Clinical validation of the early embryo viability assessment system: Analysis for the blastocyst morphology and pregnancy outcomes

Objective:To determine the relationship between the early embryo viability assessment(EEVA)and blastocyst morphological parameters and pregnancy outcomes.Methods:This retrospective cohort study was conducted on 291 intracytoplasmic sperm injection cycles including 2522 embryos with indications of prolonging embryo culture to the blastocyst stage in the Genea embryo review incubator,and 511 single vitrified-warmed blastocyst transfer cycles from January 2020 to June 2023.The EEVA system produced an EEVA score from E1(best)to E5(worse)for the potential of blastocyst formation.Blastocyst morphology was evaluated.The association between the EEVA score and each type of blastocyst morphology,implantation rate,clinical pregnancy,and ongoing pregnancy were assessed using generalized estimating equations.Results:The inner cell mass A(ICM A),trophectoderm A(TE A),blastocoele expansion degree of 3,4,5,6,7 rates were higher with lower the EEVA score.The adjusted odd ratio(aOR)(E5 vs E1)was 0.3 for ICM A,0.174 for TE A and 0.210 for BL3,4,5,6,7(all P<0.001),suggesting a significant association between lower EEVA scores and improved embryo quality.The implantation,clinical pregnancy,and ongoing pregnancy rate were also higher with lower the EEVA score.The aOR of E5 vs E1 was 0.245 for implantation,0.185 for clinical pregnancy and 0.200 for ongoing pregnancy rate(P<0.001).Conclusions:There were associations between blastocyst morphology,pregnancy outcome and EEVA scores.The good blastocyst morphology and pregnancy outcomes are higher with lower the EEVA score.

Pregnancy Outcomes for Day 5 Versus Day 6 Single Frozen-thawed Blastocyst Transfer with Different Qualities of Embryos: A Large Matched-cohort Study

Objective This study aimed to determine whether the day of blastocyst expansion affects pregnancy outcomes in frozen-thawed blastocyst transfer(FBT)cycles.Methods A retrospective match-cohort study was conducted.Patients who underwent blastocyst transfer in frozen-thawed cycles at day 5 or 6 were matched for potential confounding factors.A total of 2207 matched pairs of FBT cycles were included from January 2016 to December 2019 in our Reproductive Medicine Center.Results The clinical pregnancy rate(CPR)and live birth rate(LBR)were significantly increased in day 5 blastocyst transfers when compared to day 6 blastocyst transfers,in terms of the same embryo quality.For FBT cycles with good-quality embryo,the CPR at day 5 and 6 was 61.30%and 57.56%,respectively(P=0.045),and the LBR was 44.79%and 36.16%,respectively(P<0.001).For FBT cycles with poor-quality embryo,the CPR at day 5 and 6 was 48.61%and 40.89%,respectively(P=0.006),and the LBR was 31.71%and 25.74%,respectively(P=0.019).The CPR for FBT cycles with good-quality embryo was statistically higher at day 6 than that at day 5 with poor-quality embryo transferred(57.56%vs.48.61%,P=0.001).Maternal age,anti-Müllerian hormone(AMH),endometrial thickness,embryo quality,and the day of blastocyst expansion were independently correlated with the CPR and LBR.The FBT cycles at day 5 had significantly higher CPR(adjusted odds ratio[OR]=1.246,95%confidence intervals[CI]:1.097–1.415,P=0.001)and LBR(adjusted OR=1.435,95%CI:1.258–1.637,P<0.001)than those at day 6.Conclusion The embryo quality is the primary indicator for FBT cycles.Day 5 blastocysts should be preferred when the quality of embryo at day 5 is the same as that at day 6.

Gene Expression and Regulation of Blastocyst Formation

Blastocyst formation is a crucial stage of early embryo development.Cell junction proteins and cell adhesion associated proteins are involved in the establishment of cell junction,and subsequently induce cell compaction,blastocyst formation,differentiation of trophectoderm and maintenance of blastocyst expansion.Genes regulating development and differentiation participate in embryo development and differentiation of inner cell mass and trophectoderm,which controls the transition from the undifferentiation to differentiation state.Furthermore,cytokine and growth factor have influence on the proliferation of cells of inner cell mass.In a word,many proteins and factors are involved in the gene expression and regulation of blastocyst formation.

