Morphological quality on Day 3 affects the pregnancy outcomes of low-quality euploid blastocysts: a retrospective cohort study.

STUDY QUESTION: Does the morphological quality on Day 3 influence the pregnancy outcomes of euploid blastocysts? SUMMARY ANSWER: The morphological quality on Day 3 affects the clinical pregnancy rate (CPR) and live birth rate (LBR) of low-quality euploid blastocysts. WHAT IS KNOWN ALREADY: The morphological grading of Day 3 embryos affects the pregnancy outcome of cleavage-stage embryos and is an excellent indicator to predict embryo development potential. However, it is still unclear whether morphological quality on Day 3 is associated with pregnancy outcomes of the euploid blastocyst. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study comprised 1275 patients who received single euploid blastocyst transfer between January 2016 and August 2021 at a tertiary teaching hospital. PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients were grouped into two groups according to the morphological grading on Day 3 of transferred blastocysts: high-quality (HQ, including Grades I and II) Day 3 embryos and low-quality (LQ, Grade III) Day 3 embryos. The primary outcomes were CPR and LBR. Interactions of development days (Day 5 and Day 6) and morphological quality (high- and low-quality) of blastocysts with morphological quality of Day 3 embryos on pregnancy outcomes were tested in the stratified analysis and logistic regression models. The multivariate logistic regression analysis was conducted to investigate the independent effect of the morphological quality of Day 3 embryos on pregnancy outcomes after adjusting for potentially confounding factors. MAIN RESULTS AND THE ROLE OF CHANCE: The CPR and LBR of the HQ Day 3 embryos group were statistically higher than those of the LQ Day 3 embryos group (CPR: 59.73% versus 49.70%, respectively, P = 0.015; LBR: 49.73% versus 41.21%, respectively, P = 0.041). The development days of blastocysts did not exhibit a multiplicative interaction with the morphological quality of Day 3 embryos on the CPR (P for interaction = 0.648) and LBR (P for interaction = 0.925). The morphological quality of blastocysts exhibits a multiplicative interaction with the morphological quality of Day 3 embryos on the CPR (P for interaction = 0.020) and LBR (P for interaction = 0.012). After adjusting for potential confounders, the HQ Day 3 embryo group was positively associated with the CPR (adjusted odds ratio (aOR): 2.10, 95% CI: 1.31-3.36, P = 0.002) and LBR (aOR: 1.97, 95% CI: 1.20-3.25, P = 0.008) of LQ blastocysts. However, the morphological quality on Day 3 was not significantly associated with the CPR (aOR: 0.95, 95% CI: 0.58-1.55, P = 0.835) and LBR (aOR: 0.86, 95% CI: 0.53-1.40, P = 0.550) of HQ blastocysts. LIMITATIONS, REASONS FOR CAUTION: Selection and confounding bias introduced by the retrospective design cannot be completely eliminated in this study, although multivariable logistic analysis was conducted to adjust for potential confounders. Also, some subgroups had small sample sizes, which may reduce statistical power. Moreover, participants in our study only received single euploid blastocyst transfer, and whether the results could apply to blastocysts with unknown ploidy status is unclear. WIDER IMPLICATIONS OF THE FINDINGS: This study found that the morphological quality on Day 3 was significantly associated with the CPR and LBR of LQ blastocysts; Therefore, when only LQ euploid blastocysts are available for transfer, blastocysts derived from HQ Day 3 embryos are recommended. STUDY FUNDING/COMPETING INTEREST(S): No external funding was obtained. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

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

BACKGROUND: The Live Birth Rate (LBR) after day 5 (D5) blastocyst transfer is significantly higher than that with D6 embryos in both fresh and frozen-vitrified embryo transfer cycles, according to the most recently published meta-analyses. Therefore, for women obtaining only D6 blastocysts, the chances of pregnancy may be lower but nonetheless sufficient to warrant transferring such embryos. The best strategy for transfer (i.e., in fresh versus frozen cycles) remains unclear and there is a paucity of data on this subject. METHODS: A total of 896 couples with D6 single blastocyst transfers were retrospectively analyzed: patients receiving a fresh D6 embryo transfer (Fresh D6 transfer group, n = 109) versus those receiving a frozen-thawed D6 embryo transfer (Frozen D6 transfer group, n = 787). A subgroup comprising a freeze-all cycle without any previous fresh or frozen D5 embryo transfers (Elective frozen D6, n = 77) was considered and also compared with the Fresh D6 transfer group. We compared LBR between these two groups. Correlation between D6 blastocyst morphology according to Gardner's classification and live birth occurrence was also evaluated. Statistical analysis was carried out using univariate and multivariate logistic regression models. RESULTS: The LBR was significantly lower after a fresh D6 blastocyst transfer compared to the LBR with a frozen-thawed D6 blastocyst transfer [5.5% (6/109) vs. 12.5% (98/787), p = 0.034]. Comparison between LBR after Elective frozen D6 group to the Fresh D6 blastocyst transfers confirmed the superiority of frozen D6 blastocyst transfers. Statistical analysis of the blastocyst morphology parameters showed that both trophectoderm (TE) and inner cell mass (ICM) grades were significantly associated with the LBR after D6 embryo transfer (p < 0.001, p = 0.037). Multiple logistic regression revealed that frozen D6 thawed transfer was independently associated with a higher LBR compared with fresh D6 transfer (OR = 2.54; 95% CI: [1.05-6.17]; p = 0.038). Our results also show that transferring a good or top-quality D6 blastocyst increased the chances of a live birth by more than threefold. CONCLUSIONS: Our results indicate that transferring D6 blastocysts in frozen cycles improves the LBR, making it the best embryo transfer strategy for these slow-growing embryos. CLINICAL TRIAL NUMBER: Not applicable.

