Single Blastocyst Embryo Transfer Research Articles

P-662 Effect of rescue-dose progesterone in patients with low serum progesterone levels on the day of embryo transfer in frozen embryo transfer cycles

Abstract Study question What is the effect of rescue-dose progesterone in patients with low serum progesterone on the day of embryo transfer in frozen embryo transfer cycles? Summary answer In patients with low serum progesterone on the day of embryo transfer, rescue dose progesterone results in significantly higher clinical pregnancy rates. What is known already Frozen embryo transfer (FET) has become more common lately with many centers utilizing hormone replacement therapy (HRT) to electively plan embryo transfer with improved compliance rates. Serum progesterone level on the day of embryo transfer is a very simple, useful investigation which can be used as a predictor of clinical outcomes. Patients with lower progesterone levels (<5ng/ml) are associated with lower clinical pregnancy and ongoing pregnancy rates. Progesterone levels of > 10ng/ml are considered optimal by various studies. There is limited data on the efficacy of progesterone supplementation in patients with low progesterone levels. Study design, size, duration This study was conducted to assess the effect of rescue dose progesterone in patients with low serum progesterone levels on the day of embryo transfer in patients with HRT-FET cycles. This was a retrospective study and data was collected from prospectively maintained records of patients undergoing treatment at Miracles IVF and fertility center, Gurgaon, India between December, 2021 to November, 2023. Participants/materials, setting, methods All were HRT-FET cycles with vaginal progesterone supplementation of 800 mg/day. Serum progesterone levels were done on day of embryo transfer and if 5-10 ng/ml, rescue dose progesterone (100 mg intramuscular) was given. Single blastocyst embryo transfer was done. Inclusion criteria: 1.Age 25-35 years, 2.Endometrial thickness >7.5mm on day of start of progesterone. Exclusion criteria: 1.Transfer day progesterone <5ng/ml, 2. BMI > 30, 3. Previously failed embryo transfer The primary outcome was clinical pregnancy rate. Main results and the role of chance A total of 121 patients underwent 165 cycles during the study period with 93 patients included in the study after fulfilling the inclusion and exclusion criteria. 35 patients (37.6%) received rescue dose progesterone (RD group) and remaining 58 patients (62.4%) received no rescue dose (NRD group) as per their serum progesterone levels. All these patients were followed as per protocol and serum bhcg was done after 14 days of embryo transfer. Patients with positive values were monitored till positive clinical pregnancy. Biochemical pregnancy rates were 20 out of 35 (57.1%), 35 out of 58 ( 60.3%) and 55 out of 93 ( 59.1%) in RD group, NRD group and overall respectively. Clinical pregnancy rates were 18 out of 35 (51.4%), 34 out of 58 ( 58.6%) and 52 out of 93 ( 55.9%) in RD group, NRD group and overall respectively. RD group had significantly improved outcomes in terms of clinical pregnancy rates which were comparable to NRD group Limitations, reasons for caution Limitations, reasons for caution: Ours was a single center retrospective study with limited sample size. Though, our study revealed comparable outcome between the two groups but large volume multicenter studies are needed for making conclusive recommendations. Wider implications of the findings This study provides an insight into the role of serum progesterone levels on the day of embryo transfer. Rescue progesterone dosage for patients with sub-optimal serum progesterone levels may help in achieving similar clinical pregnancy rates and improving overall outcomes. Trial registration number not applicable

P-536 The comparison of luteal phase support in modified natural cycle-frozen embryo transfer in young patients with high quality embryos -vaginal versus vaginal and subcutaneous progesterone.

Abstract Study question Does adding subcutaneous progesterone to vaginal administration affect pregnancy outcomes in young patients undergoing modified natural-frozen embryo transfer (mNC-FTET) with top-good quality, single blastocyst ? Summary answer Adding subcutaneous progesterone supplementation to vaginal administration after frozen-thawed embryo transfer in modified natural cycles does not improve live birth rates. What is known already Vaginal progesterone supplementation during frozen-thawed embryo transfer in modified natural cycles during luteal phase may increase the rate of live birth rate and decrease the rate of miscarriage. Study design, size, duration 245 participants were included in this retrospective cohort study conducted at a single IVF center between November 2020and January 2022.The primary outcome was the live birth rate; secondary outcomes included pregnancy, clinical pregnancy and biochemical and clinical abortion rates. Participants/materials, setting, methods 245 women aged 20-35 years in mNC-FTET cycles with a single top-good quality blastocyst embryo transfer were included. Patients with fibroids, synechiae, recurrent implantation failure, recurrent pregnancy loss were excluded. After thawing embryos were evaluated for quality, hCG(Ovitrelle-Merck) triggered; 129 patients received 200 mg vaginal progesterone (Lutinus-Merck)(group I), while 116 received 200 mg. vaginal and 25 mg subcutaneous progesterone (Progestan-Dex-Kocak Pharma) (group II). The main outcome was live birth rate(LBR), secondary outcome was miscarriage rate. Main results and the role of chance Baseline demographics and background characteristics were similar in the study groups. The live birth rate in group I is 86 of 106 (66.6%) compared 74 of 116 (63.7%) in group II (odds ratio 1,135, 95% confidence interval [CI]: 0.670-0.922, P = 0.637). There were 106 pregnant patients out of 129 in group I (82.17%) and 93 pregnant patients out of 116 in group II (odds ratio 0.877, 95 CI: 0.462-1,666, P = 0.68). The clinical pregnancy rate is 95 out of 129 patients (73.6%) in group I and 90 out of 116 patients in group II (odds ratio of 0.807, 95% confidence interval [CI]: 0.449-1.45, P = 0.474). The rate of biochemical abortion in group II was 10 of 129 patients (7.75%) and 4 of 116 (3.45%) (odds ratio 2.35, 95 CI: 0.717–7.718, P = 0.687). The clinical abortion rate was 6 of 129 patients (4.6%) and 6 of 116 patients (5.17%) in group II (odds ratio 2.35, 95 CI: 0.717-7.718; P = 0.687). According to primary and secondary outcomes, there were no significant differences between the groups. Limitations, reasons for caution To avoid bias, patients older than 35 years were excluded. Subcutaneous progesterone may be beneficial for older patients undergoing euploid embryo transfer. To reduce confounding factors, the number of patients was limited. Wider implications of the findings For luteal phase support, both vaginal and subcutaneous progesterone supplementation did not increase live birth rates following frozen-thawed embryo transfer in modified natural cycles in young patients. Trial registration number not applicable

