Characteristics of the cytoplasmic halo during fertilisation correlate with the live birth rate after fresh cleaved embryo transfer on day 2 in minimal ovarian stimulation cycles: a retrospective observational study.

BACKGROUND: Information regarding the influence of cytoplasmic events during fertilisation on the clinical outcome remains limited. The cytoplasmic halo is one of these events. A previous study that used time-lapse technology found an association of the presence and morphokinetics of the cytoplasmic halo with cleavage patterns, development to the blastocyst stage, and the ongoing pregnancy rate after blastocyst transfer. Therefore, the cytoplasmic halo may be a useful predictor of the pregnancy outcome after cleaved embryo transfer. This study evaluated the ability of the cytoplasmic halo to predict a live birth after fresh cleaved embryo transfer on day 2, and sought to identify factors potentially influencing the presence and morphokinetics of the halo. METHODS: A total of 902 embryos cultured in the EmbryoScope+® time-lapse system and subjected to single fresh cleaved embryo transfer were retrospectively analysed. The presence and duration of a cytoplasmic halo were annotated. The initial positions of the pronuclei were also observed. The correlation between the cytoplasmic halo and live birth was evaluated and the association of the cytoplasmic halo with patient, cycle, and embryonic characteristics was determined. RESULTS: Absence of a cytoplasmic halo was associated with a significant decrease in the likelihood of a live birth after fresh cleaved embryo transfer. Prolongation of the halo, especially the duration of central repositioning of cytoplasmic granules, had an adverse impact on the live birth rate. The characteristics of the cytoplasmic halo were not affected by the ovarian stimulation method used, female age, the serum steroid hormone level on the day of trigger, or semen quality. However, the cytoplasmic halo was significantly affected by male age, oocyte diameter, and the initial position of the male pronucleus. CONCLUSIONS: Absence or prolongation of the cytoplasmic halo was negatively correlated with the live birth rate after fresh cleaved embryo transfer. The characteristics of the cytoplasmic halo were strongly associated with oocyte diameter, male age, and the initial position of the male pronucleus. These findings indicate that the characteristics of the cytoplasmic halo can be used to select more competent embryos for transfer at the cleavage stage.

Comparing prediction of ongoing pregnancy and live birth outcomes in patients with advanced and younger maternal age patients using KIDScore™ day 5: a large-cohort retrospective study with single vitrified-warmed blastocyst transfer.

BACKGROUND: The KIDScore™ Day 5 (KS-D5) model, version 3, is a general morphokinetic prediction model (Vitrolife, Sweden) for fetal heartbeat prediction after embryo transfer that was developed based on a large data set that included implantation results from a range of clinics with different patient populations, culture conditions and clinical practices. However, there was no study to comparing their pregnancy and live birth prediction ability among different maternal age. The aim of this study is to analyze the performance of KS-D5 in predicting pregnancy and live birth in various maternal age groups after single vitrified-warmed blastocyst transfer (SVBT). METHODS: A total of 2486 single vitrified-warmed blastocyst transfer (SVBT) cycles were analyzed retrospectively. Confirmed fetal heartbeat positive (FHB+) and live birth (LB+) rates were stratified by Society for Assisted Reproductive Technology (SART) maternal age criteria (< 35, 35-37, 38-40, 41-42 and ≥ 43 years of age). Within each age group, the performance of the prediction model was calculated using the AUC, and the results were compared across the age groups. RESULTS: In all age groups, the FHB+ rates decreased as the KIDScore decreased (P <  0.05). Conversely, the AUCs increased as the maternal age increased. The AUC of the < 35 age group (0.589) was significantly lower than the AUCs of the 41-42 age group (0.673) and the ≥43 age group (0.737), respectively (P <  0.05). In all age groups, the LB+ rates decreased as the KIDScore decreased (P <  0.05). Conversely, the AUCs increased as the maternal age increased. The AUC of the ≥43 age group (0.768) was significantly higher than the AUCs of other age groups (P <  0.05; < 35 age group = 0.596, 35-37 age group = 0.640, 38-40 age group = 0.646, 41-42 age group = 0.679). CONCLUSIONS: In the present study, we determined that the KIDScore model worked well for prediction of pregnancy and live birth outcomes in advanced age patients.