Clinical outcomes of single blastocyst transfer with machine learning guided noninvasive chromosome screening grading system in infertile patients.

BACKGROUND: Prospective observational studies have demonstrated that the machine learning (ML) -guided noninvasive chromosome screening (NICS) grading system, which we called the noninvasive chromosome screening-artificial intelligence (NICS-AI) grading system, can be used embryo selection. The current prospective interventional clinical study was conducted to investigate whether this NICS-AI grading system can be used as a powerful tool for embryo selection. METHODS: Patients who visited our centre between October 2018 and December 2021 were recruited. Grade A and B embryos with a high probability of euploidy were transferred in the NICS group. The patients in the control group selected the embryos according to the traditional morphological grading. Finally, 90 patients in the NICS group and 161 patients in the control group were compared statistically for their clinical outcomes. RESULTS: In the NICS group, the clinical pregnancy rate (70.0% vs. 54.0%, p < 0.001), the ongoing pregnancy rate (58.9% vs. 44.7%, p = 0.001), and the live birth rate (56.7% vs. 42.9%, p = 0.001) were significantly higher than those of the control group. When the female was ≥ 35 years old, the clinical pregnancy rate (67.7% vs. 32.1%, p < 0.001), ongoing pregnancy rate (56.5% vs. 25.0%, p = 0.001), and live birth rate (54.8% vs. 25.0%, p = 0.001) in the NICS group were significantly higher than those of the control group. Regardless of whether the patients had a previous record of early spontaneous abortion or not, the live birth rate of the NICS group was higher than that of the control group (61.0% vs. 46.9%; 57.9% vs. 34.8%; 33.3% vs. 0%) but the differences were not statistically significant. CONCLUSIONS: NICS-AI was able to improve embryo utilisation rate, and the live birth rate, especially for those ≥ 35 years old, with transfer of Grade A embryos being preferred, followed by Grade B embryos. NICS-AI can be used as an effective tool for embryo selection in the future.

Improved pregnancy prediction performance in an updated deep-learning embryo selection model: a retrospective independent validation study.

RESEARCH QUESTION: What is the effect of increasing training data on the performance of ongoing pregnancy prediction after single vitrified-warmed blastocyst transfer (SVBT) in a deep-learning model? DESIGN: A total of 3960 SVBT cycles were retrospectively analysed. Embryos were stratified according to the Society for Assisted Reproductive Technology age groups. Embryos were scored by deep-learning models iDAScore v1.0 (IDA-V1) and iDAScore v2.0 (IDA-V2) (15% more training data than v1.0) and by Gardner grading. The discriminative performance of the pregnancy prediction for each embryo scoring model was compared using the area under the curve (AUC) of the receiver operating characteristic curve for each maternal age group. RESULTS: The AUC of iDA-V2, iDA-V1 and Gardener grading in all cohort were 0.736, 0.720 and 0.702, respectively. iDA-V2 was significantly higher than iDA-V1 and Gardener grading (P < 0.0001). Group > 35 years (n = 757): the AUC of iDA-V2 was significantly higher than Gardener grading (0.718 versus 0.694, P = 0.015); group aged 35-37 years (n = 821), the AUC of iDA-V2 was significantly higher than iDA-V1 (0.712 versus 0.696, P = 0.035); group aged 41-42 years (n = 715, the AUC of iDA-V2 was significantly higher than Gardener grading (0.745 versus 0.696, P = 0.007); group > 42 years (n = 660) and group aged 38-40 years (n = 1007), no significant differences were found between the groups. CONCLUSION: The performance of deep learning models for pregnancy prediction will be improved by increasing the size of the training data.

Progesterone concentrations on blastocyst transfer day in modified natural cycle frozen embryo transfer cycles.

RESEARCH QUESTION: Are serum progesterone concentrations on the day of modified natural cycle (mNC) frozen blastocyst transfer (FET) without luteal phase support (LPS) associated with clinical pregnancy rate (CPR)? DESIGN: Data were collected between January 2019 and October 2022 as a sub-study of an ongoing randomized controlled trial assessing pregnancy outcomes in mNC-FET. The sub-study included all women (n = 209) randomized to mNC-FET without LPS at the time of data extraction. Participants were aged 18-41 years, had regular menstrual cycles and underwent mNC-FET treatment with single-blastocyst transfer. Associations between the serum progesterone concentration on the day of blastocyst transfer and CPR, pregnancy rate and pregnancy loss rate (PLR) were examined between groups with low and higher progesterone concentrations using the 25th and 10th percentiles as cut-offs. Multivariate logistic regression analyses were performed to adjust for potential confounding factors. RESULTS: Progesterone concentrations on the day of blastocyst transfer in mNC-FET without LPS ranged from 4.9 to 91.8 nmol/l, with the 25th and 10th percentiles at 29.0 nmol/l and 22.5 nmol/l, respectively. Serum progesterone concentrations did not differ between women with or without a clinical pregnancy (mean [SD] 38.5 [14.0] versus 36.8 [12.4] nmol/l; P = 0.350). Furthermore, the CPR, pregancy rate and PLR were similar in women with low or high progesterone concentrations when using the 25th or the 10th progesterone percentile as cut-off. Multivariate regression analyses showed no association between progesterone concentrations and CPR. CONCLUSIONS: No association was found between progesterone concentration on the day of blastocyst transfer and pregnancy outcome in women undergoing mNC-FET without progesterone LPS.

