PGT-A: who and when? Α systematic review and network meta-analysis of RCTs

Efficacy of non-invasive chromosome screening, preimplantation genetic testing for aneuploidy, and morphological grading in selecting embryos of patients with advanced maternal age: a three-armed prospective cohort study

BACKGROUND

Non-invasive chromosome screening (NICS) and trophectoderm biopsy preimplantation genetic testing for aneuploidy (TE-PGT) were both applied for embryo ploidy detection, However, the cumulative live birth rates (CLBR) of NICS and TE-PGT in older age groups have yet to be reported. This study aimed to ascertain whether NICS and TE-PGT could enhance the cumulative live birth rates among patients of advanced maternal age.

METHODS

A total of 384 couples aged 35-40 years were recruited. The patients were assigned to three groups: NICS, TE-PGT, and intracytoplasmic sperm injection (ICSI). All patients received frozen single blastocyst transfer. Patients in the NICS and TE-PGT groups underwent aneuploidy screening.

RESULTS

When compared to the ICSI group, the CLBR was significantly higher in the NICS and TE-PGT groups (27.9% vs. 44.9% vs. 51.0%, p = 0.003 for NICS vs. ICSI, p < 0.001 for TE-PGT vs. ICSI). There were no significant differences in the clinical outcomes between the NICS and TE-PGT groups. Adjusting for confounding factors, the NICS and TE-PGT groups still showed a higher CLBR than the ICSI group (adjusted odds ratio (OR) 3.847, 95% confidence interval (CI) 1.939 to 7.634; adjusted OR 3.795, 95% CI 1.981 to 7.270). Additionally, the cumulative pregnancy loss rates of the NICS and TE-PGT groups were significantly lower than that of the ICSI group (adjusted OR 0.277, 95% CI 0.087 to 0.885; adjusted OR 0.182, 95% CI 0.048 to 0.693). There was no significant difference in the birth weights of the three groups (p = 0.108).

CONCLUSIONS

In women 35-40 years old, the CLBR can be increased by selecting euploid embryos using NICS and TE-PGT. For elderly women at high risk of embryonic aneuploidy, NICS, characterized by its safety and non-invasive nature, may emerge as an alternative option for preimplantation genetic testing.

Ongoing pregnancy rates in single euploid frozen embryo transfers remain unaffected by female age: a retrospective study

RESEARCH QUESTION

Is female age a significant factor in the likelihood of an ongoing pregnancy in single euploid frozen embryo transfers (FET)?

DESIGN

Retrospective study of 1923 single euploid FET cycles in 1464 women, either in a natural cycle or a hormone replacement therapy cycle. The primary outcome was the ongoing pregnancy rate (OPR).

RESULTS

There were 990 (51.48%) ongoing pregnancies among 1923 included transfers. The OPR were 51.4%, 49.1%, 53.3% and 52.3% for women aged ≤35, >35-≤37, >37-≤40 and >40 years at oocyte retrieval (OCR), without a significant trend for decreasing OPR (P = 0.679). No significant differences in female age at embryo transfer (P = 0.609) and female age at OCR (P = 0.816) were found between the groups (ongoing pregnancy versus no pregnancy or miscarriage). Women who received good-quality embryos (P < 0.001), had a lower body mass index (BMI) (P < 0.001), had achieved at least one pregnancy previously (P < 0.001), and underwent natural cycle endometrial preparation (P < 0.001) were more likely to achieve an ongoing pregnancy. Multivariable regression analysis (adjusted for BMI, embryo quality and endometrial preparation) did not show a significant effect of female age at OCR on achieving an ongoing pregnancy. Compared with women aged ≤35 years, none of the age groups had significantly higher or lower OPR. A multinomial regression analysis showed that BMI, embryo quality and endometrial preparation were associated with miscarriage/no pregnancy versus ongoing pregnancy (P = 0.001, 0.001 and 0.001, respectively). Female age had no significant association with either outcome.

CONCLUSIONS

Female age in itself does not have a substantial impact on the OPR in single euploid FET cycles, but the OPR is impacted significantly by embryo quality, BMI, previous parity, and a natural cycle endometrial preparation protocol.

Beyond black-box models: explainable AI for embryo ploidy prediction and patient-centric consultation

PURPOSE

To determine if an explainable artificial intelligence (XAI) model enhances the accuracy and transparency of predicting embryo ploidy status based on embryonic characteristics and clinical data.

METHODS

This retrospective study utilized a dataset of 1908 blastocyst embryos. The dataset includes ploidy status, morphokinetic features, morphology grades, and 11 clinical variables. Six machine learning (ML) models including Random Forest (RF), Linear Discriminant Analysis (LDA), Logistic Regression (LR), Support Vector Machine (SVM), AdaBoost (ADA), and Light Gradient-Boosting Machine (LGBM) were trained to predict ploidy status probabilities across three distinct datasets: high-grade embryos (HGE, n = 1107), low-grade embryos (LGE, n = 364), and all-grade embryos (AGE, n = 1471). The model's performance was interpreted using XAI, including SHapley Additive exPlanations (SHAP) and Local Interpretable Model-agnostic Explanations (LIME) techniques.

