Extended culture of poor-quality supernumerary embryos improves ART outcomes

Comparative Embryo Development Outcomes following Extending Embryo Culture to Day 6: A Retrospective Cohort Study

BACKGROUND

Past studies have shown that culturing slow-growing embryos from day 5 to day 6 may increase vitrification yield. This study aims to evaluate if the proportion of embryos eligible for vitrification increases by growing embryos not vitrified by day 5 to day 6.

MATERIALS AND METHODS

In this retrospective cohort study, a Canadian tertiary-care clinic-based cohort was identified between August 2019 and December 2020. In vitro fertilization (IVF) cycles involving autologous oocytes with at least one viable day 5 embryo were selected for inclusion. We compared embryo developmental outcomes of IVF cycles performed before and after an embryo cryopreservation policy change. Prior to March 2020, good-quality day 5 blastocysts of any stage were eligible for vitrification, and after that date, good-quality expanded blastocysts on either day 5 or day 6 were eligible. The primary outcome is the comparative proportion of embryos eligible for vitrification. The secondary outcome is to identify embryo, maternal and cycle factors that are predictive of day 6 vitrification.

RESULTS

A total of 3,438 viable embryos across 679 consecutive IVF cycles were included in this study. After the policy change, we found similar mean proportions of blastocysts eligible for cryopreservation (46.9% per IVF cycle in group 2 vs. 44.4% in group 1, mean difference 0.025, 95% confidence interval -0.021 to 0.071, P=0.28). The mean number of cryopreserved embryos were significantly higher in group 2 (mean 2.2 vs. 1.7 embryos, P=0.007). Factors that predicated an embryo's progression to day 6 included: younger age of egg provider, presence of an early blastocyst on day 5, and cycles involving surgically-retrieved sperm.

CONCLUSION

A cryopreservation policy change to include good-quality full and expanded day 6 blastocysts while avoiding to vitrify early blastocysts on day 5 yielded comparable proportions of embryos eligible for vitrification per IVF cycle.

Clinical outcomes after elective double-embryo transfer in frozen cycles for women of advanced maternal age: A retrospective cohort study

We aimed to determine the clinical outcome of double cleavage-stage embryo transfers in frozen-thawed embryo transfer cycles for older women.This study analyzed a total of 8189 cleavage-stage frozen-thawed embryo transfer cycles between January 2013 and December 2017 at Sir Run Run Shaw Hospital. All cycles were sorted into 3 groups based on patient age: ≤35 years (Group A), 36 to 37 years (Group B), and ≥38 years (Group C). The clinical pregnancy rate (CPR), implantation rate (IR), live birth rate (LBR), miscarriage rate, multiple pregnancy rate (MPR), preterm birth rate, and low-birth-weight rate were compared between the 3 groups.Significant differences in CPR, IR, LBR, MPR, and premature birth rate were found among the 3 groups. The CPR, IR, LBR, and MPR in Group A were higher than those in Group C. Transfers of 2 high-quality embryos resulted in significant differences in CPR, IR, LBR, MPR, and neonatal weight among the 3 groups, but no differences in premature birth and abortion rates were observed. Transfers with 1 high-quality and 1 fair-quality embryo resulted in significant differences in CPR, IR, and LBR among the 3 groups. Comparison of transfers of 2 high-quality embryos with 1 high-quality and 1 fair-quality embryo showed that the CPR and LBR were significantly lower for the latter in Groups A and C, but Group B had no salient changes.Higher IR and LBR and lower MPR may be achieved by selection of optimal embryo types for patients of different ages. Two high-quality embryos need to be transferred in women older than 38 years. For women aged 36 to 37 years, 1 high-quality embryo or 1 high-quality plus 1 fair-quality embryo should be singled out for transfer. For women younger than 35 years, a single high-quality embryo should be selected for transfer.

