Preimplantation Genetic Testing Cycles Research Articles

Prediction of embryo euploidy and pregnancy outcome by blastocyst morphology and development speed for women receiving single embryo transfer

Background Selection of high-quality blastocysts is the most important factor determining the success of assisted reproductive technology. The objective of this study is to assess the values of blastocyst morphological quality and development speed for predicting euploidy and clinical pregnancy outcome. Methods A total of 155 preimplantation genetic testing cycles including 959 blastocysts and 154 euploid blastocyst transfer cycles conducted between January 2018 and December 2019 were retrospectively analysed. The associations of blastocyst morphological quality and development speed (D) with chromosomal status, clinical pregnancy rate, early miscarriage rate, and ongoing pregnancy rate were evaluated by univariate and multivariate regression. Results The euploidy rate of development speed D5 blastocysts was significantly greater than that of D6 blastocysts (61.4% vs. 38.1%, P < 0.001), and the euploid rate of morphologically high-grade blastocysts was significantly greater than that of non-high-grade blastocysts. Development speed D5 (OR = 1.6, 95% CI 1.2–2.2, P = 0.02) and high-grade morphology (OR = 2.1, 95% CI 1.5–2.9, P = 0.01) were independent predictors of euploidy. The ongoing pregnancy rate of D5 blastocysts was significantly higher than that of D6 blastocysts (62.3% vs. 43.8%, P = 0.04). Transfer of euploid blastocysts with high-grade morphology resulted in a greater ongoing pregnancy rate than transfer of non-high-grade euploid blastocysts (60.7% vs. 43.2%, P = 0.049). Alternatively, D6 development speed was an independent risk factor for early pregnancy loss after euploid blastocyst transfer. Multivariate regression analysis adjusting for confounding factors identified maternal age, blastocyst development speed, and blastocyst morphological grade as independent predictors of euploidy but not of clinical pregnancy. Conclusion The recommended sequence of embryo transfer based on the present study is D5 high-grade > D6 high-grade > D5 non-high-grade > D6 non-high-grade.

Demographic distributions and clinical results of assisted reproduction techniques in Turkey in 2019: a descriptive survey.

The aim of this study was to describe characteristics and outcomes of assisted reproductive technology (ART) cycles performed in 2019 in Turkey. One-hundred and sixty-five ART centers in Turkey were invited to submit data. The survey was sent to center directors via e-mail with anonymous links by Qualtrics™. The survey involved questions about their patient characteristics, clinical practices, and outcomes. Forty-one (24.8%) centers responded to e-mails, and data gathered from 25 centers was included in the analyses. In 25 centers, 18,127 fresh or frozen transfers were carried out during the study period, of which 7796 (43.0%) were fresh and the rest were either frozen (45.2%) or embryo transfers (ET) with preimplantation genetic testing (PGT) (11.8%). The live birth rate per ET was as 30.6%, 40.1%, and 50.7% in fresh, frozen and PGT cycles, respectively. A single embryo was transferred in 65.3% of all transfers and singleton live births comprised 86.1% of all deliveries. For cycles with intrauterine insemination, 1407 were started in 2019, and 195 clinical pregnancies, 150 live births with 19 multiple pregnancies occurred. A total of 1513 ART cycles were initiated for foreign patients. Russia (29.6%), Germany (7.4%), Iraq (4.6%), Uzbekistan (3.1%), and Syria (1.4%) were the top five countries with most patients coming to Turkey for ART. The survey results are in parallel with the reports of international institutions and organizations. With repeated editions, the data collected with annual surveys can be used to inform ART practices in the coming years.

Does recurrent implantation failure exist? Prevalence and outcomes of five consecutive euploid blastocyst transfers in 123987 patients.

What are the clinical pregnancy and live birth rates in women who underwent up to two more euploid blastocyst transfers after three failures in the absence of another known factor that affects implantation? The fourth and fifth euploid blastocyst transfers resulted in similar live birth rates of 40% and 53.3%, respectively, culminating in a cumulative live birth rate of 98.1% (95% CI = 96.5-99.6%) after five euploid blastocyst transfers. The first three euploid blastocysts have similar implantation and live birth rates and provide a cumulative live birth rate of 92.6%. An international multi-center retrospective study was conducted at 25 individual clinics. The study period spanned between January 2012 and December 2022. A total of 123987 patients with a total of 64572 euploid blastocyst transfers were screened for inclusion. Patients with a history of any embryo transfer at another clinic, history of any unscreened embryo transfer at participating clinics, parental karyotype abnormalities, the use of donor oocytes or a gestational carrier, untreated intracavitary uterine pathology (e.g. polyp, leiomyoma), congenital uterine anomalies, adenomyosis, communicating hydrosalpinx, endometrial thickness <6 mm prior to initiating of progesterone, use of testicular sperm due to non-obstructive azoospermia in the male partner, transfer of an embryo with a reported intermediate chromosome copy number (i.e. mosaic), preimplantation genetic testing cycles for monogenic disorders, or structural chromosome rearrangements were excluded. Ovarian stimulation protocols and embryology laboratory procedures including trophectoderm biopsy followed the usual practice of each center. The ploidy status of blastocysts was determined with comprehensive chromosome screening. Endometrial preparation protocols followed the usual practice of participating centers and included programmed cycles, natural or modified natural cycles. A total of 105 (0.085% of the total population) patients met the criteria and underwent at least one additional euploid blastocyst transfer after failing to achieve a positive pregnancy test with three consecutive euploid blastocyst transfers. Outcomes of the fourth and fifth euploid blastocyst transfers were similar across participating centers. Overall, the live birth rate was similar with the fourth and fifth euploid blastocysts (40% vs 53.3%, relative risk = 1.33, 95% CI = 0.93-1.9, P value = 0.14). Sensitivity analyses excluding blastocysts biopsied on Day 7 postfertilization, women with a BMI >30 kg/m2, cycles using non-ejaculate or donor sperm, double-embryo transfer cycles, and cycles in which the day of embryo transfer was modified due to endometrial receptivity assay test result yielded similar results. Where data were available, the fourth euploid blastocyst had similar live birth rate with the first one (relative risk = 0.84, 95% CI = 0.58-1.21, P = 0.29). The cumulative live birth rate after five euploid blastocyst transfers was 98.1% (95% CI = 96.5-99.6%). Retrospective design has its own inherent limitations. Patients continuing with a further euploid embryo transfer and patients dropping out from treatment after three failed euploid transfers can be systematically different, perhaps with regard to ovarian reserve or economic status. Implantation failure seems to be mainly due to embryonic factors. Given the stable and high live birth rates up to five euploid blastocysts, unexplained recurrent implantation failure should have a prevalence of <2%. Proceeding with another embryo transfer can be the best next step once a known etiology for implantation failure is ruled out. None. N/A.