Relationships Between Icariin and Anti-Apoptotic miRNA-21 in Mouse Blastocyst Development In vitro

In this study, the effect of icariin, a flavonoid from the Chinese traditional medicine epimedium, on miRNA-21 of mouse developmental blastocysts in vitro and the development of preimplantation embryos were studied. The possible effective targets of icariin promoting preimplantation embryo development in vitro and anti-apoptosis were determined. The embryos were cultured in modified CZB medium （mCZB） as control group. The experimental group （Ica group） was supplemented with 0.6 μg mL-1 icariin. Mouse pronuclear embryos were cultured in vitro until blastocysts. The development rates of preimplantation embryos were observed. The total cell number, apoptotic cell number and the rate of apoptotic cells in blastocysts were analysed by the staining of Hoechst33342 and labeling of TUNEL and detected under a laser confocal scanning microscope. The miRNA-21 expression, the mRNA levels of pro-apoptotic Caspase3, and the target genes of miRNA-21： pro-apoptotic PTEN, anti-apoptotic Bcl-2 were detected by real-time RT-PCR. The results showed that percentages of morulaes and blastocysts in Ica group were both extremely higher than control group （（85.14±6.57）% vs. （72.04±11.58）%; （82.50±7.11）% vs. （66.80±11.70）%, respectively, P〈0.01）. The total cell number ofblastocysts had extreme difference between Ica group and control group （（61.40±9.64） vs. （46.23±4.50）, P〈0.01）. The apoptotic cell number and rate of apoptotic cells of blastocysts were both reduced in Ica group （（1.47±0.51） vs. （2.94±0.66）; （2.40±0.27）% vs. （6.25±0.62）%, respectively, P〈0.01）. Compared to control group, addition of icariin into mCZB extremely increased the expression of anti-apoptotic miRNA-21 （P〈0.01）, down-regulated pro-apoptotic Caspase3 （P〈0.05） and PTEN （P〈0.01）, up-regulated anti-apoptotic Bcl-2 （P〈0.01）. In conclusion, icariin could reduce the apoptosis, promote the embryo development in vitro by enhancing miRNA-21 expression to up-regulated anti-apoptotic genes and down-regulated pro- apoptotic genes. These apoptosis-related genes were regulated by miRNA-21.

Predictive Value of Initial Serum Human Chorionic Gonadotropin Levels for Pregnancies after Single Fresh and Frozen Blastocyst Transfer

As one of the earliest markers for predicting pregnancy outcomes, human chorionic gonadotropin(h CG) values have been inconclusive on reliability of the prediction after frozen and fresh embryo transfer(ET). In this retrospective study, patients with positive h CG(day 12 after transfer) were included to examine the h CG levels and their predictive value for pregnancy outcomes following 214 fresh and 1513 vitrified-warmed single-blastocyst transfer cycles. For patients who got clinical pregnancy, the mean initial h CG value was significantly higher after frozen cycles than fresh cycles, and the similar result was demonstrated for patients with live births(LB). The difference in h CG value existed even after adjusting for the potential covariates. The area under curves(AUC) and threshold values calculated by receiver operator characteristic curves were 0.944 and 213.05 m IU/m L for clinical pregnancy after fresh ET, 0.894 and 399.50 m IU/m L for clinical pregnancy after frozen ET, 0.812 and 222.86 m IU/m L for LB after fresh ET, and 0.808 and 410.80 m IU/mL for LB after frozen ET with acceptable sensitivity and specificity, respectively. In conclusion, single frozen blastocyst transfer leads to higher initial h CG values than single fresh blastocyst transfer, and the initial h CG level is a reliable predictive factor for predicting IVF outcomes.

