates were reference ranges. Wider implications of the findings Despite the larger volume of medium injected with sperm, tail-first injection increases fertilization rates without adversely impacting embryo development compared to head-first injection. Therefore, the tail-first injection is better to guide the new embryologists for human oocytes Piezo-ICSI than the head-first injection. Trial registration number 17-0450221102

P-410 A modified artificial cycle-frozen embryo transfer(mAC-FET) protocol with evidence of corpus luteum(CL) formation as determined by serum relaxin-2 in early pregnancy :a prospective proof-of-concept study

Abstract Study question Can a mAC-FET protocol for endometrial preparation in ovulatory patients lead to formation of a CL as evidenced by serum relaxin-2 in the pregnant patients? Summary answer CL forms in the mAC-FET protocol as serum relaxin-2 in early pregnancy was comparable to that in spontaneous conception.Late luteal rise of relaxin-2 wasn’t demonstrated. What is known already Clinical evidence points to increased incidence of preeclampsia in pregnancies by AC-FET cycles compared to ovulatory FET cycles-natural cycle(NC) and mNC. The absence of CL and it’s secretory products like relaxin-2 is a contributing factor. FET protocols for endometrial preparation in ovulatory patients need to be optimised. NC/mNC-FET protocols need frequent monitoring. Also there is a temporal variability between LH/hCG and progesterone levels. We studied a mAC-FET protocol in ovulatory patients with a delayed start(day3-5 of the cycle),low dose transdermal 17β estradiol gel to see the formation of CL as elucidated by the presence of serum relaxin-2 in early pregnancy. Study design, size, duration A proof-of- concept prospective study was conducted at a tertiary centre (July2023-Dec2023). Serum relaxin-2(R&amp;D/Quantikine/ELISA) was determined in 4 groups of patients- Group-A. mAC-FET(n = 34) 1.On the day of start of progesterone 2.Post-ET day5-9 (along with serum progesterone) 3.In pregnancy(6-9 weeks of gestation) Group-B. AC-FET(n = 8) 1.On the day of start of progesterone 2.In pregnancy(6-9 weeks) Group-C. Spontaneous conception (n = 9) 1.In pregnancy(6-9 weeks) Group-D. Infertility patients ( n = 24) 1.Preovulatory. All patients were ≤40 years with a BMI ≤30kg/m2. Participants/materials, setting, methods In the AC-FET cohort-oral estradiol 6mg/day was started from day1/2 of the cycle. When endometrial thickness was&amp;gt;7mm,progesterone&amp;lt;1ng/ ml then intramuscular progesterone was started- 50mg/day-3 days,100mg on day4-the day of ET(Day-3 embryos) and continued every alternate day.Progesterone gel was added post-ET. In the mAC-FET cohort-17β transdermal estradiol gel(0.06%) 3mg/day was started from day3-5,rest of the protocol was similar. Statistical analysis was performed using appropriate non-parametric tests.Pearson coefficient(r) was used to assess linear-relationship.Two-tailed P&amp;lt;.05 indicated statistical significance. Main results and the role of chance Mean age and BMI of the patients with mAC-FET was 33.3±4.7 years and 24.4±3.7 kg/ m2 which was comparable across all groups (P=.14,P=.52 respectively). Clinical pregnancy rate in the mAC-FET group was 52.94%(18/34). 3 patients had an early abortion. Baseline relaxin-2 levels, median[Interquartile range(IQR)] were comparable- AC-FET cohort-9.1pg/mL(8.6-16.8), mAC-FET cohort-11.5pg/mL(9.6-13.7) and the infertility cohort-10.9pg/mL(8.4-14.5) (P=0.74) The primary outcome was the comparable levels of serum relaxin-2, in early pregnancy in the mAC-FET group and spontaneous conception group - median (IQR) 449.8pg/mL(73.1-492.3) and 487.9pg/mL(419.1-497.8) respectively (P=.12) The relaxin-2 levels, in early pregnancy in the mAC-FET group were significantly higher than the AC-FET group median(IQR) 449.8pg/mL(73.1-492.3) and 7.9pg/mL(7.8-9.5) respectively (P=.0005). As secondary outcomes, we studied the late luteal rise of relaxin-2 in the mAC-FET group and the relationship of late luteal progesterone with relaxin-2 in early pregnancies in the mAC-FET cohort. A late luteal rise of relaxin-2 was not demonstrated in the mAC-FET cohort. The serum relaxin-2, on the day of start of progesterone and on day5-9 post ET- median(IQR) 11.5pg/mL(9.6-13.7) and 11.4pg/mL(9.0-18.5), respectively was comparable (P=.18). The relationship between serum relaxin-2 in early pregnancy and the progesterone levels on day5-9 post ET in the mAC-FET cohort was not significant r = -.059 (P=.07) Limitations, reasons for caution This was a small proof- of-concept single centre study. Due to the limited numbers and short duration of the study, we could not compare efficacy, cancellation rates and pregnancy outcomes of the mAC-FET protocol with other FET protocols. Wider implications of the findings The mAC-FET protocol studied for endometrial preparation was similar to the AC -FET protocol regarding monitoring,flexibility and consistent progesterone exposure with the added advantage of the presence of the CL.This may decrease the risk of maternal/neonatal complications. Larger studies are needed to confirm it’s efficacy and impact on pregnancy outcomes. Trial registration number Not Applicable