Total duration of spontaneous blastocyst collapse during the expansion stage is an independent predictor of euploidy and live birth rates

Research question: Is the total duration of blastocyst spontaneous collapse to re-expansion before biopsy related to ploidy and live birth after single euploid blastocyst transfers?Design: This study conducted a retrospective cohort study of 600 preimplantation genetic testing cycles for aneuploidy (PGT-A) cycles, involving 2203 biopsied blastocysts, at a large reproductive medicine center. Features of blastocyst spontaneous collapse from full to expanded stage, before biopsy, were observed using an embryoscope viewer for embryos cultured in a time-lapse incubator. A total of 568 cycles of frozen blastocyst transfers, either single euploid or mosaic, were performed. Correlations between collapse features and PGT-A outcomes were evaluated, as well as live birth following euploid embryo transfers.Results: Blastocysts with lower morphological quality or delayed development had significantly higher rates of collapse, multiple collapses, and a longer duration of collapse and re-expansion. After controlling for confounders, such as oocyte age, morphological quality, and day of the biopsy, multivariate logistic regression revealed that the total duration of collapses to re-expansion was an independent predictor of lower euploidy rate; the multivariate OR was 0.85 (95% CI: 0.77–0.95, P=0.00). Furthermore, even with euploid embryo transfer, the probability of a live birth decreased as the total duration of collapse to re-expansion increased; the multivariate OR was 0.79 (95% CI: 0.64–0.98, P=0.033).Conclusion: Total duration of blastocyst collapse to re-expansion could be used as a predictor of lower euploidy and the live birth rate. When developing blastocyst algorithms for pregnancy prediction, the duration of blastocyst spontaneous collapse should be included as a significant variable.

Should non-invasive prenatal testing be recommended for patients who achieve pregnancy with PGT?

ObjectiveTo determine whether non-invasive prenatal testing is an alternative testing option to preimplantation genetic testing (PGT) in pregnant patients.MethodsThis was a retrospective study of the clinical outcomes of patients who underwent PGT and invasive or non-invasive pregnancy testing after euploid blastocyst transfer at our IVF centre between January 2017 and December 2022.ResultsIn total, 321 patients were enrolled in this study, 138 (43.0%) received invasive pregnancy testing, and 183 (57.0%) patients underwent non-invasive testing. The mean age of the patients in Group 2 was higher than that of the patients in Group 1 (35.64 ± 4.74 vs. 31.04 ± 4.15 years, P < 0.001). The basal LH and AMH levels were higher in Group 1 than in Group 2 (4.30 ± 2.68 vs. 3.40 ± 1.88, P = 0.003; 5.55 ± 11.22 vs. 4.09 ± 3.55, P = 0.012), but the clinical outcomes were not significantly different. Furthermore, the clinical outcomes of patients undergoing invasive testing were similar to those of patients undergoing non-invasive testing with the same PGT indication.ConclusionOur results suggest that non-invasive pregnancy testing is a suitable alternative option for detecting the foetal chromosomal status in a PGT cycle. However, the usefulness of non-invasive testing in PGT-M patients is still limited.

Preimplantation genetic testing in couples with balanced chromosome rearrangement: a four-year period real world retrospective cohort study

BackgroundCouples with balanced chromosome rearrangement (BCR) are at high risk of recurrent miscarriages or birth defects due to chromosomally abnormal embryos. This study aimed to provide real-world evidence of the euploidy rate of blastocysts from couples with BCR using preimplantation genetic testing (PGT) and to guide pretesting genetic counselling.MethodsA continuous four-year PGT data from couples with BCR were retrospectively analyzed. Biopsied trophectoderm cells were amplified using whole genome amplification, and next-generation sequencing was performed to detect the chromosomal numerical and segmental aberrations. Clinical data and molecular genetic testing results were analyzed and compared among the subgroups.ResultsA total of 1571 PGT cycles with 5942 blastocysts were performed chromosomal numerical and segmental aberrations detection during the four years. Of them, 1034 PGT cycles with 4129 blastocysts for BCR couples were included; 68.96% (713/1034) PGT cycles had transferable euploid embryos. The total euploidy rate of blastocysts in couples carrying the BCR was 35.29% (1457/4129). Couples with complex BCR had euploid blastocyst rates similar to those of couples with non-complex BCR (46.15% vs. 35.18%, P > 0.05). Chromosome inversion had the highest chance of obtaining a euploid blastocyst (57.27%), followed by Robertsonian translocation (RobT) (46.06%), and the lowest in reciprocal translocation (RecT) (30.11%) (P < 0.05). Couples with males carrying RobT had higher rates of euploid embryo both in each PGT cycles and total blastocysts than female RobT carriers did, despite the female age in male RobT is significant older than those with female RobT (P < 0.05). The proportions of non-carrier embryos were 52.78% (95/180) and 47.06% (40/85) in euploid blastocysts from couples with RecT and RobT, respectively (P > 0.05). RecT had the highest proportion of blastocysts with translocated chromosome-associated abnormalities (74.23%, 1527/2057), followed by RobT (54.60%, 273/500) and inversion (30.85%, 29/94) (P < 0.05).ConclusionsIn couples carrying BCR, the total euploidy rate of blastocysts was 35.29%, with the highest in inversion, followed by RobT and RecT. Even in couples carrying complex BCR, the probability of having a transferable blastocyst was 46.15%. Among the euploid blastocysts, the non-carrier ratios in RecT and RobT were 52.78% and 47.06%, respectively. RecT had the highest proportion of blastocysts with translocated chromosome-associated abnormalities.