Cyclic fertilin-derived peptide stimulates in vitro human embryo development

OBJECTIVE

To study the cyclic fertilin peptide effects on preimplantation human embryogenesis. Cyclic fertilin peptide reproduces the structure of the binding site of the sperm Fertilin β (also named A Disintegrin and Metalloprotease 2: ADAM2) disintegrin domain. It binds to the oocyte membrane and increases sperm-oocyte fusion index in human and fertilization rate in mouse, providing healthy pups. It also improves human oocyte maturation and chromosome segregation in meiosis I and binds to human embryo blastomeres, suggesting that it has a membrane receptor.

DESIGN

Thawed human embryos at the 3 to 4 cells stage were randomly included in a dose-response study with cyclic fertilin peptide. Inner cell mass (ICM), trophectoderm (TE), and total cell numbers were evaluated in top- and good-quality blastocysts.

SETTING

The study was performed in an academic hospital and research laboratory.

PATIENT(S)

Human embryos donated for research. This project was approved by the French "Agence de la Biomédecine."

INTERVENTION(S)

Immunofluorescence and tissue-specific gene expression analysis, using Clariom D microarrays, were performed to study its mechanism of action.

MAIN OUTCOME MEASURE(S)

Cyclic fertilin peptide improves blastocyst formation by almost 20%, the concentration of 1 μM being the lowest most efficient concentration. It significantly increases twice the TE cell number, without modifying the ICM. It increases the in vitro hatching rate from 14% to 45%.

RESULT(S)

Cyclic fertilin peptide stimulates TE growth. In the ICM, it induces transcriptional activation of intracellular protein and vesicle-mediated transport.

CONCLUSION(S)

Cyclic fertilin peptide dramatically improves human embryo development potential. It could be used to supplement culture medium and improve the in vitro human embryo development. Starting supplementation immediately after fertilization, instead of day 2, could significantly upgrade assisted reproductive technology outcome.

Laser-assisted hatching in lower grade cleavage stage embryos improves blastocyst formation: results from a retrospective study

Background

Laser-assisted hatching (LAH) has been widely applied to facilitate blastocyst hatching in IVF-ET treatment, however, the effect of LAH on subsequent development and clinical outcomes of the lower grade cleavage stage embryos (LGCE) remains unknown. Our study aimed at evaluating the effect of LAH on blastocyst formation and the clinical pregnancy outcomes of LGCE embryos after transfer.

Methods

A total of 608 cycles of IVF/ICSI treatment from November 2017 to September 2019 were included in our study as follows: 296 in the LAH group and 312 in the N-LAH group. The total blastocyst rate, usable blastocyst rate, good-grade blastocyst rate and clinical pregnancy rate were statistically compared between the two groups.

Results

The total blastocyst rate (50.7% vs 40.2%, P < 0.001), usable blastocyst rate (31.0% vs 18.6%, P < 0.001) were significantly higher in the LAH group than those in the N-LAH group. After analysis of generalized estimating equations, LAH was positively correlated with the blastocyst rate (B = 0.201, OR 95% CI = 1.074–1.393, P = 0.002), usable blastocyst rate (B = 0.478, OR 95% CI = 1.331–1.955, P < 0.001). However, the clinical pregnancy rate after blastocyst transfer did not differ between LAH group and N-LAH group (49.4% vs 40.0%, P > 0.05, respectively).

Conclusions

A higher proportion of total blastocysts and usable blastocysts can be obtained by LAH in LGCE, which may be beneficial to the outcome of the IVF/ICSI-ET cycle.

Cumulative live birth rate after IVF: trend over time and the impact of blastocyst culture and vitrification

STUDY QUESTION

Has cumulative live birth rate (CLBR) improved over time and which factors are associated with such an improvement?

SUMMARY ANSWER

During an 11-year period, 2007–2017, CLBR per oocyte aspiration increased significantly, from 27.0% to 36.3%, in parallel with an increase in blastocyst transfer and cryopreservation by vitrification.

