Single Euploid Embryo Transfer Research Articles

Associations between Non-Essential Trace Elements in Women's Biofluids and IVF Outcomes in Euploid Single-Embryo Transfer Cycles.

Previous studies have found inconsistent associations between heavy metals and metalloids (cadmium, lead, mercury, and arsenic), and reproductive outcomes. The biofluid concentrations of ten non-essential trace elements (Hg, Pb, As, Ba, Sr, Rb, Cs, Sn, Ni, and Co) were evaluated in 51 Spanish women undergoing ICSI, PGT-A, and SET/FET. Nine out of ten non-essential elements were detectable in follicular fluid, whole blood, and urine collected the day of vaginal oocyte retrieval (VOR) and the day of embryo transfer and then analyzed by ICP-MS or Tricell DMA-80 for mercury. Elevated mercury and strontium concentrations in follicular fluid were associated with poor ovarian response and preimplantation outcomes. Worst preimplantation outcomes were also identified in women with elevated whole-blood strontium or mercury, urinary arsenic, barium, and tin the day of VOR. High concentrations of urinary rubidium on VOR day were linked with enhanced fertilization and blastocyst development. Excessive titanium in whole blood was associated with lower odds of implantation, clinical pregnancy, and achieving a live birth in a given IVF cycle. Excessive urinary arsenic on the day of embryo transfer was associated with lower odds of live birth. Although these preliminary results need to be confirmed in larger populations, distinguishing organic and inorganic element forms, our findings show that some non-essential elements have a detrimental impact on human IVF outcomes.

P-277 Focal rather than diffuse nature of adenomyosis might be more detrimental to IVF outcomes after single euploid embryo transfer

Abstract Study question Is the nature of adenomyosis a factor to consider after a single euploid embryo transfer? Summary answer Focal adenomyosis was associated with lower live birth rate per transfer when compared to diffuse adenomyosis. What is known already Adenomyosis is widely described to hamper reproductive potential of women who suffer it. This uterine pathology has a detrimental impact on in vitro fertilization (IVF) clinical outcomes, as described by a series of recent metanalysis. Nevertheless, there is scarce evidence regarding clinical studies that address the impact of adenomyosis depending either on its diffuse or focal nature. Study design, size, duration A multicenter retrospective cohort study in which 229 patients undergoing IVF treatment were included. Patients with single embryo transfer (SET) in blastocyst stage after pregestational testing for aneuploidy (PGT-A) between years 2015 and May 2023 were divided into two groups: diffuse adenomyosis (n = 167) and focal adenomyosis (n = 62). Participants/materials, setting, methods Inclusion criteria consisted of patients in a PGT-A program who had a cryotransfer of a single euploid blastocyst-stage embryo. Patients were diagnosed within our facilities using transvaginal ultrasonography (TVUS) prior to their IVF cycle. Diffuse adenomyosis was diagnosed when irregular endometrial-myometrial junction, increased uterine volume, ill-defined myometrial heterogeneity, presence of anechoic round myometrial cysts, hyperechoic islands, fan-shaped shadows and/or echogenic subendometrial lines were detected. Focal adenomyosis was diagnosed when foci with adenomyotic characteristics were observed. Main results and the role of chance Clinical pregnancy rate per embryo transfer was 81/167 (48.5%) in those women diagnosed with diffuse adenomyosis versus 23/62 (37.1%) in the focal adenomyosis group (OR = 0.63 95% CI [0.33-1.18], NS). Differences found in clinical miscarriage rate were not statistically significant, being 33/81 (40.7%) for diffuse adenomyosis and 14/23 (60.1%) for the focal adenomyosis group (OR = 2.24 95% CI [0.79-6.63], NS). A lower live birth rate per euploid embryo transfer was observed in women diagnosed with focal adenomyosis, being 9/62 (14.5%) and 48/167 (28.7%) for women who presented diffuse adenomyosis (OR = 0.42 95% CI [0.17-0.95], p=0.027). There were no statistically significant differences between childbirth delivery method (vaginal versus caesarean section). Furthermore, means of gestational age at the time of delivery, newborn size and weight and incidences of low birth weight did not differ between the two groups. Limitations, reasons for caution The retrospective nature of this observational study implies that possible confounders cannot be completely excluded. Also, the accurate diagnostic of adenomyosis is not without complexity and although gynecologists were equally trained to identify direct and indirect markers, different criteria may have been used Wider implications of the findings To our knowledge this is the first study to use an euploid model to assess the impact of the focal versus diffuse nature of adenomyosis in IVF patients. This model permits to correct for numerous covariables attributed to patient’s age and embryo genetic constitution. Trial registration number Not applicable

P-545 Early pregnancy outcomes associated with age and AMH following Next-Generation Sequencing(NGS)-based Preimplantation Genetic Testing for Aneuploidy(PGT-A) in single euploid embryo transfers for advanced age patients