A clinical predictive model for live birth in women of advanced age undergoing PGT cycles.

The trend of delaying childbirth has resulted in a growing number of advanced-aged women who are opting for preimplantation genetic testing (PGT) to screen for monogenic diseases or structural chromosomal rearrangements (PGT-M and PGT-SR). This increase in demand necessitates the development of a clinical predictive model for live birth outcomes in these women. Therefore, the objective of this study is to construct a comprehensive predictive model that assesses the likelihood of achieving a successful live birth in advanced-aged women undergoing PGT-M and PGT-SR treatments. A retrospective cohort study of 37-45-year-old women undergoing preimplantation genetic testing for monogenic disease or structural chromosomal rearrangement cycles from 2010 to 2021 was conducted at a university hospital reproductive centre. The purpose was to develop a clinical predictive model for live birth in these women. The main outcome studied was the cumulative live birth rate in the first or subsequent cycles. Developing a decision tree enabled a comprehensive study of clinical parameters and expected outcomes. The analysis included 158 women undergoing 753 preimplantation genetic testing cycles. The cumulative live birth rate was 37.342% (59/158). Decision tree analysis revealed that women aged ≤ 40.1 or women > 40.1 with one or more top-quality transferable embryos in their first cycle had the best chance for a live baby (56% and 41%, respectively). Those older than 40.1 without top-quality embryos and seven or fewer dominant follicles had no live births. A Kaplan-Meier curve showed that for autosomal dominant diseases, there was a negligible increase in live birth rate after three cycles, compared to six cycles in autosomal recessive inheritance. In older women, the chance of delivering after repeated cycles is higher in those with at least one top-quality unaffected embryo in their first preimplantation genetic testing cycle. Additional preimplantation genetic testing cycles after three in carriers of an autosomal dominant disorder and six in those with an autosomal recessive disorder should be considered prudently.

The morphokinetic signature of human blastocysts with mosaicism and the clinical outcomes following transfer of embryos with low-level mosaicism

BackgroundGenetic mosaicism is commonly observed in human blastocysts. Embryos’ morphokinetic feature observed from time-lapse monitoring (TLM) is helpful to predict the embryos’ ploidy status in a non-invasive way. However, morphokinetic research on mosaic embryos is extremely limited. Moreover, transfer of mosaic embryos is a new attempt in reproductive medicine, while studies regarding the clinical and neonatal outcomes following transfer of embryos with different levels and types of mosaicism are needed. This study aimed to investigate the morphokinetic characteristics of mosaic blastocysts, uncover clinical outcomes of mosaic embryos, and evaluate the effect of level and type of mosaicism on transfer outcomes.ResultsA total of 923 blastocysts from 229 preimplantation genetic testing cycles were cultured in TLM incubators in a single fertilization center between July 2016 and July 2021. Multivariate logistic regression models showed mosaic embryos had significantly shorter time to reach morula when compared with euploid (P = 0.002), mosaic with aneuploid (P = 0.005), and aneuploid (P = 0.005) embryos after adjusting the potential confounders. KIDScore is an artificial intelligence scoring program from time lapse incubation system to predict embryo implantation potential. Mosaic with aneuploid embryos had significantly lower KIDScore than euploid (P = 6.47e−4), mosaic (P = 0.005), and aneuploid (P = 0.004) embryos after adjustment. Meanwhile, we compared the clinical outcomes following transfer of low-level (< 50%) mosaic embryos (N = 60) with euploid embryos (N = 1301) matched using propensity scoring collected from September 2020 to January 2023. Mosaic embryos had significantly lower clinical pregnancy rate (41.67% vs. 57.65%, P = 0.015) and live birth rate (38.33% vs. 51.35%, P = 0.048) than the euploid embryos. Subgroup analyses showed the whole, segmental, and complex chromosome mosaic embryos had the similar clinical outcomes.ConclusionsThe shortened time to reach morula in mosaic embryos and the low KIDScore in mosaic with aneuploid embryos revealed innovative clues to embryo selection with the non-invasive TLM and provided new insights into biological mechanism of chromosomal abnormality. The analyses of overall and subgroups of mosaic embryo transfer outcomes helped to optimize embryo transfer scheme for in-vitro fertilization procedures. Multi-center prospective studies with large sample sizes are warranted to validate our results in the future.

Preimplantation Genetic Testing within the Public Healthcare System in Slovenia.