RESULTS

The mean maternal age was 38.5 ± 3.85 years. The Random Forest (RF) model exhibited superior performance compared to the other five ML models, achieving an accuracy of 0.749 and an AUC of 0.808 for AGE. In the external test set, the RF model achieved an accuracy of 0.714 and an AUC of 0.750 (95% CI, 0.702-0.796). SHAP's feature impact analysis highlighted that maternal age, paternal age, time to blastocyst (tB), and day 5 morphology grade significantly impacted the predictive model. In addition, LIME offered specific case-ploidy prediction probabilities, revealing the model's assigned values for each variable within a finite range.

CONCLUSION

The model highlights the potential of using XAI algorithms to enhance ploidy prediction, optimize embryo selection as patient-centric consultation, and provides reliability and transparent insights into the decision-making process.

Developing and validating a prediction model of live birth following single vitrified-warmed blastocyst transfer

RESEARCH QUESTION

Can the developed clinical prediction model offer an accurate estimate of the likelihood of live birth, involving blastocyst morphology and vitrification day after single vitrified-warmed blastocyst transfer (SVBT), and therefore assist clinicians and patients?

STUDY DESIGN

Retrospective cohort study conducted at a Spanish university-based reproductive medicine unit (2017-2021) including consecutive vitrified-warmed blastocysts from IVF cycles. A multivariable logistic regression incorporated key live birth predictors: vitrification day, embryo score, embryo ploidy status and clinically relevant variables, i.e. maternal age.

RESULTS

The training set involved 1653 SVBT cycles carried out between 2017 and 2020; 592 SVBT cycles from 2021 constituted the external validation dataset. The model revealed that female age and embryo characteristics, including overall quality and blastulation day, is linked to live birth rate in SVBT cycles. Stratification by vitrification day and quality (from day-5A to day-6 C blastocysts) applied to genetically tested and untested embryos. The model's area under the curve was 0.66 (95% CI 0.64 to 0.69) during development and 0.65 (95% CI 0.61 to 0.70) in validation, denoting moderate discrimination. Calibration plots showed strong agreement between predicted and observed probabilities.

CONCLUSION

By incorporating essential predictors such as vitrification day, embryo morphology grade, age and preimplantation genetic testing for aneuploidy usage, this predictive model offers valuable guidance to clinicians and patients, enabling accurate forecasts of live birth rates for any given vitrified blastocyst within SVBT cycles. Additionally, it serves as a potentially indispensable laboratory tool, aiding in selecting the most promising blastocysts for optimal outcomes.

Preimplantation genetic testing: A narrative review

Preimplantation genetic testing (PGT) is a diagnostic procedure that has become a powerful complement to assisted reproduction techniques. PGT has numerous indications, and there is a wide range of techniques that can be used, each with advantages and limitations that should be considered before choosing the more adequate one. In this article, it is reviewed the indications for PGT, biopsy and diagnostic technologies, along with their evolution, while also broaching new emerging methods.

Gestational carrier cycles: embryology trends, national guideline compliance, and resultant perinatal outcomes in the United States, 2014-2020

BACKGROUND

The increased use of gestational carriers has expanded family-building opportunities for people and couples unable to carry pregnancies on their own. National American Society of Reproductive Medicine guidelines for gestational carriers have changed over time to reflect advances in reproductive technology and mounting evidence supporting the medical benefits associated with singleton gestations.

OBJECTIVE

Assess changes in gestational carrier cycle practice patterns and resultant pregnancy outcomes in the United States in relation to changing national American Society of Reproductive Medicine guidelines, which changed in 2013 and 2017.

STUDY DESIGN

This retrospective study used data from the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System and included all cycles that were reported from 2014-2020 involving an embryo transfer to a gestational carrier. Binomial regression models evaluated trends in preimplantation genetic testing for aneuploidy, American Society of Reproductive Medicine guideline adherence, number of embryos transferred, and pregnancy outcomes over time.

RESULTS

Of the 40,177 gestational carrier transfer cycles from 2014-2020, there was a significant increase in frozen-thawed cycles (41.3% increase), use of assisted hatching (53.4% increase), intracytoplasmic sperm injection (50.0% increase), and preimplantation genetic testing for aneuploidy (155.7% increase). The likelihood of preimplantation genetic testing for aneuploidy was higher in 2020 than in 2014 for autologous oocyte transfers to gestational carriers, both for those aged ≥38 years (adjusted relative risk, 2.38 [95% confidence interval, 2.11-2.70]) and than those aged <38 years (adjusted relative risk, 2.85 [95% confidence interval, 2.58-3.15]). As preimplantation genetic testing for aneuploidy usage increased, single embryo transfer rose for both autologous (adjusted relative risk, 2.22 [95% confidence interval, 1.94-2.50]) and donor cycles (relative risk, 1.91 [95% confidence interval, 1.81-2.02]). This shift toward single embryo transfer corresponded with a decrease in multiple embryo transfer by 79.2% and subsequent decreases in multiple gestations by 68.8% in donor and 73.6% in autologous oocyte cycles from 2014-2020. Gestational carrier cycles remained highly adherent to changing American Society of Reproductive Medicine guidelines throughout the study period. Among live births, there was a 19.4% and 7.9% increase in term deliveries among donor and autologous oocyte cycles, respectively, from 2014 to 2020.