Pregnancy prediction performance of an annotation-free embryo scoring system on the basis of deep learning after single vitrified-warmed blastocyst transfer: a single-center large cohort retrospective study.

OBJECTIVE: To analyze the performance of an annotation-free embryo scoring system on the basis of deep learning for pregnancy prediction after single vitrified blastocyst transfer (SVBT) compared with the performance of other blastocyst grading systems dependent on annotation or morphology scores. DESIGN: A single-center large cohort retrospective study from an independent validation test. SETTING: Infertility clinic. PATIENT(S): Patients who underwent SVBT cycles (3,018 cycles, mean ± SD patient age 39.3 ± 4.0 years). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The pregnancy prediction performances of each embryo scoring model were compared using the area under curve (AUC) for predicting the fetal heartbeat status for each maternal age group. RESULT(S): The AUCs of the <35 years age group (n = 389) for pregnancy prediction were 0.72 for iDAScore, 0.66 for KIDScore, and 0.64 for the Gardner criteria. The AUC of iDAScore was significantly greater than those of the other two models. For the 35-37 years age group (n = 514), the AUCs were 0.68, 0.68, and 0.65 for iDAScore, KIDScore, and the Gardner criteria, respectively, and were not significantly different. The AUCs of the 38-40 years age group (n = 796) were 0.67 for iDAScore, 0.65 for KIDScore, and 0.64 for the Gardner criteria, and there were no significant differences. The AUCs of the 41-42 years age group (n = 636) were 0.66, 0.66, and 0.63 for iDAScore, KIDScore, and the Gardner criteria, respectively, and there were no significant differences among the pregnancy prediction models. For the >42 years age group (n = 389), the AUCs were 0.76 for iDAScore, 0.75 for KIDScore, and 0.75 for the Gardner criteria, and there were no significant differences. Thus, iDAScore AUC was either the highest or equal to the highest AUC for all age groups, although a significant difference was observed only in the youngest age group. CONCLUSION(S): Our results showed that objective embryo assessment by a completely automatic and annotation-free model, iDAScore, performed as well as or even better than more traditional embryo assessment or annotation-dependent ranking tools. iDAScore could be an optimal pregnancy prediction model after SVBT, especially in young patients.

Comparison of Embryo and Clinical Outcomes in Different Types of Incubator Between Two Different Embryo Culture Systems.

This study aimed to compare the clinical outcomes of an oxidative stress-reducing embryo culture system (ORES) containing compounds that minimize intercellular oxidative stress, with those of a standard embryo culture system (StES). Furthermore, we investigated the efficiency of the ORES regarding the type of incubator used (time-lapse incubator [TLI] or non-time-lapse dry incubator [non-TLI]) and maternal age. In this retrospective study, we analyzed 3610 oocyte retrieval cycles (in 2537 patients) and 1726 single vitrified-warmed blastocyst transfer (SVBT) cycles (in 1726 patients) performed in a single center between April 2018 and July 2019. Transfers of single vitrified-warmed blastocysts, confirmed by fetal heartbeat, were used to assess clinical outcomes. The clinical outcomes of ORES and StES were compared in both TLI and non-TLI. Groups were stratified according to maternal age (≤39 years old, young age group; ≥40 years old, advanced age group). A significant difference in ongoing pregnancy rates was observed between the ORES and StES groups when non-TLI was used (34.9 vs. 27.0%, respectively; p < 0.05), unlike when TLI was used. Furthermore, ongoing pregnancy rates were significantly higher in the ORES group (24.8%) than in the StES group (14.9%) in the advanced age group, unlike in the young age group when non-TLI was used. In conclusion, compared to StEs, the ORES during all in vitro fertilization procedures improved ongoing pregnancy rates in the advanced age group using the non-TLI.

Perturbations of morphogenesis at the compaction stage affect blastocyst implantation and live birth rates.

