Is it time for a paradigm shift in understanding embryo selection?

Clinical outcome of different embryo transfer strategies after late rescue ICSI procedure: a 10-year total fertilisation failure cohort study

BACKGROUND

Late rescue intracytoplasmic sperm injection (r-ICSI) has not been widely accepted as an alternative solution for unexpected total fertilisation failure (TFF) after in vitro fertilisation (IVF), due to the time-dependent in vitro deterioration of oocyte quality and endometrial growth not being synchronised with embryo development. This study aimed to evaluate the safety profile and effectiveness of freeze-all blastocyst transfer in combination with late r-ICSI.

METHODS

This was a retrospective cohort study carried out at the Reproductive Centre of Peking University Third Hospital, Beijing, China. All participants received treatment between 2009 and 2019. 2,270 patients in the aggregate encountered unexpected TFF during 149,054 cycles of IVF and adopted a late r-ICSI procedure. Among these patients, 263 women did not have cleavage-stage embryos available for evaluation. The remaining patients were grouped according to different embryo transfer (ET) strategies (926 women in Group 1 underwent fresh ET, 365 women in Group 2 underwent freeze-all ET, 716 women in Group 3 experienced blastulation failure). Patients received different ET strategies after r-ICSI, with the main outcome measures included live birth rate (LBR), cumulative live birth rate (cLBR), and conservative cLBR.

RESULTS

TFF occurred in 7.4% of all IVF cycles. Group 1 tended to be older at oocyte retrieval, with more infertile years, higher follicle-stimulating hormone (FSH) levels, higher gonadotropin consumption, and fewer oocytes retrieved. Group 2 exhibited considerably better LBRs following the first ET cycle (37.53% vs. 4.64%) and cLBRs (52.60% vs. 8.21%). After adjustment for covariates using binary logistic regression analyses, Group 2 still showed better obstetric performance in LBRs [OR:11.77, 95% CI (8.42-16.45)], cLBRs (OR:11.29, 95% CI (7.84-16.27)], and conservative cLBRs (OR:2.55, 95% CI (1.83-3.55)]. Additionally, the two groups showed similar miscarriage rates, whilst no new-borns with malformations or congenital diseases were reported.

CONCLUSIONS

Freeze-all blastocyst stage ET serves as an optimal strategy to support late r-ICSI. However, for women with limited oocytes available for r-ICSI use, weighing the benefits against the costs of the procedure might be prudent before implementing in vitro blastulation.

The Effectiveness of Granulocyte Colony-Stimulating Factor (G-CSF) Against Experimental Ischemia–Reperfusion Injury in Rat Ovaries and Its Effect on In Vitro Fertilization Outcomes

Local ischemic damage resulting from ovarian torsion is a common cause of decreased follicular activity and infertility. It was aimed to evaluate the effect of granulocyte colony-stimulating factor (G-CSF) protection on in vitro fertilization (IVF) results against experimental ischemic (I) and ischemic-reperfusion (I/R) injury in rat ovaries. The study consisted of 35 adult female Sprague-Dawley albino rats (sham, ischemia, I/R, I + G-CSF, and I/R + G-CSF) randomly assigned to 5 groups, each containing 7 rats. While bilateral adnexal torsion was applied to the ischemia groups for 3 h, detorsion was applied to the reperfusion groups. Intraperitoneal 100 IU/kg G-CSF was administered 30 min prior to ischemia (I + G-CSF) or reperfusion (I/R + G-CSF). After ovulation induction (intraperitoneal 150-300 IU/kg PMSG), the oocytes were collected and IVF was applied. Statistically significant differences were observed between the collected oocyte numbers in I and I + G-CSF, I/R, and I/R + G-CSF groups (P values were P = 0.001 for the I-I + G-SCF groups and P = 0.003 for I/R-IR + G-CSF, respectively). An increase in the number of MII oocytes obtained was observed in the I + G-CSF and I/R + G-CSF groups compared to the I and I/R groups. Grade 1 and grade 2 embryo numbers were statically different between the I/R and I/R + G-CSF groups (P values were P = 0.023 for grade 1 embryos and P = 0.045 for grade 2 embryos, respectively). G-CSF treatment was found to be effective in reducing I- and I/R-induced ovarian damage.

Strategy for embryo transfer to improve pregnancy outcomes in advanced maternal age

The purpose of this retrospective study was to optimize the transplantation strategy for women of advanced maternal age to achieve live births within the shortest time. Data were collected from patients older than 40 years who underwent assisted reproductive therapy at our centre from 1 January 2009 to 31 December 2019. In total, 1023 cases of fresh cleavage embryo transfer (CET) cycles, 280 cases of frozen-thawed blastocyst transfer (FBT) cycles, and 26 cases of frozen-thawed CET (FCET) cycles were included. The main outcome was the live birth rate (LBR). The secondary outcomes were the clinical pregnancy rate (CPR) and neonatal outcomes. Multivariable logistic regression was performed to adjust for confounding factors. The blastocyst formation rate of patients older than 40 years was 23.5%, the freezing cycle rate was 19.8%, and the fresh-embryo transfer rate was 83.0%. The implantation rate, CPR, and LBR were significantly different among the CET, FCET, and FBT groups. There were no significant differences in multiple pregnancies and abortion rates among the groups, and neonatal outcomes were similar. Multivariate logistic regression analysis showed that, compared with the CET group, LBR did not increase in the FCET group, whereas LBR increased in the FBT group. For patients older than 40 years when having approximately eight embryos after fertilization, blastocyst transfer can be considered after fully discussing the advantages and disadvantages of blastocyst culture. Alternatively, CET can be performed first, followed by FBT if the cleavage embryo transfer is unsuccessful.