CONCLUSION

Practice patterns have drastically changed throughout the study period, with major increases in the use of preimplantation genetic testing for aneuploidy, intracytoplasmic sperm injection, assisted hatching, and frozen transfers. In response to changing American Society of Reproductive Medicine guidelines, the use of multiple embryo transfers has decreased for gestational carrier cycles with subsequent decreases in multiple gestations and miscarriages and slight increases in live birth rates.

The comparision among euploidy of preimplantation blastocysts in different controlled ovary stimulation (COH) protocols

PURPOSE

To compare differences in euploidy rates for blastocysts in preimplantation genetic testing for aneuploidy (PGT-A) cycles after gonadotropin-releasing hormone agonist (GnRH-a) long and short protocols, GnRH-antagonist (GnRH-ant) protocol, progestin-primed ovarian stimulation and mild stimulation protocols, and other ovary stimulation protocols.

METHODS

This was a retrospective cohort study from the Assisted Reproductive Medicine Department of Shanghai First Maternity and Infant Hospital. A total of 1657 PGT-A cycles with intracytoplasmic sperm injection after different controlled ovary hyperstimulation protocols were analyzed, and a total of 3154 embryos were biopsied. Differences in euploidy rate per embryo biopsied, embryo euploidy rate per oocyte retrieved and cycle cancellation rate were compared.

RESULTS

For the PGT-A cycles, the euploidy rate per embryo biopsied was lower in the GnRH-ant protocol than in the GnRH-a long protocol (53.26 vs. 58.68%, respectively). Multiple linear regression showed that the GnRH-ant protocol was associated with a lower euploidy rate per embryo biopsied (β =  -0.079, p = 0.011). The euploidy rate per embryo biopsied was not affected by total gonadotropin dosage, duration of stimulation and number of oocytes retrieved. The embryo euploidy rate per oocyte retrieved was similar in all protocols and was negatively correlated with the total number of oocytes retrieved (β =  -0.003, p = 0.003).

CONCLUSION

Compared with the GnRH-a long protocol, the GnRH-ant protocol was associated with a lower euploidy rate per embryo biopsied. The total gonadotropin dosage, duration of stimulation and number of oocytes retrieved did not appear to significantly influence euploidy rates.

Double vitrification and warming of blastocysts does not affect pregnancy, miscarriage or live birth rates

RESEARCH QUESTION

Does double blastocyst vitrification and warming affect pregnancy, miscarriage or live birth rates, or birth outcomes, from embryos that have undergone preimplantation genetic testing for aneuploidies (PGT-A) testing?

DESIGN

This retrospective observational analysis of embryo transfers was performed at a single centre between January 2017 and August 2022. The double-vitrification group included frozen blastocysts that were vitrified after 5-7 days of culture, warmed, biopsied (either once or twice) and re-vitrified. The single vitrification (SV) group included fresh blastocysts that were biopsied at 5-7 days and then vitrified.

RESULTS

A comparison of the 84 double-vitrification blastocysts and 729 control single-vitrification blastocysts indicated that the double-vitrification embryos were frozen later in development and had expanded more than the single-vitrification embryos. Of the 813 embryo transfer procedures reported, 452 resulted in the successful delivery of healthy infants (56%). There were no significant differences between double-vitrification and single-vitrification embryos in the pregnancy, miscarriage or live birth rates achieved after single-embryo transfer (55% versus 56%). Logistic regression indicated that while reduced live birth rates were associated with increasing maternal age at oocyte collection, longer culture prior to freezing and lower embryo quality, double vitrification was not a significant predictor of live birth rate.

CONCLUSIONS

Blastocyst double vitrification was not shown to impact pregnancy, miscarriage or live birth rates. Although caution is necessary due to the study size, no effects of double vitrification on miscarriage rates, birthweight or gestation period were noted. These data offer reassurance given the absence of the influence of double vitrification on all outcomes after PGT-A.