Artificial shrinkage before fresh blastocyst transfer and IVF outcomes: a pilot randomized controlled study.

RESEARCH QUESTION: Does artificial shrinkage before fresh blastocyst transfer improve clinical pregnancy rates in IVF? DESIGN: In this monocentric prospective, randomized, double-blind, controlled pilot study, 150 couples undergoing fresh single-blastocyst transfer were randomized between 20 May 2018 and 22 February 2022. In the artificial shrinkage group (AS group), a single laser pulse was directed to the cellular junction of the trophectoderm on the opposite side of the inner cell mass in each blastocyst. IVF outcomes were clinical pregnancy, multiple pregnancy and live birth rates. Cell-free DNA (cfDNA) concentration was also measured by quantitative real-time PCR in the blastocyst culture medium. RESULTS: In total, 142 couples underwent fresh single-blastocyst transfer: control group, no artificial shrinkage, n = 47; and AS group, artificial shrinkage, n = 95; An intention-to-treat (ITT) analysis was employed. After a reassessment and the exclusion of patients with major protocol deviations, 139 couples underwent fresh single-blastocyst transfer under optimal conditions: control group, n = 47; and AS group, n = 92; a per-protocol analysis was used here. The clinical and laboratory characteristics were not significantly different between the groups. The clinical pregnancy rate was similar in the control and AS groups (ITT: 48.9% versus 49.5%, P = 0.97; per protocol: 48.94% versus 51.1%, P = 0.89). The multiple pregnancy rate and the live birth rate were also similar between the groups. No significant differences in gestational age, birthweight or proportion of male/female newborns were observed. The concentration of cfDNA in the blastocyst culture medium was not associated with IVF outcome. CONCLUSIONS: Large-scale randomized controlled trials are required to confirm these preliminary results.

Impact of inclusion of a poor-quality embryo with a good-quality embryo on pregnancy outcomes in vitrified-warmed blastocyst transfers.

RESEARCH QUESTION: Does the co-transfer of a good-quality embryo and a poor-quality embryo influence pregnancy outcomes in comparison to the transfer of a single good-quality embryo in vitrified-warmed blastocyst transfer cycles? DESIGN: This retrospective cohort study involved a total of 11,738 women who underwent IVF/intracytoplasmic sperm injection cycles and vitrified-warmed blastocyst transfer at a tertiary-care academic medical from January 2015 to June 2022. The study population was categorized into two groups: single-blastocyst transfer (SBT; participants who underwent single good-quality embryo transfer, n = 9338) versus double-blastocyst transfer (DBT; participants who underwent transfers with a poor and a good-quality embryo, n = 2400). RESULTS: The live birth rate (LBR) was significantly higher in the DBT group in comparison with the SBT group (65.6% versus 56.3%, P < 0.001). Multivariable logistic regression analysis showed that DBT was an independent predictor for LBR with a strong potential impact (adjusted odds ratio 1.55, 95% confidence interval 1.41-1.71; P < 0.001). However, the multiple birth rate was significantly higher in the good-quality embryo and poor-quality embryo group compared with patients undergoing a single good-quality embryo transfer (41.4% versus 1.8%; P < 0.001). CONCLUSIONS: In vitrified-warmed blastocyst transfer cycles, LBR was higher following DBT with one good-quality and one poor-quality embryo compared with SBT. However, this was at the expense of a marked increase in the likelihood of multiple gestations. Physicians should still balance the benefits and risks of double-embryo transfer.

Trophectoderm biopsy is associated with lower risks of moderate to extreme prematurity and low birthweights: a national registry cohort study of singleton livebirths from frozen-thawed blastocyst transfers.