STUDY QUESTION: Do perturbations of embryo morphogenesis at compaction affect blastocyst development and clinical outcomes in assisted reproduction cycles? SUMMARY ANSWER: Cell exclusion and extrusion, i.e. cell disposal occurring respectively before or during morula compaction, affect blastocyst yield and quality, as well as rates of pregnancy and live birth. WHAT IS KNOWN ALREADY: Despite its pivotal role in morphogenesis for blastocyst organisation and cell fate determination, compaction at the morula stage has received little attention in clinical embryology. Time lapse technology (TLT) allows detailed morphokinetic analysis of this developmental stage. However, even in the vast majority of previous TLT studies, compaction was investigated without a specific focus. Recently, we reported that compaction may be affected by two clearly-distinct patterns of cell disposal, exclusion and extrusion, occurring prior to and during compaction, respectively. However, the crucial question of the specific relevance of partial compaction for embryo development and competence in ART has remained unanswered until now. STUDY DESIGN, SIZE, DURATION: This study involved the assessment of laboratory and clinical outcomes of 2,059 morula stage embryos associated with 1,117 ICSI patients, who were treated with minimal stimulation and single vitrified-warmed blastocyst transfer (SVBT) from April 2017 to March 2018. Patterns of morula compaction were assessed and analyzed in relation to embryonic and clinical outcomes. PARTICIPANTS/MATERIALS, SETTING, METHODS: Following ICSI, time-lapse videos were analysed to annotate morphokinetic parameters relevant to both pre- and post-compaction stages. According to their morphokinetic history, morulae were classified as: (I) fully compacted morulae (FCM); (II) partially compacted morulae (PCM), showing cells (a) excluded from the compaction process from the outset (Exc-PCM), (b) extruded from an already compacted morula (Ext-PCM), or (c) showing non-compacted cells arisen from both patterns (Exc/Ext-PCM). The number of excluded/extruded cells was also annotated. Possible correlations of compaction patterns with 13 morphokinetic parameters, abnormal cleavage, blastocyst yield and morphological grade, clinical and ongoing pregnancy rates, and live birth rate were evaluated. Other factors, such as patient and cycle characteristics, possibly associated with compaction patterns and their outcomes, were investigated. MAIN RESULTS AND THE ROLE OF CHANCE: Full compaction was observed in 39.0% of all embryos. However, partially compacted morulae (PCM) showing excluded (Exc-PCM), extruded (Ext-PCM) cells, or indeed both phenotypes (Exc/Ext-PCM) were frequently detected (24.8%, 16.6%, and 19.6%, respectively) and collectively (61%) exceeded fully compacted morulae. Blastomere exclusion or extrusion affected one or several cells, in different proportions. In comparison to FCM, the developmental pace of the three PCM groups, observed at 13 developmental stages starting from pronuclear fading, was progressively slower (P < 0.0001). Developmental delay at post-compaction stages was more pronounced in the group showing both patterns of partial compaction. Blastomere exclusion and/or extrusion had a large negative impact on blastocyst development. In particular, rates of blastocyst formation and cryopreservation were very low in the Ext-PCM and Exc/Ext-PCM groups (P < 0.0001). Rates of blastocysts with ICM or TE of highest quality (Grade A) were severely affected in all PCM groups (P < 0.0001). In 1,083 SVBTs, blastocysts derived from all PCM groups produced much lower clinical pregnancy, ongoing pregnancy, and live birth rates (P < 0.0001). All three patterns of partial compaction emerged as factors independently associated with live birth rate, even after multivariate logistic regression analysis including maternal/paternal age, female BMI, and number of previous embryo transfers as possible confounding factors. LIMITATIONS, REASONS FOR CAUTION: The retrospective design of the study represents a general limitation. WIDER IMPLICATIONS OF THE FINDINGS: This large-scale study represents a further important demonstration of embryo plasticity and above all indicates new robust morphokinetic parameters for improved algorithms of embryo selection. STUDY FUNDING/COMPETING INTEREST(S): This study was exclusively supported by the participating institutions. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: NA.

Establishment of day 7 blastocyst freezing criteria using blastocyst diameter for single vitrified-warmed blastocyst transfer from live birth outcomes: a single-center, large cohort, retrospectively matched study.