Preimplantation genetic testing (PGT) is the earliest form of prenatal diagnosis that has become an established procedure for couples at risk of passing a severe genetic disease to their offspring. At UMC Ljubljana, we conducted a retrospective register-based study to present 15 years of PGT service within the public healthcare system in Slovenia. We collected the data of the PGT cycles from 2004 to 2019 and compared clinical outcomes for chromosomal and monogenic diseases using different embryo biopsy and testing approaches. In addition, we assessed the extent to which PGT has become the preferred option compared to classic prenatal diagnostics. We treated 211 couples, 110 with single gene disorder, 88 with structural chromosome rearrangement and 13 for numerical chromosome aberration. There were 375 PGT cycles with oocyte retrieval, while embryo transfer was possible in 263 cases resulting in 78 deliveries and 84 children. Altogether, the clinical pregnancy rate per embryo transfer was 31% in 2004-2016 (blastomere biopsy) and 43% in 2017-19 (blastocyst biopsy), respectively. We assessed that approximately a third of couples would opt for PGT, while the rest preferred natural conception with prenatal diagnosis. Our results show that providing a PGT service within the public healthcare system has become a considerable option in pregnancy planning for couples at risk of transmitting a severe genetic disease to their offspring. In Slovenia, approximately a third of couples would opt for PGT. Although the number of cycles is small, our clinical results are comparable to larger centres.

No major differences in perinatal and maternal outcomes between uninterrupted embryo culture in time-lapse system and conventional embryo culture.

Is embryo culture in a closed time-lapse system associated with any differences in perinatal and maternal outcomes in comparison to conventional culture and spontaneous conception? There were no significant differences between time-lapse and conventional embryo culture in preterm birth (PTB, <37 weeks), low birth weight (LBW, >2500 g) and hypertensive disorders of pregnancy for singleton deliveries, the primary outcomes of this study. Evidence from prospective trials evaluating the safety of time-lapse incubation for clinical use show similar embryo development rates, implantation rates, and ongoing pregnancy and live birth rates when compared to conventional incubation. Few studies have investigated if uninterrupted culture can alter risks of adverse perinatal outcomes presently associated with IVF when compared to conventional culture and spontaneous conceptions. This study is a Swedish population-based retrospective registry study, including 7379 singleton deliveries after fresh embryo transfer between 2013 and 2018 from selected IVF clinics. Perinatal outcomes of singletons born from time-lapse-cultured embryos were compared to singletons from embryos cultured in conventional incubators and 71 300 singletons from spontaneous conceptions. Main perinatal outcomes included PTB and LBW. Main maternal outcomes included hypertensive disorders of pregnancy (pregnancy hypertension and preeclampsia). From nine IVF clinics, 2683 singletons born after fresh embryo transfer in a time-lapse system were compared to 4696 singletons born after culture in a conventional incubator and 71 300 singletons born after spontaneous conception matched for year of birth, parity, and maternal age. Patient and treatment characteristics from IVF deliveries were cross-linked with the Swedish Medical Birth Register, Register of Birth Defects, National Patient Register and Statistics Sweden. Children born after sperm and oocyte donation cycles and after Preimplantation Genetic testing cycles were excluded. Odds ratio (OR) and adjusted OR were calculated, adjusting for relevant confounders. In the adjusted analyses, no significant differences were found for risk of PTB (adjusted OR 1.11, 95% CI 0.87-1.41) and LBW (adjusted OR 0.86, 95% CI 0.66-1.14) or hypertensive disorders of pregnancy; preeclampsia and hypertension (adjusted OR 0.99, 95% CI 0.67-1.45 and adjusted OR 0.98, 95% CI 0.62-1.53, respectively) between time-lapse and conventional incubation systems. A significantly increased risk of PTB (adjusted OR 1.31, 95% CI 1.08-1.60) and LBW (adjusted OR 1.36, 95% CI 1.08-1.72) was found for singletons born after time-lapse incubation compared to singletons born after spontaneous conceptions. In addition, a lower risk for pregnancy hypertension (adjusted OR 0.72 95% CI 0.53-0.99) but no significant difference for preeclampsia (adjusted OR 0.87, 95% CI 0.68-1.12) was found compared to spontaneous conceptions. Subgroup analyses showed that some risks were related to the day of embryo transfer, with more adverse outcomes after blastocyst transfer in comparison to cleavage stage transfer. This study is retrospective in design and different clinical strategies may have been used to select specific patient groups for time-lapse versus conventional incubation. The number of patients is limited and larger datasets are required to obtain more precise estimates and adjust for possible effect of additional embryo culture variables. Embryo culture in time-lapse systems is not associated with major differences in perinatal and maternal outcomes, compared to conventional embryo culture, suggesting that this technology is an acceptable alternative for embryo incubation. The study was financed by a research grant from Gedeon Richter. There are no conflicts of interest for all authors to declare. N/A.

Steps forward in embryo transfer technique: a retrospective study comparing direct versus afterload catheters at different time frames.

To assess whether embryo transfer (ET) technique can influence the clinical pregnancy rate (CPR) and its correlation with the embryo transfer difficulty. This single center retrospective cohort analysis of fresh and frozen single blastocyst transfers performed between January 2016 and December 2021 included fresh and frozen single blastocyst transfers performed during the study timeframe. Direct technique was the only one used from January 2016 to September 2017. From September 2017 to March 2019, the choice between the two techniques was given by randomization, due to a clinical trial recruitment. From April 2019, only the afterload technique was used. Preimplantation genetic testing cycles and gamete donation procedures and cycles performed with external gametes or embryos were excluded. CPR was the primary outcome, while difficult transfer rate the secondary one. Univariate and multivariate logistic regressions were performed. During the period, 8,189 transfers were performed. CPR of the afterload group resulted significantly higher compared to the direct group (44.69% versus 41.65%, OR 1.13, 95% CI 1.02-1.25, p = 0.017) and the rate of difficult transfers two-thirds lower (9.06% versus 26.85%, OR 0.27, 95% CI 0.24-0.31, p < 0.001). Our study demonstrated that CPR is significantly affected by the ET technique. In particular, with the afterload protocol, both CPR and easy transfer rates increased. http://clinicaltrials.gov registration number: NCT05364528, retrospectively registered on 3rd of May 2022.