BACKGROUND: Trophectoderm biopsy has become the mainstay assisted reproductive technique performed for preimplantation genetic testing, accounting for 43.8% of embryo transfer cycles in the United States in 2019 alone. Despite its prevalence, data on the obstetric and perinatal outcomes post-trophectoderm biopsy remains sparse and mixed. OBJECTIVE: This study aimed to examine the risks of adverse perinatal outcomes in birthweights and prematurity after transfers of the vitrified-thawed blastocyst with trophectoderm biopsy for preimplantation genetic testing. STUDY DESIGN: This was a retrospective observational cohort study of 45,712 singleton livebirths resulting from autologous vitrified-thawed blastocyst transfer cycles with or without trophectoderm biopsy for preimplantation genetic testing, reported by participating member clinics to the Society for Assisted Reproductive Technology national registry between 2014 and 2017. Adverse perinatal outcomes of preterm births and low birthweights were analyzed. Multivariable regression analyses were performed to control for covariates. Comparing the trophectoderm biopsy (n=21,584) and no trophectoderm biopsy (n=24,128) groups, adjusted odds ratios were calculated for the outcomes of small-for-gestational-age, large-for-gestational-age, low birthweight <2500 g, very low birthweight <1500 g, extremely low birthweight <1000 g, late preterm births <37 weeks, moderate preterm births <34 weeks, and extremely preterm births <28 weeks. RESULTS: Women in the trophectoderm biopsy group were older and more likely to have prior pregnancies, deliveries, and a history of spontaneous abortions. Tobacco use, diminished ovarian reserve, and recurrent pregnancy loss were also more prevalent in the trophectoderm biopsy group. Trophectoderm biopsy was not associated with small-for-gestational-age (adjusted odds ratio, 0.97; 95% confidence interval, 0.85-1.12; P=.72) or large-for-gestational-age newborns (adjusted odds ratio, 1.10; 95% confidence interval, 0.99-1.22; P=.09). Risks of preterm births <37 weeks gestation were similar between the biopsy and nonbiopsy groups (adjusted odds ratio, 0.93; 95% confidence interval, 0.85-1.02; P=.11). Trophectoderm biopsy was associated with a significantly lower risk of low birthweight <2500 g (adjusted odds ratio, 0.80; 95% confidence interval, 0.70-0.92; P<.001), very low birthweight <1500 g (adjusted odds ratio, 0.62; 95% confidence interval, 0.46-0.83; P<.001), extremely low birthweight <1000 g (adjusted odds ratio, 0.48; 95% confidence interval, 0.31-0.74; P<.001), moderate preterm birth <34 weeks (adjusted odds ratio, 0.76; 95% confidence interval, 0.64-0.91; P=.003), and extreme preterm birth <28 weeks (adjusted odds ratio, 0.63; 95% confidence interval, 0.43-0.92; P=.02). CONCLUSION: Trophectoderm biopsy is not associated with increased risks of small-for-gestational-age, large-for-gestational-age, or late preterm birth. Risks of low birthweight, very low birthweight, and extremely low birthweight from moderate and extreme preterm births are lower after trophectoderm biopsy, possibly by selecting against confined placental mosaicism or inducing placental epigenetic changes, the mechanisms of which warrant further investigation.

Effect of Day 3 cell number on the live birth rate of vitrified-warmed Day 5 single blastocyst transfer in young women.

BACKGROUND: Previous studies have reported inconsistent results regarding blastocyst selection with a high day 3 (D3) cell number and the eventual pregnancy outcomes. Thus, in this study, the relationship between the D3 cell number and clinical outcomes of day 5 single blastocyst transfer (SBT) in vitrified-warmed transfer cycles was investigated. METHODS: Our retrospective study included 1144 day 5 SBT in vitrified-warmed cycles between February 2016 and February 2021. All cycles were the first vitrified-warmed cycles, and the female patients were less than 35 years of age. Based on the D3 cell number, the cycles were divided into four groups, as follows: group A (3-7 cells, n = 130); group B (8-9 cells, n = 621); group C (10-12 cells, n = 328); and group D (13-16 cells, n = 65). The differences in the live birth rate (LBR), clinical pregnancy rate, and miscarriage rate were examined among the four groups. RESULTS: The LBR and clinical pregnancy rate increased with the D3 cell number (P < 0.01). No significant difference was found in the miscarriage rate among the groups (P = 0.055). After adjusting for confounding factors, the LBR was significantly higher in groups C (odds ratio [OR] = 1.477, 95% confidence interval [CI]: 1.124-1.941, P = 0.005) and D (OR = 2.000, 95% CI: 1.166-3.429, P = 0.012) than in group B. CONCLUSIONS: A high D3 cell number (> 9 cells) was associated with a high LBR in the vitrified-warmed day 5 SBT cycles of patients < 35 years of age. The cell number of D3 embryos can be an important reference indicator for blastocyst selection. Among blastocysts with the same morphological score, those with > 9 cells on D3 can be preferentially selected for transplantation.

Comparison of pregnancy outcomes among patients of different ages who underwent frozen-thawed high-quality single blastocyst transfer.

OBJECTIVE: To investigate the feasibility of performing frozen-thawed high-quality single blastocyst transfer in women of different ages. METHODS: A total of 1,279 women were divided into four groups: a 38-40-year-old group (n = 147), 35-37-year-old group (n = 164), 30-34-year-old group (n = 483), and < 30-year-old group (n = 485). Intergroup comparisons of baseline characteristics and pregnancy and neonatal outcomes were made. RESULTS: The clinical pregnancy rate (47.6%), and live birth rate (34.0%) in the 38-40-year-old group were significantly lower than those in the 30-34-year-old group (64.4%, 50.9%, respectively; all P < 0.001) and < 30-year-old group (62.9%, 50.7%, respectively; all P < 0.001). However, the 35-37-year-old group did not differ from the other three groups in these two dimensions (all P > 0.05). Moreover, there were no differences in the rates of biochemical pregnancy, miscarriage, or obstetric or neonatal complications among the four groups (all P > 0.05). According to the multivariate logistic regression analysis, the 35-37-year-old group was not associated with non-live birth outcomes, adverse pregnancy outcomes, or obstetric or neonatal complications. However, being 38-40 years of age was a risk factor for non-live birth (OR = 2.121, 95% CI: 1.233-3.647) and adverse pregnancy outcomes (OR = 1.630, 95% CI: 1.010-2.633). Post hoc power analysis showed that the study was sufficiently powered to detect meaningful differences. CONCLUSION: Frozen-thawed high-quality single blastocyst transfer produces the same satisfactory pregnancy outcomes for women aged 35-37 years as younger patients. Future prospective randomized controlled studies with larger populations are needed to verify the feasibility and safety of this method.