WHAT IS KNOWN ALREADY

While it has been shown that live birth rate (LBR) per embryo transfer (ET) is higher for fresh blastocyst than for fresh cleavage stage embryo transfer, CLBR per oocyte aspiration, including one fresh ET and all subsequent frozen embryo transfers (FET), does not seem to differ between the two culture strategies.

STUDY DESIGN, SIZE, DURATION

A national register study including all oocyte aspirations performed in Sweden from 2007 to 2017 (n = 124 700 complete IVF treatment cycles) was carried out. Oocyte donation cycles were excluded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data were retrieved from the Swedish National Registry of Assisted Reproduction (Q-IVF) on all oocyte aspirations during the study period where autologous oocytes were used. CLBR was defined as the proportion of deliveries with at least one live birth per oocyte aspiration, including all fresh and/or frozen embryo transfers within 1 year, until one delivery with a live birth or until all embryos were used, whichever occurred first. The delivery of a singleton, twin, or other multiples was registered as one delivery. Cryopreservation of cleavage stage embryos was performed by slow freezing and of blastocyst by vitrification.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 124 700 oocyte aspirations were performed (in 61 313 women), with 65 304 aspirations in women <35 years and 59 396 in women ≥ 35 years, resulting in 38 403 deliveries with live born children. Overall, the CLBR per oocyte aspiration increased significantly during the study period, from 27.0% to 36.3% (odds ratio (OR) 1.039, 95% CI 1.035–1.043) and from 30.0% to 43.3% if at least one ET was performed (adjusted OR 1.055, 95% CI 1.050–1.059). The increase in CLBR was independent of maternal age, number of oocytes retrieved and number of previous IVF live births. The CLBR for women <35 and ≥35 years both increased significantly, following the same pattern. During the study period, a substantially increasing number of blastocyst transfers was performed, both in fresh and in FET cycles. Other important predicting factors for live birth, such as number of embryos transferred, could not explain the improvement. An increased single embryo transfer rate was observed with time.

LIMITATIONS, REASONS FOR CAUTION

The retrospective design implicates that other confounders of importance for CLBR cannot be ruled out. In addition, some FET cycles might be performed later than 1 year post oocyte aspiration for the last year (2017) and are, thus, not included in this study. In addition, no data on ‘dropouts’, i.e. patients that do not continue their treatment despite having cryopreserved embryos, are available, or if this drop-out rate has changed over time.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that blastocyst transfer, particularly when used in FET cycles and in combination with vitrification, is an important contributor to the improved live birth rates over time. This gives a possibility for a lower number of oocyte aspirations needed to achieve a live birth and a shortened time to live birth.

STUDY FUNDING/COMPETING INTERESTS

The study was financed by grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (ALFGBG-70940) and by Hjalmar Svensson’s research foundation. None of the authors declares any conflict of interest.

Blastocyst transfer after extended culture of cryopreserved cleavage embryos improves in vitro fertilization cycle outcomes

Cryopreserved blastocyst embryo transfer has been reported to result in better pregnancy outcomes than those by cleavage embryo transfer. Women who had previously failed in the cleavage-stage embryo transfer, underwent extended culture of their warmed cleavage embryos to the blastocyst stage, thereby improving cryopreserved embryo transfer (CET) outcomes, although the ability of embryos to reach the extended blastocyst as well as the value of the prolonged culture was limited. This study aimed to investigate the effectiveness of blastocyst transfer by extending the culture of vitrified-warmed cleavage embryos. CET cycles were collected from January 2018 to June 2020. Pregnancy outcomes were analyzed and compared between three groups: day 2 embryo transfer using cryopreserved embryos (D2 CET), blastocyst transfer (D5 CET), and extended culture vitrified day 2 embryo transfer (D2-5 CET). A total of 52.77% of vitrified-warmed cleavage embryos developed into blastocysts in D2-5 CET group. Although D2-5 CET had a lower number of transferred embryos and grade A embryos, the pregnancy outcomes were significantly better than those in D2 CET, with respect to hCG positivity, clinical pregnancy and implantation rates (59.62% vs. 24.64%, 46.15% vs. 21.71%, 27.18% vs. 9.09%, respectively, P < 0.05). There were no significant different outcomes between the D2-5 CET and D5 CET groups. This study demonstrated a way of achieving better pregnancy outcomes in 8CET cycles by means of extended culture to blastocysts in patients with vitrified cleavage embryo failure.