O-190 Hormone-free versus FSH-primed infertility treatment of women with polycystic ovary syndrome using biphasic in vitro maturation: a randomised clinical trial

Abstract Study question Is any hormone stimulation needed to treat infertility in women with polycystic ovary syndrome (PCOS) using in vitro maturation (IVM)? Summary answer Number of matured oocytes and pregnancy outcomes were similar without or with FSH-priming in women with PCOS undergoing IVM. What is known already In vitro maturation (IVM) is a low-intervention alternative to in vitro fertilisation (IVF) for infertility treatment. Current standard clinical practice for human IVM is to prime patients for 2–5 days with follicle-stimulating hormone (FSH) and/or human chorionic gonadotropin (hCG) before harvesting immature or mixed maturity oocytes for infertility treatment. This gonadotropin priming is thought necessary to induce sufficient follicle and oocyte development in vivo to support subsequent oocyte maturation and embryo development in vitro when using a single step (monophasic) oocyte maturation culture system. It is not clear whether hormone-free IVM can generate satisfactory pregnancy and live birth rates. Study design, size, duration This randomised, controlled trial was conducted at an tertiary IVF center, Ho Chi Minh City, Viet Nam. Between January 2023 and June 2023, 120 women (60 per group) were randomised. Participants/materials, setting, methods Eligible women were aged 18–37 years and had PCOS with an indication for biphasic capacitation-IVM (CAPA-IVM). After providing written informed consent, participants were randomised (1:1) to undergo CAPA-IVM with or without FSH-priming. Participants in the FSH-priming group received two days of FSH injections before oocyte pick-up; no FSH was given in the non-FSH group. After CAPA-IVM, day-5 embryos were vitrified for transfer in a subsequent cycle. The primary endpoint was number of matured oocytes. Main results and the role of chance The number [interquartile range] of matured oocytes after CAPA-IVM did not differ significantly between the non-FSH and FSH groups (13 [9; 18] vs. 14 [7; 18]; absolute difference –1 [95% confidence interval –5, 4]). There were also no significant between-group differences in other oocyte and embryology outcomes, including the number of cumulus-oocyte complexes, number of fertilized oocytes, total number of blastocysts and good blastocysts, and total number of frozen embryos. No between-group differences were found in the rates of ongoing pregnancy and live birth, which were both 38.3% in the non-FSH group and both 31.7% in the FSH group; the miscarriage rate at &amp;lt; 12 weeks’ gestation was 5.0% in both groups. Maternal complications were infrequent and occurred at a similar rate in the non-FSH and FSH groups; there were no preterm deliveries before 32 weeks’ gestation. Limitations, reasons for caution The characteristics of the study population (relatively young, lean women with PCOS from Viet Nam) limit the external generalisability of the study findings, and the findings need to be replicated in other populations. Wider implications of the findings Hormone-free assisted reproductive technology (ART) for women with PCOS appears to be feasible when using CAPA-IVM, and does not result in any loss of clinical efficacy. Benefits of hormone-free ART would be a reduction in medical risk, lower cost, fewer monitoring requirements, and greater convenience and flexibility. Trial registration number NCT05600972