PURPOSE: To establish blastocyst freezing criteria for day 7 blastocyst (day 7 BL) for single vitrified-warmed blastocyst transfer (SVBT) by examining the diameter of blastocysts. METHODS: Patients who underwent day 7 BL transfer cycles (1143 cycles, mean age: 38.5 ± 3.5) and randomly selected patients after 1:1 matching who underwent day 6 BL transfer cycles and day 2-single-embryo transfer (SET) cycles were used for analysis. Comparison of the miscarriage (per clinical pregnancy) and live birth rates were made among day 2-SET, day 7 BL, and day 6 BL. These blastocyst groups were stratified into six groups based on blastocyst diameter, namely, 180 µm, 190 µm, 200 µm, 210 µm, over 220 µm, and hatched, for making the freezing criteria. RESULTS: For each diameter, 180 µm, 190 µm, 200 µm, 210 µm, over 220 µm, and hatched, the live birth rates of day 7 BL after SVBT were 9.0%, 11.9%, 11.5%, 15.6%, 20.0%, and 19.9%, respectively. Compared with the 14.6% live birth rate of the day 2-SET group, the live birth rate of 220 µm day 7 BL was significantly higher (P < 0.05) and was around the same in other diameter groups. CONCLUSION: Our study demonstrates that sufficient live birth rates can be obtained after SVBT even from blastocysts on day 7 when blastocysts were vitrified at expanded blastocyst stage of over 180 µm of diameter or at hatched blastocyst stage and were transferred at the optimal time. This is the first study to establish a day 7 blastocyst freezing criteria using blastocyst diameter, which is an objective assessment way.

Cytoplasmic halo characteristics during fertilization and their implications for human preimplantation embryo development and pregnancy outcome.

RESEARCH QUESTION: Is the spatiotemporal phenomenology of the cytoplasmic halo during fertilization related to embryonic competence? DESIGN: Time-lapse images from 1009 zygotes were retrospectively analysed from 560 patients who underwent IVF with minimal stimulation and single vitrified-warmed blastocyst transfer between April 2017 and March 2018. Halo presence and morphokinetics were monitored and compared relative to embryo quality, blastocyst expansion and ongoing pregnancy. RESULTS: Halo was observed in 88% of fertilized oocytes. Embryos derived from zygotes without halo had significantly higher rates of rapid cleavage (P = 0.0004), cell fusion (P = 0.0028) and asymmetrical division (P = 0.0002) compared with those derived from zygotes with halo. Multivariate logistic regression analysis had significantly higher developmental rates compared with the expanded blastocyst stage in embryos displaying a halo, regardless of its distribution (adjusted odds ratio 0.435; P = 0.0004). Prolonged halo time intervals were significantly correlated with increased asymmetrical division at first cell division (P = 0.0412, P = 0.0088, respectively) and decreased developmental rates to expanded blastocyst stage (P = 0.0062, P = 0.0020, respectively). Additionally, prolonged presence of the cytoplasmic halo was associated with a decreased ongoing pregnancy rate (adjusted odds ratio 0.871; P = 0.006). Poor sperm quality and decreased oocyte diameter were correlated with absence of the cytoplasmic halo (P = 0.0477, P < 0.0001, respectively) or prolonged halo presence (P = 0.0139, P = 0.0002, respectively). CONCLUSIONS: Halo presence and morphokinetics are associated with cleavage patterns, development to blastocyst stage and ongoing pregnancy rate after single blastocyst transfer. Halo morphokinetics seems to reflect sperm and oocyte quality. Cytoplasmic halo might be valuable predictor for refining selection of more developmentally competent blastocysts.

Blastomere movement post first cell division correlates with embryonic compaction and subsequent blastocyst formation.

BACKGROUND: Blastomere movement (BMov) occurs after the first cell division in human embryos. This movement has been suggested as a prognostic parameter for pregnancy outcome prediction following cleavage-stage embryo transfer. However, the effect of BMov on preimplantation development and pregnancy outcome after blastocyst transfer remains unclear. Therefore, this study aimed to evaluate whether BMov after the first cell division is correlated with blastocyst formation rate and live birth rate after single vitrified-warmed blastocyst transfer (SVBT). METHODS: Nine hundred and sixty-six embryos cultured in the EmbryoScope+® time-lapse system were retrospectively analyzed. The BMov type was categorized into three groups; namely, bouncing, wobbling, and twist-and-crumble. The BMov duration (dBMov) between the first (t2) and second cell division (t3) was monitored, and the ratio of dBMov to the duration of the 2-cell stage was calculated [dBMov/(t3-t2)]. Developmental rates to the 4-cell, 8-cell, morula, blastocyst, and expanded blastocyst stages were assessed, as well as blastocyst morphological grade. The correlations between dBMov and clinical pregnancy, ongoing pregnancy, and live birth rates were evaluated. RESULTS: Increased dBMov/(t3-t2) was significantly correlated with decreased developmental rates to the 8-cell, morula, blastocyst, and expanded blastocyst stages, especially from the 4-cell stage to the morula stage. Analysis of different types of BMov revealed that embryos with bouncing movement exhibited significantly higher developmental rates to the 8-cell, morula, blastocyst, and expanded blastocyst stages compared with embryos with twist-and-crumble movement. The morphological quality of blastocyst-stage embryos with twist-and-crumble movement was significantly lower than that of embryos with bouncing and wobbling movements. The rates of clinical pregnancy, ongoing pregnancy, and live birth after SVBT were not correlated with BMov type or duration. CONCLUSIONS: Embryonic compaction and subsequent blastocyst formation are adversely affected by twist-and-crumble movement and prolonged movement after the first cell division. Our results indicate that the preimplantation developmental competence of human embryos could be predicted by assessing BMov after the first cell division on day 1.