Abstract Study question Does age and AMH impact early pregnancy outcomes in euploid single embryo transfers using NGS-based PGT-A for individuals aged 35 and above? Summary answer In this NGS-based PGT-A study, no significant differences in early pregnancy rates were observed based on age or AMH among individuals aged 35 and above. What is known already A recent meta-analysis suggest a decline in pregnancy rates with advancing age in the context of euploid embryo transfer following PGT-A. However, it’s crucial to acknowledge variations in PGT-A techniques across studies. While individuals with low AMH levels may encounter challenges in obtaining euploid embryos, the precise impact of AMH on pregnancy rates post-embryo acquisition remains unclear. Study design, size, duration A retrospective cohort study was conducted on 428 cycles of single euploid embryo transfers in patients aged 35 and above, performed at the single infertility center from January to December 2022. Participants/materials, setting, methods The study examined frozen-thawed embryo transfer cycles in patients aged 35 and above, analyzing early pregnancy outcomes in single euploid embryo transfers. Participants were grouped by age(35-38, 38-42, 42 and above) and AMH levels(<1, 1-3, >3 ng/ml). NGS-based PGT-A conducted embryo biopsy. The analysis aimed to detect differences in initial pregnancy rates among age and AMH subgroups. The differences between groups were compared using Pearson’s chi-squared test. Main results and the role of chance The average age at transfer was 39.05 ± 2.53 years, with a mean AMH of 2.60 ± 1.86(ng/ml). The mean number of prior frozen embryo transfer (FET) cycles was 1.9 ± 2.04, with 119 patients (27.8%) having undergone three or more transfer cycles. Transfer cycles comprised 363 (84.8%) artificial cycles and 65 (15.2%) ovulatory cycles, with an average endometrial thickness of 8.95 ± 1.73 mm at the time of transfer. The β-hCG positive rate was 57.7% (247/428), and the clinical pregnancy rate was 53.5% (229/428). When analyzing positive b-hCG results by age, rates were 59.9% (82/137) for ages 35-38, 55.5% (121/218) for ages 38-42, and 60.3% (44/73) for ages 42 and above (p = 0.641). In terms of AMH, β-hCG positive rates were 52.1% (37/71) for <1, 59.1% (120/203) for 1-3, and 58.0% (83/143) for ≥3, with no statistically significant differences (p = 0.584). Clinical pregnancy rates were 54.0% for ages 35-38, 51.8% for ages 38-42, and 57.5% for ages 42 and above. For AMH, rates were 50.7% for <1, 53.2% for 1-3, and 54.5% for ≥3, with no statistically significant differences (p = 0.869). Limitations, reasons for caution Being a retrospective study analyzing patients undergoing embryo transfer, our study overlooks variables related to oocyte retrieval. Given the challenges of obtaining euploid embryos in advanced age, further investigation is warranted to explore the probability and duration of embryo acquisition in this population. Wider implications of the findings In this study, utilizing NGS-based PGT-A after generating euploid embryos, no significant differences in early pregnancy outcomes were observed for women aged 35 and older, considering age and AMH levels. The study suggests further research is needed to explore if NGS-based PGT-A can address limitations of traditional chromosomal testing methods. Trial registration number not applicable

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

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

P-399 Beyond chromosome screening: The impact of progesterone and in vitro oxidative stress on failed euploid blastocyst transfers

Abstract Study question To assess the effect of serum progesterone levels on the production of radical oxygen species (ROS) by endometrial immune cells in patients with non-genetic miscarriages. Summary answer Elevated serum pre-transfer progesterone levels favour the development of an endometrial microenvironment that is not conducive to a healthy pregnancy, by increasing ROS production. What is known already Endometrial immune cells, especially uterine Natural Killer (uNK) cells, play an essential role in the proper development of pregnancy, promoting angiogenesis and adequate placentation. The maturation of these cells is indirectly determined by progesterone levels, which, during the secretory phase, enhance the synthesis of key cytokines for uNKs’ functionality. Previous studies have already indicated that increases in progesterone levels during the follicular phase can alter the endometrial microenvironment, affecting its receptivity. However, the molecular effect that imbalances of this hormone may have on the endometrium on the day of embryo transfer and directly in relation to uNK is still unknown. Study design, size, duration We conducted a prospective exploratory study, between September 2022 and January 2024, including 15 patients with previous miscarriages after euploid single embryo transfer (SET), ruling out the genetic cause for such gestational losses. We obtained endometrial biopsies of all patients, after 5 days of progesterone, in a cycle with hormone replacement therapy. The same day of the biopsy, serum progesterone levels were measured in all the patients included. Participants/materials, setting, methods In vitro cultures enriched in uNK cells (CD56+CD16-) were established from the patients’ endometrial biopsies and cell enrichment was confirmed by flow cytometry. These cells were co-cultured with the JEG-3 cell line (placental cells), simulating the microenvironment of early pregnancy. Cellular ROS production was measured by fluorescence detection 40 hours post-culture using a commercial kit. A linear regression model was used to determine statistically significant correlations (p < 0.05) between ROS and progesterone levels. Main results and the role of chance The mean age of the participating patients was 38.9 years and the BMI was 23.2 kg/m2. The mean progesterone level the day of the biopsy was 15.6 ng/ml. The cell cultures obtained from patients were successfully enriched in the desired cell population, with an average percentage of 89.6% uNK cells (CD56+CD16-) of total leukocytes (CD45+) obtained by flow cytometry. After culturing the same number of cells from each patient with the same number of spheroids of the JEG-3 cell line, an average ROS production of 31341.2 arbitrary units (a.u.) was obtained. Taking into account the co-cultures stablished from the 15 patients, a positive correlation between cellular ROS production and progesterone level was observed (r = 0.6728, p = 0.006). Limitations, reasons for caution Although the results shown may provide clues about the molecular dynamics of the endometrium during early pregnancy, they should be taken with caution, as it is not yet known whether this progesterone elevation is the cause or rather the consequence of an unfavourable endometrial microenvironment with high oxidative stress. Wider implications of the findings This study provides new information on the endometrial microenvironment of patients suffering non-genetic miscarriages and, although much remains to be studied, this association between hormone levels and oxidative stress may point the way to future studies investigating a possible explanation for these undesirable reproductive outcomes. Trial registration number Not Applicable

P-643 Menopause should not be considered a confounding factor in endometrial preparation protocol’s comparative clinical trials: a retrospective cohort study with 1.109 euploid single embryo transfers