O-040 Pro -better late than never

Abstract In IVF, blastocysts developed on Day5-6 are typically selected for transfer, cryopreservation, or biopsy, while embryos that do not reach this developmental stage before 144 hours post-insemination (hpi) are often discarded. Recently, there has been an increased adoption of blastocyst culture aimed at enhancing embryo selection potential and supporting a single embryo transfer approach. Consequently, the clinical significance of Day7 blastocysts (embryos reaching this stage beyond 144 hpi) has become a prominent topic of discussion, particularly in the context of treating patients with poor prognosis. Numerous studies worldwide have reported lower competence for these embryos, as evidenced by poorer morphological quality, higher aneuploidy rates, and lower implantation rates following both untested and euploid transfer. Nonetheless, a notable proportion of these blastocysts are euploid and result in healthy live births. While their clinical utilization may entail lower efficiency per transfer, it ultimately increases the cumulative live birth rate per cycle. However, most studies have encountered challenges due to diverse definitions of Day7, varying clinical settings, culture strategies, incubators, and local regulations. Presently in IVF, leveraging time-lapse technology (TLT), artificial intelligence (AI), and preimplantation genetic testing for aneuploidies (PGT-A) could standardize and enhance Day7 blastocyst characterization and clinical assessment. Consequently, we designed a study exclusively in freeze-all PGT-A cycles with vitrified-warmed euploid single embryo transfer after continuous culture in time-lapse incubators, trophectoderm biopsy without zona pellucida drilling on day3, comprehensive chromosome testing, confirming embryo morphological assessments through an AI-powered software, and utilizing this tool also to automate developmental timing annotations. Our analysis confirmed that all blastocysts were biopsied only after reaching an expansion level suitable for the procedure (approximately 24,000 µm²) and consistent across all embryos clustered every 12 hours in 6 groups (&amp;lt;120, 120-132, 132-144, 144-156, 156-168, and &amp;gt;168 hpi). Day7 blastocysts accounted for approximately 15% of all blastocysts obtained over 8 years, derived from older oocytes, exhibiting poorer quality according to both Gardner’s score and AI score, slower development from early stages, and accumulating delays across various intermediate processes like blastocyst expansion from tEB to the time of biopsy. They were less euploid and resulted in a lower live birth rate per euploid transfer. However, only the latter association was significant when adjusted for confounders (e.g., blastocyst quality). Comparing only embryos biopsied before 144 hpi versus embryos biopsied after this threshold, neither the euploidy nor the live birth rate were significantly different, supporting the extension of embryo culture beyond Day6. Overall, we estimated that Day7 embryos contribute to a relative increase of 4.4%, 13.7%, and 5.2% in the number of patients who achieved a live birth, who were not pregnant after the transfer of faster embryos, and who have supernumerary transferable embryos after a live birth, respectively. The main limitations of our investigation were its retrospective nature and the fact that retrospective associations do not provide evidence of causation. There might be a bias towards poor prognosis patients being subject to the transfer of Day 7 embryos, for instance. Lastly, more data are required regarding the putative impact of extended embryo culture including post-natal outcomes (reassuring to date), as well as the cost-effectiveness of this clinical choice. Considering the increasing personalization and patient-centeredness of IVF, where permitted by local regulations, the decision to culture embryos to Day7 should be based on a careful evaluation of couples’ reproductive history and future prognosis, and should be subject to a patient-centered decision-making process. In the future, AI can be harnessed to support IVF practitioners by objectifying the assessment of poor-quality and slow-growing embryos with measurable information and reliable predictions, thereby mitigating the inherent subjectivity of embryologists’ decisions.

P-233 Embryo transfer timing and clinical pregnancy success: a retrospective study

Abstract Study question The aim of this study is to compare the clinical outcome of day5 versus day6 genetically normal blastocyst transfers. Summary answer 1000 oocytes were analyzed showing a highly significant difference in the number of normal embryos and clinical pregnancy rates in day5 versus day6 blastocysts What is known already studies have shown that day 5 embryos have a higher pregnancy rate compared to day 6 embryos, some studies had only euploid embryos transferred and others did not have any genetic testing done on embryos. No study had a sample size as large as 1760 and the number of embryos studied was a limiting factor in their results. Study design, size, duration The study is a retrospective cross-sectional chart review with multivariate analysis, data from January 2019 up to February 2023 were extracted. 1760 patients were recruited, 1000 in the day5 group and 760 in the day6 group. The data recorded for each patient included maternal age, body mass index (BMI), anti-Müllerian hormone (AMH) level, number, prenatal genetic diagnostic testing, frozen embryo transfer, sperm parameters, and pregnancy status. Participants/materials, setting, methods All embryos were genetically tested for aneuploidy before transfer, using next-generation sequencing technology to rule out 24-chromosome aneuploidies (1-22, X, Y). All patients who have single embryo transfer, frozen embryos and pre-implantation genetic diagnosis (PGD) were included in the study. Continuous variables were expressed as mean with standard deviation and categorical variables as numbers and frequencies (percentages). Statistical differences between groups were estimated using the chi-square or Fisher’s test. All analyses were performed using SAS studio. Main results and the role of chance 1,000 cycles were analyzed for Day 5 and 760 for Day 6 embryo. The number of blastocysts formed, and genetically diagnosed embryos significantly favor the Day 5 group. There’s a significant difference in the number of normal embryos, with the Day 5 group having more. There is a highly significant difference in clinical pregnancy rates. On the other hand, the differences in biochemical pregnancies are not statistically significant. The occurrence of ectopic pregnancies shows no significant difference. Additionally, there is no statistically significant difference in the rates of miscarriage. There is a highly significant difference in blastocyst formation rates, with Day 5 embryos. This indicates that Day 5 embryos have a significantly higher likelihood of forming blastocysts compared to Day 6 embryos. Implantation: Day 5 embryos have an implantation rate of 62.0% compared to 49.7% for Day 6 embryos. Day 5 embryos exhibit a significantly higher likelihood of successful implantation. Euploid: The difference in euploid rates is statistically significant, albeit with a lower p-value of 0.0236. Day 5 embryos have a rate of 59.6%, while Day 6 embryos have a rate of 56.0%. Day 5 embryos are associated with a lower likelihood of being aneuploid Limitations, reasons for caution Limitation of this study is that we do not have data available regarding complications during pregnancy in the day 5 versus day 6 groups and we had no data regarding the the live birth rate between the two groups. Wider implications of the findings This study has the potential to revolutionize worldwide discussions during IVF consultations. With the large sample size we can provide for the first time a statistically significant difference in the percentage of success when transferring a day5 (61%) versus day6 (49%) euploid embryo. Trial registration number not applicable