Closed embryo culture system improved embryological and clinical outcome for single vitrified-warmed blastocyst transfer: A single-center large cohort study.

While some studies have shown that the closed embryo culture system (CCS) is a possible improvement over standard embryo culture systems (STS) in terms of early embryonic development, information on clinical outcomes of culturing blastocysts following single vitrified-warmed blastocyst transfer (SVBT) in the CCS and STS remains limited. Therefore, the objective of this single-center, large-cohort, retrospective study was to compare embryonic development until the blastocyst stage and clinical outcomes following SVBT between CCS and STS. From May 2017 to October 2018, 2420 oocytes from 1402 patients who underwent in vitro fertilization and blastocyst culture after minimal stimulation were divided into two groups (CCS and STS). The main outcome measures in the two groups were embryological (blastocyst formation rates and utilized blastocyst rates) and clinical outcomes (ongoing pregnancy rates) after a single vitrified-warmed blastocyst transfer (SVBT). There were no significant differences in the blastocyst formation rates between the CCS and STS groups (59.6% versus 59.1%, p = 0.81). However, there were significant differences in utilized blastocyst rates (51.0% versus 46.6%, p < 0.05). Ongoing pregnancy rates per SVBT cycle were significantly higher in the CCS group than in the STS group (41.4% versus 34.4%, p < 0.05). Moreover, after applying multivariable logistic regression analysis, the type of embryo culture system (CCS to STS, adjusted odds ratios: 1.41, 95% CI: 1.04-1.91) was correlated with ongoing pregnancy. Our study suggests that compared to STS, CCS could improve utilized blastocyst rates and ongoing pregnancy rates to a greater extent, following SVBT.

Prolonged blastomere movement induced by the delay of pronuclear fading and first cell division adversely affects pregnancy outcomes after fresh embryo transfer on Day 2: a time-lapse study.

RESEARCH QUESTION: What is the incidence, origin and clinical significance of blastomere movement after the first cell division in the human embryo? DESIGN: A total of 1096 embryos, cultured in the EmbryoScope+ ® time-lapse system and subjected to a single fresh cleaved embryo transfer, were retrospectively analysed. Type and duration of blastomere movement (dBMov) between the first (t2) and second cell division (t3) was monitored, and the ratio of dBMov during the 2-cell stage [dBMov/(t3-t2)] was calculated. Morphological evaluation of embryos was performed by referring to the size of the blastomere and fragmentation after first division in addition to Veeck's criteria on Day 2. The correlation between dBMov and ongoing pregnancy was evaluated and the association of dBMov with patient and embryonic characteristics was determined. RESULTS: Both movement type and the value of dBMov/(t3-t2) were significantly associated with asymmetrical first division, fragment formation and morphological grade on Day 2. Multivariate logistic regression analysis revealed that a higher value of dBMov/(t3-t2) significantly correlated with a decreased ongoing pregnancy rate, even after adjustment for co-founders (odds ratio 0.399, P = 0.0419). The time intervals of pronuclear (PN) alignment and PN fading were significantly correlated with the dBMov/(t3-t2) value. CONCLUSIONS: Embryos with extended blastomere movement after the first cell division, which is associated with the delay of PN fading and first cell division, have a lower competence to initiate an ongoing pregnancy after fresh embryo transfer on Day 2. Thus, blastomere movement could be a useful predictive parameter for selecting embryos at the early cleavage stage.