Oocyte quality in assisted reproduction techniques

The metaphase II (MII) oocyte is the mature female gamete, produced from a complex maturation process called oogenesis that starts in the first weeks of embryogenesis in the female embryo tract, continues during puberty, and is completed at fertilization with the spermatozoon. Oogenesis is closely related to folliculogenesis. In assisted reproduction techniques, oocytes are retrieved in cumulus-oocyte complexes after ovarian stimulation. Before being used for in vitro fertilization or cryopreservation, the metaphase (MII) oocytes can be classified according to different morphological traits and by the presence/absence of the meiotic spindle. Except for a few and rare morphological characteristics that make the oocyte discarded, none of the morphological characteristics is predictive of oocyte competence in giving a viable embryo. On the other side, specific key performance indicators based on MII oocytes test the efficacy of in vitro treatments. Molecular, cellular, or genetic abnormalities in the oocytes have observable consequences on the embryo development dynamics and its genetic content. Besides what can be seen in vitro, several intrinsic and extrinsic factors related to the patient are responsible for the oocyte quality. The clinician and the patient herself must be aware of these factors to preserve the reproductive functions as much as possible. In the present review, we have revised oogenesis and the role of mature oocytes in supporting the fertilization process and early embryo development; we have also listed the oocyte morphological traits and key performance indicators related to the oocyte quality and studied the intrinsic and extrinsic factors that irreversibly impact female fertility.

From contemplation to classification of chromosomal mosaicism in human preimplantation embryos

Chromosomal mosaicism is a hallmark of early human embryo development. The last decade yielded an enormous amount of information about diversity and prevalence of mosaicism in preimplantation embryos due to progress in preimplantation genetic testing of aneuploidies (PGT-A) based exclusively on molecular karyotyping of trophectoderm biopsy. However, the inner cell mass karyotype is still missing for mosaic embryos affecting the success rate of assisted reproductive medicine. Here, a classification model of chromosomal mosaicism is proposed based on the analysis of the primary zygote karyotype, the timing and types of primary and secondary chromosome segregation errors, and the distribution of mosaic cell clones between different embryonic and extraembryonic compartments of the blastocyst. Five basic principles for mosaicism analysis are introduced, namely, the estimation of the primary zygote karyotype, the investigation of additional sample point, the requirement of the second time point analysis, the delineating of reciprocity of chromosome segregation, and comprehensive chromosome screening at the single-cell level. The suggested model allows the prediction of the inner cell mass karyotype of the blastocyst and its developmental potential based on information from trophectoderm biopsy and non-invasive PGT-A using blastocoele fluid sample or spent culture medium as additional sample and time points for analysis and considering the reciprocity as a basic process in chromosome segregation errors between daughter cells in postzygotic cell divisions.

Comparison of live birth rates after IVF-embryo transfer with and without preimplantation genetic testing for aneuploidies

RESEARCH QUESTION

Does the use of preimplantation genetic testing for aneuploidies (PGT-A) result in higher live birth rates when compared with both fresh and frozen embryo transfers (FET) not utilizing PGT-A?

DESIGN

Retrospective cohort study at a single tertiary centre using inverse probability of treatment weighting (IPTW) to adjust for differences in baseline characteristics between groups.

RESULTS

A total of 107 FET using PGT-A from 74 patients, along with 321 fresh and 286 FET not using PGT-A from 381 patients met the inclusion criteria for this study. In the IPTW-adjusted analysis of transfer-level data, PGT-A transfers resulted in a significantly higher live birth rate when compared with both non-PGT-A fresh (49.5% versus 38.6%, P = 0.036) and FET (50.6% versus 35.8%, P = 0.016). When data were analysed per retrieval level, the live birth rate was similar and acceptably high with or without PGT-A (63.7% versus 52.3%, P = 0.09).

CONCLUSION

When comparing PGT-A to non-PGT-A fresh and FET, PGT-A embryo transfers have a significantly higher live birth rate. However, this difference did not persist at a per-retrieval level. Further investigation is needed to understand in what scenarios PGT-A has clinical significance and whether differences in the number of available embryos for transfer negates the benefit of PGT-A.

'Two countries-two labs': the transnational gamete donation (TGD) programme to support egg donation

PURPOSE

To evaluate the effectiveness, efficiency, and safety of a transnational gamete donation (TGD) programme based on the shipping of vitrified donor oocytes.

METHODS

A retro-prospective observational study was conducted in the Assisted Reproductive Technology Center of the University Hospital of Florence, Italy. The study population included 622 consecutive donor oocyte cycles. A mean number of 6 vitrified oocytes per couple were shipped from two Spanish biobanks. In the receiving centre, gametes were warmed and inseminated and the subsequent embryo transfer (ET) was performed. The main outcome measurement was LBR. Secondary outcomes included oocyte survival rate, ICSI damage rate, normal fertilization, cleavage, and implantation rate (IR) in both 'fresh' and cryotransfer cycles.

RESULTS

A total number of 3536 mature oocytes were warmed with 81.4% surviving oocytes. 2PN oocytes were 1941 with an ICSI normal fertilization rate of 70.4% and a cleavage rate of 93.4%; 857 day-3 embryos were transferred in 498 women, 63 blastocysts in 44. Couples with at least one vitrified embryo were 181 (32.3%). IR was 25.1% and 33.1% for day-3 ET and blastocyst stage respectively. Crude pregnancy rate and LBR after the first ET were 35.5% and 27% correspondingly with a conservative cumulative LBR of 34% and an optimal LBR of 51.4%.