Abstract Study question Does menopause have an impact on obstetric and perinatal outcomes when performing elective euploid single-blastocyst transfers (eeSBT) in a hormonal replacement treatment (HRT) protocol? Summary answer eeSBT in a non-menopause elective HRT group(eHRT) did not show higher success rates nor better obstetric and perinatal outcomes compared to a menopause HRT group(mHRT). What is known already Menopause has been suggested to be a confounding factor in clinical trials when comparing the results and success rates for endometrial preparation in modified natural cycle (mNC) Vs HRT: including menopause patients could lead to selection bias seen that they can never be included in the mNC group. Few data are available on eeSBT ≥3BB (Gardner score) cryotransfers comparing obstetric and perinatal results between eHRT and mHRT, to have the opportunity to include them all in further comparative trials, with a low bias risk. Study design, size, duration Retrospective single-centre comparative study, including 1.109 eeSBT (≥3BB, Gardner score) between Jan-2018 and Dec-2022: 1.025 (92,4%) in eHRT and 84 (7,6%) in mHRT. The eHRT and mHRT groups were homogeneous for egg donor’s age (29,1±5,9 yo Vs 25,8±4,1 yo) recipient’s age (41,4±4,9 yo Vs 44,9±4,7 yo), body mass index (22,6±4,7 Vs 22,6±5,3) severe male factor (3,5% Vs 3,6%), the need for sperm donation (30,0% Vs 35,7%), and the average throphoectoderm embryo quality (A = 32,5% Vs A = 29,8%). Participants/materials, setting, methods We studied the clinical, obstetric and perinatal outcomes of the 1.109 eeSBT, comparing eHRT and mHRT groups for: pregnancy rate, miscarriage rate, live birth rate, twin pregnancy rate, severe preeclampsia, preterm birth rate (<37, <35, <32 and <28 weeks) and neonatal weight. We used Chi-square test and T-Test to compare groups (p < 0,05). Main results and the role of chance There were no statistically significant differences between eHRT and mHRT groups when comparing pregnancy rates (63,7% Vs 64,3%, p = 0,92), miscarriage rates (15,6% Vs 11,1%, p = 0,053) and live birth rates (44,3% Vs 48,8%, p = 0,42); no significant differences were found in the severe preeclampsia rate(2,0 Vs 1,2, p = 0,84), nor in the twin pregnancy rate (0,9 Vs 2,4, p = 0,34) even if it almost tripled in the mHRT group. Preterm, major and extreme preterm birth rates were comprable between eHRT and mHRT groups: <37 weeks (9,9% Vs 4,9%, p = 0,29) < 35 weeks (3,3% Vs 0, p = 0,23) <32 weeks (1,3% Vs 0, p = 0,46) <28 weeks (0,2% Vs 0, p = 0,76). There were no significant differences in neonatal weight (3292 + 481g Vs 3.135 + 419g, p = 0,052). Limitations, reasons for caution In a preliminary study, we compared and additional 245 eeSBT in mNC with the HRT group, and no significant differences in obstetric or perinatal outcomes were reported when including or excluding the mHRT sub-group. Wider implications of the findings In eeSBT, the eHRT group did not report better obstetric nor perinatal results compared to the mHRT group; further prospective clinical trials comparing mNC Vs HRT should not consider menopause as a major confouding factor, when using eeSBT. Trial registration number Not Applicable

P-398 Lower ectopic pregnancy prevalence with natural endometrial preparation in single euploid frozen embryo transfers

Abstract Study question Does the endometrial preparation approach for an euploid-frozen embryo transfer have an impact on the incidence of an ectopic pregnancy? Summary answer The natural cycle endometrial preparation approach seems to have a lower incidence of ectopic pregnancies compared to a hormonal replacement therapy cycle. What is known already Ectopic pregnancy (EP) is an uncommon complication of pregnancy and is associated with significant morbidity. IVF pregnancies have been implicated as a risk factor, but this finding is mostly confounded by multiple embryo transfer and complicated medical history of women undergoing IVF treatment (tubal disease, surgery, endometriosis, etc.). Recent studies have suggested that frozen embryo transfer may reduce the risk of EP, but it is not yet known whether embryo ploidy status and different endometrial preparation regimens affect the risk of EP. Study design, size, duration Retrospective cohort of 1517 pregnancies from 2607 single euploid frozen embryo transfers. Comparator estimates were estimated using multiple large cohort studies in the literature including 58,203,239 pregnancies from unselected cohorts and 220,167 pregnancies from IVF-treated women with the transfer of non-tested embryos. Participants/materials, setting, methods The rate of ectopic per pregnancies were compared to ectopic rate derived from multiple cohorts of IVF-treated women and population level reports of unselected pregnancies (natural conception and IVF). Comparator estimates were obtained with proportion meta-analyses using generalized linear mixed models. Factors associated with ectopic pregnancies were investigated with mixed-effects logistic regression analyses. Main results and the role of chance EP rate in our cohort was 10/1000 pregnancies (95% CI: 5 to 16 per 1000) resulting from single euploid embryo transfers (1.1%, 16/1517). The observed prevalence of EP was 12/1000 pregnancies (95% CI: 6.8 to 21 per 1000) in unselected cohorts and 14/1000 pregnancies (95% CI: 13 to 15 per 1000) after IVF-treatment. Ectopic rate in our study was not significantly different than rates reported in the literature from unselected and IVF pregnancies (P = 0.579 and 0.223, respectively). There were no significant differences between women with ectopic pregnancies and those with clinical pregnancies in terms of age (33.6±5.5 vs. 35.1±5.2 years, P = 0.290), BMI (26.7±4.8 vs. 25.8±4.6 kg/m2, P = 0.475) and serum AMH levels (3.3±2.9 vs. 3.4±3.9 ng/mL, P = 0.854), nor between the quality of embryo transferred between top, good, fair and poor (1.8% vs 0.7% vs 1.9% vs 0.9%, p = 0.088, 0.997 and 0.508 respectively). Ectopic rates were also similar between women with history of cesarean section (1.1% vs 1.0%, P = 0.847) or isthmocele (1.0 vs 1.1%, P = 0.857). There were less ectopic pregnancies following transfers with natural endometrial preparation (0.5 vs 1.5%, natural vs programmed) and the effect showed statistical significance in multivariable analyses (OR: 0.28, 95% CI: 0.06 – 0.88, P = 0.049). Limitations, reasons for caution Small sample size as well as infrequent occurrence of the studied event reduces the power of our study to detect small but clinically meaningful effects with statistical significance. Wider implications of the findings We did not observe a lower than reported prevalence of EP among euploid embryo transfer. However, rate of EP was significantly lower in natural endometrial preparation cycles compared to preparation with exogenous hormones, indicating that a natural cycle might have a protective effect against the development of an ectopic pregnancy. Trial registration number Not applicable

P-531 Embryo grading in PGT-A testing: does it really matter?