P-666 Comparison of IVF outcomes in women undergoing IVF stimulation using progestin primed ovarian stimulation (PPOS) Vs GnRH antagonist (GnRH-Antag) protocol

Abstract Study question Can PPOS achieve improved patient &amp; provider satisfaction while simultaneously blocking LH-surge, maintaining similar IVF outcomes like oocyte/embryo yield/clinical pregnancy rates(CPR) when compared to GnRH-Antag? Summary answer PPOS can achieve similar IVF outcomes as compared to GnRH-Antag protocol and is a patient friendly, cost-effective choice for ovarian stimulation without affecting oocyte/embryo yield/CPR. What is known already GnRH-Antag protocol is among the most widely used methods, as it blocks LH surge &amp; significantly lowers the risk of OHSS [Lambalk CB,2017]. However, this protocol has disadvantages like frequent monitoring, dose adjustment, high therapeutic cost and multiple injections[Ata B,2015]. PPOS successfully prevents ovulation and provides comparable IVFoutcomes (oocyte yield, blastocyst/euploid embryo rates, CPR) along with patient cost savings and increased convenience across all infertility diagnoses [Annalyn M.Welp, 2023]. It should be noted that most studies are non-randomized and comprise low to moderate-quality evidence. However, the consistency of the findings across different studies from different centres provides assurance in effect estimates. Study design, size, duration A retrospective cohort study conducted at a tertiary care fertility unit. Data for 449 women aged 21 to 40 years undergoing IVF stimulation using PPOS (n = 226) and GnRH-Antag (n = 223) protocol was retrieved from the hospital’s electronic database and analysed for a period between September 2022 to October 2023. Study population consisted of women undergoing freeze-all strategy either for lowering the risk of OHSS (hyper-responders) or for embryo pooling in view of very low ovarian reserve. Participants/materials, setting, methods For both groups either rFSH/rLH/HMG were used &amp; doses were indivisualised based on patient’s age, BMI &amp; ovarian reserve. PPOS group received twice daily dose of medroxyprogesterone acetate tablet(10 mg)/dydrogesterone(10 mg) from Day2 of cycle. GnRH-Antag group received Inj.Cetrorelix acetate (0.25 mg) daily as flexible protocol. Final oocyte maturation was induced with Triptorelin(0.2mg)/Choriogonadotropin alfa(250mcg)/both, once 2-3follicles reached 18-20mm. Transvaginal oocyte pick-up was performed 35-36h later. Women in PPOS group underwent freeze-all strategy followed by Frozen-Thawed Embryo-transfer. Main results and the role of chance Normally distributed continuous variables were compared using independent t-test, and categorical variables were compared by χ2 and Fisher’s exact test, where appropriate. Patient demographics, clinical/ovarian stimulation characteristics, embryological and IVF outcomes were compared for two groups. Patient demographics {Age(p-value:0.08), BMI(p-value:0.06), duration(p-value:0.09)/type(p-value:0.76) of infertlity}, total gonadotropin dose (p-value: 0.39) and duration of ovarian stimulation (p-value: 0.81) were comparable between the two groups. Though the mean LH level on trigger day was slightly higher in PPOS group (5.53 IU/L) than GnRH-Antag group (3.24 IU/L) (p-value: 0.02), statistically significant difference was not seen in the oocyte yield (p-value: 0.18), M-II oocytes (p-value: 0.17) &amp; fertilization rate (p-value: 0.23) in the two groups. The number of Day3 (p-value: 0.65), Day5 (p-value: 0.07) &amp; Day6 (p-value: 0.08) embryos available in the two groups were also comparable. IVF outcomes in terms of positive B-HCG result (p-value: 0.68), clinical pregnancy rate (p-value: 0.61) &amp; miscarriage rate (p-value: 0.27) showed no statistically significant difference in the two groups. Thus, we conclude that PPOS can achieve similar IVF outcomes as compared to the GnRH-Antag protocol, while at the same time proving to be patient friendly by reducing the need of multiple injection pricks, injection cost and the frequency of hospital visits. Limitations, reasons for caution This is a retrospective study and hence randomized comparison was not possible. PPOS can be used only when freeze-all strategy is planned, fresh embryo-transfer cannot be considered if need arises depending upon embryo quality. IVF service providers have to depend on patient compliance for using oral progestins to block LH-surge. Wider implications of the findings Study findings suggest that PPOS is a patient friendly and equally effective and safe IVF stimulation protocol when compared to GnRH-Antagonist. More RCT will be useful for investigating different aspects of PPOS (it’s utility for women with different ovarian reserve functions, conventional versus flexible approach, optimal dose of each progestin). Trial registration number Not applicable

