Correlation between aneuploidy, standard morphology evaluation and morphokinetic development in 1730 biopsied blastocysts: a consecutive case series study

Contraction behaviour reduces embryo competence in high-quality euploid blastocysts

PURPOSE

The aim of the study is to investigate how blastocyst contraction behaviour affects the reproductive competence in high-quality euploid embryos.

METHODS

Eight hundred ninety-six high-quality blastocysts derived from 190 patients (mean age 38.05 (SD = 2.9) years) who underwent preimplantation genetic testing for aneuploidies (PGT-A) from January 2016 to October 2017 were included in this study. PGT-A results were reported as euploid or aneuploid. Aneuploid embryos were sub-classified into three categories: monosomy, trisomy and complex aneuploid. Retrospective studies of time-lapse monitoring (TLM) of those embryos were analysed and reproductive outcome of transferred embryos was collected.

RESULTS

A total of 234/896 were euploid (26.1%) whilst 662/896 (73.9%) blastocysts were proven to be aneuploid from which 116 (17.6%) presented monosomies, 136 (20.5%) trisomies and 410 (61.9%) were complex aneuploid. The most frequent chromosomal complements were trisomies affecting chromosome 21 and monosomies involving chromosomes 16 and 22. Data analysis showed a statistical difference in the number of contractions being reported greater in aneuploid when compared to euploid embryos (0.6 vs 1.57; p < 0.001). Analysis of the aneuploid embryos showed that monosomies present less number of contractions when compared to embryos affected with trisomies or complex aneuploidies (1.23 vs 1.53 and 1.40; p < 0.05). No difference was observed when comparing the latter two groups. Euploid embryos presenting at least one contraction resulted in lower implantation and clinical pregnancy rates when compared to blastocysts that do not display this event (47.6 vs 78.5% and 40.0 vs 59.0% respectively).

CONCLUSIONS

Most aneuploid blastocysts diagnosed by PGT-A have complex aneuploidies, showing that aneuploid embryos can develop after genomic activation and reaching high morphological scores. It becomes clear that embryo contraction, despite being a physiological feature during blastulation, is conditioned by the ploidy status of the embryo. Furthermore, the presence of contractions may compromise implantation rates.

Hypoxic Stress Forces Adaptive and Maladaptive Placental Stress Responses in Early Pregnancy

This review focuses on hypoxic stress and its effects on the placental lineage and the earliest differentiation events in mouse and human placental trophoblast stem cells (TSCs). Although the placenta is a decidual organ at the end of pregnancy, its earliest rapid growth and function at the start of pregnancy precedes and supports growth and function of the embryo. Earliest function requires that TSCs differentiate, however, "hypoxia" supports rapid growth, but not differentiation of TSCs. Most of the literature on earliest placental "hypoxia" studies used 2% oxygen which is normoxic for TSCs. Hypoxic stress happens when oxygen level drops below 2%. It decreases anabolism, proliferation, potency/stemness and increases differentiation, despite culture conditions that would sustain proliferation and potency. Thus, to study the pathogenesis due to TSC dysfunction, it is important to study hypoxic stress below 2%. Many studies have been performed using 0.5 to 1% oxygen in cultured mouse TSCs. From all these studies, a small number has examined human trophoblast lines and primary first trimester placental hypoxic stress responses in culture. Some other stress stimuli, aside from hypoxic stress, are used to elucidate common and unique aspects of hypoxic stress. The key outcomes produced by hypoxic stress are mitochondrial, anabolic, and proliferation arrest, and this is coupled with stemness loss and differentiation. Hypoxic stress can lead to depletion of stem cells and miscarriage, or can lead to later dysfunctions in placentation and fetal development. Birth Defects Research 109:1330-1344, 2017. © 2017 Wiley Periodicals, Inc.

Blastocyst development rate influences implantation and live birth rates of similarly graded euploid blastocysts

OBJECTIVE

To determine whether the blastocyst development rate, as assessed by the day of trophectoderm biopsy (day 5 vs. day 6), affects the live birth rate (LBR) of similarly graded euploid blastocysts.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

Patients who underwent frozen-thawed single euploid blastocyst transfers from 2013 to 2016 were included. Blastocyst morphologic grading was performed on day 5 or day 6 before the biopsy, with embryos designated into the following groups: good (3-6AA, 3-6AB, and 3-6BA), average (2-6BB), and poor (2-6BC and 2-6CB).