Abstract Study question Can embryo morphology grading be a good parameter to predict the embryo transfer’s outcome when euploid embryos are used? Summary answer Gardner’s grading is a useful predictor of LBR per euploid embryo transferred. Morphologic grading should be used for the embryo selection among euploid blastocysts. What is known already When preimplantation genetic testing for aneuploidies (PGT-A) is not performed, the selection of the embryo(s) to be transferred is based on embryo morphology. In PGT-A cycle, some studies have minimised the importance of embryo morphology, when euploid embryos are present. However, others still consider it as good predictor. Understanding the role of morphology in biopsied euploid embryos may help in optimizing frozen embryo transfer cycles. Study design, size, duration We retrospectively analysed PGT-A frozen embryo transfers with reported outcome, performed in our clinics between 2018 and 2022. The cycles included were divided into two groups based on Gardner’s grading of euploid embryos transferred: “good” embryos (AA, AB, BA and BB; n = 263) versus “poor” embryos (including AC, CA, BC, CB, and CC; n =112). Participants/materials, setting, methods We included in the study only single euploid embryo transfers, double embryos transfers and mosaic embryo transfers excluded. Body mass index (BMI), oocyte age and outcomes (pregnancy and live birth rates) were compared between the two groups. Data was statistically analysed using MedCalc Software, where P < 0.05 was considered as significant. Main results and the role of chance A total of 375 embryo transfer cycles were included in the study. Maternal ages were not significantly different between groups (good vs poor embryos) (37.5 vs 38.2). Similarly, oocyte age (37.7 vs 38.1, respectively), and BMI (22 vs 22.7, respectively) did not differ between good and poor embryos. On the contrary, clinical pregnancy (56.6% vs 40.1%) and live birth rates (27.7% vs 13.4%) were significantly higher when morphologically good grade embryos were transferred (p < 0.05). In fact, both rates were significantly higher after the transfer of blastocysts that exhibited A-grade or B-grade in inner cell mass and/or trophectoderm, as opposed to the transfers of blastocysts that exhibited a C-grade trophectoderm and/or inner cell mass. Limitations, reasons for caution The findings apply to the participating centres and may not represent worldwide trends. Data was analysed retrospectively, but details of the follow-up on PGT pregnancies and babies born were limited. The degree of blastocyst expansion and the day of biopsy were not taken into consideration in this study. Wider implications of the findings The Gardner embryo quality assessment improves the clinics’ ability to prioritize embryos after PGT. Preferential transfer based on morphologic criteria increases the chances of a positive outcome in terms of live birth rates. Trial registration number not applicable

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 (<120, 120-132, 132-144, 144-156, 156-168, and >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-755 Effect of female age and specific cycle characteristics on success in modified natural frozen-thawed single euploid embryo transfer cycles (mNC/FET)

Abstract Study question Does the age of woman and specific cycle characteristics impact the success of modified natural frozen-thawed single euploid embryo transfer cycles (mNC/FET)? Summary answer The success rate of mNC/FET cycles is similar in all age groups. As the LH level increased ( above 23.5ng/dL) the success was significantly increased. What is known already The success of frozen embryo transfer can depend on various factors such as the patient’s age, the number of transferred embryos, the duration of embryo culture, and the method used to prepare the endometrium (Holschbach et al. 2023). However, there is currently insufficient evidence in the literature about the effect of age and cycle characteristics on the effectiveness of mNC/FET cycles in patients who have received single top and good quality euploid embryos. Study design, size, duration This study, conducted at Istanbul Memorial Hospital, ART and Reproductive Genetics Center, is a retrospective, single-centre analysis of 583 cycles of euploid mNC/FET in women aged 22-44 years. The study period was from July 2017 to January 2024. The cycles were divided into two groups based on the age of the women. Group A (n = 408) included women under the age of 38, while Group B (n = 175) included women aged 38 or above. Participants/materials, setting, methods The study investigated success predictors in mNC/FET with top and good-quality embryos. Excluded were women with recurrent pregnancy losses, recurrent implantation failure, high BMI (>35kg/m2), uterine/endometrial problems, severe male infertility, and autoimmune diseases. The mNC/FET success was a pregnancy lasting 12 weeks or more. The analysis included patient demographics and cycle outcomes. Chi-square, t-tests, and Mann-Whitney U tests assessed variables with a p-value < 0.005, indicating statistical significance. Main results and the role of chance No significant demographic differences were observed between the two groups, except for AMH levels. AMH levels were significantly higher in younger group than older group (3.02 ng/ml vs. 1.96 ng/ml, p = 0.000). The mNC/FET success rates were similar, with 76% in the younger group and 73% in the older group. Estradiol levels the day before trigger day were significantly higher in older group (278.02 pg/ml vs. 237.84pg/ml, p = 0.028). Both groups had similar mean LH levels (32.50 IU/L and 32.41 IU/L, respectively), estradiol levels and endometrial thickness on the trigger day. In the younger group, LH rise was observed later, follicular phase was longer, and embryo transfer day was later than the older group (p = 0.001). Univariate regression analysis revealed that increased LH level was an important independent variable in achieving mNC/FET success, with a 1.001-fold increase (p = 0.043). The LH levels of 23.5 IU/L or higher predicted high mNC/FET success with 60% sensitivity and 43% specificity based on the Receiver Operating Characteristic curve. (AUC: 0.606, %95 CI 0.540-0.671, p = 0.002). Prolonged infertility duration and previous ET failures reduced mNC/FET success by 0.889 and 0.544-fold, respectively (p = 0.002, p < 0.001). Higher β-hCG levels on days 14 and 16 increased mNC/FET success by 1.038-fold and 1.008-fold, respectively (p < 0.001). Limitations, reasons for caution Our study has limitations as it was retrospective. Prospective randomized studies are needed to evaluate the differences between the young (age <38) and old patient groups (age ≥38) based on mNC/FET success. The association between LH rise and mNC/FET success needs verification with a larger sample. Wider implications of the findings The mNC/FET success rates are similar in young (age <38) and old patient groups (age ≥38). However, prolonged infertility duration and previous failed ET cycles decreased the success of mNC/FET. Additionally, It is important to schedule trigger time after the optimum LH rise, which is 23.5 IU/L or higher. Trial registration number not applicable

P-318 Reproductive ageing: the seed, the soil, or both?