Trade-off between double cleavage-stage embryos transfer and single blastocyst-stage embryo transfer in patients with few good quality embryos in antagonist cycles: a retrospective study using a propensity score matching analysis.

OBJECTIVE: This study aimed to compare the per OPU clinical outcomes for transfer of Day 3 double cleavage-stage embryos (DET) and Day 5 single blastocyst-stage (SBT) in patients with five or fewer good quality embryos on day 3 per occyte pick-up cycle (OPU) in antagonist cycles with consideration of blastocyst formation failure. METHODS: This was a retrospective, observational cohort study of 2,116 cases of OPU treated with antagonist protocol in the affiliated Chenggong Hospital of Xiamen University between January 2013 and December 2020. DET was performed in 1,811cycles and SBT was performed in 305 cycles. The DET group was matched to the SBT group by propensity score (PS) matching according to multiple maternal baseline covariates. After PS matching, there were 303 ET cycles in each group. The primary outcomes were the cumulative live birth rate (CLBR), cumulative multiple pregnancy rate(CMPR)per OPU and the number of ET to achieve live birth per OPU. Secondary outcomes were the percentage of clinical pregnancy(CPR), live birth rate(LBR), multiple pregnancy rate(MPR). RESULTS: Following PS mating, the CLBR was slightly higher (48.8% versus 40.3% ; P = 0.041) and the CMPR was significantly higher in the DET group compared to SBT group(44.2% versus 7.9%, P < 0.001). The CPR, LBR and MPR per fresh transfer were higher in DET group compared to SBT group(50.2% versus 28.7%; 41.3% versus 21.5%;29.6% versus 0%, P < 0.001). The number of ET to achieve live birth per OPU in SBT group was obiviously more than in DET group(1.48 ± 0.578 versus 1.22 ± 0.557 ,P < 0.001). CONCLUSION: With a marginal difference cumulative live birth rate, the lower live birth rate per fresh transfer and higher number of ET per OPU in the SBT group suggested that it might take longer time to achieve a live birth with single blastocyst strategy. A trade-off decision should be made between efficiency and safety.

Single versus double blastocyst transfer in first and second frozen-thawed embryo transfer cycle in advance-aged women: a two-center retrospective cohort study.

BACKGROUND: The present evidence is deficient for the trade-offs between the pros and cons of single blastocyst transfer (SBT) versus double blastocyst transfer (DBT) in frozen-thawed embryo transfer cycles for women in advanced reproductive age, especially in the second cycle. The current study aimed to investigate the impact of transferred blastocyst numbers on pregnancy outcomes in the first and second embryo transfer for women ≥ 35 years. METHODS: This was a retrospective cohort study including 1284 frozen-thawed blastocyst transfer (FBT) cycles from two reproductive centers. We analyzed the pregnancy outcomes after SBT and DBT in the first and second FBT cycles. Moreover, stratified analysis was conducted by maternal age. RESULTS: In the first FBT cycle, the LBR was higher in the DBT group than that in the SBT group [52.3% vs. 33.9%; adjusted odds ratio (aOR), 1.65; 95% confidence interval (CI), 1.26-2.15, P < 0.001]. However, the LBR of the DBT group showed no remarkable difference compared with that of the SBT group in the second cycle of FBT (44.3% vs. 33.3%; aOR, 1.30; 95% CI, 0.81-2.08; P = 0.271). Furthermore, stratified analysis by age showed a higher LBR for the DBT group than the SBT group in patients aged 38-42 years (43.1% vs. 33.9%; aOR, 2.27; 95% CI, 1.05-4.90; P = 0.036). CONCLUSIONS: The present study demonstrated that the SBT regimen is a better choice for both, the first and second frozen-thawed embryo transfer cycles, for women aged 35-37 years. Additionally, the DBT regimen is still recommended to achieve a high LBR in women aged 38-42 years in the second FBT cycle. These findings may be beneficial for deciding the embryo transfer regimens in women of advanced reproductive age.

Benefits of Blastocyst Transfer With at Least Three Good-Quality Cleavage-stage Embryos in Women of Advanced Maternal Age: A Retrospective Analysis.