Usable blastocysts developed from in-vitro-matured metaphase I oocytes in preimplantation genetic testing cycles

Research questionAre blastocysts derived from in-vitro-matured metaphase I (MI) oocytes less likely to produce usable embryos for transfer compared with those derived from in-vivo-matured oocytes in cycles undergoing preimplantation genetic testing (PGT)? DesignThe primary outcome was usable blastocyst rate, which was compared between blastocysts derived from in-vitro-matured MI oocytes after ovarian stimulation and from in-vivo-matured oocytes. Logistic regression analysis using generalized estimating equations was used to control for confounders in the analysis of factors that may influence the chance of a blastocyst being usable and in the comparison of embryological outcomes. Student's t-test, Mann–Whitney U test, chi-squared tests or Fisher's exact tests were used to compare clinical and pregnancy outcomes. ResultsA total of 1810 injected metaphase II (MII) oocytes from 154 PGT cycles involving 154 couples were included in this study. A total of 1577 MII oocytes were in-vivo-matured and 233 were in-vitro-matured MI oocytes. The usable blastocyst rate was similar between the in-vitro-matured MI oocyte group and the in-vivo-matured oocyte group (adjusted RR 0.97, 95% CI 0.40 to 2.34). Three live births were achieved using usable blastocysts derived from in-vitro-matured MI oocytes. ConclusionsIf in-vitro-matured MI oocytes can be fertilized and develop into blastocysts, their ability to provide usable embryos for transfer is similar compared with those developed from in-vivo-matured oocytes. These blastocysts could be considered valuable for women with few viable embryos in assisted reproductive technology cycles.

Double vitrification and warming does not compromise the chance of live birth after single unbiopsied blastocyst transfer.

Does double vitrification and thawing of an embryo compromise the chance of live birth after a single blastocyst transfer? The live birth rate (LBR) obtained after double vitrification was comparable to that obtained after single vitrification. Double vitrification-warming (DVW) is commonly practiced to accommodate surplus viable embryos suitable for transfer, to allow retesting of inconclusively diagnosed blastocysts in preimplantation genetic testing (PGT), and to circumvent limitations associated with national policies on embryo culture in certain countries. Despite its popularity, the evidence concerning the impact of DVW practice on ART outcomes is limited and lacking credibility. This is the first thorough investigation of clinical pregnancy and LBR following DVW in the case where the first round of vitrification occurred at the zygote stage and the second round occurred at the blastocyst stage in the absence of biopsy. This is a retrospective observational analysis of n = 407 single blastocyst transfers whereby embryos created by IVF/ICSI were vitrified-warmed once (single vitrification-warming (SVW) n = 310) or twice (DVW, n = 97) between January 2017 and December 2021. In the SVW group, blastocysts were vitrified on Day 5/6 and warmed on the day of embryo transfer (ET). In the DVW group, two pronuclear (2PN) zygotes were first vitrified-warmed and then re-vitrified on Day 5/6 and warmed on the day of ET. Exclusion criteria were ETs from PGT and vitrified-warmed oocyte cycles. All of the ETs were single blastocyst transfers performed at the University Hospital Zurich in Switzerland following natural or artificial endometrial preparation. The biochemical pregnancy rate, clinical pregnancy rate (CPR), and LBR were all comparable between the DVW and SVW groups. The CPR for DVW was 44.3% and for SVW it was 42.3% (P = 0.719). The LBR for DVW was 30.9% and for SVW it was 28.7% (P = 0.675). The miscarriage rate was additionally similar between the groups: 27.9% for DVW and 32.1% for SVW groups (P = 0.765). The study is limited by its retrospective nature. Caution should be taken concerning interpretation of these findings in cases where DVW occurs at different stages of embryo development. The result of the present study on DVW procedure provides a framework for counselling couples on their chance of clinical pregnancy per warming cycle. It additionally provides confidence and reassurance to laboratory professionals in certain countries where national policies limit embryo culture strategies making DVW inevitable. This work was supported by the University Research Priority Program 'Human Reproduction Reloaded' of the University of Zurich. The authors have no conflict of interest related to this study to declare. N/A.

Sex ratio of offspring is not statistically altered following pre-implantation genetic testing under a specific sex selection policy.

To determine whether the use of pre-implantation genetic testing (PGT) under a specific sex selection policy is associated with alterations in offspring sex ratio. This was a single-center retrospective cohort study of singleton live births from January 2018-December 2020 achieved via single blastocyst non-PGT or PGT frozen embryo transfer (FET). Per institutional policy, sex may be disclosed following PGT. If both sexes are available and morphologic grade is similar, patients may select the sex of the embryo to be transferred. Demographics and cycle characteristics were compared between non-PGT vs. PGT cycles with Mann-Whitney U or χ2. Poisson regression with robust variance estimates was used to model the probability of female vs. male offspring among non-PGT vs. PGT cycles, reported as risk ratio (RR) and 95% confidence interval (CI). Among 541 live births, 350 (64.7%) were achieved with PGT and 191 (35.3%) without PGT. In both groups, female sex was more common, representing 59.4% of PGT-offspring and 55.0% of non-PGT offspring. After adjusting for potential confounders, the use of PGT was not significantly associated with an increased likelihood of female offspring (RR 1.04, 95% CI 0.98-1.11, p = 0.22). Singletons born following FET had a higher rate of female sex than male. Allowing sex selection per institutional policy did not increase this ratio. These results contrast with those of prior publications and should motivate individual centers to monitor their own sex ratios. As utilization of PGT increases, local, regional, and national monitoring will become increasingly important.