Abstract Study question Is it all about the embryo? Can a single euploid blastocyst transfer sustain reproductive outcomes in women with advanced reproductive age? Summary answer Despite euploid embryo transfer, endometrial senescence appears to play a crucial role in determining reproductive success, particularly in older patients undergoing in vitro fertilization (IVF). What is known already Advanced reproductive age significantly impairs oocyte and embryo quality. Effective crosstalk and synchronization between embryo and endometrium are pivotal for successful pregnancies, both in vivo and in vitro. Implantation failure remains a persistent challenge in IVF, exacerbated by delayed family planning trends. The transfer of euploid blastocysts through preimplantation genetic testing for aneuploidy (PGT-A) is a potential strategy to address implantation issues, decrease miscarriages, and shorten time-to-pregnancy. However, a significant proportion of IVF treatments remain unsuccessful, suggesting critical factors beyond the embryo. Study design, size, duration This retrospective study analyzed 457 single euploid blastocyst transfers performed by two doctors at a private IVF center from January to November 2023. Inclusion criteria encompassed cases with PGT-A indications (advanced maternal age, repeated implantation failure, recurrent pregnancy loss, etc.) or cases where embryo biopsy was patient-requested. The primary outcome was ongoing pregnancy rate (OPR), with secondary outcomes including pregnancy rate (PR) and clinical pregnancy rate (CPR). Participants/materials, setting, methods Participants were categorized into four groups: Group 1 (< 35 years old; N = 100), Group 2 (35-37 years old; N = 102), Group 3 (38-40 years old; N = 118), and Group 4 (> 41 years old; N = 87). A control group (oocyte donation; N = 50) with single euploid embryo transfers showed a mean recipient age of 43 years. Donors were always less than 32 years old. Endometrial preparation protocols were consistent across all groups. Chi-square test was used to compare groups. Main results and the role of chance Among the 457 transfers analyzed, with a mean female age of 37 years, the overall PR was 71.3%, CPR was 64.8%, and OPR was 60.2%. Groups showed no differences in demographic variables and cycle parameters. Group 1 demonstrated higher PR (83.3%), CPR (78.4%), and OPR (73.5%) compared to Group 2 (PR 70.9%, p = 0.034; CPR 66%, p = 0.047; OPR 62.1%, p = 0.081), Group 3 (PR 68.2%, p = 0.009; CPR 61.2%, p = 0.005; OPR 56.6%, p = 0.008), and Group 4 (PR 65%, p = 0.002; CPR 56.1%, p < 0.001; OPR 51.2%, p = 0.001). Furthermore, the control group (oocyte recipients) showed significantly lower PR (68%, p = 0.031), CPR (54%, p = 0.002), and OPR (46%, p < 0.001) compared to Group 1, but not with the other groups. These findings demonstrate that even with euploid embryos originating from young donors, older women exhibited lower pregnancy rates than young women transferring single euploid blastocysts from their own oocytes and similar rates compared to those with advanced reproductive age transferring their own euploid blastocysts, implying that endometrial ageing may disproportionately influence IVF treatment outcomes. Limitations, reasons for caution The retrospective design introduces inherent bias, notably selection bias and unmeasured confounders. This preliminary data did not account for male infertility factors and their impact on embryo quality. Wider implications of the findings Reproductive aging appears to be influenced by factors beyond the embryo itself, especially in women above 35 years. Further research is warranted to elucidate the causes and impact of reproductive aging on implantation potential, aiming to refine clinical practices and enhance the success of IVF treatments. Trial registration number not applicable

P-407 Exploring the effectiveness of tailoring estradiol supplementation duration to mimic the natural cycle length in artificial endometrial preparation for frozen embryo transfer cycles

Abstract Study question Is an estrogen supplementation duration similar in length to the follicular phase of a natural cycle associated with a better clinical pregnancy rate? Summary answer An estradiol supplementation duration, which is proportional to the natural follicular phase length, results in significantly better outcomes compared to shorter exposure durations What is known already The last decade witnessed a major increase in the use of single euploid frozen embryos. Artificial endometrial preparation (AEP) has proven to be effective to prepare the endometrium for implantation. However, several features of AEP need to be clarified mainly the duration of estrogen supplementation and until now no study took into consideration the difference between exogenous estrogen supplementation and the actual length of the follicular phase of each patient during AEP. Furthermore, most of the studies focused on upper limit of estrogen exposure while few considered the lower limit. Unfortunately, the results on pregnancy rates were mixed. Study design, size, duration 663 single euploid frozen embryo transfer cycles were included. Patients underwent vaginal ultrasound and hormonal blood measurement (Estradiol, Progesterone) on day 2 of their cycle. Estradiol valerate (4 mg the first 2 days then 6 mg daily, Orally) was started on the same day and another control was done around day 10. When triple lining pattern of the endometrium was seen, vaginal progesterone was initiated (800 mg daily) and SET was done after 120 hours. Participants/materials, setting, methods Patients with reported regular menstrual cycle (25-35 days) were included and the difference between estrogen supplementation and the actual follicular phase was calculated for each patient. Patients were sorted into 2 groups as follows: 231 women with normal interval (±2 days of follicular phase length), and 432 women with short interval (-3 days or shorter). Only the first single euploid embryo transfer cycles were analyzed for these patients. Main results and the role of chance Whereas patients had similar characteristics in both groups, the corresponding clinical pregnancy rates in normal and short supplementation groups were 69.3% (160/231) and 64% (277/432), respectively. After balancing the groups for BMI, embryo quality and endometrial thickness with inverse treatment probability weighting, those who received estradiol supplementation proportional to their natural follicular phase length had significantly higher clinical pregnancy rates compared to those who received it for shorter durations (adjusted OR: 1.48, 95% CI: 1.16 – 1.89, P = 0.002). Serum estradiol levels were available for 523 cycles, the clinical pregnancy rate in those within the 1st quartile (<155pmol/L), 2nd to 3rd quartile (155 to 275pmol/L) and 4th quartile (>275pmol/L) were 70%, 64.7% and 63%. After adjusting for BMI and embryo quality, higher (>275pmol/L) (adjusted OR: 0.84, 95% CI: 0.53-1.32, P = 0.442) and lower(<155pmol/L) (adjusted OR: 1.37, 95% CI: 0.85-2.22, P = 0.202) estradiol levels were not significantly associated with clinical pregnancy. Limitations, reasons for caution The present study could not address the influence of very long estrogen supplementation on clinical pregnancy rate due to limited samples. Further prospective studies, including larger populations, are needed to confirm our findings Wider implications of the findings Our data indicate that mimicking individually the natural cycle regarding estrogen supplementation duration in AEP for single euploid embryo transfer cycles can produce significant improvement in clinical pregnancy rates. Trial registration number not applicable