P-168 Follow-up survey of deliveries derived from Day 7 blastocysts

Abstract Study question Does Day 7 blastocyst-transfer affect prognosis of babies born? Summary answer There was no effect on growth up to 3 years of age in babies from Day 7 blastocyst-derived births. What is known already Culture medium and technology have advanced, and the efficiency to culture up to the blastocyst stage in order to obtain viable embryos has increased dramatically. As a result, blastocyst transfer is associated with higher clinical pregnancy outcomes than cleavage transfer. In 1998, it was first reported that some embryos may develop into blastocysts on Day 7. However, there are few reports on neonatal outcomes from Day 7 blastocyst transfer. Therefore, the utility of Day 7 blastocysts is controversial. Study design, size, duration This was retrospective study which included 23 cases where there was a live birth after single embryo transfer of a Day 7-derived blastocyst. The incidence of birth defects, birth weight was recorded as well as a physical development survey. The height and weight were recorded in 10 children aged 18-months and 4 children aged 3 who responded to follow-up survey. The time period was from January 2013 to December 2021. Participants/materials, setting, methods Patient seeking fertility treatment at an established private IVF clinic. We compared the birth weight, and birth after 18-months and 3 years height and weight of children born to a Day 7 blastocyst with data from babies born from Day 5 and Day 6 derived blastocysts. Statistical significance was determined using Kruskal-Wallis test. Main results and the role of chance The incidence of birth defects was 2.4% (115/4828), 1.7% (16/954) and 0% (0/23) in the Day 5, Day 6 and Day 7 groups, respectively. The average birth weight of the Day 7 group was 3057+/-532 g, which was not significantly different from 3024+/-472 g and 3041+/-480 g in the Day 5 and Day 6 groups. The average height at 18-months, was 80.0+/-5.3 cm, 79.8+/-5.1 cm, 77.8+/-6.9 cm in the Day 5, Day 6 and Day 7 groups, respectively. The average weight at 18-months, was 10.5+/-1.2 kg, 10.4+/-1.1 kg, 10.5+/-1.4 kg. The average height at 3 years old, was 93.2+/-4.8 cm, 92.9+/-4.7 cm, 93.4+/-5.9 cm. The average weight at 3 years old, was 13.9+/-1.6 kg, 13.8+/-1.4 kg, 14.1+/-2.6 kg, respectively. There was no significant difference in average height and weight up-to the 3 years old follow-up survey. Limitations, reasons for caution The incidence of Day 7 blastocyst-transfer is low and the study was limited to cases of single blastocyst embryo transfer. The study was not separated by sex, because sample size was small. Wider implications of the findings There was no difference in growth up to a 3-year-old follow-up survey of the Day 7 blastocyst compared with the Day 5 and Day 6 groups. Transfer of a Day 7-derived blastocyst does not appear to affect infant development and should be considered in cases where blastocyst development is delayed. Trial registration number not applicable

P-163 Three-year follow-up of babies born derived from mono-pronuclear zygotes

Abstract Study question Are neonatal outcomes normal up to 3 years of ages from the transfer of blastocysts derived from mono-pronuclear(1PN) zygotes? Summary answer There was no effect on growth up to 3 years of ages in babies born from 1PN-implanted blastocysts. What is known already In human ART, 1PN zygotes are observed at low rates. We have previously reported that 80.7% of 1PN zygotes had a biparental chromosome using a Live-Cell imaging technique, and some of these developed to the blastocyst stage (Tokoro et al. ASRM 2013). Furthermore, we have reported that these blastocysts can result in a viable pregnancy and healthy live birth (Tsuji et al. ASRM 2020), and there was no effect on growth up to 18-months (Tsuji et al. ESHRE 2021). However, there is no information on the long-term prognosis of babies derived from1PN-zygotes. Study design, size, duration This was a retrospective study which included 86 cases where there was a live birth after single embryo transfer of a blastocyst derived from 1PN zygote. The incidence of birth defects, birth weight were recorded as well as a physical development survey of 19 children who responded to a 3-years follow-up survey. The time period was 108 months (January 2013 to December 2021). Participants/materials, setting, methods Patients seeking fertility treatment at an established private IVF clinic. We compared the birth weight, 3-years old height and weight of children born from 1PN zygotes with data from a control, 2PN group. Statistical significance was determined using the t-test (level of P < 0.05). Main results and the role of chance The incidence of birth defects in 1PN embryo-derived infants was 1.2% (1/86). The average birth weight of boys in the 1PN group was 3147.6+/-408.7 g, which was not significantly different from 3070.5+/-479.5 g in the 2PN group. In girls, the average birth weight was 3048.1+/-510.7 g in the 1PN group, which was not significantly different from the 2PN group (2966.2+/-462.7 g). The average height at 18-months, was 81.3+/-2.5 cm vs 80.9+/-3.4 cm for boys; 79.5+/-2.2 cm vs 79.5+/-3.0 cm for girls in the 1PN and 2PN groups, respectively. The average body weights of the 1PN and 2PN groups were 11.0+/-1.2 kg vs 10.8+/-1.1 kg for boys; 9.8+/-1.0 kg vs 10.2+/-1.1 kg for girls, respectively. The average height at 3-years, was 95.2+/-3.1 cm vs 93.8+/-4.5 cm for boys; 91.5+/-2.9 cm vs 92.5+/-4.9 cm for girls in the 1PN and 2PN groups, respectively. The average body weights of the 1PN and 2PN groups were 14.7+/-1.2 kg vs 14.1+/-1.5 kg for boys; 13.2+/-1.9 kg vs 13.6+/-1.5 kg for girls, respectively. There was no significant difference in average height and weight up-to the 3-years follow-up survey. Limitations, reasons for caution The incidence of 1PN- zygotes that develop to blastocysts resulting in births is low and the study was limited to cases of single blastocyst embryo transfer. Wider implications of the findings The incidence of congenital anomalies in Japan is around 1.7 to 2%, and the incidence was similar in the 1PN group. Also, there was no difference in 3-years follow-up survey of the 1PN compared with the 2PN. These data are reassuring for the clinical utility of 1PN derived embryos. Trial registration number not applicable