Comparison of Fetal Crown-Rump Length Measurements between Thawed and Fresh Embryo Transfer

Background and Objectives: Neonates born from thawed embryo transfers tend to have a significantly higher birthweight compared to those from fresh embryo transfers. The aim of this study was to compare the crown-rump length (CRL) between thawed and fresh embryos to investigate the potential causes of different growth patterns between them. Materials and Methods: This was a retrospective study (July 2010-December 2023) conducted at the Third Department of Obstetrics and Gynecology, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece. In total, 3082 assisted reproductive technology (ART) pregnancies (4044 embryos) underwent a routine scan at 11+0-13+6 gestational weeks and were included in the study. Maternal age, the type of embryo transfer (thawed vs. fresh, donor vs. their own oocytes), CRL, twin and singleton gestations were analyzed. Results: The mean maternal age in thawed was significantly higher than in fresh embryos (39.8 vs. 35.8 years, p-value < 0.001). The mean CRL z-score was significantly higher in thawed compared to fresh embryo transfers (0.309 vs. 0.199, p-value < 0.001). A subgroup analysis on singleton gestations showed that the mean CRL z-score was higher in thawed blastocysts compared to fresh (0.327 vs. 0.215, p-value < 0.001). Accordingly, an analysis on twins revealed that the mean CRL z-score was higher in thawed blastocysts (0.285 vs. 0.184, p-value: 0.015) and in oocytes' recipients compared to own oocytes' cases (0.431 vs. 0.191, p-value: 0.002). Conclusions: The difference in CRL measurements between thawed and fresh embryos may be a first indication of the subsequent difference in sonographically estimated fetal weight and birthweight. This finding highlights the need for additional research into the underlying causes, including maternal factors and the culture media used.

Clinical outcomes of preimplantation genetic testing for aneuploidy in high-risk patients: a retrospective cohort study

OBJECTIVE

The purpose of this study was to evaluate the impact of preimplantation genetic testing for aneuploidy (PGT-A) on clinical outcomes among high-risk patients.

METHODS

This retrospective study involved 1,368 patients and the same number of cycles, including 520 cycles with PGT-A and 848 cycles without PGT-A. The study participants comprised women of advanced maternal age (AMA) and those affected by recurrent implantation failure (RIF), recurrent pregnancy loss (RPL), or severe male factor infertility (SMF).

RESULTS

PGT-A was associated with significant improvements in the implantation rate (IR) and the ongoing pregnancy rate/live birth rate (OPR/LBR) per embryo transfer cycle in the AMA (39.3% vs. 16.2% [p<0.001] and 42.0% vs. 21.8% [p<0.001], respectively), RIF (41.7% vs. 22.0% [p<0.001] and 47.0% vs. 28.6% [p<0.001], respectively), and RPL (45.6% vs. 19.5% [p<0.001] and 49.1% vs. 24.2% [p<0.001], respectively) groups, as well as the IR in the SMF group (43.3% vs. 26.5%, p=0.011). Additionally, PGT-A was associated with lower overall incidence rates of early pregnancy loss in the AMA (16.7% vs. 34.3%, p=0.001) and RPL (16.7% vs. 50.0%, p<0.001) groups. However, the OPR/LBR per total cycle across all PGT-A groups did not significantly exceed that for the non-PGT-A groups.

CONCLUSION

PGT-A demonstrated beneficial effects in high-risk patients. However, our findings indicate that these benefits are more pronounced in carefully selected candidates than in the entire high-risk patient population.

Mosaic embryo transfer versus additional IVF with PGT-A Cycle: a decision model comparing live birth rate and cost

PURPOSE

To evaluate the relative live birth rate and net cost difference between mosaic embryo transfer and an additional cycle of IVF with PGT-A for patients whose only remaining embryos are non-euploid.

METHODS

A decision analytic model was designed with model parameters varying based on discrete age cutoffs (<35, 35-37, 38-39, 40-42, 43-44, >44). Model inputs included probabilities of successful IVF, clinical pregnancy, and live birth as well as costs of IVF with PGT-A, embryo transfer, live birth, amniocentesis, and dilation and curettage. All costs were modeled from the healthcare system perspective and adjusted for inflation to 2023 $USD. Model outcomes were sub-stratified by degree and type of mosaicism.

RESULTS

For patients younger than 43, an additional cycle of IVF with PGT-A resulted in a higher relative live birth rate (<35, +20%; 35-37, +15%; 38-39, +17%; 40-42, +6%; average, +14.5%) compared to mosaic embryo transfer with an average additional cost of $16,633. For patients older than 42, mosaic embryo transfer resulted in a higher live birth rate (43-44, +5%; >44, +3%; average, +4%) while on average costing $9572 less than an additional cycle of IVF with PGT-A.

CONCLUSION

Mosaic embryo transfers are a superior alternative to an additional cycle of IVF with PGT-A for patients older than 42 whose only remaining embryos are non-euploid. Mosaic embryo transfers also should be considered for patients younger than 42 who are unable to pursue additional autologous IVF cycles. Counseling and care should be personalized to individual patients and embryos.

Optimizing non-invasive preimplantation genetic testing: investigating culture conditions, sample collection, and IVF treatment for improved non-invasive PGT-A results

PURPOSE

This study aimed to optimize the non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) in the laboratory by comparing two collection timing of the spent culture medium (SCM), two embryo rinsing protocols, and the use of conventional insemination instead of intracytoplasmic sperm injection (ICSI).

METHODS

Results of two embryo rinsing methods (one-step vs sequential) and SCM collected on day 5 vs day 6 after retrieval were compared against trophectoderm (TE) biopsies as reference. Results from day 6 SCM in cycles fertilized by conventional insemination were compared with PGT-A using ICSI.