CONCLUSION

Imported vitrified donor oocytes retain their competence and are capable of resulting in ongoing pregnancies and healthy babies in a proportion comparable to other existing systems as egg donation with vitrification/warming in the same laboratory and transnational fresh oocyte donation.

The Association Between Embryo Quality, Number of Transferred Embryos and Live Birth Rate After Vitrified Cleavage-Stage Embryos and Blastocyst Transfer

Objective

The single-embryo transfer (SET) is the recommended approach to improve the live birth rate and reduce the complications related with multiple pregnancies. However, the physicians generally chose to transfer two embryos when the embryo quality decreased. The effect on the in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) outcomes following the transfer of a poor-quality embryo (PQE) along with a good-quality embryo (GQE) has been explored. However, previous studies were limited by the fresh embryo transfer cycles or the small sample size.

Methods

A retrospective cohort study was performed among 26,676 women (the mean age was 31.72 years) undergoing first frozen embryo transfer (FET) from January 2011 to December 2017. Patients were grouped into five subgroups, including SET with one GQE (SET-GQE, 2235 patients for cleavage-stage embryo transfer and 756 patients for blastocyst transfer), SET with one PQE (SET-PQE, 148 patients for cleavage-stage embryo transfer and 362 patients for blastocyst transfer), double-embryo transfer with two GQE (DET-2GQE, 20,461 patients for cleavage-stage embryo transfer and 519 patients for blastocyst transfer), double-embryo transfer (DET) with one GQE plus one PQE (DET-GQE+PQE, 1541 patients for cleavage-stage embryo transfer and 266 patients for blastocyst transfer), and DET with two PQE (DET-2PQE, 228 patients for cleavage-stage embryo transfer and 160 patients for blastocyst transfer). Multivariable logistic regression models were performed after controlling for other potential confounders to estimate the effect of number and quality of transferred embryos on pregnancy outcomes.

Result

Although the live birth rate was significantly higher after DET-GQE+PQE compared with SET-GQE for cleavage-stage embryo transfer [574 of 1541 (37.25%) vs. 571 of 2235 (25.55%)], no significant difference was found between DET-GQE+PQE and SET-GQE for blastocyst transfer [143 of 266 (53.76%) vs. 325 of 756 (42.99%)]. However, DET-GQE+PQE also had the highest multiple live births in both cleavage-stage embryo transfer [134 of 1541 (8.70%)] and blastocyst transfer [46 of 266 (17.29%)]. The live birth rate after SET-PQE significantly decreased in comparison with SET-GQE [cleavage-stage embryo transfer: 18 of 148 (12.16%) vs. 571 of 2235 (25.55%); blastocyst transfer: 107 of 362 (29.56%) vs. 325 of 756 (42.99%)] and significantly increased after DET-2GQE compared with SET-GQE [cleavage-stage embryo transfer: 9357 of 20,461 (45.73%) vs. 571 of 2235 (25.55%); blastocyst transfer: 313 of 519 (60.31%) vs. 325 of 756 (42.99%)]. The live birth rate was also not different between DET-2PQE and SET-GQE for cleavage-stage embryo transfer and blastocyst transfer [cleavage-stage embryo transfer: 75 of 228 (32.89%) vs. 571 of 2235 (25.55%); blastocyst transfer: 74 of 160 (46.25%) vs. 325 of 756 (42.99)].

Conclusion

In order to minimize the risk of multiple births, the data from this study did not support transferring DET with a GQE plus a PQE compared with SET with a GQE, especially for blastocyst transfer. However, the proportion of patients older than 35 years was small (12.07% for patients aged 36-39 years and 7.31% for patients 40 years or older), which limited the generalization of these results to other population.

Morula transfer achieves better clinical outcomes than post-thawed cleavage embryos after overnight culture in frozen embryo transfer (FET) cycles

PURPOSE

This study aimed to investigate the clinical outcomes of morula stage transfer derived from post-thawed cleavage embryos undergoing overnight culture in frozen embryo transfer (FET) cycles.

METHODS

We performed a retrospective study that included 392 FET cycles with 784 thawed embryos undergoing overnight culture between January 2014 and December 2018. Embryos were divided into three groups in terms of their status: 8-16 cells without morula (group I), one morula (group II), and two morulae (group III). The clinical outcomes of these cycles were then compared between the three groups. Logistic regression analysis was performed to control for confounders.

RESULTS

Group III was associated with a significantly higher clinical pregnancy rate (odds ratio [OR] 2.35; 95% confidence interval [CI] 1.29-4.27; P = 0.005), implantation rate (OR 3.00; CI 1.75-5.16; P < 0.001), multiple pregnancy rate (OR 4.91; CI 2.11-11.40; P < 0.001), and live birth rate (OR 1.96; CI 1.10-3.49; P = 0.022) than group I. Group II had a higher live birth rate than group I after adjustment (OR 1.70; CI 1.04-2.79; P = 0.035). There was no difference in the rate of premature delivery when compared across the three groups after adjustment.

CONCLUSION

The transfer of morula stage embryos following the overnight culture of post-thawed cleavage embryos led to an improvement in the clinical outcomes of FET cycles. It is important to reduce the number of morula embryos transferred in order to achieve a singleton pregnancy.