Progestin Primed Ovarian Stimulation (PPOS) protocol yields lower euploidy rate in older patients undergoing IVF

BackgroundTo explore if exogenous progestin required for progestin primed ovarian stimulation (PPOS) protocol compromises the euploidy rate of patients who underwent preimplantation genetic testing cycles when compared to those who received the conventional gonadotropin-releasing hormone (GnRH) antagonist protocol.MethodsThis retrospective cohort study analyzed 128 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed from January 2018 to December 2021 in a single university hospital-affiliated fertility center. Infertile women aged 27 to 45 years old requiring PGT-A underwent either PPOS protocol or GnRH-antagonist protocol with in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) for fertilization. Frozen embryo transfers were performed following each PGT-A cycle. Data regarding the two groups were analyzed using the Statistical Package for Social Sciences (SPSS) version 22.0 (SPSS Inc., Chicago, IL).ResultsPatients who underwent PPOS treatment had significantly reduced blastocyst formation rate and euploidy rate compared to those who received the GnRH antagonist protocol. Subgroup-analysis was performed by stratifying patients’ age into elder and young subgroups (elder: ≥ 38-year-old, young: < 38-year-old). In the elder sub-population, the blastocyst formation rate of the PPOS group was significantly lower than that of the GnRH-antagonist group (45.8 ± 6.1% vs. 59.9 ± 3.8%, p = 0.036). Moreover, the euploidy rate of the PPOS group was only about 20% of that of  the GnRH-antagonist group (5.4% and 26.7%, p = 0.006). In contrast, no significant differences in blastocyst formation rate (63.5 ± 5.7% vs. 67.1 ± 3.2%, p = 0.45) or euploidy rate (30.1% vs. 38.5%, p = 0.221) were observed in the young sub-population. Secondary outcomes, which included implantation rate, biochemical pregnancy rate, clinical pregnancy rate, live birth rate, and miscarriage rate, were comparable between the two treatment groups, regardless of age.ConclusionWhen compared to the conventional GnRH-antagonist approach, PPOS protocol could potentially reduce the euploidy rate in aging IVF patients. However, due to the retrospective nature of this study, the results are to be interpreted with caution. Before the PPOS protocol is widely implemented, further studies exploring its efficacy in larger populations are needed to define the optimal patient selection suitable for this method.Trial registrationHuman Investigation and Ethical Committee of Chang Gung Medical Foundation (202200194B0).

P-179 Euploid blastocysts rate in pre-implantation genetic testing (PGT) cycles with high levels of sperm DNA fragmentation does not improve after Magnetic Activated Cell Sorting (MACS)

Abstract Study question Is there any benefit when using MACS before PGT to increase the euploid blastocysts rate in patients with high sperm DNA fragmentation? Summary answer Euploid blastocysts rate was not improved after the use of MACS in PGT patients where the male partner has high DNA fragmentation. What is known already The presence of apoptotic markers in spermatozoa is highly correlated with the failure of assisted reproduction treatments. Under normal physiological conditions, apoptotic sperm cells with externalized phosphatidylserine (PS) residues on the plasma membrane can be recognized and efficiently eliminated in the female genital tract, preventing the fertilization of the oocyte by a spermatozoon with alterations in its DNA integrity. MACS eliminates apoptotic sperm with PS residues using magnetic microbeads conjugated with Annexin V. This technique reduces the proportion of sperm with high rates of sperm DNA fragmentation and can be used to maximize assisted reproduction technique (ART) outcomes. Study design, size, duration This retrospective cohort study included 54 PGT cycles with high sperm DNA fragmentation between March 2018 and November 2022. Among them, some cycles used MACS as a selection tool for non-apoptotic sperm. The control group consisted of cycles that did not perform MACS due to the patients' decision. We compared the euploid blastocysts, fertilisation and blastocysts formation rates. Participants/materials, setting, methods PGT cycles using their own oocytes and with high sperm DNA fragmentation were separated into two groups according to the use of MACS as a selection technique (n = 25) or not (n = 29). Both groups were comparable regarding patients' age, number of mature oocytes collected and cleavage embryo quality. Semen samples were considered with high sperm DNA fragmentation after a TUNEL test ≥ 20%. Data was compared through Chi-square test with significance set at P &amp;lt; 0.05. Main results and the role of chance The primary outcome was the euploid blastocysts rate, while secondary outcomes included fertilisation and blastocysts formation rate. No differences between MACS and control groups were observed regarding the euploid blastocyst rate [45.3% (34 euploid blastocysts/75 total blastocysts) vs. 43.4% (63/145)] or the blastocysts formation rate [43.6% (75 total blastocysts/172 normal fertilized oocytes) vs. 28.6% (18/63)]. Fertilization rate was better in the control group [72.9% (172 fertilized oocytes/236 inseminated oocytes) vs. 80.1% (145/181)], P &amp;lt; 0.05. Limitations, reasons for caution These results need confirmation with a bigger population size. As with any retrospective study, the potential for residual confounding factors exists. Even though no significant differences were observed in terms of blastocysts formation and euploidy, other parameters such as embryo quality or birth results should be evaluated in the future. Wider implications of the findings These data suggest that MACS in PGT cycles offers no clinical benefit to increase the euploid blastocyst rate. The use of add-ons must be well justified when introduced in the laboratories' everyday work. Trial registration number Not applicable

P-742 Universal genome-wide haplotyping-based preimplantation genetic testing: a systematic seven-year experience at a single center