Prenatal cell-free DNA screening for chromosomal aneuploidies after euploid embryo transfer shows high concordance with preimplantation genetic testing for aneuploidy results and low positive predictive values

To evaluate the positive predictive value (PPV) of prenatal cell-free DNA screening for chromosomal aneuploidies in pregnancies achieved either after single euploid transfer in IVF/PGT cycles or transfer of single untested embryo, and to assess the concordance of prenatal-cfDNA-screening and PGT-A results. Single centre retrospective cohort study SUBJECTS: 2973 prenatal-cfDNA-screening results for the most common trisomies(T)(T13,T18,T21,X,Y) and microdeletions(1p36;4p16.3;5p15.2;15q11.2;22q11.2) from singleton pregnancies allocated into 2 groups: PGT-A group (n=1204) pregnancy after single euploid transfer and non-PGT-A group (n=1769) pregnancy after transfer of single untested embryo, between 2016 and 2023. Primary outcome measure was accuracy of prenatal-cell-free-DNA-screening. Positive and negative prenatal-cell-free-DNA-screening results, and subsequent prenatal or postnatal diagnostic testing were used to classify each positive prenatal-cell-free-DNA-screening result as a true or a false positive. Secondary endpoints were to evaluate the concordance of PGT-A and prenatal-cell-free-DNA-screening results and to assess the differences of the fetal fraction of cell-free-DNA used for prenatal-cell-free-DNA-screening report between the study groups. Prenatal-cell-free-DNA-screening was performed at mean 11.3±1.8weeks gestational age (GA) and yielded results in 99.9% of the patients (0.1% cancellation rate). There was no difference in the fetal fraction between PGT-A tested and not tested pregnancies (9.5%±4% vs 10.3%±4%). 13 positive prenatal-cell-free-DNA-screening results (2-T21,2-X0,4-XXX,1-XYY, 1-indeterminate sex, 2-22q11 del/dup, 1-15q11.2) were received for PGT-A group. Only one (22q11 dup) was confirmed with amniocentesis and fetal autopsy, giving a PPV for an abnormal prenatal-cfDNA-screening of 7.7%, the rest had results concordant with PGT-A. Sex chromosomes were 100% concordant between prenatal-cell-free-DNA-screening and PGT-A results, giving a 100% PPV for PGT-A for sex chromosomes and 100% NPV for aneuploidies. Positive prenatal-cell-free-DNA-screening results were received for 27 pregnancies from untested embryos (1.5%), follow up testing was electively performed for 21, and 8 had confirmed the prenatal-cell-free-DNA-screening result, giving a PPV for the non-PGT-A group of 38%. This study demonstrates that patients undergoing IVF/PGT and single euploid embryo transfer can reliably do prenatal-cell-free-DNA-screening during their first trimester. Fetal fraction in singleton pregnancies after PGT-A tested embryos is not different from pregnancies with untested embryos. PPV for an abnormal prenatal-cell-free-DNA-screening result after euploid embryo transfer was reassuringly low (7.7%). PGT-A reliably selects against aneuploidy with 100% concordance with fetal sex.

Racial disparities in the outcomes of euploid single frozen-thawed embryo transfer cycles – analysis of the Clinical Outcome Reporting System of the Society for Assisted Reproductive Technology 2016–2018 data

ObjectiveTo evaluate if in pregnancies conceived with the transfer of single genetically tested embryos, maternal race and ethnicity relate to pregnancy outcome. DesignRetrospective cohort. SubjectsAutologous frozen -thaw embryo transfer (FET) cycles with transfer of single genetically tested embryo in SART-CORS for years 2016-2018; cycles associated with diagnoses of recurrent pregnancy loss, gestational carrier, donor egg and donor embryo were excluded. ExposureInformation on race and ethnicity linked with in vitro fertilization and FET cycles available in the SART-CORS. Main Outcome MeasuresMultivariable analyses utilizing generalized estimating equation examined the relationship between categories of race and ethnicity with the following outcomes: Pregnancy (+βhCG following FET), clinical pregnancy, pregnancy loss (early [at gestation <13 weeks] and late [loss between ≥13 and <20 weeks]), preterm (<37 weeks), term (≥37 weeks) and live birth. Covariates adjusted for included age, BMI, AMH, infertility diagnosis and smoking history. Results79,416 FET cycles met the eligibility criteria. Information on race and ethnicity was specified for 50,820 (64.0%) and was not known in 28, 723 (36%) of the cycles . The population was predominantly non-Hispanic White (NHW, 44%). Non-Hispanic Black [NHB] comprised 2.7%, Asian 12.3%, Hispanic 3.4%, American Indian, Pacific Islander, Hawaiian and Alaskan [AI_AL_PI_H] 0.2%. Nearly 1.0 % self-identified with more than one race. On multivariable analyses, pregnancies in NHB and in Hispanic women (compared to NHWs) were significantly more likely to result in in preterm birth (p<0.001). Compared to NHW women, the likelihood of live birth was significantly lower in NHBs (p<0.01), Asian (p=0.04), Hispanic (<0.01) and AI_AL_PI_H women (p<0.01). . The likelihood for delivery by Cesarean was also disproportionately higher in the NHB (p=0.047), Hispanic (p=0.007) and in women identifying with more than one race (0.023)compared to NHWs . ConclusionRacial and ethnic differentials are apparent in the outcomes of FET conceived pregnancies resulting from the transfer of single genetically tested embryos.