INTERVENTION(S)

Frozen-thawed embryo transfer.

MAIN OUTCOME MEASURE(S)

Implantation rate (IR) and LBR.

RESULT(S)

A total of 701 frozen-thawed single euploid blastocyst transfer cycles were included. Cycles in which day 5 blastocysts were transferred (n = 366) were associated with a significantly higher LBR than those in which day 6 blastocysts were transferred (n = 335; 60.4% vs. 44.8%). The odds ratio remained significant after controlling for all confounders, including the blastocyst grading. Furthermore, there was a significant difference in LBRs between good-quality, average-quality, and poor-quality blastocysts (67.8%, 53.4%, and 29.5%, respectively). Embryos reaching good-quality blastocysts on day 5 yielded significantly higher LBR (72.8% vs. 56.5%) and IR (77.7% vs. 58.7%) compared with those reaching similar quality blastocysts on day 6. Similarly, day 5 average-quality embryos conveyed a significantly higher IR compared with day 6 embryos of the same quality (64.4% vs. 53.4%).

CONCLUSION(S)

In addition to aneuploidy assessment, the speed of embryo development to the blastocyst stage and an evaluation of blastocyst morphology are critical to selecting the best embryo.

Prospective study of automated versus manual annotation of early time-lapse markers in the human preimplantation embryo

STUDY QUESTION

How does automated time-lapse annotation (Eeva™) compare to manual annotation of the same video images performed by embryologists certified in measuring durations of the 2-cell (P2; time to the 3-cell minus time to the 2-cell, or t3-t2) and 3-cell (P3; time to 4-cell minus time to the 3-cell, or t4-t3) stages?

SUMMARY ANSWER

Manual annotation was superior to the automated annotation provided by Eeva™ version 2.2, because manual annotation assigned a rating to a higher proportion of embryos and yielded a greater sensitivity for blastocyst prediction than automated annotation.

WHAT IS KNOWN ALREADY

While use of the Eeva™ test has been shown to improve an embryologist's ability to predict blastocyst formation compared to Day 3 morphology alone, the accuracy of the automated image analysis employed by the Eeva™ system has never been compared to manual annotation of the same time-lapse markers by a trained embryologist.

STUDY DESIGN, SIZE, DURATION

We conducted a prospective cohort study of embryos (n = 1477) cultured in the Eeva™ system (n = 8 microscopes) at our institution from August 2014 to February 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Embryos were assigned a blastocyst prediction rating of High (H), Medium (M), Low (L), or Not Rated (NR) by Eeva™ version 2.2 according to P2 and P3. An embryologist from a team of 10, then manually annotated each embryo and if the automated and manual ratings differed, a second embryologist independently annotated the embryo. If both embryologists disagreed with the automated Eeva™ rating, then the rating was classified as discordant. If the second embryologist agreed with the automated Eeva™ score, the rating was not considered discordant. Spearman's correlation (ρ), weighted kappa statistics and the intra-class correlation (ICC) coefficients with 95% confidence intervals (CI) between Eeva™ and manual annotation were calculated, as were the proportions of discordant embryos, and the sensitivity, specificity, positive predictive value (PPV) and NPV of each method for blastocyst prediction.

MAIN RESULTS AND THE ROLE OF CHANCE

The distribution of H, M and L ratings differed by annotation method (P < 0.0001). The correlation between Eeva™ and manual annotation was higher for P2 (ρ = 0.75; ICC = 0.82; 95% CI 0.82-0.83) than for P3 (ρ = 0.39; ICC = 0.20; 95% CI 0.16-0.26). Eeva™ was more likely than an embryologist to rate an embryo as NR (11.1% vs. 3.0%, P < 0.0001). Discordance occurred in 30.0% (443/1477) of all embryos and was not associated with factors such as Day 3 cell number, fragmentation, symmetry or presence of abnormal cleavage. Rather, discordance was associated with direct cleavage (P2 ≤ 5 h) and short P3 (≤0.25 h), and also factors intrinsic to the Eeva™ system, such as the automated rating (proportion of discordant embryos by rating: H: 9.3%; M: 18.1%; L: 41.3%; NR: 31.4%; P < 0.0001), microwell location (peripheral: 31.2%; central: 23.8%; P = 0.02) and Eeva™ microscope (n = 8; range 22.9-42.6%; P < 0.0001). Manual annotation upgraded 82.6% of all discordant embryos from a lower to a higher rating, and improved the sensitivity for predicting blastocyst formation.