Cleavage Stage versus Blastocyst Stage Embryo Transfer in Oocyte Donation Cycles

Background and Objective: During the last few years, a trend has been noted towards embryos being transferred at the blastocyst stage, which has been associated with improved rates regarding implantation and clinical pregnancy in comparison to cleavage stage embryo transfers. There is a limited number of studies investigating this notion in oocyte donation cycles employing cryopreserved embryos. The aim of this study is to evaluate the implantation potential and clinical pregnancy rates between the day 3 cleavage stage and blastocyst stage embryo transfers in oocyte donation cycles employing vitrified embryos. Methods: This is a retrospective evaluation of oocyte donation frozen–thawed transfers completed in our clinic from January 2017 to December 2017. Intracytoplasmic sperm injection was conducted for all oocytes. Following fertilization, all embryos were cryopreserved either at the cleavage or blastocyst stage. Embryo transfer of two embryos was performed under direct sonographic guidance in all cases. Results: Our results confirmed a 55.6% clinical pregnancy (CP) resulting from day 3 embryo transfers, a 68.8% CP from day 5, and 71.4% CP from day 6. Significantly improved pregnancy rates were related to embryo transfers at the blastocyst stage when compared to cleavage stage transfers (68.9% and 55.6% respectively, p = 0.016). The risk with regards to multiple pregnancies was similar. Conclusion: Our findings indicate that in oocyte donation cycles employing vitrified embryos, embryo transfer at the blastocyst stage is accompanied with a significant improvement in pregnancy rates and merits further investigation.

Frozen versus fresh single blastocyst transfer in ovulatory women: a multicentre, randomised controlled trial

BACKGROUND

Elective single embryo transfer (eSET) has been increasingly advocated, but concerns about the lower pregnancy rate after reducing the number of embryos transferred have encouraged transfer of multiple embryos. Extended embryo culture combined with electively freezing all embryos and undertaking a deferred frozen embryo transfer might increase pregnancy rate after eSET. We aimed to establish whether elective frozen single blastocyst transfer improved singleton livebirth rate compared with fresh single blastocyst transfer.

METHODS

This multicentre, non-blinded, randomised controlled trial was undertaken in 21 academic fertility centres in China. 1650 women with regular menstrual cycles undergoing their first cycle of in-vitro fertilisation were enrolled from Aug 1, 2016, to June 3, 2017. Eligible women were randomly assigned to either fresh or frozen single blastocyst transfer. The randomisation sequence was computer generated, with block sizes of two, four, or six, stratified by study site. For those assigned to frozen blastocyst transfer, all blastocysts were cryopreserved and a delayed frozen-thawed single blastocyst transfer was done. The primary outcome was singleton livebirth rate. Analysis was by intention to treat. This trial is registered at the Chinese Clinical Trial Registry, number ChiCTR-IOR-14005405.

FINDINGS

825 women were assigned to each group and included in analyses. Frozen single blastocyst transfer resulted in higher rates of singleton livebirth than did fresh single blastocyst transfer (416 [50%] vs 329 [40%]; relative risk [RR] 1·26, 95% CI 1·14-1·41, p<0·0001). The risks of moderate or severe ovarian hyperstimulation syndrome (four of 825 [0·5%] in frozen single blastocyst transfer vs nine of 825 [1·1%] in fresh single blastocyst transfer; p=0·16), pregnancy loss (134 of 583 [23·0%] vs 124 of 481 [25·8%]; p=0·29), other obstetric complications, and neonatal morbidity were similar between the two groups. Frozen single blastocyst transfer was associated with a higher risk of pre-eclampsia (16 of 512 [3·1%] vs four of 401 [1·0%]; RR 3·13, 95% CI 1·06-9·30, p=0·029).

INTERPRETATION

Frozen single blastocyst transfer resulted in a higher singleton livebirth rate than did fresh single blastocyst transfer in ovulatory women with good prognosis. The increased risk of pre-eclampsia after frozen blastocyst transfer warrants further studies.

FUNDING

The National Key Research and Development Program of China.

Preimplantation genetic screening: results of a worldwide web-based survey

Our objective was to evaluate and characterize the extent and patterns of worldwide usage of preimplantation genetic screening (PGS) among the assisted reproductive technique community. A prospective, web-based questionnaire with questions relating to practices of, and views on, PGS was directed to users and non-users of PGS. A total of 386 IVF units from 70 countries conducting 342,600 IVF cycles annually responded to the survey. A total of 77% of respondents routinely carry out PGS in their clinics for a variety of indications: advanced maternal age (27%), recurrent implantation failure (32%) and recurrent pregnancy loss (31%). Few (6%) offer PGS to all their patients. In most cycles (72%), trophectoderm biopsy is carried out and either array-comparative genomic hybridization (59%) or next-generation sequencing (16%) are used for genetic analysis. Only 30% of respondents regard PGS as clearly evidenced-based, and most (84%) believe that more randomized controlled trials are needed to support the use of PGS. Despite ongoing debate and lack of robust evidence, most respondents support the use of PGS, and believe that it may aid in transferring only euploid embryos, thereby reducing miscarriage rates and multiple pregnancies, increasing live birth rates and reducing the risk of aneuploid pregnancies and births.

Does time-lapse imaging have favorable results for embryo incubation and selection compared with conventional methods in clinical in vitro fertilization? A meta-analysis and systematic review of randomized controlled trials

OBJECTIVE

The present study aimed to undertake a review of available evidence assessing whether time-lapse imaging (TLI) has favorable outcomes for embryo incubation and selection compared with conventional methods in clinical in vitro fertilization (IVF).

METHODS

Using PubMed, EMBASE, Cochrane library and ClinicalTrial.gov up to February 2017 to search for randomized controlled trials (RCTs) comparing TLI versus conventional methods. Both studies randomized women and oocytes were included. For studies randomized women, the primary outcomes were live birth and ongoing pregnancy, the secondary outcomes were clinical pregnancy and miscarriage; for studies randomized oocytes, the primary outcome was blastocyst rate, the secondary outcome was good quality embryo on Day 2/3. Subgroup analysis was conducted based on different incubation and embryo selection between groups.