Are there associations between clinical and embryological factors with pregnancy loss following transfer of a single euploid embryo?

First trimester pregnancy losses are commonly attributed to chromosomal abnormalities. The causes of pregnancy loss following transfer of a euploid embryo are not fully elucidated. The aim of this study was to evaluate clinical and embryological parameters for pregnancy failure following the transfer of a single euploid embryo. Pregnancy outcomes of single euploid embryo transfers from a single centre between January 2017 and March 2020 were retrospectively evaluated. Several clinical and embryological parameters were evaluated in consideration to pregnancy outcomes; total pregnancy loss and live birth. Endometrial preparation type, number of previous frozen embryo transfer cycles, history of recurrent pregnancy loss, higher body mass index, presence of endometriosis and/or adenomyosis and embryo quality were found to be significantly different between two groups. Morphokinetic parameter analysis of 523 euploid embryos using time-lapse imaging did not show any statistical differences between the two groups, however a significantly higher rate of uneven blastomeres in the cleavage stage was observed in the total preganncy loss group. Evaluation of clinical and embryological data can reveal possible factors associated with pregnancy loss that can facilitate improved patient consultation. Feasible interventions can potentially increase the chance of achieving a live birth.

Higher Concentrations of Essential Trace Elements in Women Undergoing IVF May Be Associated with Poor Reproductive Outcomes Following Single Euploid Embryo Transfer.

Essential trace elements are micronutrients whose deficiency has been associated with altered fertility and/or adverse pregnancy outcomes, while surplus may be toxic. The concentrations of eight essential trace elements were measured using inductively coupled mass spectrometry (ICP-MS) and assessed with respect to clinical in vitro fertilization (IVF) outcomes in a population of 51 women undergoing IVF with intracytoplasmic sperm injection (ICSI), pre-implantation genetic screening for aneuploidy (PGT-A), and single frozen euploid embryo transfer (SET/FET). Specifically, copper (Cu), zinc (Zn), molybdenum, selenium, lithium, iron, chromium, and manganese were quantified in follicular fluid and whole blood collected the day of vaginal oocyte retrieval (VOR) and in urine collected the day of VOR and embryo transfer. We found that the whole blood Cu/Zn ratio was significantly associated with superior responses to ovarian stimulation. Conversely, the whole blood zinc and selenium concentrations were significantly associated with poor ovarian response outcomes. Higher levels of whole blood zinc and selenium, urinary selenium, lithium, and iron had significant negative associations with embryologic outcomes following IVF. Regarding clinical IVF outcomes, higher urinary molybdenum concentrations the day of VOR were associated with significantly lower odds of implantation and live birth, while higher urinary Cu/Mo ratios on the day of VOR were associated with significantly higher odds of implantation, clinical pregnancy, and live birth. Our results suggest that essential trace element levels may directly influence the IVF outcomes of Spanish patients, with selenium and molybdenum exerting negative effects and copper-related ratios exerting positive effects. Additional studies are warranted to confirm these relationships in other human populations.

Effect of intraovarian platelet-rich plasma injection on IVF outcomes in women with poor ovarian response: the PROVA randomized controlled trial.

Does intraovarian platelet-rich plasma (PRP) injection increase the number of mature oocytes obtained after controlled ovarian stimulation (COS) in young women with poor ovarian response (POR) undergoing IVF? Intraovarian PRP injection procedure does not improve mature oocyte yield after COS in women less than 38 years old with an established IVF history of POR. POR is frequently encountered among the infertile population and the number of women seeking infertility treatment related to POR is increasing. Effective treatment options for this patient population to conceive with autologous oocytes are lacking. Case series and cohort studies suggest that intraovarian PRP injection may improve follicular recruitment in women with premature ovarian insufficiency (POI) and POR, yet robust randomized studies have not been performed to date to determine the clinical utility of this intervention. This was a multi-center randomized controlled trial (RCT) conducted at university-affiliated reproductive centers in the USA and Turkey, between January 2020 and November 2022. Patients who met inclusion criteria (<38 years old, two or more prior cycles with <3 oocytes retrieved; and without single gene disorders, prior ovarian surgery, endometriomas, BMI >35 kg/m2, or severe male factor infertility) were randomized to either the PRP or control group. Patients in both groups subsequently underwent COS, oocyte retrieval, ICSI, preimplantation genetic testing for aneuploidy (PGT-A), and single euploid embryo transfer. Number of metaphase II (MII) oocytes obtained was the primary outcome. Secondary outcomes included ovarian reserve tests (antral follicle count [AFC] and anti-Müllerian hormone [AMH]), blastocyst and euploid blastocyst yields, and sustained implantation. The study was powered to detect a difference of one mature oocyte obtained at oocyte retrieval. In total, 83 patients met inclusion criteria and were randomized to receive autologous intraovarian PRP injection (n = 41) or to no intervention (n = 42). No significant differences were observed in number of MII oocytes retrieved per cycle (2.8 ± 2.4 vs 3.1 ± 3.3 in PRP vs control, respectively; P = 0.9), blastocysts (1.0 ± 1.3 vs 1.3 ± 2.1, P = 0.8), or euploid blastocysts (0.8 ± 1.1 vs 0.9 ± 1.6; P = 0.5). Similarly, no differences were observed in the likelihood of obtaining at least one euploid blastocyst (45% vs 37%, P = 0.4; relative risk [RR], 95% CI = 0.9, 0.6-1.2) or the rate of sustained implantation (31% vs 29%, P = 0.9; RR 1.0, 0.7-1.3). Posttreatment AFC (7.9 ± 4.5 vs 6.8 ± 4.8, P = 0.3) and AMH (0.99 ± 0.98 vs 0.7 ± 0.6, P = 0.2) were also not different between the groups. Results from this RCT may not be generalizable to other PRP preparations owing to heterogeneity and lack of standardization. The control groups did not undergo a sham ovarian injection, which would have been relevant had the results shown benefit of PRP injection. Only patients with POR were included in this study, and these results may not be generalizable to more severe diminution of ovarian reserve, as seen with POI. The intraovarian PRP injection procedure does not improve mature oocyte yield or other parameters of IVF outcome in women less than 38 years old with an established IVF history of POR. The results from this study do not support the use of intraovarian PRP injection in this population. Departmental funds were used and no external funding was requested for this study. ES is a consultant for and receives grant funding from the Foundation for Embryonic Competence. All other authors have no conflict of interest to declare. Clinicaltrials.gov Registry Identifier: NCT04163640. 15 November 2019. 24 February 2020.