Abstract Study question To record the outcome and clinical benefit of universal genome-wide haplotyping-based preimplantation genetic testing (PGT). Summary answer Universal PGT allows for standardization of protocols and reduces turnaround time. Apart from accurate genetic diagnosis, it also provides chromosome information, improving embryo selection strategies. What is known already Developments in genome-wide technologies leveraged the implementation of universal PGT that combines haplotyping and copy number typing across the whole genome. Universal PGT provides diagnosis for any familial monogenic disorder (PGT-M) or structural rearrangement (PGT-SR), and allows for concurrent aneuploidy screening (PGT-A) in PGT-M/SR cycles, all using the same generic protocol and the same biopsy. For this reason, various universal PGT approaches have been developed in the last 2-3 years and are increasingly making their way to the clinic worldwide. Study design, size, duration Universal PGT as a first-tier test was implemented at UZ Leuven mid-2014, using in-house developed algorithm (siCHILD/haplarithmisis). This is a retrospective analysis of universal PGT data, collected between 1 January 2015 and 31 December 2022. Data on PGT indication, PGT cycles and biopsy results was extracted. Implantation rate (IR; with IU/EU fetal sac) per embryo transfer was calculated from frozen embryo transfer (FET) cycles for patients with known result by the end of 2021. Participants/materials, setting, methods By the end of 2022, 718 couples have successfully finalized preclinical PGT workup. At the time of writing, 573 couples (80%) have further proceeded with PGT cycles. In total, 1264 PGT cycles were performed with day-3 (D3) cleavage-stage (n = 3344) or trophectoderm (TE) biopsies (n = 1524). For 403 patients with known outcome from 954 FET cycles, IR per embryo transfer was calculated per biopsy type and embryo ranking, considering genome-wide chromosome information. Main results and the role of chance Couples were referred to PGT due to various autosomal dominant (AD, 65%), autosomal recessive (AR, 14%) and X-linked disorders (XL, 10%). Various PGT-M indications encompassed &amp;gt;200 genes in total, but almost 20% of couples enrolled due to inherited BRCA1/BRCA2 mutations. PGT-SR was indication in 7% of cases, mainly for familial microduplications/deletions (64%). For all PGT cycles, approximately 15% and 18% of all performed D3 and TE biopsies, respectively, were scored as abnormal largely due to meiotic errors in the embryo. All unaffected embryos were further ranked as R1 (euploid) or R2 (mosaic), and the number of R2 embryos was expectedly higher after D3 biopsies, compared to TE biopsies (250/1063, 23.6% vs 37/510, 7.3%, p&amp;lt;0.001). In accordance with inheritance mode, the number of unaffected embryos suitable for transfer was significantly lower in AD PGT cycles, compared to AR (32.3% (1116/3455) vs 44.0% (262/596) ; p&amp;lt;0.0001)). For 403 patients with FET cycles, IR was higher in R1 vs R2 embryos after D3 biopsy (231/590, 39.2% vs 30/159, 18.9 %, p &amp;lt;0.0001), whereas no difference was observed between R1 and R2 embryos after TE biopsy, although low number of R2 embryos after TE biopsy was transferred (85/142, 59.9% vs 7/12, 58.3%, p=ns). Limitations, reasons for caution The analyzed data is derived from a single center and the clinical outcome may not reflect the experience of other IVF/PGT centers due to confounding factors, such as PGT indication, used PGT technology and IVF lab practice. Wider implications of the findings The current dataset provides a comprehensive overview on general trends and outcome of universal PGT practice. Apart from accurate genetic diagnosis, universal PGT provides information on chromosomes, which improves embryo selection for transfer. This in turn impacts clinical counselling, interpretation and reporting of the results, and embryo transfer policies. Trial registration number Not applicable

P-709 Predictive heatmap in Preimplantation Genetic Testing for Monogenic disorders (PGT-M) and Structural Rearrangements (PGT-SR)

Abstract Study question What is the predicted cumulative live birth rate (CLBR) relative to AMH-level for women undergoing preimplantation genetic testing (PGT) for monogenic disorders and structural rearrangements? Summary answer Anti-müllerian hormone (AMH) and age allow to give an estimate of the CLBR in PGT and becomes poor when AMH is ≤ 2µg/L and age ≥42y. What is known already Ovarian response is an important contributory factor in PGT in order to obtain a sufficient number of embryos for genetic analysis. A proportion of the obtained embryos will be carrier of the disease tested, and another small proportion of the embryos will fail to have a genetic diagnosis hence will not be available for embryo transfer. The number of embryos not suitable for embryo transfer as a result of PGT varies between 25-81% according to the indication for PGT. The combination of female age and AMH are good predictors for CLBR in conventional IVF. Study design, size, duration This is a single-centre retrospective cohort study including 1,522 females undergoing 3,130 PGT cycles over a 6-year period (01/01/2015-31/12/2020) at a university-based referral centre for PGT. The principal outcome measure was CLBR per intention to treat (ITT), and the secondary outcome was live birth rate (LBR) per embryo transfer, in couples undergoing PGT-M and PGT-SR either by polymerase chain reaction (PCR), single nucleotide polymorphism (SNP) array, microarray-based comparative genomic hybridization (aCGH), or next-generation sequencing (NGS). Participants/materials, setting, methods Mean ±SD was applied for continuous outcomes, whereas (relative) frequency was applied for dichotomous outcomes. Multivariable logistic regression analysis was applied with dependent variable being the CLBR or LBR and the independent variables the AMH, female age, BMI, inheritance mode and PGT-technique. Best-fit (Akaike information criterion (AIC)) versus polynomials were analysed. Non-inferiority testing between different technologies was performed. A 3D-prediction mosaic (including AMH, age and CLBR) was created, which can be used for counseling purposes. Main results and the role of chance The mean female age is 32.46 years (SD 4.43), with a mean AMH level of 2.75 µg/L (SD 2.58) and a mean BMI of 24.24 (SD 4.43). Age and AMH significantly affect CLBR irrespective of the inheritance mode or PGT technique used. There is a gradual decline of CLBR from a female age of 25 years onwards reaching a critical threshold of less than 10% CLBR per ITT over the age of 42 with AMH levels ≤2 µg/L. Between cleavage stage biopsy techniques (PCR) and trophectoderm biopsy PGT techniques (SNP array, aCGH, NGS) used there was no significant difference in outcome per ITT, however per embryo transfer there is a significantly higher chance of live birth in SNP array, aCGH and NGS cycles compared to PCR cycles. Limitations, reasons for caution Despite the large sample size, the findings are confined by limited confounder adjustment. Wider implications of the findings In a PGT-program, couples need to be informed on the limited prognosis, if the combination of female age and AMH is unfavourable, in order to allow them to make other reproductive choices. The prediction mosaic produced in this study can be used as an insightful visual tool in counseling PGT-couples. Trial registration number Not applicable