Disposition of embryos from women who only produced morphologically poor embryos on day three

Background

The presence of only morphologically poor embryos (MPEs) on day3 is common in autologous in vitro fertilization (IVF), particularly among p Tel: 886-7-7317123 Ext. 8916. Fax: 886-7-7322915.atients who have advanced maternal age or are poor responders. However, there are limited data regarding the disposition of embryos from patients who only produced MPEs on day3. The present study was designed to investigate the possible benefits of extended culturing MPEs. Try to detect whether the extended culture (day4 or day5 culture) can improve the live birth rate per cycle?

Methods

This retrospective, observational, single-center, cohort study examined 224 IVF/intracytoplasmic sperm injection (ICSI) cycles between January 2010 and June 2015, in which women only produced MPEs on day3. A total of 544 MPEs were analyzed. The defines a day3 embryo as an MPE if it fails to develop to eight cells, blastomeres of equal size, and less than 20% cytoplasmic fragments. Of the 224 cycles, 89 (39.7%) underwent fresh embryo transfer on day3, and 135 (60.3%) underwent extended culture. Of the 135 extended cultures, 54 cycles (40.0%) experienced day4, or day5 embryo transfer, 16 cycles (11.9%) had all embryos frozen, and 65 cycles (48.1%) had total embryo arrest.

Results

Analysis of patient baseline demographic data, cycle characteristics, and cycle outcomes for day3 transfer group and extended culture group indicated that a higher body mass index in the day3 transfer group was the only significant difference (p = 0.006). Both fresh transfer groups had low live birth rates (LBRs) (4.5% vs. 7.4% p = 0.46). After extended culture, 65 cycles (48.1%) were cancelled because the embryos exhibited developmental arrest and 70 cycles (51.9%) grew to day4 or day5. Thirteen frozen embryo transfer (FET) cycles and 22 frozen blastocysts derived from MPEs were thawed. There were more high-quality embryos (p < 0.001), higher implantation rates (IRs) (p = 0.038), and higher LBRs (p = 0.042) for embryos that underwent FET cycles. MPES in extended culture transfer have favorable survival than MPES in day3 transfer.

Conclusion

The extended culture of MPEs in fresh transfer cycles did not increase the LBR. However, younger females with the extended culture of MPEs followed by FET resulted in significantly higher LBRs and may be a feasible strategy to improve outcomes for patients with poor embryo quality. However, day3 embryo transfer may be a better choice if a fresh transfer is unrestricted and avoid the cycle cancellation. Extended culture may decrease to the transfer of developmental potential arrest embryos to patients.

Developmental Potential of Abnormally Fertilized Oocytes and the Associated Clinical Outcomes

This study aims to investigate the embryo development potential of extending the culture of abnormally fertilized zygotes with no pronuclear (0PN), monopronuclear (1PN), and poor-quality day 3 embryos and to determine the associated clinical outcomes. This is a retrospective study performed between January 2014 and May 2018 at Jinhua People's Hospital. The normal developed embryos and the abnormal 0PN, 1PN, and poor-quality day 3 embryos were cultured to day 5 or 6 for embryo transfer. Clinical outcomes resulting from abnormal embryos and normally developed embryos were compared. A total of 6466 embryos (1542 0PN, 852 1PN, and 4072 poor-quality day 3 embryos) from 831 treatment cycles were cultured to the blastocyst stage. The total blastulation rate was 17.3% (1121/6466) with 18.2% in 0PN, 26.1% in 1PN, and 15.2% in poor-quality day 3 embryos. The rate for good-quality blastocyst formation was 9.5% (616/6466) with 11.2% in 0PN group, 14.8% in 1PN group, and 7.8% in poor-quality day 3 embryos, respectively. Blastulation rates of 0PN and 1PN derived from intracytoplasmic sperm injection (ICSI) were significantly lower compared with the in vitro fertilization group. A total of 243 cycles were transferred with blastocysts originating from abnormal embryos, resulting in 109 (44.9%) clinical pregnancies and 19 (17.4%) miscarriages; in the control group, a total of 350 cycles resulted in 214 (61.1%) clinical pregnancies and 18 (8.4%) miscarriages. The live birth rate was significantly lower in the abnormal embryo group than that in the control group. Collectively, conventional in vitro fertilization derived 0PN and 1PN zygotes, not ICSI, together with day 3 embryos with poor quality, that were able to reach the blastocyst stage and produce a fair pregnancy rate and live birth rate.