OBJECTIVES: Limited studies on the benefits of blastocyst transfer in advanced maternal age (AMA) (≥40 years) have been reported. Our objective was to find whether blastocyst-stage embryo transfer improves pregnancy and live birth rates in women ≥40 years who have 3 or more good-quality cleavage-stage embryos. METHODS: All fresh in vitro fertilization-intracytoplasmic sperm injection cycles performed from January 2020 to December 2021 in AMA women that progressed to transfer were considered for analysis. We compared fresh and cumulative ongoing pregnancy rates in AMA women of those who had a cleavage-stage transfer, while meeting the criteria for extended culture (≥3 high-quality embryos, group 1), and those who underwent blastocyst transfer (group 2). Demographic parameters, stimulation, embryology, fresh and cumulative ongoing pregnancy rates, and clinical miscarriage rates were compared. RESULTS: During the study period, 255 cycles were analyzed including group 1 (n = 99) and group 2 (n = 156). Group 1 participants were older and had a greater number of embryos for transfer. Fresh and cumulative ongoing pregnancy rates per transfer were higher in group 2 compared to group 1 (23.4% vs. 13.1%, P = 0.04; 25.5% vs. 14.1%, P = 0.03), while overall miscarriage rates were higher in group 1 than group 2 (51.7% vs. 25%, P = 0.01). CONCLUSIONS: Blastocyst culture provides a benefit to AMA women who have at least 3 good-quality embryos on day 3 resulting in significantly higher fresh and cumulative ongoing pregnancy rates and lower miscarriage compared to cleavage-stage transfers.

Does cleavage stage morphology increase the discriminatory power of prediction in blastocyst transfer outcome?

PURPOSE: To evaluate the contribution of the cleavage stage morphological parameters to the prediction of blastocyst transfer outcomes. METHODS: A retrospective study was conducted on 8383 single-blastocyst transfer cycles including 2246 fresh and 6137 vitrified-warmed cycles. XGboost, LASSO, and GLM algorithms were employed to establish models for assessing the predictive value of the cleavage stage morphological parameters in transfer outcomes. Four models were developed using each algorithm: all-in model with or without day 3 morphology and embryo quality-only model with or without day 3 morphology. RESULTS: The live birth rate was 48.04% in the overall cohort. The AUCs of the models with the algorithm of XGboost were 0.83, 0.82, 0.63, and 0.60; with LASSO were 0.66, 0.66, 0.61, and 0.60; and with GLM were 0.66, 0.66, 0.61, and 0.60 respectively. In models 1 and 2, female age, basal FSH, peak E2, endometrial thickness, and female BMI were the top five critical features for predicting live birth; In models 3 and 4, the most crucial factor was blastocyst formation on D5 rather than D6. In model 3, incorporating cleavage stage morphology, including early cleavage, D3 cell number, and fragmentation, was significantly associated with successful live birth. Additionally, the live birth rates for blastocysts derived from on-time, slow, and fast D3 embryos were 49.7%, 39.5%, and 52%, respectively. CONCLUSIONS: The value of cleavage stage morphological parameters in predicting the live birth outcome of single blastocyst transfer is limited.

Prioritized single vitrified blastocyst to be warmed between grades 3 or 4 blastocyst on day 5 transfer cycles.

PURPOSE: Selecting the optimal blastocyst to implant during cryopreservation and warming is critial for in vitro fertilization success. Therefore, the aim of this study was to explore which blastocyst should be prioritized to be thawed when facing a single vitrified blastocyst on day 5 transfer. METHODS: A retrospective study including 1,976 single vitrified-warmed blastocyst transfer cycles was conducted from January 2016 to December 2020. RESULTS: We found that grade 4 vitrified blastocyst had a higher clinical pregnancy (60.64% vs. 49.48%, P < 0.001) and live birth rates (50.12% vs 39.59%, P < 0.001) than the grade 3 vitrified blastocyst. However, no statistical difference was found between groups in miscarriage rate, birth weight, or gestational age. Besides, the grade 4 vitrified-thawed blastocyst had significant potential to develop into grade 6 blastocyst after further culturing for 16 h (73.68% vs. 48.60%, P < 0.001). The grade 6 transferred blastocyst was markedly higher in both clinical pregnancy rate (61.88% vs. 51.53%, P < 0.001) and live birth rate (50.91% vs. 40.46%, P < 0.001) compared to grade 5 transferred blastocyst. CONCLUSIONS: Grade 4 vitrified blastocyst is recommended when facing single vitrified blastocyst on day 5 transfer. More importantly, the "embryonic escape hypothesis" was firstly proposed to reveal the findings.

Blastocyst quality and reproductive and perinatal outcomes: a multinational multicentre observational study.