LIMITATIONS, REASONS FOR CAUTION

One team of embryologists performed the manual annotations; however, the study staff was trained and certified by the company sponsor. Only two time-lapse markers were evaluated, so the results are not generalizable to other parameters; likewise, the results are not generalizable to future versions of Eeva™ or other automated image analysis systems.

WIDER IMPLICATIONS OF THE FINDINGS

Based on the proportion of discordance and the improved performance of manual annotation, clinics using the Eeva™ system should consider manual annotation of P2 and P3 to confirm the automated ratings generated by Eeva™.

STUDY FUNDING/COMPETING INTEREST(S)

These data were acquired in a study funded by Progyny, Inc. There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Cumulative live birth rates and perinatal outcomes with the use of time-lapse imaging incubators for embryo culture: a retrospective cohort study of 1882 ART cycles

OBJECTIVE

Comparison of live birth rates and the perinatal outcomes after fresh and frozen embryo transfer between time-lapse imaging (TLI) and standard culture (SC) incubators.

DESIGN

Retrospective cohort study.

SETTING

A single tertiary level IVF unit.

POPULATION

Women undergoing IVF between January 2014 and October 2015.

METHODS

Comparison was done between 1064 IVF cycles using TLI (TLI cycles) and 818 IVF cycles using SC (SC cycles).

MAIN OUTCOME MEASURES

Cumulative live birth rate per oocyte retrieval and perinatal outcomes including birthweight, gestational age, preterm birth (PTB) (<37 weeks), early preterm birth (PTB; <32 weeks), low birthweight (LBW; <2500 g), very LBW (<1500 g) and macrosomia (>4500 g).

RESULTS

The fresh embryo transfer live birth rate was noted to be higher for TLI cycles [TLI 36.8 versus SC 33.9%, adjusted odds ratio (aOR) 1.28, 95% CI 1.05-1.57], but the frozen embryo transfer live birth rates were not significantly different. The mean birthweight was higher in the TLI group after both fresh [adjusted mean difference (aMD) 174.78 g, 95% CI 64.80-284.77] and frozen embryo transfers (aMD 175.91 g, 95% CI 16.98-334.84). After a fresh embryo transfer, there was a lower risk of early PTB and very LBW in the TLI group. Among frozen embryo transfers, there was a lower risk of early PTB and LBW in the TLI group.

CONCLUSIONS

TLI incubators are associated with improved perinatal outcomes and higher mean birthweight after fresh and frozen embryo transfer.

TWEETABLE ABSTRACT

Time-lapse imaging incubators in IVF improve perinatal outcomes after both fresh and frozen embryo transfers.

Are cleavage anomalies, multinucleation, or specific cell cycle kinetics observed with time-lapse imaging predictive of embryo developmental capacity or ploidy?

OBJECTIVE

To determine whether cleavage anomalies, multinucleation, and specific cellular kinetic parameters available from time-lapse imaging are predictive of developmental capacity or blastocyst chromosomal status.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Single academic center.

PATIENT(S)

A total of 1,478 zygotes from patients with blastocysts biopsied for preimplantation genetic screening were cultured in the EmbryoScope.

INTERVENTION(S)

Trophectoderm biopsy.

MAIN OUTCOME MEASURE(S)

Embryo dysmorphisms, developmental kinetics, and euploidy.