Birth of monozygotic dichorionic twins after a single blastocyst embryo transfer: a case report of genetic determination of zygosity

To report a case of monozygotic dichorionic (DC) twins after a single cryopreserved blastocyst embryo transfer followed by genetic determination of zygosity postpartum. Case report. University hospital. A 26-year-old woman with polycystic ovary syndrome and her 36-year-old male partner with severe oligozoospermia, resulting in a 1.5-year history of primary infertility. Controlled ovarian stimulation and intracytoplasmic sperm injection treatment with single cryopreserved embryo transfer at blastocyst stage. Ultrasound images of the fetuses and short tandem repeat genotyping postpartum. A DC twin pregnancy following a single cryopreserved blastocyst embryo transfer was confirmed at the first trimester screening. Confirmatory testing performed postpartum included short tandem repeat analysis determining monozygosity and pathology examination reporting DC placental configuration. Dichorionic monozygotic twins are thought to arise from the splitting of an embryo before the blastocyst stage. This case suggests that placental configuration of monozygotic twins may not strictly depend on timing of embryo division. Genetic analysis is the only tool to confirm the zygosity.

Development and validation of a nomogram for predicting ongoing pregnancy in single vitrified-warmed blastocyst embryo transfer cycles.

The global adoption of the "freeze-all strategy" has led to a continuous increase in utilization of single vitrified-warmed blastocyst embryo transfer (SVBT) owing to its clinical effectiveness. Accurate prediction of clinical pregnancy is crucial from a patient-centered perspective. However, this remains challenging, with inherent limitations due to the absence of precise and user-friendly prediction tools. Thus, this study primarily aimed to develop and assess a nomogram based on quantitative clinical data to optimize the efficacy of personalized prognosis assessment. We conducted a retrospective cohort analysis of ongoing pregnancy data from 658 patients with infertility who underwent SVBT at our center between October 17, 2017, and December 18, 2021. Patients were randomly assigned to the training (n=461) or validation (n=197) cohort for nomogram development and testing, respectively. A nomogram was constructed using the results of the multivariable logistic regression (MLR), which included clinical covariates that were assessed for their association with ongoing pregnancy. The MLR identified eight significant variables that independently predicted ongoing pregnancy outcomes in the study population. These predictors encompassed maternal physiology, including maternal age at oocyte retrieval and serum anti-Müllerian hormone levels; uterine factors, such as adenomyosis; and various embryo assessment parameters, including the number of fertilized embryos, blastocyst morphology, blastulation day, blastocyst re-expansion speed, and presence of embryo string. The area under the receiver operating characteristic curve in our prediction model was 0.675 (95% confidence interval [CI], 0.622-0.729) and 0.656 (95% CI, 0.573-0.739) in the training and validation cohorts, respectively, indicating good discrimination performance in both cohorts. Our individualized nomogram is a practical and user-friendly tool that can provide accurate and useful SVBT information for patients and clinicians. By offering this model to patients, clinical stakeholders can alleviate uncertainty and confusion about fertility treatment options and enhance patients' confidence in making informed decisions.

What to advise to patients with only one good quality blastocyst, PGT-A or not? Outcomes of 2064 cycles

PurposeTo evaluate whether preimplantation genetic testing for aneuploidy (PGT-A) is beneficial for patients who have only one blastocyst available for biopsy or transfer.MethodsThis retrospective study was based on 1126 single blastocyst PGT-A and 938 non-PGT-A cycles, a total of 2064 ART cycles which resulted in a single good quality blastocyst in women between 20 and 45 years old. The PGT-A group had 225 single euploid embryo transfer cycles and the non-PGT-A group had 938 single blastocyst embryo transfer cycles.ResultsIn the generalized linear mixed model (GLMM), female age and PGT-A variables were found to be significant variables on pregnancy outcomes. In the PGT-A cases, regardless of the effect of other variables, the probabilities of clinical pregnancy and live birth were found to be 3.907 and 3.448 fold higher respectively than in the non-PGT-A cases (p < 0.001). In non PGT-A cases, the probability of a total pregnancy loss was found to be 1.943 fold higher (p = 0.013).ConclusionPGT-A in the presence of a single blastocyst significantly increases clinical pregnancy and live birth rates and decreases total pregnancy losses regardless of age. In addition, aneuploid embryo transfer cancelations prevent ineffective and potentially risky transfers.