High in vitro survival rate of sheep in vitro produced blastocysts vitrified with a new method and device

Background:To advance the use of embryo vitrification in veterinary practice,we developed a system in which embryo vitrification,warming and dilution can be performed within a straw.Ovine in vitro produced embryos(IVEP)were vitrified at either early(EBs:n=74)or fully expanded blastocyst stage(FEBs:n=195),using a new device named"E.Vit",composed by a 0.25-m L straw with a 50-μm pore polycarbonate grid at one end.Embryos at each stage(EBs and FEBs)were vitrified by either Two-step(TS)or Multi-step(MS;6 different concentrations of vitrification solutions)protocol.Non-vitrified embryos(n=102)were maintained in in vitro culture as a control.Warming consisted of placing the straws directly into 1.5 m L tubes containing a TCM-199 solution with three decreasing concentrations of sucrose.Blastocyst re-expansion,embryo survival and hatching rate were evaluated at2,24 and 48 h post warming.The number of apoptotic cells was determined by TUNEL assay.Results:Blastocyst re-expansion(2 h)after warming was higher(P<0.05)in FEBs group,vitrified with the MS and TS methods(77.90%and 71.25%,respectively)compared with the EBs group(MS:59.38%and TS:48.50%,respectively).Survival rates of vitrified FEBs after 24 h IVC were higher(P<0.001)in both methods(MS and TS)than vitrified EBs(MS:56.25%;TS:42.42%)and was higher(P<0.05)in the MS method(94.19%)compared with those in TS(83.75%).After 48 h of culture the hatching rate for FEBs vitrified in MS system(91.86%)was similar to control(91.89%),but higher than FEB TS(77.5%)and EBs vitrified in MS(37.5%)and TS(33.33%).Number of apoptotic cells were higher in EBs,irrespective of the system used,compared to FEBs.The number of apoptotic cells in FEBs vitrified with MS was comparable to the control.Conclusions:A high survival rate of IVP embryos can be achieved by the new"E.Vit"device with hatching rates in vitro comparable with control fresh embryos.This method has the potential for use in direct embryo transfer in field conditions.

Controlled Freezing and Open-Pulled Straw (OPS) Vitrification of In vitro Produced Bovine Blastocysts FollowingAnalysis of ATP Content and Reactive Oxygen Species (ROS) Level

To our knowledge,no single study has systemically compared cryopreservation efficiencies of bovine blastocysts derived from in vitro fertilization （IVF）,intracytoplasmic sperm injection （ICSI） and somatic cell nuclear transfer （SCNT） by controlled freezing and vitrification.This experiment,therefore,was designed to compare the cryopreservation of these blastocysts with controlled freezing and OPS vitrification.Adenosine-5’-triphosphate （ATP） content and reactive oxygen species （ROS） level in blastocysts were also analyzed.Firstly,for each type of blastocyst （IVF,ICSI or SCNT）,significant differences were observed between the survival rates of the controlled freezing （（81.56±2.33）,（68.18±4.72） or （47.89±5.83）%） and OPS vitrification groups （（92.24±4.54）,（82.40±3.76） or （78.71±5.91）%;P〈0.05）.Secondly,for each type of blastocyst （IVF,ICSI or SCNT）,ATP content was significantly decreased after controlled freezing or vitrification,and the ATP content in the controlled freezing group （0.43±0.06）,（0.35±0.05） or （0.21±0.02） pmol） was significantly lower than that found in the OPS vitrification group （0.62±0.04）,（0.46±0.03） or （0.30±0.01） pmol;P〈0.05）.Thirdly,ROS level in fresh IVF （（47.33±3.56） c.p.s （counted photons per second）,ICSI （（36.51±2.58） c.p.s） or SCNT blastocysts （（26.44±1.49） c.p.s） was significantly lower than that found in the OPS vitrification group （（72.14±4.31）,（58.89±3.89） or （40.11±5.73） c.p.s;P〈0.05）,but higher than that of the controlled freezing group （34.41±3.32）,（23.13±1.26） or （15.46±2.45） c.p.s;P〈0.05）.The present study indicated that vitrification is more efficient in the cryopreservation of bovine blastocysts derived from IVF,ICSI or SCNT than controlled freezing.Furthermore,both vitrification and controlled freezing significantly altered the ATP content and ROS level in those blastocysts.