RESULT(S)

Of the 767 biopsied blastocysts, 41.6% (95% confidence interval [CI], 38%-45%) were diagnosed as euploid. Individual dysmorphisms such as multinucleation, reverse cleavage, irregular chaotic division, or direct uneven cleavage were not associated with aneuploidy. Direct uneven cleavage and irregular chaotic division embryos did, however, exhibit lower developmental potential. The presence of two or more dysmorphisms was associated with an overall lower euploidy rate, 27.6% (95% CI 19%-39%). Early embryo kinetics were predictive of blastocyst development but not ploidy status. In contrast, chromosomal status correlated significantly with start time of blastulation (tSB), expansion (tEB), and the tEB-tSB interval. A lower euploidy rate, 36.6% (95% CI 33%-42%) was observed with tSB ≥ 96.2 hours, compared with 48.2% with tSB < 96.2 (95% CI 42%-54%). A drop in euploidy rate to 30% (95% CI 25%-37%) was observed in blastocysts with delayed expansion (tEB > 116). The proportion of euploid blastocysts was increased with tEB-tSB intervals of ≤13 hours. A logistic regression model to enhance the probability of selecting a euploid blastocyst was constructed.

CONCLUSION(S)

Morphokinetics may aid in selection of euploid embryos from a cohort of day 5/6 blastocysts.

Time-Lapse Imaging for the Detection of Chromosomal Abnormalities in Primate Preimplantation Embryos

The use of time-lapse microscopic imaging has proven to be a powerful tool for the study of mitotic divisions and other cellular processes across diverse species and cell types. Although time-lapse monitoring (TLM) of human preimplantation development was first introduced to the in vitro fertilization (IVF) community several decades ago, it was not until relatively recently that TLM systems were commercialized for clinical embryology purposes. Traditionally, human IVF embryos are assessed by successful progression and morphology under a stereomicroscope at distinct time points prior to selection for transfer. Due to the high frequency of aneuploidy, embryos may also be biopsied at the cleavage or blastocyst stage for preimplantation genetic screening (PGS) of whole and/or partial chromosomal abnormalities. However, embryo biopsy is invasive and can hinder subsequent development, and there are additional concerns over chromosomal mosaicism and resolution with PGS. Moreover, embryos are typically outside of the incubator in suboptimal culture conditions for extended periods of time during these procedures. With TLM systems, embryos remain in the stable microenvironment of an incubator and are simultaneously imaged for noninvasive embryo evaluation using a fraction of the light exposure as compared to a stereomicroscope. Each image is then compiled into a time-lapse movie, the information from which can be extrapolated to correlate morphological, spatial, and temporal parameters with embryo quality and copy number status. Here, we describe the various TLM systems available for clinical and/or research use in detail and provide step-by-step instructions on how the measurement of specific timing intervals and certain morphological criteria can be implemented into IVF protocols to enhance embryo assessment and avoid the selection of aneuploid embryos. We also discuss the biological significance of processes unique to mitotically dividing embryos and the likelihood that complex chromosomal events such as chromothripsis occur during preimplantation development in humans and other mammals, particularly nonhuman primates.

Artificial cryopreserved embryo transfer cycle success depends on blastocyst developmental rate and progesterone timing

This retrospective cohort analysis compared the developmental competence of cryopreserved day-4 and 5 blastocysts, and investigated the effect of progesterone administration duration on the success of artificial frozen embryo transfers. Between October 2015 and March 2016, 868 intracytoplasmic sperm injection blastocyst cryo-all cycles were carried out, with 586 subsequently undergoing frozen embryo transfer. Of these, 243 were day-5 single blastocyst transfers (SBT) and 152 were day-4 SBT. Day-4 blastocysts were transferred on day-5 progesterone (day-4 group) and day-5 blastocysts were transferred on day-5 (short-protocol day-5 sub-group, n = 104) or day-6 (standard-protocol day-5 sub-group, n = 139) progesterone. Although more blastocysts were transferred in the standard-protocol day-5 sub-group (P = 0.009), pregnancy, clinical pregnancy and live birth rates were similar to those of the day-4 group, but were significantly lower in the short-protocol day-5 sub-group (P = 0.004, P = 0.008 and P = 0.02 respectively). For optimal outcomes, day-4 blastulating embryos should be prioritized for transfer on day 5 of progesterone and for day-5 blastocysts, transfer should be delayed by 1 day. The retrospective analysis and lack of adjustment for all known confounding variables limit the study.