Effect of postthaw change in embryo score on single euploid embryo transfer success rates

ObjectiveTo assess whether the change in embryo morphology from pre-cryopreservation to post-thaw is associated with embryo transfer success rates in single euploid embryo transfer cycles. DesignRetrospective cohort study SubjectsPatients who underwent a single euploid embryo transfer cycle from September 2016 – April 2022 were included. A decision support tool was used to assign each embryo a reproductive potential score based on the day of biopsy, expansion, and grade of trophectoderm and inner cell mass (ICM) at the time of cryopreservation and post-thaw.(1) Embryos were divided into 4 groups: Group 1 included embryos with the same score post-thaw (reference), Group 2 higher score, Group 3 lower score, and Group 4 embryos that did not re-expand post-thaw. Intervention(s)No interventions administered. Main Outcome MeasuresPrimary outcome was live birth rates per embryo transfer (LBR). Secondary outcomes included chemical pregnancy, clinical pregnancy, and clinical pregnancy loss rate. Comparative statistics and univariate analyses were performed using Kruskal-Wallis and chi-square tests. Multivariate logistic regression fitted with generalized estimating equation was performed to compare the odds of live birth between groups. ResultsA total of 7750 embryo transfers performed for 4613 patients met inclusion criteria: 5331 in Group 1, 486 in Group 2, 1726 in Group 3, and 207 in group 4. On univariate analysis, there was a statistically significant difference in LBR between groups 1, 2, 3, and 4 (55.8% vs 51.4%, 47.5%, 26.6%, p<0.0001). Logistic regression controlling for oocyte age, AMH, BMI, endometrial thickness, year of embryo transfer, time from thaw to final grading, and embryo score prior to cryopreservation showed significantly lower odds of LBR when the embryo was downgraded (OR 0.70, CI 0.62-0.79, p=<.0001) or did not re-expand (OR 0.36, CI 0.26-0.51 p=<.0001) compared with no change in score. When controlling for all variables, there was a significant increase in odds of live birth between embryos that had higher score post-thaw versus those without a change (OR 1.42, CI 1.14-1.76, p=0.002). There was no significant difference in clinical pregnancy loss rate among the 4 groups. ConclusionsThe change in quality of the embryo post-thaw is an important factor in embryo transfer success. In an adjusted analysis, the chemical pregnancy, clinical pregnancy, and LBR per embryo transfer are all significantly decreased in embryos that were downgraded or did not expand on the day of single euploid embryo transfer. Embryos that re-expand and improve their quality post-thaw have the highest odds of live birth.

Single Euploid Embryo Transfer Outcomes After Uterine Septum Resection

ObjectiveTo study pregnancy outcomes after single euploid embryo transfer (SEET) in patients who underwent prior uterine septum resection to those with uteri of normal contour, without Müllerian anomalies or uterine abnormalities including polyps or fibroids, and without a history of prior uterine surgeries. DesignRetrospective cohort study SettingSingle academic affiliated center Patients60 cycles of patients with prior hysteroscopic uterine septum resection who underwent an autologous SEET between 2012-2020 were used as the investigational cohort. A 3:1 ratio propensity score matched control cohort of 180 single euploid embryo transfer cycles from patients without a history of uterine septa were used as the control group. Intervention(s)No interventions administered. Measurements and Main ResultsPregnancy, clinical pregnancy loss, ongoing clinical pregnancy, and live birth rates in patients with history of uterine septum resection compared to matched patients without Müllerian anomalies or uterine surgeries. Patients with a prior uterine septum had significantly lower rates of chemical pregnancy (58.33% vs 77.2%, p=0.004), implantation (41.67% vs 65.6%, p=0.001), and live birth (33.33% vs 57.8%, p=0.001) per transfer. No statistical difference in clinical pregnancy loss rates was found when comparing septum patients with controls (8.33% vs 7.8%, p=0.89). ConclusionPatients with history of hysteroscopic resection who undergo in vitro fertilization are more susceptible to suboptimal clinical outcomes compared to patients with normal uteri. Early pregnancy loss rates in patients with a uterine septum are higher than in those without, however, after resection, the rates are comparable. Patients born with septate uteri require assessment of surgical intervention prior to SEET and to optimize their reproductive outcomes.

Correlation of self-reported racial background to euploidy status and live birth rates in assisted reproductive technology cycles.

To determine whether the embryonic euploidy rate and live birth outcomes following single, euploid embryo transfer (SEET) differ among women of self-reported racial and ethnic backgrounds. This retrospective cohort study included all infertile patients of different self-reported racial backgrounds who underwent In vitro fertilization (IVF) with preimplantation genetic testing for aneuploidy (PGT-A) and an autologous single euploid embryo transfer (SEET) from December 2015 to December 2019 at a single private and academic assisted reproduction technology center. Primary outcome measures included ploidy rates among different racial groups. Secondary outcomes included clinical pregnancy, clinical pregnancy loss, and live birth rates. Five thousand five hundred sixty-two patients who underwent an IVF cycle with ICSI-PGT-A were included. A total of 24,491 blastocysts were analyzed. White participants had on average more euploid embryos and higher euploidy rates when compared to their counterparts (p ≤ 0.0001). However, after controlling for confounding factors, there was no association between race and the odds of having ahigher euploidy rate (aOR 1.31; 95% CI 0.63-2.17, p = 0.42). A total of 4949 patients underwent SEET. Pregnancy outcomes did not differ among patients of varying self-reported races. Euploidy rates and pregnancy outcomes were comparable among patients of different racial backgrounds who underwent a SEET.