RESULTS

The rate of concordance was higher in day 6 samples than in day 5 samples when the sequential method was used, in terms of total concordance (TC; day 6 vs day 5: 85.0% vs 60.0%, p = 0.0228), total concordance with same sex (TCS, 82.5% vs 28,0%, p < 0.0001), and full concordance with same sex (FCS, 62.5% vs 24.0%, p = 0.0025). The sequential method significantly out-performed the one-step method when SCM were collected on day 6 (sequential vs one-step, TC: 85.0% vs 64.5%, p = 0.0449; TCS: 82.5% vs 54.8%, p = 0.0113; FCS: 62.5% vs 25.8%, p = 0.0021). There was no significant difference in niPGT-A results between cycles fertilized by the conventional insemination and ICSI.

CONCLUSION

We have shown a higher concordance rate when SCM was collected on day 6 and the embryos were rinsed in a sequential manner. Comparable results of niPGT-A when oocytes were fertilized by conventional insemination or ICSI. These optimization steps are important prior to commencement of a randomized trial in niPGT-A.

The Association between Embryo Development and Chromosomal Results from PGT-A in Women of Advanced Age: A Prospective Cohort Study

Embryo morphology and morphokinetics have been studied for their association with euploid embryos. However, the results are controversial, especially in the advanced-aged women group, when the risk of aneuploidy increases significantly. This prospective cohort study evaluated the association between embryo development between day-3 cleavage and day-5 blastocyst stages and euploidy rates, determined using preimplantation genetic testing for aneuploidy (PGT-A). Embryos from women aged 35 years and above who underwent intracytoplasmic sperm injections and PGT-A were studied. Day-3 cleavage-stage embryos were evaluated for their cell number, and day-5 blastocyst-stage embryos were evaluated for their morphological grade. Embryo development from day 3 to day 5 was categorized as either good or poor development and evaluated for its association with the PGT-A results. We evaluated 325 embryos from 101 infertile couples. It was found that 55.17% of blastocysts with good development and 29.83% with poor development were euploid. A significant association was found between embryo development and euploidy rates in advanced-aged women (p < 0.001). Also, there were significantly higher rates of euploid embryos with good blastocyst morphological grades, especially blastocyst expansion grades and trophectoderm grades. In conclusion, embryo morphokinetics shows promising results in predicting euploidy in advanced female age.

Developmental competence and neonatal outcomes of nonpronuclear zygotes following single vitrified-warmed blastocyst transfers using propensity score matching analysis

PURPOSE

To investigate developmental competence and neonatal outcomes of nonpronuclear (0PN) zygotes following single vitrified-warmed blastocyst transfers (VBT).

METHODS

The clinical, laboratorial and neonatal data of 996 patients with ≤ 38 years who underwent blastocyst culture and single VBT were retrospectively analyzed. The pregnancy and neonatal outcomes of VBT were compared between 0PN and 2PN blastocysts using propensity score matching (PSM). Moreover, Day 3 (D3) embryo development and blastocyst formation were compared between 0PN and 2PN zygotes.

RESULTS

There were no significant differences in clinical pregnancy rate (CPR), live birth rate (LBR) and neonatal outcomes of VBT between the 0PN and 2PN blastocysts irrespectively of whether PSM was used. However, early abortion rate (EAR) was higher in blastocysts from 0PN D3 embryos > 10 cells (p < 0.05) before PSM. Moreover, the early developmental competence of 0PN zygotes was different from that of 2PN zygotes presenting higher percentages of D3 embryos ≤ 6 cells (p < 0.01) and > 10 cells (p < 0.01), lower available blastocyst formation rate (ABFR) (p < 0.01) and good-quality blastocyst formation rate (GBFR) (p < 0.01) in D3 embryos with 4-6 cells. ABFR and GBFR increased with cell number when compared among embryos with 4-6 cells, 7-10 cells and > 10 cells, irrespectively of 0PN or 2PN embryos.

CONCLUSION

The early developmental competence of 0PN zygotes was different from that of 2PN zygotes, but did not influence pregnancy and neonatal outcomes following VBT. ABFR and GBFR increased with cell number, irrespectively of 0PN or 2PN embryos.

Polygenic embryo screening: are there potential maternal and fetal harms?

Polygenic embryo screening (PES) and its derivate the Embryo Health Score (EHS) have generated interest in both infertile and fertile populations due to their potential ability to select embryos with a reduced risk of disease and improved long-term health outcomes. Concerns have been raised regarding the potential harms of IVF itself, including possible epigenetic changes that may affect the health of the offspring in late adulthood, which are not fully captured in the EHS calculation. Knowledge of the potential impacts of the trophectoderm biopsy, which is a key component of the PES procedure, on the offsprings' health is limited by the heterogeneity of the population characteristics used in the published studies. Nonetheless, the literature suggests a possible increased risk of preterm delivery, birth defects and pre-eclampsia after trophectoderm biopsy. Overall, the risks of PES for prenatal and postnatal health remain uncertain, and further research is needed. Counselling patients regarding these risks before considering PES is important, to provide an understanding of the risks and benefits. This review aims to highlight some of these issues, the need for continued investigation in this area, and the importance of informed decision-making in the context of PES.