P-294 Use of Artificial Intelligence to Assess the Effects of Assisted Hatching on Embryo Development and Implantation Potential

Abstract Study question Does the use of laser-assisted hatching (AH) on cleavage stage embryos affect in vitro preimplantation embryo development or implantation potential? Summary answer There is no difference in blastocyst conversion rate or implantation potential of embryos following AH at the cleavage stage for patients under age 35 years. What is known already Laser-AH is the process of creating an opening within the zona pellucida on cleavage stage embryos to facilitate biopsy of trophectoderm cells for preimplantation genetic testing (PGT). Studies have shown that PGT for aneuploidy (PGT-A) in patients under 35 years have reduced pregnancy rates compared to those not undergoing biopsy. This is attributed to the additional micromanipulation events involved with PGT-A may decrease the viability of embryos and compromise their implantation potential. We aimed to objectively compare the impact of AH on embryo development using an artificial intelligence (AI)-algorithm trained to assess embryo quality and predict developmental fate. Study design, size, duration A retrospective dataset from patients under 35 years was generated from two timepoints: cleavage stage embryos immediately before AH between 60-64 hours post insemination (hpi); and blastocyst stage embryos between 110-115 hpi prior to transfer or vitrification. Time-lapse imaging was obtained using the EmbryoScope (Vitrolife). Cleavage stage embryo images were used to train a convolutional neural networks (CNN) to predict and classify the development and implantation potential of cleavage and blastocyst stage embryos. Participants/materials, setting, methods Time-lapse images were collected for 1444 cleavage stage embryos spanning 189 in vitro fertilization (IVF) cycles between January 2014 – December 2021 at a single academic fertility center in Boston. Embryos were categorized into two groups: Day 3 embryos with AH (D3+AH) and without AH (D3-No AH). Each patient had a single blastocyst embryo transfer with a known outcome. Two-tailed t-tests were used to compare differences, with p-value less than 0.05 set for statistical significance. Main results and the role of chance The dataset included 1035 embryos with AH (D3+AH) and 409 embryos without AH (D3-No AH). There were no differences in AI-predicted blastocyst development between Day 3 embryos with AH and without AH (64.1% vs 64.1%) or AI-predicted high quality blastocyst development rate between these two groups (43.8% vs 40.8%), respectively. On Day 5 there were no differences in the AI-categorization of embryos at the blastocyst stage between embryos with or without AH (62.3% vs 62.5%) or AI-categorization of high-quality blastocyst development (45.2% vs 41.8%), respectively. AI predicted a similar implantation potential between embryos with and without AH at the cleavage stage (61.1% vs 69.9%). When stratifying to only the embryos transferred, there were no differences in the AI-predicted blastocyst development between Day 3 embryos with AH and without AH (96.0% vs 97.1%) or in the AI-predicted high quality blastocyst development rate between these two groups (72.0% vs 82.7%). AI predicted a similar implantation potential between embryos with and without AH at the cleavage stage (72.0% vs 69.0%). These results correspond with the true clinical pregnancy rate between the AH and Non-AH groups (68.0% vs 61.9%, p = 0.44). Limitations, reasons for caution These retrospective findings were of patients who had time-lapse imaging of cleavage stage and blastocysts available. Additionally, we focused on high prognosis patients that were eligible for single blastocyst stage embryo transfer. Clinical pregnancy rate was examined, not spontaneous abortion or live birth rates. Wider implications of the findings Utilization of AI technology allows for more objective and standardized methods for examining the impact of laboratory procedures on the developmental fate of embryos. This study demonstrated the safety of utilizing laser-assisted hatching on embryo development within this study population. Trial registration number None

Developmental stage and morphology of the competent blastocyst are associated with sex of the child but not with other obstetric outcomes: a multicenter cohort study.

Are transfer day, developmental stage and morphology of the competent blastocyst in pregnancies leading to live birth associated with preterm birth, birthweight, length at birth and sex of the child? A high score in blastocyst developmental stage and in trophectoderm (TE) showed a significant association with the sex of the child, while no other associations with obstetric outcomes were observed. The association between blastocyst assessment scores and obstetric outcomes have been reported in small single-center studies and the results are conflicting. Multicenter historical cohort study based on exposure data (transfer day (blastocyst developmental stage reached by Day 5 or Day 6)) blastocyst developmental stage (1-6) and morphology (TE and inner cell mass (ICM): A, B, C)) and outcome data (preterm birth, birthweight, length at birth, and sex of the child) from women undergoing single blastocyst transfer resulting in a singleton pregnancy and live birth. Data from 16 private and university-based facilities for clinical services and research were used. A total of 7246 women, who in 2014-2018 underwent fresh-embryo transfer with a single blastocyst or frozen-thawed embryo transfer (FET) with a single blastocyst resulting in a singleton pregnancy were identified. Linking to the Danish Medical Birth Registry resulted in a total of 4842 women with a live birth being included. Cycles with pre-implantation genetic testing and donated gametes were excluded. The analyses were adjusted for female age (n = 4842), female BMI (n = 4302), female smoking (n = 4290), parity (n = 4365), infertility diagnosis (n = 4765), type of treatment (n = 4842) and center (n = 4842); some analyses additionally included gestational age (n = 4368) and sex of the child (n = 4833). No statistically significant associations between blastocyst assessment scores (transfer day, developmental stage, TE, ICM) and preterm birth (8.3%) or birthweight (mean 3461.7 g) were found. The adjusted association between blastocysts with a TE score of C and a TE score of A and length at birth (mean 51.6 cm) were statistically significant (adjusted mean difference 0.4 cm (95% CI: 0.02; 0.77)). Blastocysts transferred with developmental stage score 5 compared to blastocysts transferred with score 3 had a 34% increased probability of being a boy (odds ratio (OR) 1.34 (95% CI: 1.09; 1.64). Further, TE score B blastocysts compared to TE score A blastocysts had a 31% reduced probability of being a boy (OR 0.69 (95% CI: 0.60; 0.80)). It is possible that some residual confounding remains. Blastocyst selection during ART does not appear to introduce any negative effects on obstetric outcome. Therefore, clinicians and patients can be reassured that the assessment scores of the selected blastocyst will not in themselves pose a risk of preterm birth or affect birthweight and the length at birth. Unrestricted grant from Gedeon Richter Nordics AB, Sweden. None of the authors have any competing interest to declare. N/A.