P-117 Extracellular vesicles from fallopian tubal fluid benefit human embryo development in vitro

Abstract Study question Do extracellular vesicles (EVs) from Fallopian tubes benefit human embryo development, and how do they affect preimplantation embryo development? Summary answer The Fallopian tubal EVs can be internalized by human embryos, and they contain miR-21-5p that downregulated P53 in blastocysts. What is known already EVs in the Fallopian tubes are identified as key mediators in embryo-oviduct interactions that contribute to a successful pregnancy in vivo. We previously showed Fallopian tubal EVs can benefit mouse embryo development in vitro. However, if a similar phenomenon can be observed in human embryos and what is the key component in Fallopian tubal EVs remains elusive. Study design, size, duration The EVs were isolated from the luminal fluid of human Fallopian tubes (n = 23). Immature human oocytes were collected and in vitro matured and fertilized, and 2-pronuclei embryos were included in this study and randomly divided (n = 87). We cocultured these zygotes with Fallopian tubal EVs until the blastocyst stage. Further, two-cell mouse embryos were used to explore the expression levels of miRNAs in Fallopian tubal EVs. The effects of miR-21-5p on mouse embryos were analyzed. Participants/materials, setting, methods EVs were isolated using ultracentrifugation. The uptake of labeled EVs by human embryos was analyzed using confocal microscopy. The fragmentation of the day-3 embryos and the blastocyst rate were compared between the control and the EV-treatment group. Then the stage-specific expression of miRNAs was compared in mouse embryos that were either developed in vivo or cultured in vitro. miR-21-5p were supplemented to the culture medium and the p53-related apoptosis in embryos was evaluated. Main results and the role of chance EVs were measured less than 200 nm in diameter with a typical bi-layer membrane structure and expressed protein markers Heat shock protein 70 (HSP70) and CD9. Most of the fluorescence-labeled EVs were attached to the zona pellucida within 2 h of co-culture. However, human embryos internalized EV within 4 h, with fluorescence signals observed in embryonic cells. The fragmentation rate was decreased and the blastocyst rate was increased by EVs. miR-21-5p, which was highly enriched in EVs, was found to be expressed at a significantly lower level in in-vitro-cultured mouse embryos compared to the in-vivo-developed embryos, through the two-cell stage to the eight-cell stage. miR-21-5p agomir supplementation to the culture medium was found to increase the mouse blastocyst formation rate, decrease apoptosis, and downregulate the P53 expression level in mouse blastocysts. Limitations, reasons for caution Though we observed that Fallopian tubal EVs could be internalized by human embryos and improve embryo development morphologically, the subsequent mechanism exploration was conducted using mouse embryos. Whether the stage-specific expression level of miR-21-5p and the effects of miR-21-5p are the same in human embryos remains to be determined. Wider implications of the findings This study showed miRNAs in Fallopian tubal EVs can act as embryonic survival signals, which opens the insight into further explorations to demonstrate the molecular mechanisms during early embryo development, as well as holds the potential to optimize the culture medium used in ART in the future. Trial registration number 2022YFC2702503

P-609 Impact of low versus air oxygen tension on the oocyte maturation in PCOS women undergoing capacitation IVM: a sibling oocyte pilot study