STUDY QUESTION: Does the transfer of single low-grade blastocysts result in acceptable reproductive and perinatal outcomes compared to the transfer of single good-grade blastocysts? SUMMARY ANSWER: The transfer of single low-grade blastocysts resulted in a reduced live birth rate of around 30% (14% for very low-grade blastocysts) compared to 44% for single good-grade blastocysts, but does not lead to more adverse perinatal outcomes. WHAT IS KNOWN ALREADY: It is known that low-grade blastocysts can result in live births. However, the current studies are limited by relatively small sample sizes and single-centre designs. Furthermore, evidence on perinatal outcomes after transferring low-grade blastocysts is limited. STUDY DESIGN, SIZE, DURATION: We conducted a multi-centre, multi-national retrospective cohort study of 10 018 women undergoing 10 964 single blastocyst transfer cycles between 2009 and 2020 from 14 clinics across Australia, China, and New Zealand. PARTICIPANTS/MATERIALS, SETTING, METHODS: Blastocysts were graded individually based on assessment of the morphology and development of the inner cell mass (ICM) and trophectoderm (TE), and were grouped into three quality categories: good- (AB, AB, or BA), moderate- (BB), and low-grade (grade C for ICM or TE) blastocysts. CC blastocysts were individually grouped as very low-grade blastocysts. Logistic regression with generalized estimating equation was used to analyse the association between blastocyst quality and live birth as well as other reproductive outcomes. Binomial, multinomial logistic, or linear regression was used to investigate the association between blastocyst quality and perinatal outcomes. Odds ratio (OR), adjusted OR (aOR), adjusted regression coefficient, and their 95% CIs are presented. Statistical significance was set at P < 0.05. MAIN RESULTS AND THE ROLE OF CHANCE: There were 4386 good-grade blastocysts, 3735 moderate-grade blastocysts, and 2843 low-grade blastocysts were included in the analysis, for which the live birth rates were 44.4%, 38.6%, and 30.2%, respectively. Compared to good-grade blastocysts, the live birth rate of low-grade blastocysts was significantly lower (aOR of 0.48 (0.41-0.55)). Very low-grade blastocysts were associated with an even lower live birth rate (aOR 0.30 (0.18-0.52)) and their absolute live birth rate was 13.7%. There were 4132 singleton live births included in the analysis of perinatal outcomes. Compared with good-grade blastocysts, low-grade blastocysts had comparable preterm birth rates (<37 weeks, aOR 1.00 (0.65-1.54)), birthweight Z-scores (adjusted regression coefficient 0.02 (0.09-0.14)), and rates of very low birth weight (<1500 g, aOR 0.84 (0.22-3.25)), low birth weight (1500-2500 g, aOR 0.96 (0.56-1.65)), high birth weight (>4500 g, aOR 0.93 (0.37-2.32)), small for gestational age (aOR 1.63 (0.91-2.93)), and large for gestational age (aOR 1.28 (0.97-1.70)). LIMITATIONS, REASONS FOR CAUTION: Due to the nature of the retrospective design, residual confounding could not be excluded. In addition, the number of events for some perinatal outcomes was small. Between-operator and between-laboratory variations in blastocyst assessment were difficult to control. WIDER IMPLICATIONS OF THE FINDINGS: Patients undergoing IVF should be informed that low-grade blastocysts result in a lower live birth rate, however they do not increase the risk of adverse perinatal outcomes. Further research should focus on the criteria for embryos that should not be transferred and on the follow-up of long-term outcomes of offspring. STUDY FUNDING/COMPETING INTEREST(S): H.Z. is supported by a Monash Research Scholarship. B.W.J.M. is supported by a NHMRC Investigator grant (GNT1176437). R.W. is supported by an NHMRC Emerging Leadership Investigator grant (2009767). B.W.J.M. reports consultancy, travel support, and research funding from Merck. The other authors do not have competing interests to disclose. TRIAL REGISTRATION NUMBER: N/A.

Day after rescue ICSI: eliminating total fertilization failure after conventional IVF with high live birth rates following cryopreserved blastocyst transfer.

STUDY QUESTION: What is the impact of day after rescue ICSI (r-ICSI) on success of fresh and frozen embryo transfers? SUMMARY ANSWER: The use of r-ICSI can virtually allay fears of total fertilization failure (TFF) after conventional IVF (C-IVF) and achieve high live birth rates after frozen blastocyst transfer. WHAT IS KNOWN ALREADY: More infertility clinics have resorted to the use of ICSI in place of C-IVF in IVF treatment owing to fear of TFF or a low fertilization rate. r-ICSI has been attempted either on the day of IVF or the day after. Day after r-ICSI has proved unsuccessful in the past. STUDY DESIGN, SIZE, DURATION: A retrospective data analysis was performed of 16 608 qualifying cases between April 2010 and July 2021 conducted at a single private academically affiliated fertility clinic. PARTICIPANTS/MATERIALS, SETTING, METHODS: r-ICSI was performed principally on patients with >4 metaphase II oocytes, showing no signs of fertilization 18 h after C-IVF. C-IVF was performed on patients who had >4 million total motile sperm after preparation. r-ICSI was then performed 18-24 h after insemination, using the sperm sample from the previous day. r-ICSI fertilization rates, cryopreservation of cleavage and blastocysts embryos, and pregnancy rates after fresh or frozen transfer were then assessed. MAIN RESULTS AND THE ROLE OF CHANCE: r-ICSI was performed on 377 patients (2.3% of eligible retrieval cycles) who had a mean (±SD) female and male age of 35.9 ± 4.5 and 38.1 ± 9.1 years, respectively. A total of 5459 oocytes were initially retrieved. Of the oocytes undergoing r-ICSI, 2389 (49.5%) fertilized normally, and 205 (54.4%) patients underwent a fresh embryo transfer. The live birth rates were 23/186 (12.3%) for fresh cleavage and 5/19 (26.3%) for fresh blastocyst stage transfers. In 145 cycles a blastocyst was frozen, and 137 transfers were performed with a 64/137 (46.7%) live birth rate. Of the 377 cycles receiving r-ICSI only, 25 of the qualifying cases failed to have any fertilization, reducing TFF to 25/16 608 (0.15%). LIMITATIONS, REASONS FOR CAUTION: This was a single-center retrospective study on a specific subset of patients, which may limit its generalizability to other clinics. WIDER IMPLICATIONS OF THE FINDINGS: r-ICSI allows a second opportunity to fertilize oocytes despite poor initial outcomes. Patients who had a frozen blastocyst transfer achieved high live birth rates, indicating that a resynchronization of the embryo with the endometrium can optimize r-ICSI cases. r-ICSI allays fears of TFF when using C-IVF, providing evidence that the overuse of ICSI in patients without male factor may not be warranted. STUDY FUNDING/COMPETING INTEREST(S): The study was internally funded by Boston IVF. The authors declare that they have no conflict of interest in relation to the data published in the article. TRIAL REGISTRATION NUMBER: N/A.