RESULTS

Ten RCTs were included, four randomized oocytes and six randomized women. For oocyte-based review, the pool-analysis observed no significant difference between TLI group and control group for blastocyst rate [relative risk (RR) 1.08, 95% CI 0.94-1.25, I2 = 0%, two studies, including 1154 embryos]. The quality of evidence was moderate for all outcomes in oocyte-based review. For woman-based review, only one study provided live birth rate (RR 1,23, 95% CI 1.06-1.44,I2 N/A, one study, including 842 women), the pooled result showed no significant difference in ongoing pregnancy rate (RR 1.04, 95% CI 0.80-1.36, I2 = 59%, four studies, including 1403 women) between two groups. The quality of the evidence was low or very low for all outcomes in woman-based review.

CONCLUSIONS

Currently there is insufficient evidence to support that TLI is superior to conventional methods for human embryo incubation and selection. In consideration of the limitations and flaws of included studies, more well designed RCTs are still in need to comprehensively evaluate the effectiveness of clinical TLI use.

A single trophectoderm biopsy at blastocyst stage is mathematically unable to determine embryo ploidy accurately enough for clinical use

BACKGROUND

It has become increasingly apparent that the trophectoderm (TE) at blastocyst stage is much more mosaic than has been appreciated. Whether preimplantation genetic screening (PGS), utilizing a single TE biopsy (TEB), can reliably determine embryo ploidy has, therefore, increasingly been questioned in parallel.

METHODS

We for that reason here established 2 mathematical models to assess probabilities of false-negative and false-positive results of an on average 6-cell biopsy from an approximately 300-cell TE. This study was a collaborative effort between investigators at The Center for Human Reproduction in New York City and the Center for Studies in Physics and Biology and the Brivanlou Laboratory of Stem Cell Biology and Molecular Embryology, the latter two both at Rockefeller University in New York City.

RESULTS

Both models revealed that even under best case scenario, assuming even distribution of mosaicism in TE (since mosaicism is usually clonal, a highly unlikely scenario), a biopsy of at least 27 TE cells would be required to reach minimal diagnostic predictability from a single TEB.

CONCLUSIONS

As currently performed, a single TEB is, therefore, mathematically incapable of reliably determining whether an embryo can be transferred or should be discarded. Since a single TEB, as currently performed, apparently is not representative of the complete TE, this study, thus, raises additional concern about the clinical utilization of PGS.

Is the hypothesis of preimplantation genetic screening (PGS) still supportable? A review

The hypothesis of preimplantation genetic diagnosis (PGS) was first proposed 20 years ago, suggesting that elimination of aneuploid embryos prior to transfer will improve implantation rates of remaining embryos during in vitro fertilization (IVF), increase pregnancy and live birth rates and reduce miscarriages. The aforementioned improved outcome was based on 5 essential assumptions: (i) Most IVF cycles fail because of aneuploid embryos. (ii) Their elimination prior to embryo transfer will improve IVF outcomes. (iii) A single trophectoderm biopsy (TEB) at blastocyst stage is representative of the whole TE. (iv) TE ploidy reliably represents the inner cell mass (ICM). (v) Ploidy does not change (i.e., self-correct) downstream from blastocyst stage. We aim to offer a review of the aforementioned assumptions and challenge the general hypothesis of PGS. We reviewed 455 publications, which as of January 20, 2017 were listed in PubMed under the search phrase < preimplantation genetic screening (PGS) for aneuploidy>. The literature review was performed by both authors who agreed on the final 55 references. Various reports over the last 18 months have raised significant questions not only about the basic clinical utility of PGS but the biological underpinnings of the hypothesis, the technical ability of a single trophectoderm (TE) biopsy to accurately assess an embryo’s ploidy, and suggested that PGS actually negatively affects IVF outcomes while not affecting miscarriage rates. Moreover, due to high rates of false positive diagnoses as a consequence of high mosaicism rates in TE, PGS leads to the discarding of large numbers of normal embryos with potential for normal euploid pregnancies if transferred rather than disposed of. We found all 5 basic assumptions underlying the hypothesis of PGS to be unsupported: (i) The association of embryo aneuploidy with IVF failure has to be reevaluated in view how much more common TE mosaicism is than has until recently been appreciated. (ii) Reliable elimination of presumed aneuploid embryos prior to embryo transfer appears unrealistic. (iii) Mathematical models demonstrate that a single TEB cannot provide reliable information about the whole TE. (iv) TE does not reliably reflect the ICM. (v) Embryos, likely, still have strong innate ability to self-correct downstream from blastocyst stage, with ICM doing so better than TE. The hypothesis of PGS, therefore, no longer appears supportable. With all 5 basic assumptions underlying the hypothesis of PGS demonstrated to have been mistaken, the hypothesis of PGS, itself, appears to be discredited. Clinical use of PGS for the purpose of IVF outcome improvements should, therefore, going forward be restricted to research studies.

Systematic review of worldwide trends in assisted reproductive technology 2004-2013

BACKGROUND

Assisted Reproductive Technology (ART) has undergone considerable changes over the last decade, with consequences on ART outcomes in different regions of the world being unknown.

METHODS

We conducted a systematic review of published national and regional ART registry data to assess how changes in clinical practice between 2004 and 2013 have impacted outcomes in Australia and New Zealand, Canada, Continental Europe, the United Kingdom (U.K.), Japan, Latin America, and the United States (U.S.). The data reflect 7,079,145 total ART cycles utilizing both fresh and previously cryopreserved embryos from autologous oocytes that resulted in 1,454,724 live births. This review focused on the following measures: ART cycle volume, use of cryopreserved embryos, single embryo transfer (SET), live birth rates in fresh and frozen-thawed cycles, and perinatal outcomes in recent years.