Abstract Study question Does low or air oxygen tension improve the oocyte maturation rate in biphasic capacitation IVM (CAPA-IVM)? Summary answer Low oxygen tension resulted in a lower maturation rate and two-pronuclei fertilization rate compared with air oxygen tension in the CAPA-IVM culture. What is known already CAPA-IVM, with a pre-maturation step, improves the competence of oocytes matured in-vitro. The current CAPA-IVM culture condition is under air oxygen concentration. However, the impact of oxygen tension on in-vitro oocyte maturation needs to be better understood, and it remains uncertain whether the maturation process aligns with in-vivo conditions. Study design, size, duration A sibling oocyte pilot study of 416 cumulus-oocyte complexes (COCs) recruited from fifteen polycystic ovary syndrome (PCOS) women was performed at IVFMD, My Duc Phu Nhuan Hospital, Ho Chi Minh City, Vietnam from November 2023 to January 2024. The study was approved by the Institutional Ethics Committee (22/23/DD-BVMD, dated October 12th, 2023) and conducted according to Good Clinical Practice and Declaration of Helsinki 2002 principles. All participants provided written informed consent. Participants/materials, setting, methods Women (18–37 years) diagnosed with PCOS undergoing CAPA-IVM were recruited. At collection, COCs from each woman were divided into two groups based on the oxygen tension used in the two steps of CAPA-IVM culture, low oxygen tension (5% O2, 6% CO2 at 37 °C) and air oxygen tension (20% O2, 6% CO2 at 37 °C). Embryos were cultured to blastocyst stage. Primary outcome was the oocyte maturation rate. Secondary outcomes were embryology outcomes. Main results and the role of chance A total of 416 COCs from fifteen eligible women were assigned to the low oxygen (207 COCs) and air oxygen tension (209 COCs) groups. Mean age and body max index were 29.0±2.5 years and 22.6±2.6, respectively. The maturation rate was significantly lower in the low oxygen group compared to the air oxygen group (54.1% vs. 66.5%, p = 0.01, respectively). The two-pronuclei fertilization rate per COC was significantly decreased in the low oxygen group compared to the air oxygen group (35.7% vs. 49.3%, p = 0.005, respectively). Rates of day-3 embryos, blastocyst formation rate, and good quality blastocyst rate were also lower but not significant in the low oxygen tension group as compared to the air oxygen tension group. Limitations, reasons for caution The study’s limitations include a relatively small sample size and a single ethnicity group. There was a lack of data on clinical outcomes after transferring embryos from the study. Wider implications of the findings Oocyte maturation rate and two-pronuclei fertilization rate were significantly lower when oxygen tension was reduced in the process of CAPA-IVM culture. Therefore, air oxygen tension should be considered as a standard for oocyte culture in the pre-maturation step of CAPA-IVM. Trial registration number NCT06087354

O-274 An Artificial Intelligence (AI) based screening test can reliably predict embryo ploidy

Abstract Study question Can calibrated AI ploidy screening test results provide reliable, biologically-justified estimates of embryo euploidy? Summary answer The AI ploidy screening test, rooted in the embryo’s morphokinetic profile and clinical metadata, provides reliable probabilistic estimates of euploidy. What is known already Published ploidy algorithms typically provide a binary classification of embryo ploidy (aneuploidy/euploidy). Algorithmic outputs are thresholded; a value above/below the threshold indicates a euploid/aneuploid label, respectively, and the confidence in the label prediction is tested. Experience shows, however, that decision-makers have difficulty interpreting how well these algorithm predictions match the true prevalence of euploidy in their clinics, especially when taking into consideration patient age and embryo quality. An AI embryo ploidy screening tool that uses biologically-relevant inputs to provide reliable euploidy probabilities is needed. Study design, size, duration The AI tool was trained on 5,000 time-lapse video sequences, along with associated clinical parameters: biological age at time of retrieval, Day-5 embryo quality, and morphokinetic parameters ranging from time of pronuclear fading to time to blastulation. Probability calibration was applied and its performance was evaluated using a blind test dataset (N = 708 embryos; euploid=352; aneuploid=356) with known prevalences of euploidy, aneuploidy, and live-birth. Mean ± SD patient age: 35.9 ± 5.4 years. Participants/materials, setting, methods The AI ploidy screening tool used known embryo ploidy status as ground-truth labels; biological age and visual quality parameters were incorporated as continuous input features to maintain biological validity. Reliability curve analysis, which plots the observed frequencies of euploidy in the clinical input data (y-axis) against the predicted probability frequencies by the screening test (x-axis), was used to assess model confidence. Odds ratios (OR) confirmed significance between associations. Main results and the role of chance Logistic regression analysis shows that AI scores are robustly associated with euploidy probability (OR = 2.79 [95% CI = 2.04-3.81] at a threshold of 0.5 when comparing euploid likelihood for high-versus-low AI scores). For embryo cohorts in the blind test set containing ≥1 aneuploid and euploid embryos in the test dataset, (N = 57 cohorts), the highest AI ranked embryo was euploid in 64% of the cohorts. Embryos were divided into four predefined brackets according to their scores (1-32, 33-49, 50-66, 67-99) and euploidy rate per bracket was determined: 28%, 44%, 58%, 71%, respectively. There was a linear association between ascending AI scores and percentage of euploid embryos, with the highest level of model confidence achieved at the tail ends of the scalar; embryos with a score above 66 were 2.5X more likely to be euploid than an embryo with a score below 33. Limitations, reasons for caution This analysis used historical time-lapse sequences. Moving forward, we must evaluate prospective AI use for ploidy screening. Genetic status in utero/birth was not evaluated. Wider implications of the findings A novel AI approach for preimplantation embryo screening using clinical metadata and time-lapse videos can improve our ability to non-invasively predict euploid likelihood prior to confirmatory diagnostic preimplantation genetic testing. Trial registration number Not applicable