Derivation and transcriptional profiling analysis of pluripotent stem cell lines from rat blastocysts

Embryonic stem （ES） cells are derived from blastocyst-stage embryos. Their unique properties of self-renewal and pluripotency make them an attractive tool for basic research and a potential cell resource for therapy. ES cells of mouse and human have been successfully generated and applied in a wide range of research. However, no genuine ES cell lines have been obtained from rat to date. In this study, we identified pluripotent cells in early rat embryos using specific antibodies against markers of pluripotent stem ceils. Subsequently, by modifying the culture medium for rat blastocysts, we derived pluripotent rat ES-like cell lines, which expressed pluripotency markers and formed embryoid bodies （EBs） in vitro. Importantly, these rat ES-like cells were able to produce teratomas. Both EBs and teratomas contained tissues from all three embryonic germ layers. In addition, from the rat ES-like cells, we derived a rat primitive endoderm （PrE） cell line. Furthermore, we conducted transcriptional profiling of the rat ES-like cells and identified the unique molecular signature of the rat pluripotent stem cells. Our analysis demonstrates that multiple signaling pathways, including the BMP, Activin and mTOR pathways, may be involved in keeping the rat ES-like cells in an undifferentiated state. The cell lines and information obtained in this study will accelerate our understanding of the molecular regulation underlying pluripotency and guide us in the appropriate manipulation of ES cells from a particular species.

Chromatin remodeler INO80 mediates trophectoderm permeability barrier to modulate morula-to-blastocyst transition

Inositol requiring mutant 80(INO80)is a chromatin remodeler that regulates pluripotency maintenance of embryonic stem cells and reprogramming of somatic cells into pluripotent stem cells.However,the roles and mechanisms of INO80 in porcine preimplantation embryonic development remain largely unknown.Here,we show that INO80 modulates trophectoderm epithelium permeability to promote porcine blastocyst development.The INO80 protein is highly expressed in the nuclei during morula-toblastocyst transition.Functional studies revealed that RNA interference(RNAi)-mediated knockdown of INO80 severely blocks blastocyst formation and disrupts lineage allocation between the inner cell mass and trophectoderm.Mechanistically,singleembryo RNA sequencing revealed that INO80 regulates multiple genes,which are important for lineage specification,tight junction assembly,and fluid accumulation.Consistent with the altered expression of key genes required for tight junction assembly,a permeability assay showed that paracellular sealing is defective in the trophectoderm epithelium of INO80 knockdown blastocysts.Importantly,aggregation of 8-cell embryos from the control and INO80 knockdown groups restores blastocyst development and lineage allocation via direct complementation of the defective trophectoderm epithelium.Taken together,these results demonstrate that INO80 promotes blastocyst development by regulating the expression of key genes required for lineage specification,tight junction assembly,and fluid accumulation.

The outcomes of human blastocyst cryopreservation:vitrification using cryoloop versus slow-freezing method

Objective:To compare the outcomes of vitrification using cryoloop with slow-freezing meth-od for human blastocyst cryopreservation.Methods:In IVF-ET cycles,supernumerary embryos were cultured to Day 5 or Day 6,blas-tocysts were cryopreserved by vitrification using cryoloops or slow-freezing method,then blasto-cyst survival rate and pregnant rate were compared.Results:115 vitrified blastocysts from 39 cycles were warmed,104(90.4%)blastocysts sur-vived.After the transfer of 74 blastocysts in 38 cycles,28(73.7%)women got clinically preg-nant,2(7.1%)of them suffered from miscarriage,2 healthy babies were born in 2 deliveries,and the other 24 pregnancies are ongoing.As to slow-freezing method,87 blastocysts from 21 cy-cles were thawed,37(42.5%)of them survived,28 blastoeysts were transferred in 15 cycles,6(40%)women got clinically pregnant,1 of them miscarried,3 healthy babies were born in 2 de-liveries,and the other 3 pregnancies are ongoing.Conclusion:The survival rate and pregnant rate of vitrification using cryoloop are superior totraditional slow-freezing method,and the transfer cancel rate is lower than that of slow-freezingmethod.The miscarriage rate is similar in two methods.