THE EARLIER THE BETTER: INITIAL SERUM HCG LEVELS PREDICT LIVE BIRTH AFTER SINGLE EMBRYO TRANSFER

To examine how early serum human chorionic gonadotropin (hCG) levels predict live birth (LB) after single embryo transfer (SET). All fresh and frozen embryo transfers between 2002 and 2019 where a single embryo was transferred and a detectable hCG level was confirmed were reviewed. In our practice, serum hCG levels are routinely examined with serum testing done eight days after blastocyst SET (B-SET) and ten days after cleavage stage SET (C-SET). In order to compare hCG levels across IVF cycles where embryos were transferred at different stages, hCG levels were determined in reference to days “after oocyte retrieval (AOR),” which was calculated as the number of days after fertilization. Two hCG parameters were examined to evaluate their relationship with live birth: “reached 100” which was defined as an hCG level of >100 mIU/mL 15 days AOR and “doubled” which was defined as an hCG level that at least doubled over a 48 hour period between the first and second measurements. Analysis of the descriptive statistics was performed. A total of 1397 IVF cycles (1065 patients) where an SET was performed and the initial hCG level was detectable were included in the analysis (82% B-SET and 18 % C-SET). 35% were fresh and 65% were frozen. The mean age at the time of SET was 35.5 years. 62% of cycles where hCG was detectable on first examination ended in LB. In the cycles that ended in LB the median hCG level was 268.4 mIU/mL (interquartile range [IQR] 181.6, 375.0) 15 days AOR. In the cycles that did not end in LB the median hCG level was 56.7 mIU/mL (IQR 18.8, 142.6) 15 days AOR. In cycles where hCG levels only “doubled” the LB rate was 33%, while in cycles where hCG levels only “reached 100” by 15 days AOR the LB rate was 54%. In cycles where hCG levels both “doubled” and “reached 100” by 15 days AOR the LB rate was 84%. In cycles where hCG levels did not “double” or “reach 100” by 15 days AOR the LB rate was 9%. Among cycles that ended in LB there was no relationship between patient age at time of SET and early hCG levels. In those <35, the median hCG level was 121.7 mIU/mL (IQR 86.0, 115.5), in those 35 - 40 the median hCG level was 110.2 mIU/mL (IQR 75.8, 155.8), and in those > 40 the median hCG level was 119.8 mIU/mL (IQR 78.2, 173.8) at mean of 13.4 days AOR. Specific rises in early hCG levels after SET were associated with LB when hCG levels were checked 15 days AOR. In cycles where hCG levels both doubled and reached 100 mIU/mL by 15 days AOR, the LB rate was 84% and this was a stronger predictor of LB than either parameter alone. LB was only achieved in 9% of cycles where hCG levels neither “doubled” nor “reached 100”. Age was not associated with early hCG levels in cycles that ended in LB.

P–264 Clinical relevance of re-expansion after blastocyst thawing

Abstract Study question Are there any differences in clinical outcomes after SET of re-expanded versus non-re-expanded blastocysts? Summary answer The transfer of re-expanded thawed blastocysts is associated with improved clinical outcomes. What is known already Improvements in embryo culture conditions, endometrial receptivity protocols and vitrification as a revolutionary cryopreservation technique have allowed the expansion of blastocyst stage transfers (Lieberman and Tucker, 2006; Stanger et al., 2012; Rienzi et al., 2017), increasing clinical pregnancy and implantation rates in IVF cycles. The re-expansion of thawed blastocyst at the time of transfer has been considered as a good prognosis factor, but not always thawed embryos re-expand. To evaluate the relevance of this event, we compared the clinical results of the re-expanded embryos versus the collapsed ones after their thawing and transfer. Study design, size, duration A total number of 1.125 frozen-thawed blastocyst transfers were included in this retrospective observational study between January 2018 and December 2020. Seven hundred and eighty-six thawed blastocyst were fully expanded at the time of the transfer and 339 thawed blastocysts were non-re-expanded when they were transferred. Participants/materials, setting, methods 1.125 single frozen-thawed blastocyst embryo transfer (SET) cycles (802 from donated and 319 from autologous oocytes) were divided in two groups (re-expanded vs non-re-expanded). Positive beta human chorionic gonadotrophin (bHCG), pregnancy rate (PR), early miscarriage rate (EMR) and live birth rate (LBR) were compared between the two groups. Blastocysts were thawed using an Irvine Scientific® Thaw kit, Irvine Scientific® and were transferring in culture medium (Global® Total® LP, CooperSurgical®). Main results and the role of chance During 2018, 190 re-expanded blastocyst and 94 non-re-expanded were transferred. Statistical significant differences were found in the percentage of positive bHCG (48.4% vs 30.9%, p &amp;lt; 0,0048) and PR (39.5% vs 25.5%, p &amp;lt; 0,0203), respectively. In 2019, statistical differences were found in the LBR between 307 re-expanded blastocyst and 124 non-re-expanded (30.6% vs 12.9%; p &amp;lt; 0,00001). Differences were also found in positive bHCG (50.2% vs 21.8%, p &amp;lt; 0,00001) and PR (40.7% vs 15.3%, p &amp;lt; 0,00001), respectively. Finally, in 2020, 289 re-expanded blastocyst and 121 non-re-expanded were transferred, and significant differences were obtained in the percentage of positive bHCG (46.8% vs 22.3%, p &amp;lt; 0,00001) and PR (32.9% vs 15.7%, p &amp;lt; 0,00001), respectively. Globally, all the variables analysed were statistically significant in favour of the re-expanded embryo group: positive bHCG (48.7% vs 24.5%; p &amp;lt; 0,00001), PR (37.5% vs 18.3%; p &amp;lt; 0,00001) and LBR (20.1% vs 9.5%; p &amp;lt; 0,00001), except for EMR. Limitations, reasons for caution The inherent limitations to a retrospective design. Larger studies are warranted in order to reach robust conclusions on the subject. Wider implications of the findings: Transfer of re-expand blastocyst could be a positive indicator of clinical outcomes. In case of non-re-expand embryos, transfer of two could be reasonable. Trial registration number NONE