Associations between perfluorinated alkyl acids in blood and ovarian follicular fluid and ovarian function in women undergoing assisted reproductive treatment

Endocrine disrupting contaminants, in combination with other environmental variables, are associated with altered reproductive health. Assisted reproductive technology (ART) procedures offer valuable opportunities to explore the connections between environmental contaminants in the ovarian microenvironment and measures of fertility, including impaired responsiveness to gonadotropins. Here, we investigate an emerging class of environmental contaminants, the perfluorinated alkyl acids (PFAAs), to determine whether ovarian contaminant levels are associated with measures of ovarian responsiveness and fertility outcomes in a South Carolina population of women undergoing ART. Levels of PFAAs in plasma and follicular fluid samples collected from women undergoing ovarian stimulation were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Six PFAAs were detected in both plasma and follicular fluid. PFAA concentrations in plasma correlate strongly to those detected in ovary and, with the exception of one compound, remain stable throughout ovarian stimulation. The concentration of PFHxS in follicular fluid inversely relates to baseline follicle counts. While no significant relationships were detected between ovarian response measures and PFAA concentrations, we identified a negative relationship between follicular fluid PFDA and PFuNA and blastocyst conversion rates. Our assessments indicate that plasma levels of PFAAs serve as a sound proxy of those in the ovarian compartment and that follicular fluid levels of specific PFAA compounds are inversely related to important clinical measures of reproductive health including baseline follicle count and post-fertilization success.

Female age, serum antimüllerian hormone level, and number of oocytes affect the rate and number of euploid blastocysts in in vitro fertilization/intracytoplasmic sperm injection cycles

OBJECTIVE

To study the relative role of female age and ovarian reserve, measured through serum antimüllerian hormone (AMH) in determining the rate and number of euploid blastocysts in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles.

DESIGN

Retrospective analysis of cycles performed in 2014-2015.

SETTING

Tertiary referral IVF center.

PATIENT(S)

A total of 578 infertile couples undergoing IVF/ICSI and preimplantation genetic screening (PGS) analysis.

INTERVENTIONS(S)

All embryos were cultured and biopsied at the blastocyst stage. The method involved whole-genome amplification followed by array comparative genome hybridization. Serum AMH was measured by means of the modified Beckman Coulter AMH Gen II assay.

MAIN OUTCOME MEASURES

The rate and number of euploid blastocysts and their correlation with ovarian reserve and response to stimulation.

RESULT(S)

The mean (±SD) age of patients was 37.6 ± 4.1 years, and the mean number of blastocysts per patient was 3.1 ± 2. The total number of blastocysts available to the analysis was 1,814, and 36% of them were euploid after PGS. Age and serum AMH were significantly and independently related to the rate of euploid blastocysts available for patients. As an effect of the cohort size, the number of mature oocytes positively affected the total number of euploid blastocysts per patient.

CONCLUSION(S)

A strong positive age-independent relationship between AMH level and the rate of euploid blastocysts was found. This confirms that the measurement of ovarian reserve by means of AMH has high relevance when counseling infertile patients.

Dichorionic triplets following frozen-thawed poor-stage embryo transfer: a report of two cases and a review

BACKGROUND

We describe two cases of dichorionic triplet pregnancy after a frozen-thawed poor-stage embryo transfer. A 39-year-old and a 41-year-old woman underwent ART treatment. The first patient underwent intracytoplasmic sperm injection (ICSI) at 34 years of age, and two frozen-thawed poor-stage embryos were transferred at 39 years of age with assisted hatching, resulting in a trichorionic triamniotic triplet pregnancy. The second patient underwent ICSI, and two poor-grade blastocysts were transferred followed by assisted hatching, resulting in a dichorionic triamniotic triplet pregnancy. In the first case, the heartbeat of one monozygotic twin fetus had stopped on day 48 post-transfer (9 weeks 2 days), resulting in a dichorionic diamniotic twin pregnancy. A healthy boy and girl were delivered by elective caesarean section at 36 weeks, 5-days gestation. In the second case, the patient underwent selective reduction of the monochorionic twins, resulting in a single pregnancy that was vaginally delivered without any problems at 38 weeks 0-days gestation.

SHORT CONCLUSIONS

Numerous factors may be associated with the development of a monochorionic pregnancy; however, controversies still remain. The present morphological grading for embryos is insufficient for inhibiting the development of a monochorionic pregnancy.

Earlier day of blastocyst development is predictive of embryonic euploidy across all ages: essential data for physician decision-making and counseling patients

PURPOSE

The purpose of this study is to evaluate whether day of blastocyst development is associated with embryo chromosomal status as determined by high-density oligonucleotide microarray comparative genomic hybridization (aCGH).