Beneficial effect of reduced oxygen concentration with transfer of blastocysts in IVF patients older than 40 years old

The aim of the present study was to determine the impact of oxygen concentration on implantation, pregnancy and delivery rates in IVF patients older than 40 year old with transfer of blastocysts. Included were 558 women aged 23-45 years old undergoing IVF/ICSI procedures whose embryos were cultured at blastocyst stage under two different oxygen environments (a bi-gas system: 5.6% CO2 in air and a tri-gas system: 5.6% CO2, 5% de O2 and 89.4% N2). The main outcome measures of this study are implantation, pregnancy and delivery rates. Implantation, pregnancy and delivery rates are found to be reduced in women older than 40 years old. The implantation and pregnancy rates are significantly higher in women older than 40 years old from the 5% of O2 group, in comparison to the 20% group (25.00% versus 2.70% and 41.38% versus 5.56%;P < 0.05). The deliveries rates were 13.79% and 5.56% in the 5% and 20% oxygen groups respectively (P: NS). The birthweight was similar in both study groups (P: NS). Gestational age was significantly longer in wo- men from the 5% of O2 group, in comparison to the 20% (36.87 versus 35.87 weeks, P < 0.05). Results indicated that the embryonic culture with 5% of oxygen and transfer of blastocysts in women older than 40 years old improve the results in the in Vitro fertilization/intracytoplasmic injection procedures (IVF/ICSI).

High-quality Cleavage Embryo versus Low-quality Blastocyst in Frozen-thawed Cycles:Comparison of Clinical Outcomes

This study compared the clinical outcomes of the frozen-thawed cycles of high-quality cleavage embryos with low-quality blastocysts to provide a reference for the choice of frozen-thawed embryo transfer schemes and to improve clinical pregnancy rates.A retrospective analysis was performed on the clinical data of patients undergoing frozen-thawed embryo transfer at the Reproductive Medicine Center of Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology from 2016 to 2017.In total,845 cases were divided into a high-quality cleavage embryo group(group A)and a low-quality blastocyst group(group B).Each group was further divided into subgroups based on the number of transplants.Group A was categorized into two subgroups comprising of 94 cases in subgroup Al(1 high-quality 8-cell group)and 201 cases in subgroup A2(2 high-quality 8-cell group).Group B was divided into four subgroups consisting of 73 cases in subgroup B I(D53BC group),65 cases in subgroup B2(D54BC group),110 cases in subgroup B3(D63BC group),and 282 cases in subgroup B4(D64BC group).The pregnancy outcomes and neonatal outcomes between the groups were compared.The clinical pregnancy rates(56.72%and 60.00%)and live birth rates(47.76%and 46.15%)in subgroups A2 and B2 showed no significant differences,but these rates were significantly higher in subgroups A2 and B2 than in the rest subgroups(P<0.05).The multiple birth rate(26.32%)in the subgroup A2 was significantly higher than that in the rest subgroups(P<0.05).There were no statistically significant differences in the abortion rates among all groups(P>0.05).In terms of neonatal outcomes,there were no statistically significant differences in the proportion of premature births,sex ratios,and birth defects among the low-weight and gigantic infants(P>0.05).Transplanting two high-quality cleavage embryos during the frozen-thawed embryo transfer cycles could significantly increase clinical pregnancy rates and live birth rates,but at the same time,it also increased the risks of multiple births and complications to mothers and infants.The D54BC subgroup had the most significant advantages among all groups(P<0.05).The rest low-quality blastocysts had clinical outcomes similar to the single high-quality cleavage embryo group.