A Controversial Old Topic Revisited: Should Diagnostic Hysteroscopy Be Routinely Performed Prior to the First IVF Cycle? A Systematic Review and Updated Meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to analyze the impact of performing diagnostic hysteroscopy before the first in vitro fertilization (IVF) cycle on the clinical pregnancy rate and live birth.

DATA SOURCES

PubMed-MEDLINE, Embase, Web of Science, The Cochrane Library, Gynecology and Fertility Specialized Register of Controlled Trials, and Google Scholar were consulted from inception to June 2022 using combinations of the relevant Medical Subject Headings terms and keywords. The search included major clinical trial registries such as ClinicalTrials.gov and the European EudraCT registry without language restrictions. In addition, manual cross-reference searches were also performed.

METHODS OF STUDY SELECTION

All randomized and controlled clinical trials, prospective and retrospective cohort studies, and case-control studies comparing the probability of pregnancy and live birth among patients who underwent diagnostic hysteroscopy with possible treatment of any abnormal findings before the IVF cycle and patients who underwent the IVF cycle directly have been considered for inclusion. Studies with insufficient information on the results of interest or without the necessary information to perform the pooled analysis, those without a control group or with end points considered different than those of interest, were excluded. The review protocol was registered in PROSPERO (CRD42022354764).

TABULATION, INTEGRATION, AND RESULTS

A total of 12 studies were included in the quantitative synthesis, reporting the reproductive outcomes of 5056 patients undergoing ART treatment for the first time. Selected studies included 6 randomized controlled trials, 1 prospective cohort study, 3 retrospective cohort studies, and 2 case-control studies. The likelihood of clinical pregnancy of patients undergoing hysteroscopy before IVF was significantly higher than those without hysteroscopy (odds ratio [OR], 1.49; 95% confidence CI 1.16-1.91; I2 = 69%). (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.22-1.88; I2 59%). Eight studies included live birth rate; no statistically significant differences were found between the 2 groups for this outcome (OR,1.24; 95% CI, 0.94-1.64; I2 = 62%). Subsequently, a sensitivity analysis was performed, including only randomized clinical trials. Clinical pregnancy OR of patients undergoing hysteroscopy before starting the IVF cycle remained significantly higher than the control group (OR,1.62, 95% CI, 1.15-2.29; I2 = 62%). Risk of bias assessment was performed using the Grading of Recommendations Assessment, Development, and Evaluation.

CONCLUSION

The available scientific evidence suggests that performing routine hysteroscopy before the first IVF attempt improves the clinical pregnancy rate; however, the live birth rate is unaffected.

Single-cell multi-omics sequencing reveals chromosome copy number inconsistency between trophectoderm and inner cell mass in human reconstituted embryos after spindle transfer

STUDY QUESTION

Is the chromosome copy number of the trophectoderm (TE) of a human reconstituted embryos after spindle transfer (ST) representative of the inner cell mass (ICM)?

SUMMARY ANSWER

Single-cell multi-omics sequencing revealed that ST blastocysts have a higher proportion of cell lineages exhibiting intermediate mosaicism than conventional ICSI blastocysts, and that the TE of ST blastocysts does not represent the chromosome copy number of ICM.

WHAT IS KNOWN ALREADY

Preimplantation genetic testing for aneuploidy (PGT-A) assumes that TE biopsies are representative of the ICM, but the TE and ICM originate from different cell lineages, and concordance between TE and ICM is not well-studied, especially in ST embryos.

STUDY DESIGN, SIZE, DURATION

We recruited 30 infertile women who received treatment at our clinic and obtained 45 usable blastocysts (22 from conventional ICSI and 23 reconstituted embryos after ST). We performed single-cell multi-omics sequencing on all blastocysts to predict and verify copy number variations (CNVs) in each cell. We determined the chromosome copy number of each embryo by analysing the proportion of abnormal cells in each blastocyst. We used the Bland-Altman concordance and the Kappa test to evaluate the concordance between TE and ICM in the both groups.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was conducted at a public tertiary hospital in China, where all the embryo operations, including oocytes retrieval, ST, and ICSI, were performed in the embryo laboratory. We utilized single-cell multi-omics sequencing technology at the Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, to analyse the blastocysts. Transcriptome sequencing was used to predict the CNV of each cell through bioinformatics analysis, and the results were validated using the DNA methylation library of each cell to confirm chromosomal normalcy. We conducted statistical analysis and graphical plotting using R 4.2.1, SPSS 27, and GraphPad Prism 9.3.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean age of the volunteers, the blastocyst morphology, and the developmental ratewere similar in ST and ICSI groups. The blastocysts in the ST group had some additional chromosomal types that were prone to variations beyond those enriched in the blastocysts of the ICSI group. Finally, both Bland-Altman concordance test and kappa concordancetest showed good chromosomal concordance between TE and ICM in the ICSI blastocysts (kappa = 0.659, P < 0.05), but not in ST blastocysts (P = 1.000), suggesting that the TE in reconstituted embryos is not representative of ICM. Gene functional annotation (GO and KEGG analyses) suggests that there may be new or additional pathways for CNV generation in ST embryos compared to ICSI embryos.