METHODS

This is a retrospective cohort analysis, including women who underwent in vitro fertilization (IVF) with trophectoderm biopsy at a single private fertility center from January 2014 to December 2014. Repeat cycles were excluded. Cycles were assessed for percentage of blastocysts biopsied on days 5, 6, or 7 and rate of euploid embryos per cycle. Cycles were stratified by Society for Assisted Reproductive Technology (SART) age groups (< 35, 35-37, 38-40, 41-42, > 42) and by donor status.

RESULTS

A total of 388 IVF cycles and 2132 biopsied blastocysts were evaluated. The percentages of blastocysts biopsied on days 5, 6, and 7 were 62.5, 35.8, and 1.7%, respectively. Blastocyst euploid rates on days 5, 6, and 7 were 49.5, 36.5, and 32.9%, respectively. Earlier blastocyst development was associated with a significantly increased euploid rate (p < 0.0001). Younger maternal age (p < 0.0001) and higher number of blastocysts biopsied per patient (p = 0.0063) were both independently associated with greater percentage of euploidy.

CONCLUSIONS

Earlier blastocyst development is independently associated with a higher likelihood of embryonic euploidy in both autologous and donor embryos. In non-biopsied embryos, these data support selection of day 5 blastocysts for transfer over later-developing embryos. These results can assist with patient counseling regarding expectations and outcomes. To our knowledge, this is the first study to examine embryonic euploidy as stratified by both day of blastocyst development and SART age group.

Does air pollution play a role in infertility?: a systematic review

BACKGROUND

Air pollution is involved in many pathologies. These pollutants act through several mechanisms that can affect numerous physiological functions, including reproduction: as endocrine disruptors or reactive oxygen species inducers, and through the formation of DNA adducts and/or epigenetic modifications. We conducted a systematic review of the published literature on the impact of air pollution on reproductive function. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. Search terms included (1) ovary or follicle or oocyte or testis or testicular or sperm or spermatozoa or fertility or infertility and (2) air quality or O3 or NO2 or PM2.5 or diesel or SO2 or traffic or PM10 or air pollution or air pollutants. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We have included the human and animal studies corresponding to the search terms and published in English. We have excluded articles whose results did not concern fertility or gamete function and those focused on cancer or allergy. We have also excluded genetic, auto-immune or iatrogenic causes of reduced reproduction function from our analysis. Finally, we have excluded animal data that does not concern mammals and studies based on results from in vitro culture. Data have been grouped according to the studied pollutants in order to synthetize their impact on fertility and the molecular pathways involved.

CONCLUSION

Both animal and human epidemiological studies support the idea that air pollutants cause defects during gametogenesis leading to a drop in reproductive capacities in exposed populations. Air quality has an impact on overall health as well as on the reproductive function, so increased awareness of environmental protection issues is needed among the general public and the authorities.

Morphokinetic parameters from a time-lapse monitoring system cannot accurately predict the ploidy of embryos

PURPOSE

This study aimed to test whether there is an association between embryo morphokinetic parameters and ploidy status.

METHODS

Patients with high risk of aneuploidy were analyzed by time-lapse microscopy combined with preimplantation genetic screening (PGS). Accordingly, 256 blastocysts from 75 patients were subjected to trophectoderm biopsy and microarray comparative genomic hybridization (array-CGH). Blastocyst development process was analyzed using time-lapse images.

RESULTS

Morphokinetic parameters: tPNf, t2, t3, t4, t5, t8, t9, tcom, tM, tSB, tB, tEB, CC1, CC2, CC3, S2, S3, t5-t2, and tB-tSB showed no significant difference in euploid embryos compared to aneuploid counterparts. In addition, two risk models based on previously published morphokinetic parameters failed to segregate euploid from aneuploid embryos.

CONCLUSIONS

Morphokinetic parameters subjected to investigation in the present study failed to improve the chance of selecting euploid embryos.

Association between growth dynamics, morphological parameters, the chromosomal status of the blastocysts, and clinical outcomes in IVF PGS cycles with single embryo transfer

PURPOSE

The purpose of the present study is to examine interconnection between speed of embryo development, the genetic status of the blastocysts, and clinical outcomes in IVF preimplantation genetic screening (PGS) cycles with single embryo transfer (SET).