P–784 Neonatal follow-up of babies born derived from mono-pronuclear zygotes

Abstract Study question Are the neonatal outcomes normal of babies derived from the transfer of blastocysts derived from mono-pronuclear(1PN) zygotes? Summary answer There was no effect on growth or increase in congenital anomalies up to 18-months in babies of 1PN-derived births. What is known already 1PN zygotes are observed in ART, albeit at a low rate. We have previously reported that 80.7% of 1PN zygotes derived from IVF or ICSI had a biparental chromosome using Live Cell imaging techniques, and some of these developed to the blastocyst stage (Tokoro et al. ASRM 2013). Furthermore, we have reported that these blastocysts can result in a viable pregnancy and healthy live birth (Tsuji et al. ASRM2020). However, there is some uncertainty about the developmental mechanism of 1PN zygotes, and there is no clear consensus on their clinical utility. Study design, size, duration This was a retrospective study which included 55 cases where there was a live birth after single embryo transfer of a blastocyst derived from 1PN zygote. The incidence of birth defects, birth weight was recorded as well as a physical development survey of 25 children who responded to the 18-months follow-up survey. The time period was 72 months (January 2013 to December 2018). Participants/materials, setting, methods Patients seeking fertility treatment at an established private IVF clinic. We compared the birth weight, birth after18-months height and weight of children born to 1PN zygotes with data from a control, 2PN group. Statistical significance was determined using the t-test (level of P &amp;lt; 0.05). Main results and the role of chance The incidence of birth defects in 1PN embryo-derived infants was 1.8% (1/55). The average birth weight of boys in the 1PN group was 3105.6+/–360.3g, which was not significantly different from 3041.0+/–443.3 g in the 2PN group. In girls, the average birth weight was 3085.7+/–454.9 g in the 1PN group, which was not significantly different from the 2PN group (2938.9+/–311.5 g). The average height at 18-months, was 81.6+/–2.5 cm vs 80.5+/–3.4 cm for boys; 79.0+/–1.8 cm vs 79.0+/–3.4 cm for girls in the 1PN and 2PN groups, respectively. The average body weights of the 1PN and 2PN groups were 11.1+/–1.1 kg vs 10.7+/–1.1 kg for boys; 9.7+/–0.9 kg vs 10.1+/–1.0 kg for girls, respectively. There was no significant difference in average height and weight up-to the 18-months follow-up survey. Limitations, reasons for caution The incidence of 1PN derived births is low and the study was limited to cases of single blastocyst embryo transfer. Wider implications of the findings: The incidence of congenital anomalies in Japan was around 1.7 to 2%, and the incidence was similar in the 1PN. There was no difference in the birth weight and 18-months follow-up survey of the 1PN compared with the 2PN. We have demonstrated that there is clinical utility of 1PN embryo. Trial registration number Not applicable

Association between estradiol levels and clinical outcomes of IVF cycles with single blastocyst embryo transfer

Objective: To determine the correlation of different serum estradiol levels on the trigger day with the clinical and laboratory outcomes of in-vitro fertilization (IVF) cycles comprising a single fresh top-quality blastocyst transfer. Methods: This was a retrospective observational study performed in Morula IVF Clinic Jakarta. Five hundred forty-two women were recruited and grouped according to their serum estradiol levels on the trigger day of follicular maturation as follows: &lt;2 000 pg/mL, 2 000-2 999 pg/mL, 3 000-3 999 pg/mL, and ≥ 4 000 pg/mL. Clinical pregnancy and miscarriage rates were evaluated as the primary outcomes and embryology laboratory results as the secondary outcomes which consisted of the number of retrieved, mature, and fertilized oocytes, the total sum of derived embryos, and top-quality embryos at cleavage and blastocyst stage. Results: Clinical pregnancy and miscarriage rates did not differ among the groups (P&gt;0.05). Nonetheless, the study demonstrated a positive correlation of the serum estradiol levels with the overall laboratory outcomes including the number of retrieved, mature, and fertilized oocytes, the total sum of derived embryos, and top-quality embryos at cleavage and blastocyst stage (P&lt;0.001). The subject group with estradiol level of ≥4 000 pg/mL was superior to the other groups in its respective median number of retrieved, mature, fertilized oocytes, total derived embryos, and top-quality cleavage- and blastocyst-stage embryos. Conclusions: Although an apparent positive correlation is observed between estradiol levels and laboratory outcomes, serum estradiol level on hCG trigger day is not associated with the clinical outcomes of IVF.

Clinical outcomes after single-versus double-embryo transfers in women with adenomyosis: a retrospective study.

Adenomyosis affects the outcomes of spontaneous fertility and assisted reproductive technology. The single blastocyst embryo transfer (SBT) policy is an effective strategy known to minimize the risk of multiple pregnancy for non-adenomyosis women. However, little is known about its applicability to women with adenomyosis. The purpose of this study is to compare pregnancy outcomes between SBT, double-blastocyst embryo transfer (DBT), single-cleavage-stage embryo transfer (SET) and double-cleavage-stage embryo transfer (DET) in the frozen-thawed embryo transfer cycles among adenomyosis patients. This retrospective study was conducted in all frozen-thawed autologous embryo transfer cycles. 393 frozen-thawed embryo transfer cycles performed in adenomyosis patients were enrolled. The major clinical outcomes were implantation rate (IR), clinical pregnancy rate (CPR), miscarriage rate (MR), multiple pregnancy rate (MPR) and live birth rate (LBR). The SBT and DBT groups achieved higher IR (P < 0.001), CPR (P = 0.017), LBR (P = 0.040) and lower MR (P = 0.020) than the SET and DET groups. But the SBT and DBT groups achieved similar CPR and LBR. The SBT and SET groups achieved lower MPR (P < 0.001) than the DBT and DET groups. The average birth weight (BW) of SBT groups was higher than the DBT and DET groups (P = 0.016). When compared with SBT group, low-birth-weight infants were significantly higher with DBT and DET. When performing frozen-thawed embryo transfer cycles among adenomyosis patients, the SBT group has similar IR, CPR, MR, LBR but lower MPR compared to the DBT group. Therefore, SBT might be offered as standard practice.