LIMITATIONS, REASONS FOR CAUTION

This study was mainly limited by the small sample size and the limitations of single-cell multi-omics sequencing technology. To select eligible single cells, some cells of the embryos were eliminated or not labelled, resulting in a loss of information about them. The findings of this study are innovative and exploratory. A larger sample size of human embryos (especially ST embryos) and more accurate molecular genetics techniques for detecting CNV in single cells are needed to validate our results.

WIDER IMPLICATIONS OF THE FINDINGS

Our study justifies the routine clinical use of PGT-A in ICSI blastocysts, as we found that the TE is a good substitute for ICM in predicting chromosomal abnormalities. While PGT-A is not entirely accurate, our data demonstrate good clinical feasibility. This trial was able to provide correct genetic counselling to patients regarding the reliability of PGT-A. Regarding ST blastocysts, the increased mosaicism rate and the inability of the TE to represent the chromosomal copy number of the ICM are both biological characteristics that differentiate them from ICSI blastocysts. Currently, ST is not used clinically on a large scale to produce blastocysts. However, if ST becomes more widely used in the future, our study will be the first to demonstrate that the use of PGT-A in ST blastocysts may not be as accurate as PGT-A for ICSI blastocysts.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the National Key R&D Program of China (2018YFA0107601) and the National Key R&D Program of China (2018YFC1003003). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Exploring the efficacy and beneficial population of preimplantation genetic testing for aneuploidy start from the oocyte retrieval cycle: a real-world study

BACKGROUND

Preimplantation genetic testing for aneuploidy (PGT-A) is widely used as an embryo selection technique in in vitro fertilization (IVF), but its effectiveness and potential beneficiary populations are unclear.

METHODS

This retrospective cohort study included patients who underwent their first oocyte retrieval cycles at CITIC-Xiangya between January 2016 and November 2019, and the associated fresh and thawed embryo transfer cycles up to November 30, 2020. PGT-A (PGT-A group) and intracytoplasmic sperm injection (ICSI)/IVF (non-PGT-A group) cycles were included. The numbers of oocytes and embryos obtained were unrestricted. In total, 60,580 patients were enrolled, and baseline data were matched between groups using 1:3 propensity score matching. Sensitivity analyses, including propensity score stratification and traditional multivariate logistic regression, were performed on the original unmatched cohort to check the robustness of the overall results. Analyses were stratified by age, body mass index, ovarian reserve/responsiveness, and potential indications to explore benefits in subgroups. The primary outcome was cumulative live birth rate (CLBR). The other outcomes included live birth rate (LBR), pregnancy loss rate, clinical pregnancy rate, pregnancy complications, low birth weight rate, and neonatal malformation rate.

RESULTS

In total, 4195 PGT-A users were matched with 10,140 non-PGT-A users. A significant reduction in CLBR was observed in women using PGT-A (27.5% vs. 31.1%; odds ratio (OR) = 0.84, 95% confidence interval (CI) 0.78-0.91; P < 0.001). However, women using PGT-A had higher first-transfer pregnancy (63.9% vs. 46.9%; OR = 2.01, 95% CI 1.81-2.23; P < 0.001) and LBR (52.6% vs. 34.2%, OR = 2.13, 95% CI 1.92-2.36; P < 0.001) rates and lower rates of early miscarriage (12.8% vs. 20.2%; OR = 0.58, 95% CI 0.48-0.70; P < 0.001), preterm birth (8.6% vs 17.3%; P < 0.001), and low birth weight (4.9% vs. 19.3%; P < 0.001). Moreover, subgroup analyses revealed that women aged ≥ 38 years, diagnosed with recurrent pregnancy loss or intrauterine adhesions benefited from PGT-A, with a significant increase in first-transfer LBR without a decrease in CLBR.

CONCLUSION

PGT-A does not increase and decrease CLBR per oocyte retrieval cycle; nonetheless, it is effective in infertile populations with specific indications. PGT-A reduces complications associated with multiple gestations.

Evaluation of pre-implantation genetic testing for aneuploidy outcomes in patients without infertility undergoing in vitro fertilization compared to infertile controls

PURPOSE

To evaluate pre-implantation genetic testing for aneuploidy (PGT-A) outcomes in patients without infertility compared to infertile patients.

METHODS

We performed a retrospective cohort study of all patients without an infertility diagnosis ("fertile" patients) who utilized PGT-A at a large university-affiliated fertility center between 2016 and 2021. Fertile patients were 1-to-3 matched to infertile controls by age and number of oocytes retrieved. The primary outcome was blastocyst aneuploidy rate. Secondary outcomes included ovarian reserve markers, laboratory outcomes, and other PGT-A outcomes [rates of euploidy, mosaicism, and potentially transferrable (euploid + mosaic) embryos].