Interpretable artificial intelligence-assisted embryo selection improved single-blastocyst transfer outcomes: a prospective cohort study.

RESEARCH QUESTION: What is the pregnancy and neonatal outcomes of an interpretable artificial intelligence (AI) model for embryo selection in a prospective clinical trial? DESIGN: This single-centre prospective cohort study was carried out from October 2021 to March 2022. A total of 330 eligible patients were assigned to their preferred groups, with 250 patients undergoing a fresh single-blastocyst transfer cycle after the exclusion criteria had been applied. For the AI-assisted group (AAG), embryologists selected the embryos for transfer based on the ranking recommendations provided by an interpretable AI system, while with the manual group, embryologists used the Gardner grading system to make their decisions. RESULTS: The implantation rate was significantly higher in the AAG than the manual group (80.87% versus 68.15%, P = 0.022). No significant difference was found in terms of monozygotic twin rate, miscarriage rate, live birth rate and ectopic pregnancy rate between the groups. Furthermore, there was no significant difference in terms of neonatal outcomes, including gestational weeks, premature birth rate, birth height, birthweight, sex ratio at birth and newborn malformation rate. The consensus rate between the AI and retrospective analysis by the embryologists was significantly higher for good-quality embryos (i.e. grade 4BB or higher) versus poor-quality embryos (i.e. less than 4BB) (84.71% versus 25%, P < 0.001). CONCLUSIONS: These prospective trial results suggest that the proposed AI system could effectively help embryologists to improve the implantation rate with single-blastocyst transfer compared with traditional manual evaluation methods.

Using blastocyst re-expansion rate for deciding when to warm a new blastocyst for single vitrified-warmed blastocyst transfer.

RESEARCH QUESTION: Can predictive post-warm parameters that support the decision to transfer a warmed blastocyst or to warm another blastocyst be identified in women with multiple frozen-vitrified blastocysts? DESIGN: Retrospective single-centre observational cohort analysis. A total of 1092 single vitrified-warmed blastocyst transfers (SVBT) with known Gardner score, maternal age and live birth were used to develop live birth prediction models based on logistic regression, including post-warm re-expansion parameters. Time-lapse incubation was used for pre-vitrification and post-warm embryo culture. A dataset of 558 SVBT with the same inclusion criteria was used to validate the model, but with known clinical pregnancy outcome instead of live birth outcome. RESULTS: Three different logistic regression models were developed for predicting live birth based on post-warm blastocyst re-expansion. Different post-warm assessment times indicated that a 2-h post-warm culture period was optimal for live birth prediction (model 1). Adjusting for pre-vitrification Gardner score (model 2) and in combination with maternal age (model 3) further increased predictability (area under the curve [AUC] = 0.623, 0.633, 0.666, respectively). Model validation gave an AUC of 0.617, 0.609 and 0.624, respectively. The false negative rate and true negative rate for model 3 were 2.0 and 10.1 in the development dataset and 3.5 and 8.0 in the validation dataset. CONCLUSIONS: Clinical application of a simple model based on 2 h of post-warm re-expansion data, pre-vitrification Gardner score and maternal age can support a standardized approach for deciding if warming another blastocyst may increase the likelihood of live birth in SVBT.

Polycystic ovary syndrome increases the rate of early spontaneous miscarriage in women who have undergone single vitrified euploid blastocyst transfer.

RESEARCH QUESTION: Does polycystic ovary syndrome (PCOS) independently influence the risk of early spontaneous miscarriage in patients undergoing single euploid vitrified blastocyst transfer? DESIGN: This observational cohort study retrospectively analysed 1498 patients undergoing their first single euploid blastocyst frozen transfer cycles between October 2016 and December 2021. Patients were divided into PCOS and non-PCOS groups according to the Rotterdam criteria. Logistic regression analysis was conducted to study the independent effect of maternal PCOS status on early spontaneous miscarriage after single euploid embryo transfer after adjusting for confounding factors. RESULTS: No statistically significant differences were identified in the rates of positive pregnancy test (68.95% versus 64.86%, P = 0.196) or clinical pregnancy (59.93% versus 57.33%, P = 0.429) between the PCOS and non-PCOS groups after single euploid embryo transfer. Early spontaneous miscarriage occurred more frequently in women with PCOS compared with controls (18.67% versus 12.00%, P = 0.023). In single euploid embryo transfer cycles, PCOS significantly increased the incidence of early spontaneous miscarriage after adjusting for some potential confounders (adjusted odds ratio 1.649, 95% CI 1.032 to 2.635, P = 0.036). CONCLUSIONS: Although no significant difference was observed in clinical pregnancy rates, PCOS status increased the risk of early spontaneous miscarriage after single vitrified euploid blastocyst transfer, suggesting an additional role of endometrial dysfunction affected by endocrine disorders. Further studies are needed to investigate the specific mechanisms and effective intervention strategies.