BIRTH OF HEALTHY BABIES FROM BLASTOCYSTS DERIVED FROM MONO-PRONUCLEAR ZYGOTES FOLLOWING INTRACYTOPLASMIC SPERM INJECTION

We have previously reported that 80.7% of 1PN zygotes derived from IVF or ICSI had a biparental chromosome, and some of these developed to the blastocyst stage (Tokoro et al. ASRM 2013). However, it has also been demonstrated that all embryos derived from 1PN-ICSI zygotes are chromosomally abnormal and these zygotes should be discarded, though 1PN zygotes derived from IVF(1PN-IVF) could be used for reproductive purposes (Mateo et al. Fertil Steril. 2013; 99: 897-902). In addition, it has been reported that zygotes derived from 1PN-ICSI produced blastocysts but did not lead to pregnancies (Igashira et al. ASRM 2016). In this study, we examined mono-pronuclear zygotes derived after ICSI (1PN-ICSI) can develop normally and result in a healthy live birth. Retrospective cohort study This was a retrospective study including 2482 ART patients treated in 2814 cycles and where 3618 zygotes formed 1PN after ICSI. The time period was 72 months (January 2013 to December 2018). Patients seeking infertility treatment in a well-established private IVF clinic. Blastocyst rates, clinical pregnancy and miscarriage rates after a single blastocyst embryo transfer following the culture of 1PN-ICSI zygotes were compared with data on 1PN-IVF or normal 2PN zygotes during the same time period. Furthermore, follow up information was obtained on the health status of live births derived from 1PN-ICSI zygotes. Statistical significance was determined using the chi-square test (level of P<0.05). The formation rate of 1PN-ICSI was 2.8%(3618/127728), significantly lower (P<0.05) than 1PN-IVF (4.6%; 1044/22799). The blastocyst rate of 1PN-ICSI zygotes (14.8%; 525/3547) was significantly lower (P<0.05) compared to 1PN-IVF zygotes (26.5%; 274/1035) or normal 2PN (62.0%, 22420/36189) . The clinical pregnancy rate of 1PN-ICSI transferred zygotes (24.4%; 53/217) was significantly lower (P<0.05) compared to 1PN-IVF transferred zygotes(36.6%; 41/112) or normal transferred zygotes from 2PN (40.2%; 4802/11947). However, the miscarriage rates were not significantly different (respectively, 30.2%, 34.1% and 23.3%) 21 healthy newborns were obtained from the successful pregnancies after embryo transfer of 1PN-ICSI blastocysts. These results suggest that not all 1PN-ICSI zygotes are abnormal, and these can result in a viable pregnancy and healthy live birth. Continued culture to blastocyst of 1PN-ICSI zygotes should be carried out in order to further assess their potential for transfer.

Pregnancy Outcomes of Single/Double Blastocysts and Cleavage Embryo Transfers: a Retrospective Cohort Study of 24,422 Frozen-Thawed Cycles

This study aims to evaluate the effect of blastocyst- and cleavage-stage embryo transfers with different numbers of transferred embryos on pregnancy outcomes in China. This was a retrospective cohort study that collected 24,422 frozen-thawed embryo transfer (FET) cycles in two affiliated hospitals of Peking University Health Science Center between January 2015 and May 2018. They were divided into four groups: the single cleavage-stage embryo transfer group (C-1) (763 cycles), double cleavage-stage embryo transfer group (C-2) (13,004 cycles), single blastocyst-stage embryo transfer group (B-1) (7913 cycles), and double blastocyst-stage embryo transfer group (B-2) (2046 cycles). Of the four groups, the live birth rate was the lowest in the C-1 group (11.8%) while it was the highest in the B-2 group (33.6%). However, the B-2 group was accompanied with higher risks of miscarriages, maternal complications, twin births, preterm births, and low birth weight. Compared with the C-2 group, the B-1 group had a lower live birth rate (23.0 vs 29.0%; aOR, 0.78; 95% CI, 0.72–0.85), but also had a lower risk for twin births (1.9 vs 23.4%; aOR, 0.06; 95% CI, 0.04–0.09) and preterm births (9.6 vs 16.1%; aOR, 0.51; 95% CI, 0.41–0.65). The probability of live birth in the B-1 group declined from 0.25 at 20–29 years old to 0.08 at > 40 years old, while the probabilities of adverse outcomes went up with maternal age. It can be concluded that single-blastocyst embryo transfer seems to be the best choice for all maternal ages. This group of embryo transfer has significantly reduced adverse neonatal outcomes. Especially, women with younger maternal age in this group appear to prominently benefit from single-blastocyst transfer.

Endometrial volume measured on the day of embryo transfer is not associated with live birth rates in IVF: A prospective study and review of the literature

ObjectiveTo evaluate the effect of endometrial volume (EV) on the live birth rates (LBR)s in fresh or frozen embryo transfer (ET) cycles. Material and methodsThis is a prospective study including all women who underwent a fresh or frozen single blastocyst transfer between January 2017 and September 2018 in a university affiliated private hospital. Patients with advanced age (>42years), congenital uterine anomalies, endometrial or myometrial abnormalities, those with a difficult ET, those with only poor-quality blastocysts available for transfer, those in whom an optimal 3D TVUS image could not be obtained and those who were lost to follow-up were excluded. Endometrial volume was assessed using Virtual Organ Computer Aided Analysis program immediately prior to ET by two different observers using a standardized technique. The association of ET outcome and EV was evaluated by receiver operating characteristics (ROC) curve and logistic regression analysis. ResultsA total of 142 patients were included in the final analysis. Patients were grouped according the EV percentiles (p); 5thp (1.7 mL), 10thp (2.2 mL), 25thp (2.9 mL), 50thp (4.3 mL) and >75thp (>5.3 mL) groups. ROC curve analysis was not predictive of LBRs, with an AUC (95 % CI) = 0.48 (0.38–0.58). There was no critical threshold, below which pregnancy was unlikely to occur. No significant association was observed between EV and any of the evaluated clinical outcomes. Conclusion(s)When controlled for potential confounders, EV assessed by 3D TVUS is not a useful tool for predicting pregnancy in single blastocyst ET cycles.