RESULTS

SETs and utilization of frozen-thawed embryos increased worldwide over the study period. In 2012 SET utilization in all ART cycles was highest in Japan and Australia/New Zealand (82.6% and 76.3% respectively) and lowest in Latin America (16.0%). While gradual improvements in live birth rates were observed in most regions, some demonstrated declines. By 2012-2013, fresh cycle live birth rates were highest in the U.S. (29%) and lowest in Japan (5%). In Japan, the observed decline in fresh cycle live birth rate coincided with transition to minimal stimulation protocols, transfer of frozen-thawed rather than fresh embryos, and implementation of an SET policy. Similarly, implementation of an SET policy in parts of Canada was followed by a decline in fresh cycle live birth rate. Increasing live birth rates in frozen-thawed embryo cycles, seen all over the world, partially compensated for declines in fresh ART cycles. During 2012-2013 Australia/New Zealand and Japan reported the lowest multiple delivery rates of 5.6 and 4% respectively while the US had the highest of 27%. In recent years, preterm delivery rates in all regions ranged between 9.0 to 16.6% for singletons, 53.9 to 67.3% for twins, and 91.4 to 100% for triplets and higher order multiples. Inconsistencies in the way perinatal outcome data are presented by various registries, made comparison between regions difficult.

CONCLUSIONS

ART practices are characterized by outcome differences between regions. International consensus on the definition of ART success, which accounts for perinatal outcomes, may help to standardize worldwide ART practice and improve outcomes.

TRIAL REGISTRATION

PROSPERO ( CRD42016033011 ).

The novel POSEIDON stratification of 'Low prognosis patients in Assisted Reproductive Technology' and its proposed marker of successful outcome

In reproductive medicine little progress has been achieved regarding the clinical management of patients with a reduced ovarian reserve or poor ovarian response (POR) to stimulation with exogenous gonadotropins -a frustrating experience for clinicians as well as patients. Despite the efforts to optimize the definition of this subgroup of patients, the existing POR criteria unfortunately comprise a heterogeneous population and, importantly, do not offer any recommendations for clinical handling. Recently, the POSEIDON group ( Patient- Oriented Strategies Encompassing Individualize D Oocyte Number) proposed a new stratification of assisted reproductive technology (ART) in patients with a reduced ovarian reserve or unexpected inappropriate ovarian response to exogenous gonadotropins. In brief, four subgroups have been suggested based on quantitative and qualitative parameters, namely, i. Age and the expected aneuploidy rate; ii. Ovarian biomarkers (i.e. antral follicle count [AFC] and anti-Müllerian hormone [AMH]), and iii. Ovarian response - provided a previous stimulation cycle was performed. The new classification introduces a more nuanced picture of the "low prognosis patient" in ART, using clinically relevant criteria to guide the physician to most optimally manage this group of patients. The POSEIDON group also introduced a new measure for successful ART treatment, namely, the ability to retrieve the number of oocytes needed for the specific patient to obtain at least one euploid embryo for transfer. This feature represents a pragmatic endpoint to clinicians and enables the development of prediction models aiming to reduce the time-to-pregnancy (TTP). Consequently, the POSEIDON stratification should not be applied for retrospective analyses having live birth rate (LBR) as endpoint. Such an approach would fail as the attribution of patients to each Poseidon group is related to specific requirements and could only be made prospectively. On the other hand, any prospective approach (i.e. RCT) should be performed separately in each specific group.

Fresh versus cryopreserved oocyte donation

PURPOSE OF REVIEW

Utilization of cryopreserved instead of fresh donor oocytes has rapidly increased in recent years. Whether treatment outcomes are comparable has, however, remained controversial.

RECENT FINDINGS

More than 24% of initiated oocyte donation cycles in the USA during 2013-2014 involved previously cryopreserved oocytes. The use of cryopreserved-donated oocytes may simplify logistics and lower costs per treatment cycle. Whether cryopreserved donor oocytes also lower costs per live birth is still undetermined as they result in lower live birth rates in comparison to fresh donor oocyte cycles. National data regarding the safety of donated oocytes, including miscarriage rates and neonatal health outcomes, are lacking.

SUMMARY

Currently available data on cryopreserved-donated oocytes are incomplete and, therefore, still insufficient to claim equivalency between fresh and cryopreserved donor oocytes. Until sufficient data are available, patients should be advised about advantages and disadvantages of both methods of oocyte donation, and the use of cryopreserved oocytes should be considered only with caution and appropriate informed consent. Because banking of donated human oocytes facilities their commercial trade, it challenges basic ethical considerations, which have been the basis of oocyte donation since its inception.

Different effectiveness of closed embryo culture system with time-lapse imaging (EmbryoScope(TM)) in comparison to standard manual embryology in good and poor prognosis patients: a prospectively randomized pilot study

BACKGROUND

Previously manual human embryology in many in vitro fertilization (IVF) centers is rapidly being replaced by closed embryo incubation systems with time-lapse imaging. Whether such systems perform comparably to manual embryology in different IVF patient populations has, however, never before been investigated. We, therefore, prospectively compared embryo quality following closed system culture with time-lapse photography (EmbryoScope™) and standard embryology. We performed a two-part prospectively randomized study in IVF (clinical trial # NCT92256309). Part A involved 31 infertile poor prognosis patients prospectively randomized to EmbryoScope™ and standard embryology. Part B involved embryos from 17 egg donor-recipient cycles resulting in large egg/embryo numbers, thus permitting prospectively alternative embryo assignments to EmbryoScope™ and standard embryology. We then compared pregnancy rates and embryo quality on day-3 after fertilization and embryologist time utilized per processed embryo.