METHODS

The retrospective comparative study has been performed between January 2013 and January 2016. Seven hundred thirty-seven cycles of IVF treatment with PGS, followed by 503 SETs, were included in the study. Normally fertilized oocytes were hatched on day 3, were cultured to the blastocyst stage, and were biopsied only when at least three to seven cells were herniating from zona pellucida on the morning of day 5 (≤118 h) or day 6 (≥139 h). A total of 3705 embryos were analyzed for euploidy rates and blastocyst morphology. All embryos were vitrified after the biopsy, and selected embryos were subsequently thawed for a hormone replacement frozen embryo transfer cycle.

RESULTS

The euploidy rate was significantly higher among embryos biopsied on day 5 versus day 6: 59.44 ± 4.1 and 48.19 ± 3.8, respectively, p < 0.05. The difference in euploidy rates between embryos biopsied on day 5 versus day 6 in matched age groups increased from 5.83 to 25.46% with advancing maternal age. Our data demonstrated no statistically significant difference in euploidy rates between good-quality embryos biopsied on day 5 in the group of patients <38 years old and embryos in PGS cycles using donor oocytes: 71.12% (336/472) and 75.68% (221/292), respectively, p = 0.174, χ ² = 1.848. In 270 out of 503 SETs, transferred embryos were biopsied on day 5 (ongoing pregnancy rate was 64.6% in a group of patients <38 years old, and in a group of patients ≥38 years old, ongoing PR was 64.2%). In 233 out of 503 cycles, transferred embryos were biopsied on day 6 (ongoing PR was 46.6% in a group of patients <38 years old, and in a group of patients ≥38 years old, ongoing PR was 50.8%). In all study groups, the ongoing pregnancy rate was higher when the transferred embryo was available for biopsy on day 5.

CONCLUSIONS

Good- and fair-quality embryos available for biopsy on day 5 have higher euploidy rates and have a higher chance to result in an ongoing pregnancy. Euploidy rate has significant variations within the same age group depending on the morphology of the blastocysts.

Novel technologies emerging for preimplantation genetic diagnosis and preimplantation genetic testing for aneuploidy

INTRODUCTION

Preimplantation genetic diagnosis (PGD) was introduced as an alternative to prenatal diagnosis: embryos cultured in vitro were analysed for a monogenic disease and only disease-free embryos were transferred to the mother, to avoid the termination of pregnancy with an affected foetus. It soon transpired that human embryos show a great deal of acquired chromosomal abnormalities, thought to explain the low success rate of IVF - hence preimplantation genetic testing for aneuploidy (PGT-A) was developed to select euploid embryos for transfer. Areas covered: PGD has followed the tremendous evolution in genetic analysis, with only a slight delay due to adaptations for diagnosis on small samples. Currently, next generation sequencing combining chromosome with single-base pair analysis is on the verge of becoming the golden standard in PGD and PGT-A. Papers highlighting the different steps in the evolution of PGD/PGT-A were selected. Expert commentary: Different methodologies used in PGD/PGT-A with their pros and cons are discussed.

Assessment of human embryo development using morphological criteria in an era of time-lapse, algorithms and 'OMICS': is looking good still important?

With the worldwide move towards single embryo transfer there has been a renewed focus on the requirement for reliable means of assessing embryo viability. In an era of 'OMICS' technologies, and algorithms created through the use of time-lapse microscopy, the actual appearance of the human embryo as it progresses through each successive developmental stage to the blastocyst appears to have been somewhat neglected in recent years. Here we review the key features of the human preimplantation embryo and consider the relationship between morphological characteristics and developmental potential. Further, the impact of the culture environment on morphological traits, how key morphological qualities reflect aspects of embryo physiology, and how computer-assisted analysis of embryo morphology may facilitate a more quantitative approach to selection are discussed. The clinical introduction of time-lapse systems has reopened our eyes and given us a new vantage point from which to view the beauty of the initial stages of human life. Rather than a future in which the morphology of the embryo is deemed irrelevant, we propose that key features, such as multinucleation, cell size and blastocyst differentiation should be included in future iterations of selection/deselection algorithms.