The Incidence of Dichorionic Diamniotic Twin Pregnancy After Single Blastocyst Embryo Transfer and Zygosity: 8 Years of Single-Center Experience.

Dichorionic diamniotic (DCDA) twin pregnancies after single blastocyst embryo transfer have been reported recently, although a blastocyst ovum is generally believed to divide into monochorionic twin pregnancy. We investigated the incidence of DCDA twin pregnancy after single blastocyst embryo transfer and their zygosity. This prospective cohort study included 655 consecutive twin pregnancies that were managed from 2006 to 2014 at our institution. Chorionicity and amnionicity were determined using first-trimester ultrasonography and/or placental pathology. Zygosity was analyzed if the cases were DCDA twins after single blastocyst embryo transfer. Among 655 twin pregnancies, there were 348 DCDA cases, 295 monochorionic diamniotic (MCDA) cases and 12 monochorionic monoamniotic cases. Single blastocyst embryo transfer was performed in 43 cases. Six out of the 43 (14%) cases involved DCDA twin pregnancies and the other 37 cases involved MCDA twin pregnancies. Three DCDA twins born after single blastocyst embryo transfer, wherein frozen embryo transfer (FET) was performed in the natural cycle, were dizygotic, and the other three cases, wherein FET with hormone replacement therapy was performed, were monozygotic. DCDA twin pregnancy occurred in 14% (7% for monozygotic and 7% for dizygotic) of twin pregnancies after single blastocyst embryo transfer cases.

Single blastocyst transfer yields similar pregnancy rates compared with multiple cleavage embryo transfer, with reduced twin rate, in patients with low number of fertilized oocytes

BackgroundIn patients with low numbers of embryos, there is not yet consensus on whether to extend culture to the blastocyst stage, especially due to the risk that some or all of the embryos will not make it to the blastocyst stage. The objective of our study was to evaluate pregnancy outcomes in patients with a low number of fertilized oocytes (< 4), comparing single blastocyst transfer to one or more cleavage embryo transfer.ResultsWe analyzed 6795 cycles from the 2014–2105 Society for Assisted Reproductive Technology (SART) registry. All patients were ≤ 38 years old, had less than four fertilized oocytes, and were undergoing first fresh in vitro fertilization (IVF) transfer. Primary outcomes were clinical pregnancy (CP), live birth (LB), and miscarriage rate in both cleavage stage transfer and single blastocyst transfer. A secondary outcome was the rate of twin gestation. The comparison of interest in day of transfer included (1) single blastocyst vs single cleavage and (2) single blastocyst vs multiple cleavage stage. The association between day of transfer and primary outcome was investigated using logistic regression, controlling for the age, race/ethnicity, BMI, smoking, gravidity, parity, infertility diagnoses, and assisted hatching.Single blastocyst transfer was associated with an increased odds of CP (adjusted OR 2.03) and LB (adjusted OR 1.86) when compared to single cleavage transfer, and no statistically significant association was observed when comparing single blastocyst transfer to multiple cleavage embryo transfer for CP (adjusted OR 0.94) and LB (adjusted OR = 0.88). The odds of having twins among single blastocyst transfer was significantly lower compared to those odds that among multiple cleavage stage transfer (unadjusted OR 0.09).ConclusionsWhile pregnancy outcomes are similar between single blastocyst and multiple cleavage embryo transfer, the twin rate is reduced significantly among the single blastocyst transfers in patients with a low number of fertilized oocytes.

Comparison of pregnancy outcomes in women undergoing frozen thawed embryo transfer (FET) cycles following ultrasound for endometrial morphology with and without Doppler studies- a prospective cohort study

Introduction: There is a paucity of data evaluating role of endometrial blood flow in frozen thawed embryo transfer cycles (FET cycles) in hormone replacement treatment (HRT) cycles. Objective: To compare pregnancy outcomes in women undergoing ultrasound for endometrial morphology alone to those with endometrial morphology with blood flows in frozen embryo transfer cycles. Patients: Patients aged 23 to 38 years undergoing first two frozen thawed single blastocyst embryo transfer cycles. From August 2019 to January 2020, 163 patients undergoing hormone replacement frozen embryo transfer cycles were enrolled in the study. Patients were divided in two groups. Patients in group A (n = 92) had ultrasonographic evaluation of endometrial thickness and morphology and in group B (n = 71) patients underwent ultrasound for endometrial thickness, morphology along with Doppler blood flow studies. Outcome measures: Primary outcome was clinical pregnancy rate. Secondary outcome measures were pregnancy loss rate, ongoing pregnancy rate, and ectopic pregnancy rate. Results: Clinical pregnancy rate in group A and group B was 54.34% and 47.88%. Clinical pregnancy rate was similar between both the groups (P = 0.779). Ongoing pregnancy rate in group A and B was 48.91% and 40.84%, respectively. Pregnancy loss rate (7–13 wks) was 5.4% and 7.04% in group A and group B, respectively. There was no significant difference in ongoing pregnancy rate and pregnancy loss rate between both the groups (P = 0.756). Conclusion: Additional measurement of doppler studies do not help in improving implantation and thus seems unnecessary in improving pregnancy rates and reducing pregnancy loss rates in FET cycles.