RESULTS

Part A revealed in poor prognosis patients no differences in day-3 embryo scores, implantation and clinical pregnancy rates between EmbryoScope™ and standard embryology. The EmbryoScope™, however, more than doubled embryology staff time (P < 0.0001). In Part B, embryos grown in the EmbyoScope™ demonstrated significantly poorer day-3 quality (depending on embryo parameter between P = 0.005 and P = 0.01). Suspicion that conical culture dishes of the EmbryoScope™ (EmbryoSlide™) may be the cause was disproven when standard culture dishes demonstrated no outcome difference in standard incubation.

CONCLUSIONS

Though due to small patient numbers preliminary, this study raises concerns about the mostly uncontrolled introduction of closed incubation systems with time lapse imaging into routine clinical embryology. Appropriately designed and powered prospectively randomized studies appear urgently needed in well-defined patient populations before the uncontrolled utilization of these instruments further expands.

TRIAL REGISTRATION

NCT02246309 Registered September 18, 2014.

Improvements in IVF in women of advanced age

Women above age 40 years in the US now represent the most rapidly growing age group having children. Patients undergoing in vitro fertilization (IVF) are rapidly aging in parallel. Especially where egg donations are legal, donation cycles, therefore, multiply more rapidly than autologous IVF cycles. The donor oocytes, however, are hardly ever a preferred patient choice. Since with use of own eggs, live birth rates decline with advancing age but remain stable (and higher) with donor eggs, older patients always face the difficult and very personal choice between poorer chances with own and better chances with donor oocytes. Physician contribution to this decision should in our opinion be restricted to accurate outcome information for both options. Achievable pregnancy and live birth rates in older women are, however, frequently underestimated, thereby mistakenly biasing fertility providers, private insurance companies and even regulatory government agencies. Restriction on access to IVF for older women is then often the consequence. In this review, we summarize the limited published data on best treatments of 'older' ovaries, while also addressing treatment approaches that should be avoided in older women. This focused review, therefore, to a degree is subjective. Research addressing aging ovaries in IVF has been disappointingly sparse, and has in our opinion too heavily concentrated on methods of embryo selection (ES), which, especially in older women, not only fail to improve IVF outcomes, but actually, negatively affect live birth chances. We conclude that, aside from breakthroughs in gamete creation, only pharmacological interventions into early (small growing follicle stages) follicle maturation will offer new potential to positively impact oocyte and embryo quality and, therefore, IVF outcomes. Research, therefore, should be accordingly redirected.

IVF outcomes in average- and poor-prognosis infertile women according to the number of embryos transferred

Outcome measures of IVF success, which account for effectiveness of IVF and perinatal outcome risks, have recently been described. The association between number of embryos transferred in average and poor-prognosis IVF patients, and the chances of having good or poor IVF and perinatal outcomes, was investigated. Good IVF and perinatal outcome was defined as the birth of a live, term, normal-weight infant (≥2500 g). Poor IVF and perinatal outcome was defined as no live birth or birth of a very low weight neonate (<1500 g) or severe prematurity (birth at <32 weeks gestation). Each neonate was analysed as a separate outcome. A total of 713 IVF cycles in 504 average and poor-prognosis patients from January 2010 to December 2013 were identified. The odds of having good IVF and perinatal outcomes increased by 28% for each additional embryo transferred. The odds of poor IVF and perinatal outcome decreased by 32% with an additional embryo transferred. The likelihood of live birth with good perinatal outcome in average- and poor-prognosis patients after IVF increases with additional embryos being transferred. These data add to recently reported evidence in favour of multiple embryo transfer in older women and those with average or poor IVF prognosis.

The German Middleway as Precursor for Single Embryo Transfer. A Retrospective Data-analysis of the Düsseldorf University Hospital's Interdisciplinary Fertility Centre - UniKiD

Introduction: Patients receiving fertility treatment in Germany appear to be disadvantaged in comparison to those in other countries due to the restrictive Embryo Protection Act ("Embryonenschutzgesetz, ESchG"), which prohibits the selection of a "top" embryo. The so-called German Middleway ("Deutscher Mittelweg, DMW") now provides for a liberal interpretation of the ESchG by allowing the culture of numerous pronuclear stages (2PN stage). Materials and Methods: Retrospective cohort study of 2 assisted reproduction treatment cycles in n = 400 patients between the ages of 21 and 45 years, either treated 2× conservatively or 1× conservatively and 1× liberally according to DMW. Results: Pregnancy was achieved in 35 % of patients in the DMW group and 31 % of controls. The birth rate among controls was 28.5 % and 30.5 % in the DMW group. Most pregnancies resulted from the culture of 4 × 2PN stages. Conclusion: Patients in the DMW group had significantly higher pregnancy and birth rates compared to their previous cycles despite significantly increased age and significantly fewer transferred embryos. Key factors were the number of 2PNs generated and the quality of embryos transferred. Thus it can be assumed that particularly older patients with adequate ovarian reserves will benefit from DMW, i.e. the transfer of fewer embryos of the best possible quality.

Definition by FSH, AMH and embryo numbers of good-, intermediate- and poor-prognosis patients suggests previously unknown IVF outcome-determining factor associated with AMH

BACKGROUND

Though outcome models have been proposed previously, it is unknown whether cutoffs in clinical pregnancy and live birth rates at all ages are able to classify in vitro fertilization (IVF) patients into good-, intermediate- and poor prognosis.