Cryostorage duration does not affect pregnancy and neonatal outcomes: a retrospective single-centre cohort study of vitrified-warmed blastocysts.

A retrospective cohort study of 8736 autologous single vitrified-warmed blastocyst transfer cycles was conducted in a single centre to investigate the effect of cryostorage on clinical and neonatal outcomes. Cryostorage duration was classified into three groups: (A) 0-2 months (n = 4702); (B) 2-13 months (n = 2853) and (C) 13-97 months (n = 1181). Blastocysts were vitrified using the Cryotop method. No significant differences were observed in live birth rates: (A) 37.3%; (B) 34.9%; (C) (35.2%). Gestational period was significantly shorter in group C: (A) 38.7 ± 1.8; (B) 38.6 ± 1.6; (C) 38.1 ± 1.7; P < 0.05. This was clinically unimportant as the average gestational age was more than 38 weeks. No significant differences between groups were observed in birth weight: (A) 3060 ± 455 g; (B) 3052 ± 449 g; (C) 2992 ± 445 g, or congenital malformation rates: (A) 2.2%; (B) 1.9%; (C) 1.8%. The limitation of this study was that maximum storage duration was 8 years; most blastocysts were in cryostorage for much shorter periods. Long-term storage of blastocysts that are vitrified using an open device vitrification system has no negative effect on pregnancy and neonatal outcomes.

Complete zona pellucida removal from vitrified-warmed human blastocysts facilitates earlier in-vitro attachment and outgrowth.

Partial removal of the zona pellucida (ZP) has been performed using a laser system to promote hatching of vitrified-warmed blastocysts. However, low-viability blastocysts cannot hatch even after partial ZP removal. This study examined whether complete removal of the ZP improves embryonic adhesion and outgrowth of vitrified-warmed blastocysts compared with partial removal, using a blastocyst outgrowth model. In all, 217 vitrified human blastocysts, which were discarded and donated for research by consenting couples, were warmed and subjected to assisted hatching to remove the ZP partially or completely, or did not undergo assisted hatching (zona intact controls). Blastocysts were cultured using time-lapse microscopy to monitor hatching, adhesion and outgrowth. Despite partial ZP removal, 36% of blastocysts failed to hatch. Blastocyst outgrowth assays showed improved adhesion rate, shorter time for adhesion and larger outgrowth area in the blastocysts with completely removed ZP compared with those with partially-removed ZP. mRNA expression of integrin α5 and ß1 was upregulated in blastocysts with completely removed ZP compared with those with partially-removed ZP. Study findings reveal the advantages of complete ZP removal for assisted hatching. In conclusion, complete ZP removal increases the chance of blastocyst adhesion and subsequent outgrowth in vitro after the vitrification-warming procedure.

Hydroxypropyl cellulose as an option for supplementation of cryoprotectant solutions for embryo vitrification in human assisted reproductive technologies.

Hydroxypropyl cellulose (HPC) was investigated as a replacement for serum substitute supplement (SSS) for use in cryoprotectant solutions for embryo vitrification. Mouse blastocysts from inbred (n = 1056), hybrid (n = 128) strains, and 121 vitrified blastocysts donated by infertile patients (n = 102) were used. Mouse and human blastocysts, with or without zona pellucida, were vitrified and warmed in either 1% or 5% HPC or in 5% or 20% SSS-supplemented media using the Cryotop (Kitazato BioPharma Co. Ltd, Fuji, Japan) method, and the survival and oxygen consumption rates were assessed. Viscosity of each vitrification solution was compared. Survival rates of mouse hybrid blastocysts and human zona pellucida-intact blastocysts were comparable among the groups. Mouse and human zona pellucida-free blastocysts, which normally exhibit poor cryoresistance, showed significantly higher survival rates in 5% HPC than 5% SSS (P < 0.05). The 5% HPC-supplemented vitrification solution showed a significantly higher viscosity (P < 0.05). The blastocysts were easily detached from the Cryotop strip during warming when HPC-supplemented vitrification solution was used. The oxygen consumption rates were similar between non-vitrified and 5% HPC groups. The results suggest possible use of HPC for supplementation of cryoprotectant solutions and provide useful information to improve vitrification protocols.

Developmental potential of zona pellucida-free oocytes obtained following mild in vitro fertilization.