Effect of Retinoic Acid on Apoptosis and Expression of Fas Proteins in Mouse Blastocysts Cultured In Vitro

Mouse blastocysts were exposed to doses of 0, 1 and 10 μmol/L retinoic acid （RA） for 24 h and the cytotoxic effect of RA on the mouse blastocysts in vitro was observed. FITC-labeled terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL-FITC） assay was employed to stain apoptotic cells and immunohistochemical S-P staining method was used to detect the expression of Fas protein in mouse blastocysts in vitro. The results showed that RA could induce apoptosis and increase the expression of Fas proteins of trophectoderm （TE） and inner cell mass （ICM） cells in blastocysts. Compared with the findings for the control blastocysts, exposure to RA （10 μmol/L） resulted in a more significant apoptosis and higher expression level of Fas proteins （P〈0.01）. It was concluded that RA could induce apoptosis, which may result in a significant reduction in the average number of total cells and the trophectoderm/inner cell mass in blastocysts and an increased expression of Fas protein, suggesting that RA had a cytotoxic effect on the growth and development of early embryos in mice.

Unveiling how vitrification affects the porcine blastocyst: clues from a transcriptomic study

Background:Currently,there is a high demand for efficient pig embryo cryopreservation procedures in the porcine industry as well as for genetic diversity preservation and research purposes.To date,vitrification(VIT)is the most efficient method for pig embryo cryopreservation.Despite a high number of embryos survives in vitro after vitrification/warming procedures,the in vivo embryo survival rates after embryo transfer are variable among laboratories.So far,most studies have focused on cryoprotective agents and devices,while the VIT effects on porcine embryonic gene expression remained unclear.The few studies performed were based on vitrified/warmed embryos that were cultured in vitro(IVC)to allow them to re–expand.Thus,the specific alterations of VIT,IVC,and the cumulative effect of both remained unknown.To unveil the VIT-specific embryonic alterations,gene expression in VIT versus(vs.)IVC embryos was analyzed.Additionally,changes derived from both VIT and IVC vs.control embryos(CO)were analyzed to confirm the VIT embryonic alterations.Three groups of in vivo embryos at the blastocyst stage were analyzed by RNA–sequencing:(1)VIT embryos(vitrified/warmed and cultured in vitro),(2)IVC embryos and(3)CO embryos.Results:RNA–sequencing revealed three clearly different mRNA profiles for VIT,IVC and CO embryos.Comparative analysis of mRNA profiles between VIT and IVC identified 321,differentially expressed genes(DEG)(FDR<0.006).In VIT vs.CO and IVC vs.CO,1901 and 1519 DEG were found,respectively,with an overlap of 1045 genes.VIT-specific functional alterations were associated to response to osmotic stress,response to hormones,and developmental growth.While alterations in response to hypoxia and mitophagy were related to the sum of VIT and IVC effects.Conclusions:Our findings revealed new insights into the VIT procedure-specific alterations of embryonic gene expression by first comparing differences in VIT vs.IVC embryos and second by an integrative transcriptome analysis including in vivo control embryos.The identified VIT alterations might reflect the transcriptional signature of the embryo cryodamage but also the embryo healing process overcoming the VIT impacts.Selected validated genes were pointed as potential biomarkers that may help to improve vitrification.

Sperm DNA fragmentation does not affect the clinical outcomes in the cumulative transfers of an ICSI cycle along with blastocyst transfers in couples with normozoospermic male patients

Objective:To know whether sperm DNA fragmentation(SDF)affects the clinical outcomes in the cumulative transfers of an intracytoplasmic sperm injection(ICSI)cycle along with blastocyst transfers in couples with normozoospermic males.Methods:The study included 252 couples who underwent their first ICSI cycles along with blastocyst transfer and whose male partner semen samples were normozoospermic according to the World Health Organization 2010 criteria.All the couples were classified into two groups based on the SDF:the low SDF group(SDF≤30%,n=162)and the high SDF group(SDF>30%,n=90).Clinical as well as laboratory outcomes were correlated between the two groups.Sperm DNA fragmentation was assessed on the post-wash semen samples by acridine orange test.The main outcome measures were the live birth rate and miscarriage rate.Results:A significant decrease in the live birth rates was observed in the high SDF group compared to the low SDF group in fresh embryo transfer cycles(P<0.05).However,no significant difference was observed in the clinical outcomes either in the frozen embryo transfer cycles or in the overall cumulative transfer cycles(P>0.05).No significant difference was observed in the laboratory outcomes between the two SDF groups.A remarkable decrease in sperm motility was observed in the high SDF group compared to the low SDF group(P<0.05).Conclusions:Sperm DNA fragmentation does not affect the clinical outcomes in the cumulative transfers of an ICSI cycle along with blastocyst transfers in couples with normozoospermic males.