METHODS

We here in 3 infertile patient cohorts, involving 1247, 1514 and 632 women, built logistic regression models based on 3 functional ovarian reserve (FOR) parameters, including (1) number of good quality embryos, (2) follicle stimulating hormone (FSH, mIU/mL) and (3) anti-Müllerian hormone (AMH, ng/mL), determining whether clinical pregnancy and live birth rates can discriminate between good, intermediate and poor prognosis patients.

RESULTS

All models, indeed, allowed at all ages for separation by prognosis, though cut offs changed with age. In the embryo model, increasing embryo production resulted in linear improvement of IVF outcomes despite transfer of similar embryo numbers; in the FSH model outcomes and FSH levels related inversely, while the association of AMH followed a bell-shaped polynomial pattern, demonstrating "best" outcomes at mid-ranges. All 3 models demonstrated increasingly poor outcomes with advancing ages, though "best" AMH even above age 43 was still associated with unexpectedly good pregnancy and delivery outcomes. Excessively high AMH, in contrast, was at all ages associated with spiking miscarriage rates.

CONCLUSIONS

At varying peripheral serum concentrations, AMH, thus, demonstrates hithero unknown and contradictory effects on IVF outcomes, deserving at different concentrations investigation as a potential therapeutic agent, with pregnancy-supporting and pregnancy-interrupting properties.

The impact of patient preselection on reported IVF outcomes

We, in this manuscript, address the fact that increasing numbers of published studies in reproductive medicine selectively report outcomes for only favorably selected patients; while failing to note that, so reported outcome data,therefore, cannot be applied to unselected patient populations. Almost all favorable patient selection methods, starting with prolonged embryo culture to blastocyst stage, have, thus, been widely misrepresented in the literature since they almost universally report outcomes only in reference to embryo transfer. These outcome reports, however, do not include outcomes for poorer prognosis patients who do not reach embryo transfer. Study outcomes are universally applicable only if performed in unselected patient populations and reported with reference point cycle start (intent to treat). All other studies greatly exaggerate clinical pregnancy and live birth rates if applied to general populations, unless specifically noting that they can be extrapolated only to women who reach embryo transfer.

Oocyte Scoring Enhances Embryo-Scoring in Predicting Pregnancy Chances with IVF Where It Counts Most

Context

Our center’s quality improvement optimization process on many occasions anecdotally suggested that oocyte assessments might enhance embryo assessment in predicting pregnancy chances with in vitro fertilization (IVF).

Objective

To prospectively compare a morphologic oocyte grading system to standard day-3 morphologic embryo assessment.

Design, Setting, Patients

We prospectively investigated in a private academically-affiliated infertility center 94 consecutive IVF cycles based on 6 criteria for oocyte quality: morphology, cytoplasm, perivitelline space (PVS), zona pellucida (ZP), polar body (PB) and oocyte size, each assigned a value of -1 (worst), 0 (average) or +1 (best), so establishing an average total oocyte score (TOS). Embryo assessment utilized grade and cell numbers of each embryo on day-3 after oocyte retrieval. Clinical pregnancy was defined by presence of at least one intrauterine gestational sac.

Interventions

Standard IVF cycles in infertile women.

Main Outcome Measures

Predictability of pregnancy based on oocyte and embryo-grading systems.

Results

Average age for all patients was 36.5 ± 7.3 years; mean oocyte yield was 7.97± 5.76; Patient specific total oocyte score (PTOS) was -1.05 ± 2.24. PTOS, adjusted for patient age, was directly related to odds of increased embryo cell numbers (OR 1.12, P = 0.025), embryo grade (OR 1.19, P < 0.001) and clinical pregnancy [OR 1.58 (95%CI 1.23 to 2.02), P < 0.001]. Restricting the analysis to day three embryos of high quality (8-cell/ good grades), TOS was still predictive of clinical pregnancy (OR 2.08 (95%CI 1.26 to 3.44, P = 0.004). Among the 69 patients with embryos of Grade 4 or better available for transfer 23 achieved Clinical Pregnancy. When the analysis was restricted to the 69 transfers with good quality embryos (≥ Grade 4) the Oocyte Scoring System (TOS) (AUC±SE 0.863±0.044, oocyte score) provided significantly greater predictive value for clinical pregnancy compared to the embryo grade alone (AUC 0.646 ± 0.072, embryo grade) p = 0.015.

Conclusions

Oocyte-scoring, thus, provides useful clinical information especially in good prognosis patients with large numbers of high quality embryos. This finding appears of particular importance at a time when many IVF centers are committing sizable investments to closed incubation systems with time-lapse photography, which are exclusively meant to define embryo morphology.

Prognostic value of three pro-nuclei (3PN) incidence in elective single blastocyst-stage embryo transfer

OBJECTIVES

To investigate whether 3PN incidence could lead to a worse pregnancy outcome of elective single blastocyst stage embryo transfer (eSBET).

METHODS

This study included 706 eSBET cycles from January 2013 to March 2015. The patients were divided into two groups as follows: group 1 included 286 patients with no 3PN zygotes and group 2 included 420 patients with 3PN zygotes.

MAIN OUTCOME MEASURE

female age, endometrial thickness, infertility duration, type of infertility, main etiology of infertility, clinical pregnancy and abortion rate.

RESULTS

We observed that there was no significant difference in female age, endometrial thickness, infertility duration and abortion rate between two groups. It's worth noting that the clinical pregnancy rate in 3PN > 0% group was significantly lower than 3PN = 0 group (P = 0.021).

CONCLUSIONS

3PN incidence might make anegative effect on pregnancy outcomes in elective single blastocyst stage embryo transfer.