Improving the clinical outcomes by extended culture of day 3 embryos with low blastomere number to blastocyst stage following frozen-thawed embryo transfer

Purpose

This study aimed to investigate whether the extended culture of day 3 (D3) embryos with low blastomere number to blastocyst following frozen–thawed embryo transfer improved the clinical outcomes.

Methods

This was a retrospective study of clinical data of women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles in the Tangdu Hospital. The patients were divided into groups with 4–5, 6, 7–9 and > 9 cells based on the blastomere number of D3 embryos. The clinical outcomes were compared.

Results

In fresh transfer cycles, the implantation and clinical pregnancy rates significantly decreased, while the abortion rate significantly increased in the groups with 4–5 and 6 cells compared with those with 7–9 and > 9 cells. In frozen–thawed transfer cycles, the clinical pregnancy and implantation rates for a single blastocyst transfer cycle showed no significant differences in the groups with 4–5 and 6 cells compared with those with 7–9 and > 9 cells. However, the abortion rate was significantly higher in the group with 4–5 cells than in that with 7–9 and > 9 cells. In the double blastocyst transfer cycle, the clinical pregnancy rate showed no significant differences among the groups with 4–5, 6, and 7–9 cells.

Conclusion

The implantation and clinical pregnancy rates of D3 embryos with 6 cells significantly decreased; these embryos were not considered as high-quality embryos. Extended culture of D3 embryos with ≤ 6 blastomeres to blastocysts, particularly 6-cell embryos, resulted in a similar clinical pregnancy rate as that of blastocysts derived from D3 embryos with ≥ 7 blastomeres.

Generation of viable blastocysts from discarded human cleavage embryos

Background

While a relationship between embryo morphology, developmental ability, and genetic integrity exists, the selection of embryos with higher implantation potential remains a major challenge in assisted reproductive technology (ART). This study investigated blastocyst developmental competence and euploidy status in human embryos that had been classed as too poor quality to transfer (ET) or cryopreserve at the cleavage stage.

Embryos were divided into three groups. Group 1 (n = 41) included good quality embryos from candidates of preimplantation genetic testing for aneuploidy (PGT-A). Groups II and III were the “rejected” supernumerary embryos, defined as suboptimal for ET or vitrification after morphological examination, with embryos randomly divided between the groups. Group II embryos (n = 31) were cultured up to the day 3 cleavage stage, when they were biopsied and fixed. Group III embryos (n = 27) were cultured up to the day 5 blastocyst stage, when they were evaluated for morphology and chromosomal status. Chromosomal status in all groups was assessed by multi-color fluorescence in situ hybridization (FISH) for chromosomes 13, 18, 21, X, and Y.

Results

Euploidy rates in groups I, II, and III were 56.1%, 38.7%, and 55.5 %, respectively. Among the blastocysts that developed from “rejected” embryos, 59.3% were classed as good quality. The most frequent chromosomal aneuploidy was related to the sex chromosome (22.2%). The mosaicism rate was not significantly different between the group II and III embryos (25.8% vs. 37.0%, p = 0.28).