Comparison of Pregnancy Outcomes of High-Quality D5- and D6-Blastocyst Transfer in Hormone-Replacement Frozen-Thawed Cycles

This study aimed to assess pregnancy outcomes after high-quality D5- and D6-blastocyst transfer in frozen cycles of in vitro fertilization and embryo transfer and to further evaluate whether there was a difference in blastocyst development potentials with different developmental speeds and in pregnancy outcomes. A retrospective analysis was conducted to analyze 247 frozen cycles in our center from September 2015 to July 2017, which were divided into two groups: a D5-FET group with 193 cycles of D5-blastocyst transfer, and a D6-FET group with 54 cycles of D6-blastocyst transfer. Hormone replacement method was utilized to prepare frozen-cycle endometria. Pregnancy outcomes were analyzed and compared between these two groups. The mean ages of the two groups were 31.45 ± 4.43 years and 31.98 ± 4.84 years, respectively, with no statistically significant differences (P > 0.05). The difference in the endometrial thickness during transfer was also not statistically significant. The implantation rate in the D5-FET group was 60.13%, significantly higher than that in the D6-FET group (31.58%, P P < 0.05). No statistically significant differences were found in the abortion rate and ectopic pregnancy rate between the two groups. The implantation, biochemical pregnancy, and clinical pregnancy rates of the blastocyst D5 were all superior to those of the blastocyst D6. In clinics, therefore, D5-blastocyst transfer could be prioritized for embryo transfer.

Effects of Mifepristone (RU486) on Development and Ultrastructure of Mouse Blastocysts

Objective To investigate effects of mifepristone （MP） on the development and ultrastructure of mouse blastocysts in vivo Methods Sixty female mice were equally divided into 4 groups： control group （group A）, 1.9 mg/kg MP group （group B）, 5.6 mg/kg MP group （group C）, and 16.8 mg/kg MP group （group D）. The female mice of 4 groups undertook a superovulation method. The development of obtained blastocysts was evaluated, and ultrastructural changes of the blastocysts were observed by transmission electron microscope. Results In comparison with group A, the development rate of blastocysts in group B showed no difference （P〉0.05）, while the development rate of blastocysts in both group C and group D was significantly lower （P〈0.05）. With doses of 5.6 mg/kg and 16.8 mg/kg, the blastocysts showed granular appearance of the cytoplasm, irregular cell borders, enlarged perivitelline space and degeneration. Ultrastructure of the blastocysts in group B was similar to group A, except a little number of fat droplets in the cytoplasm. In group C, the microvilli on apical surface was decreased in number or even disappeared, mitochondria were under developed, a lot of filamentous crystals were found in the cytoplasm. Cellular junctions were defected. In group D, the blastocyst cells were irregular in shape, mitochondria were frequently vacuolated, the nucleolus was enlarged, nuclear membrane was ruptured, and chromatin was slack. Conclusion MP could damage to the ultrastructure of mouse blastocyst, and was responsible for the inhibition of blastocyst development. The inhibitory effect of MP would be in a dose-dependent fashion.