OBJECTIVE: To determine the developmental potential of oocytes in which the zona pellucida was damaged and subsequently removed, producing "zona-free" (ZF) oocytes that were cultured until the blastocyst stage. DESIGN: ZF eggs from cycles with more than one oocytes retrieved (n = 97) were compared with zona-intact (ZI) oocytes originating from the same patient. SETTING: Private infertility clinic. PATIENT(S): Infertile patients (n = 135) undergoing minimal ovarian stimulation or natural-cycle in vitro fertilization treatment during 2010-2012. INTERVENTION(S): ZF oocytes undergoing intracytoplasmic sperm injection (ICSI) fertilization, blastocyst culture, elective vitrification, and subsequent single vitrified-thawed blastocyst transfer (SVBT). MAIN OUTCOME MEASURE(S): Rate of fertilization, cleavage, and blastocyst development. Live birth rate and neonatal outcome in subsequent SVBT cycles. RESULT(S): There were no significant differences in fertilization (77% vs. 77%), cleavage (75% vs. 75%), or blastocyst development rates (39% vs. 32%) between the internally controlled ZF and ZI groups, respectively. Survival after thawing (90% vs. 100%) and live birth rates (37% vs. 36%) per thawed blastocyst were also similar. Newborns originating from all ZF and ZI oocytes had a similar gestational age at delivery (38.3 ± 3.7 wk vs. 39.5 ± 1.5 wk) and birth weight (3,115 ± 946 g vs. 3,010 ± 441 g). CONCLUSION(S): Our retrospective comparative study suggests that ZF eggs could be as successfully fertilized and cultured until the blastocyst stage as ZI control eggs without adversely affecting subsequent pregnancy rates and basic neonatal outcome.

Women's age and embryo developmental speed accurately predict clinical pregnancy after single vitrified-warmed blastocyst transfer.

The aim of this study was to establish a simple, objective blastocyst grading system using women's age and embryo developmental speed to predict clinical pregnancy after single vitrified-warmed blastocyst transfer. A 6-year retrospective cohort study was conducted in a private infertility centre. A total of 7341 single vitrified-armed blastocyst transfer cycles were included, divided into those carried out between 2006 and 2011 (6046 cycles) and 2012 (1295 cycles). Clinical pregnancy rate, ongoing pregnancy rate and delivery rates were stratified by women's age (<35, 35-37, 38-39, 40-41, 42-45 years) and time to blastocyst expansion (<120, 120-129, 130-139, 140-149, >149 h) as embryo developmental speed. In all the age groups, clinical pregnancy rate, ongoing pregnancy rate and delivery rates decreased as the embryo developmental speed decreased (P < 0.0001). A simple five-grade score based on women's age and embryo developmental speed was determined by actual clinical pregnancy rates observed in the 2006-2011 cohort. Subsequently, the novel grading score was validated in the 2012 cohort (1295 cycles), finding an excellent association. In conclusion, we established a novel blastocyst grading system using women's age and embryo developmental speed as objective parameters.

Maternal age and initial ß-hCG levels predict pregnancy outcome after single vitrified-warmed blastocyst transfer.

PURPOSE: We retrospectively examined a large cohort of females who underwent single blastocyst transfer to determine if initial ß-human chorionic gonadotrophin (ß-hCG) levels on day 7 after single vitrified-warmed blastocyst transfer (SVBT) could be used to predict pregnancy outcome. METHODS: The treatment cycles that gave rise to the early pregnancies included in this study were performed from 2004 to 2011 in a private infertility center. In SVBT cycles, embryos were transferred during a natural cycle or after endometrial preparation with exogenous estrogen and progesterone. A total of 11,458 cycles with ß-hCG levels ≥1.0 UI/ml on day 7 after SVBT were evaluated. The proportion of live births per positive ß-hCG cycle was established for 10 ß-hCG ranges in 3 different age groups (Group A: 21-34 years old; Group B: 35-39 years old; Group C: 40-44 years old). RESULTS: The proportion of live births gradually increased from 1.5 to 93.7%, 0.8 to 87.9%, and 0.6 to 76.2% in Groups A, B, and C, respectively. For each range of ß-hCG levels, the proportion of live births was higher for the younger age group, which reflected the increased risk of early pregnancy loss with advancing female age. CONCLUSIONS: ß-hCG levels on day 7 after SVBT, in conjunction with maternal age, may be used to predict pregnancy outcomes.