P-444 The battle between a machine learning model, a gynecologist and an embryologist to predict pregnancy outcomes after single day-5 embryo transfer

Abstract Study question Are algorithms more effective than clinicians/embryologists at predicting pregnancy outcomes in the context of Assisted Reproductive Technology (ART) following the transfer of a single blastocyst? Summary answer Evaluation of a pregnancy prediction algorithm, trained on local data and assessed by two ART professionals, yielded an accuracy comparable to a coin toss. What is known already Artificial Intelligence’s ability to synthesize multifaceted embryological and clinical data and process extensive datasets holds promise for elevating IVF success rates through data-driven, individualized treatments. Refining embryo selection through deep learning and computer vision, individualizing treatment protocols, predicting oocyte retrieval after Controlled Ovarian Hyperstimulation (COH) and ultimately predicting Live Birth (LB) following embryo transfer are one of the early promises of this technology. Study design, size, duration A retrospective analysis was conducted on 475 stimulation cycles that resulted in a single day-5 blastocyst transfer (fresh or frozen, classical IVF or ICSI) from January 2015 to January 2022 at the Poissy/Saint-Germain-En-Laye hospital, France. The study encompassed 32 clinical and biological parameters, ranging from general characteristics of patients to controlled ovarian hyperstimulation (COH) details and embryo grading. Exclusively, embryos fertilized with autologous oocytes and sperm were considered, excluding any donor-fertilized embryos. Participants/materials, setting, methods Preliminary testing with Machine Learning algorithms (XGboost, LightGBM, Random Forest (RF), Support Vector Machine (SVM), Multi-layer Perceptron (MLP)) were conducted before selecting XGboost model for this study. Data was split into a training (n = 331) and testing (n = 144) set. Pregnancy outcome predictions (binary) were compared between the model, a clinician, and an embryologist. Feature extraction was conducted, and both professionals were asked to give the top 5 most relevant parameters used to make the pregnancy predictions. Main results and the role of chance The study analyzed 475 stimulation cycles, including 362 frozen and 114 fresh transfers. Participants’ mean age was 33, with a Body Mass Index (BMI) of 24.9. The average Antral Follicle Count (AFC) was 16.8, and the mean starting gonadotropin dose was 225 UI, yielding 8.3 MII oocytes on average. 36 patients were active smokers. Preliminary AUC results showed XGboost leading (AUC = 0.57) compared to LightGBM (AUC = 0.56), Random Forest (AUC = 0.56), SVM (AUC = 0.49), and MLP (AUC = 0.47) in predicting pregnancy outcomes. After hyperparameter optimization via GridSearch, the XGboost model enhanced its AUC to 0.61, outperforming the embryologist (AUC = 0.58) and the gynecologist (AUC = 0.44). Top predictive features identified after feature extraction included endometrial thickness at or before ovulation trigger, AMH levels at patient admission, AFC, BMI, and age. The gynecologist primarily prioritized age, BMI, embryo grading (TE and ICM), and the number of mature oocytes retrieved. The embryologist, valued embryo grading (TE and ICM) foremost, followed by age, smoking status, BMI, and COH duration. Limitations, reasons for caution The study’s limited dataset due to dynamic practices and difficulty maintaining curated data over the years, necessitates caution. The selected 32 parameters from 762 available reflect typical incomplete datasets in such settings, highlighting the importance of careful interpretation and potential need for broader data integration to enhance representativeness and reliability. Wider implications of the findings The findings advocate for developing ART-specific AI, integrating multimodal data and novel parameters, to enhance live birth predictions. This approach underscores the complex synergy between algorithmic precision and clinical expertise in ART, highlighting the stochastic nature of pregnancy prediction and the potential of tailored, data-driven strategies to improve outcomes. Trial registration number not applicable

P-131 Let’s not forget the day-6 blastocysts: what is the clinical pregnancy prediction of day-6 blastocysts from a commercial software for day-5 embryo selection?