Conclusion

In conclusion, surplus poor-quality embryos rejected from clinical utilization at the cleavage stage may develop into viable blastocysts with normal chromosomal status for at least 5 chromosomes. Recovery of euploidy during poor-quality embryo transition from cleavage stage to blastocyst could provide an alternative choice for ET.

Developmental Plasticity in Response to Embryo Cryopreservation: The Importance of the Vitrification Device in Rabbits

Simple Summary

This study was conducted to demonstrate how embryo manipulation techniques incur phenotypic changes throughout life. This study reports the first evidence demonstrating that the vitrification device used is not a trivial decision, providing valuable information about how the cooling–warming rates during vitrification can be partly responsible of the postnatal phenotypic variations.

Abstract

In this study, we evaluated the effect of embryo vitrification using two different devices on adulthood phenotype in rabbits. In vitro development, prenatal embryo survival, body weight, growth performance, haematological and biochemical peripheral blood analysis, reproductive performance, and lactation performance traits were compared between the experimental groups. They derived from naturally-conceived embryos (NC), fresh-transferred embryos (FT), vitrified-transferred embryos using mini-straw (VTs), or vitrified-transferred embryos using Cryotop (VTc). Straw-vitrified embryos exhibited lower in vitro developmental rates and in vivo survival rates following embryo transfer compared to its Cryotop-vitrified counterparts. Moreover, the VTs group exhibited higher foetal losses than VTc, FT, and NC groups. Independently of the vitrification device, vitrified-transferred (VT) offspring showed a skewed sex ratio in favour of males, and an increased birth bodyweight. In contrast, postnatal daily growth was diminished in all ART (i.e., FT and VT) animals. In adulthood, significant differences in body weight between all groups was founded—all ART progenies weighed less than NC animals and, within ART, VT animals weighed less than FT. For VT groups, weight at adulthood was higher for the VTs group compared with the VTc group. Peripheral blood parameters ranged between common values. Moreover, no differences were found in the fertility rates between experimental groups. Furthermore, similar pregnancy rates, litter sizes, and the number of liveborns were observed, regardless of the experimental group. However, decreased milk yield occurred for VTc and FT animals compared to VTs and NC animals. A similar trend was observed for the milk composition of dry matter and fat. Concordantly, reduced body weight was found for suckling kits in the VTc and FT groups compared to VTs and NC animals. Our findings reveal that developmental changes after the embryo vitrification procedure could be associated with an exhibition of the embryonic developmental plasticity. Moreover, to our best knowledge, this study reports the first evidence demonstrating that the vitrification device used is not a trivial decision, providing valuable information about how the cooling–warming rates during vitrification can be partly responsible of the postnatal phenotypic variations.

Miscarriage Rate Is High With Frozen-Thawed Blastocysts Arising From Poor-Quality Cleavage Stage Embryos

Embryos with low morphological scores can still develop to the blastocyst stage and result in good clinical outcomes. However, no studies have reported the possible effects of transferring cryopreserved blastocysts developed from poor-quality cleavage stage embryos on pregnancy and perinatal outcomes. In this retrospective study, the clinical value of transferring blastocysts derived from day 3 poor-quality cleavage stage embryos during in vitro fertilization and embryo transfer procedures was evaluated. According to the quality of embryos on day 3 from which the transferred blastocyst originated, patients were divided into three groups: poor-quality (111 cycles, group A), good-quality (235 cycles, group B), and top-quality (119 cycles, group C). Group A experienced the highest miscarriage rate (30.2%) which was increased when compared to group C (12.5%) (P = 0.03). The clinical pregnancy rates and live birth rates were not significantly different among the three groups. However, good blastocyst originating from top day 3 embryos resulted in higher live birth rate. Of the 218 live births, no differences in obstetric and perinatal outcomes were noted among the three groups. The results showed that extended culture of poor-quality cleavage stage embryos could resulted in favorable clinical pregnancy rates but at a higher incidence of miscarriages. Meanwhile, the risk of adverse perinatal outcomes was not increased.