Developmental competence and ultrastructural changes of heat-stressed mouse early blastocysts produced in vitro

Mouse early blastocysts were exposed to temperatures of 39℃ and 41℃ for 2 h, respectively, to determine their developmental competence and ultrastructural changes. The results showed that heat stress at 41 ℃ for 2 h, significantly reduced the percentages of expanded and hatched blastocysts, but not at 39℃ for 2 h. The average cell numbers in expanded blastocysts, which developed from early blastoeysts heat-stressed at temperatures of 39℃ and 41 ℃, were significantly reduced. The average cell numbers in hatched blastocysts subjected to heat stress were no different from those in the control group cultured at 37 ℃ . The mitochondria of the early blastocysts heat-stressed at 39℃ for 2 h, were slightly swollen, but they had recovered after culturing at 37 ℃ for 2 h. However, the mitochondria in the blastocysts heat stressed at 41 ℃ for 2 h were severely swollen, and their number increased. The ribosomes shed from the rough endoplasmic reticulum, and the number of secondary lysosomes in the plasma increased. The integrity of desmosomes was disrupted. The space between the nuclear envelope and the perivitelline membrane enlarged. The fibre fraction and the particulate fraction of nueleoli were separated. The heterochromatin in nueleoli was also increased in its quantity. There were some lamellar-shape structures and heterogeneous dense materials exhibiting in the cytoplasm. The ultrastructural changes induced by heat shock at 41 ℃ for 2 h were not reversible. In conclusion, the damage of heat stress to mitoehondria, lysosomes, ribosomes and cell nucleus, may be one of the most important factors that inhibit the normal development of mouse early blastoeysts .

Factors Analysis of Spontaneous Abortion after Thawed-vitrified Blastocysts Transfer

Objective To investigate the factors resulting in spontaneous abortion after transferring frozen-thawing blastocysts.Methods A total of 108 cases transferring vitrified blastocysts were divided into two groups. abortion group （n=20） and ongoing group （n=88）. Cytogenetic analysis of apoblemas was performed in 12 cases of the abortion.Results The overall spontaneous abortion rate was 18.50%（20/108） and the early spontaneous rate was 16.67%（18/108）. A significant difference in maternal age was observed （abortion group： 33.3±4.0years, ongoing group： 31.0 ±3.6years, P=0.02）. No difference in other parameters was found. Cytogenetic analysis of apoblemas was obtained for 12 cases, and 2 specimens were contaminated. Seven often patients had abnormal karyotypes.Conclusion The underlying cause of spontaneous abortion after transferring frozenthawing blastoeysts appears to be abnormal karyotypes. Advancing maternal age seems to increase the risk of spontaneous abortion.

Blastocyst elective single embryo transfer improves perinatal outcomes among women undergoing assisted reproductive technology in Indonesia

Objective:To compare the effectiveness of blastocyst elective single embryo transfer(eSET)and double embryo transfer(DET)in reducing low birth weight,preterm birth,and perinatal mortality in in vitro fertilization(IVF)cycles of Indonesian women.Methods:A retrospective observational study was conducted at Morula IVF Clinic,Jakarta,Indonesia.A total of 179 women who underwent either eSET or DET and had met the eligibility criteria were included.Seventy-six women underwent eSET while 103 underwent DET in their IVF cycles.Low birth-weight rate,preterm birth rate,and perinatal mortality rate of both groups were measured as the primary study outcomes.Neonatal intensive care unit(NICU)admission rate,Apgar score,multiple pregnancy,and maternal complications during pregnancy were also evaluated.Results:The risk of low birth weight[odds ratio(OR)=0.21,95%confidential interval(CI):0.10-0.45,P<0.001]and preterm birth(OR=0.25,95%CI:0.13-0.49,P<0.001)was significantly lower in the eSET group compared with the DET group.Furthermore,eSET efficiently reduced the incidence of NICU admission and multiple pregnancy(P=0.01 and P<0.001,respectively).No significant difference was observed in terms of perinatal mortality rate,Apgar score,and maternal complications including gestational diabetes,preeclampsia as well as pregnancy-induced hypertension(P≥0.05).However,a lower incidence of antepartum hemorrhage was noticed in the eSET group than in the DET group(P=0.03).Conclusions:Compared with DET,infants conceived through IVF cycles with eSET have a significantly lower risk of low birth weight,preterm birth,and NICU admissions.Moreover,eSET is shown to reduce multiple pregnancy rate,yet no significant differences are observed in the perinatal mortality rates,Apgar score and maternal complications(except for the incidence of antepartum hemorrhage)between both groups.