Abstract Study question How is the performance of KIDScoreTM D5 version 3 for clinical pregnancy prediction in day 6 blastocysts? Summary answer Differing on Day 5 performance, KIDScoreTM D5 algorithm does not predict clinical pregnancy for day 6 blastocysts according to score subgroup grades. What is known already Embryo selection is a crucial step for a successful outcome in assisted reproductive technologies (ART). In the past years, the use of software and algorithms developed with artificial intelligence (A.I.) tools brought new parameters to be considered by the embryologists in embryo decision at the ART lab. KIDScoreTM is a commercial software (Vitrolife®, Sweden) developed and validated with a large database of known clinical outcome embryos transferred on day 3 or day 5 of development. Yet, it is unknown the performance of KIDScore D5 v3 on day 6 blastocysts, which are widely used for embryo transfer. Study design, size, duration Large retrospective cohort study including sequential single embryo transfers with blastocysts submitted or not to trophoectoderm biopsy for PGT-A, cultured in the Embryoscope® Plus incubator (Vitrolife®) in a single private IVF center between Jan/2020 and Jul/2023. Positive or negative clinical pregnancy, CP (presence/absence fetal heartbeat and gestational sac) from 738 patients/771 blastocysts developed on day 5 or day 6 were considered. Biochemical pregnancy and miscarriage were excluded from this analysis. Participants/materials, setting, methods Day 5 and day 6 embryo transfer outcomes data were compared considering three KIDScoreTM subgroups, according to the following score intervals: subgroup 1: 1.0-3.9 (n = 102), subgroup 2: 4.0-6.9 (n = 273) and subgroup 3: 7.0-9.9 (n = 396 blastocysts). Euploid (n = 517) and non-biopsied embryos (n = 254) were also analyzed in the described subgroups. For the analysis, Mann-Whitney, Chi-square and Fisher tests were used properly for statistical analysis, values of p &amp;lt; 0.05 were considered significant. Main results and the role of chance Maternal age were similar between positive and negative pregnancies in D5 and D6 transfers (D5:39,32±4,34 vs 39,02±4,47 and D6:38,75±3,99 vs 38,18±3,76, p = 0,35 and 0,28 respectively). In D5 transfers, CP rates significantly increased in higher score subgroups [subgroup 1:42.9% (6/14); subgroup 2:48.9% (86/176); subgroup 3:61.6% (236/383),p=0.01]. As expected, subgroup 3 showed a higher CP rate when compared to subgroup 1 + 2 (scores from 1.0 to 6.9,p=0,003). However, in D6 transfers, CP rates were similar between score subgroups 2 and 3 and lower in group 1 [subgroup 1:28.4% (25/88); subgroup 2:50.5% (49/87); subgroup 3:53.8% (7/13),p=0.005 and p = 0,001 between subgroup 1 and subgroups 2 + 3]. Similar results were seen in euploid and non-biopsied embryo transfers; in D5, CP rates were increased in higher scores subgroup (7.0-9.9) when compared to subgroups 1 + 2 (euploid:61,6% vs 42,9% p = 0,05, and non-biopsied:61,3% vs 42,6%,p=0,01 for positive and negative CP respectively in subgroup 3 vs subgroup 1 + 2). And in D6 embryo transfers CP rates were lower in subgroup 1 (1.0-3.9) and similar in subgroups 2 and 3 for both euploid and non-biopsied embryos (euploid:31,5% vs 49,4% p = 0,02, and non-biopsied:13,6% vs 56,5%,p=0,007 for positive and negative CP respectively in subgroup 1 vs subgroup 2 + 3, respectively). Limitations, reasons for caution The KIDScoreTM D5 v3 algorithm is validated for blastocyst on day 5 of development; the results showed here recognizes the limitations of evaluate the potential of CP prediction on Day 6 blastocysts and the score were not considered for embryo selection decision during the time of study. Wider implications of the findings The KIDScoreTM is effective to predict the potential of clinical pregnancy in blastocysts on day 5 of development, with higher rates on higher score subgroups, but not for blastocysts on day 6 of development, where the embryos had similar rates with score greater than 4.0. Trial registration number Not applicable.