P-755 Timeless importance of the embryo transfer technique: a real-life retrospective study comparing direct versus afterload catheters

Abstract Study question Can the embryo transfer (ET) technique influence clinical pregnancy rate (CPR)? Summary answer Our study demonstrated that CPR is significantly affected by the ET technique. In particular, with the afterload technique both CPR and easy transfer rates increased. What is known already Despite it having widely demonstrated that the occurrence of difficult ETs reduces the success of assisted reproductive technology (ART) cycles and that afterload technique has showed a decrease in the number of difficult transfers compared to the direct one, few data are available assessing pregnancy outcomes in the two different techniques. The present study represents the progression of a published prospective randomized controlled trial (RCT) performed in the same setting on a smaller population comparing direct and afterload techniques on the difficult transfer rate, but not designed to demonstrate differences in terms of CPR. Study design, size, duration Single center retrospective cohort analysis of 8,189 fresh and frozen single blastocyst transfers performed between January 2016 and December 2021 in a tertiary University affiliated fertility center. Of the total, 2,000 ETs were performed with the direct technique and 6,189 with the afterload one. All fresh single day-5 and single day-5 and day-6 frozen blastocyst transfers performed during the study timeframe were included. Participants/materials, setting, methods Direct technique was the only one used from January 2016 to September 2017. In the clinical trial recruitment period, the choice was given by randomization. From April 2019, only the afterload technique was used: the operator never had chance to choose the technique. Preimplantation genetic testing cycles, gamete donation and day-7 blastocyst transfers were excluded. CPR was the primary outcome, while difficult transfer rate the secondary one. Univariate and multivariate logistic regression have been performed. Main results and the role of chance During the period, 8,189 single blastocyst transfers were performed. Afterload ET showed a percentage of difficult transfers which was almost one third compared to that of the direct ET, being respectively 9.06% and 26.85% (OR 0.27, 95% CI 0.24-0.31p &amp;lt;0.001). Overall, the CPR between the two groups was significantly different: 44.69% in afterload ET and 41.65% in direct ET (OR 1.13, 95% CI 1.02-1.25, p = 0.017). As for the interaction between the two techniques and difficult transfer on CPR, only the direct difficult ET resulted in a significantly lower CPR with an OR of 0.62 (95%CI 0.49-0.77, p &amp;lt; 0.001). Lastly, among the 15 operators that performed the ETs, a range of difficult transfers from 3.8% to 45.4 % in the direct group and 0.8% to 20.5% in the afterload group was found (p &amp;lt; 0.001). Limitations, reasons for caution The main limitations of the study are the difference in sample sizes between the two groups, the wide range of time considered, and the 15 operators included. A further possible reason is the high prevalence of difficult transfer, probably due to the broad definition we used. Wider implications of the findings The study points out how in embryo transfers the use of the afterload technique instead of the direct one significantly improves clinical pregnancy rate and easy transfer rate. Since there is a limited knowledge on the embryo transfer technique impact, our findings aim to increase the effectiveness of embryo transfers. Trial registration number NCT05364528.

P-699 A clinical predictive model for live birth in women of advanced age undergoing PGT cycles

Abstract Study question In 37–45-year-old women undergoing preimplantation genetic testing, who will benefit from repeated cycles until birth? Summary answer The chance of delivering after repeated cycles is higher in those with at least one top-quality unaffected embryo in their first preimplantation genetic testing cycle. What is known already PGT for monogenic disease or structural chromosomal rearrangement (PGT-M and PGT-SR) is offered to couples when one or both carry a monogenic mutation or chromosomal rearrangement that put their future offspring at risk of having a genetic disorder so they can select an unaffected embryo for uterine transfer. The tendency to delay childbirth has led to an increase in advanced-aged women seeking PGT treatments. This poses a major challenge to PGT treatments. Study design, size, duration A retrospective cohort study was conducted at a university hospital reproductive center. The computerized database of 158 women aged 37–45 undergoing 753 PGT-M/SR cycles between 2010 and 2021 was analyzed. Participants/materials, setting, methods The reproductive outcomes of women who were 37–45 years of age, starting a PGT-M/SR cycle, were analyzed until the first live birth or until the patient reached the age of 45. Data were analyzed using univariate analysis, multivariable stepwise logistic regression, Kaplan–Meier method, and decision tree analysis. The cumulative live birth rate was calculated in a conservative manner because the assumption that patients who did not return for subsequent cycles had negative results was made. Main results and the role of chance The analysis included 158 women undergoing 753 preimplantation genetic testing cycles. The cumulative live birth rate was 37.342% (59/158). Decision tree analysis revealed that women aged ≤ 40.1 or women &amp;gt; 40.1 with one or more top-quality embryos in their first cycle had the best chance for a live baby (41% and 56%, respectively). Those older than 40.1 without top-quality embryos and seven or fewer dominant follicles had no live births. A Kaplan–Meier curve showed that for autosomal dominant diseases, there was a negligible increase in live birth rate after three cycles, compared to six cycles in autosomal recessive inheritance. Limitations, reasons for caution This study is limited by its retrospective design and the low birth rate in this age group, which reduces its power to detect differences in birth rates between different modes of inheritance. Wider implications of the findings The predictive model for live births in women aged 37-45 developed in this study can be used for clinical decision making and patient consultation. Additional PGT cycles after three in carriers of an autosomal dominant disorder and six in those with an autosomal recessive disorder should be considered prudently. Trial registration number Not applicable