RESULTS

283 fertile and 849 infertile patients were included. Median age, anti-Mullerian hormone, and day 2 estradiol levels were equivalent among groups; day 2 follicle-stimulating hormone levels were higher in fertile patients (6.9 vs. 6.5 IU/mL, p < 0.01). The aneuploidy rate was similar among fertile and infertile patients (33.7% vs. 31.8%, p = 0.11); the euploidy rate was higher (50.8% vs. 47.0%, p < 0.01), and the mosaicism rate was lower in fertile patients (13.3% vs. 19.2%, p < 0.01). The rate of transferrable embryos was similar among groups (64.0% vs. 66.3%, p = 0.07), as was the percentage of patients yielding ≥ 1 euploid embryo (90.1% vs. 87.3%, p = 0.25). When controlling for significant covariates, multiple linear regression showed that aneuploidy rate was equivalent in both cohorts.

CONCLUSION

Aneuploidy rate was similar in fertile and infertile patients. Fertile patients had slightly higher euploidy and lower mosaicism than infertile patients. Still, compared to fertile patients, infertile patients had equivalent rates of transferrable embryos and were just as likely to yield ≥ 1 euploid embryo.

Systematic review and meta-analysis: does pre-implantation genetic testing for aneuploidy at the blastocyst stage improve live birth rate?

PURPOSE

To establish if preimplantation genetic testing for aneuploidy (PGT-A) at the blastocyst stage improves the composite outcome of live birth rate and ongoing pregnancy rate per embryo transfer compared to conventional morphological assessment.

METHODS

A systematic literature search was conducted using PubMed, EMBASE and Cochrane database from 1st March 2000 until 1st March 2022. Studies comparing reproductive outcomes following in vitro fertilisation using comprehensive chromosome screening (CCS) at the blastocyst stage with traditional morphological methods were evaluated.

RESULTS

Of the 1307 citations identified, six randomised control trials (RCTs) and ten cohort studies fulfilled the inclusion criteria. The pooled data identified a benefit between PGT-A and control groups in the composite outcome of live birth rate and ongoing pregnancy per embryo transfer in both the RCT (RR 1.09, 95% CI 1.02-1.16) and cohort studies (RR 1.50, 95% CI 1.28-1.76). Euploid embryos identified by CCS were more likely to be successfully implanted amongst the RCT (RR 1.20, 95% CI 1.10-1.31) and cohort (RR 1.69, 95% CI 1.29-2.21) studies. The rate of miscarriage per clinical pregnancy is also significantly lower when CCS is implemented (RCT: RR 0.73, 95% CI 0.56-0.96 and cohort: RR 0.48, 95% CI 0.32-0.72).

CONCLUSIONS

CCS-based PGT-A at the blastocyst biopsy stage increases the composite outcome of live births and ongoing pregnancies per embryo transfer and reduces the rate of miscarriage compared to morphological assessment alone. In view of the limited number of studies included and the variation in methodology between studies, future reviews and analyses are required to confirm these findings.

Outcomes of random-start letrozole protocol with PGT-A in women with breast cancer undergoing fertility preservation

PURPOSE  : To compare the cycle characteristics and outcomes of random-start-controlled ovarian stimulation (RSCOS) protocols to the outcomes of standard-start-controlled ovarian stimulation (SSCOS) cycles and to report the utility of PGT-A in these cycles.

METHODS

One hundred and seventeen who underwent SSCOS and 39 who underwent RSCOS for oocyte and/or embryo cryopreservation before breast cancer chemotherapy were retrospectively evaluated. Mean number of embryos and blastocyst euploidy rates were the main outcome measures.

RESULTS

A majority of RSCOS cycles were initiated in the luteal phase (66.6% luteal vs. 33.3% follicular). While the total dose of gonadotropins was significantly higher in the RSCOS (3720.8 ± 1230.0 vs. 2345.1 ± 803.6 IU; P < 0.001), the mean number of mature oocytes and embryos was similar to SSCOS. However, there was a trend for a higher number of mean embryos with luteal start RSCOS (6.9 ± 2.7 in late follicular start vs. 9.4 ± 4.2 in luteal start, P = 0.08). PGT-A was performed in 48% of the cases that underwent embryo cryopreservation in RSCOS (12 women, mean age = 35.3 ± 4.1; 87 blastocysts), revealing a euploidy rate of 36.2 ± 22.3% per patient. This rate was comparable to a 45% aneuploidy rate from similarly aged published data. Of the 7 RSCOS patients who returned for frozen embryo transfer, 5 delivered and one has an ongoing pregnancy, while in SSCOS, 18 out of 40 cycles resulted in live birth.

CONCLUSION

Our data suggests that RSCOS fertility preservation cycle outcomes are similar to those with SSCOS and result in age-appropriate euploidy rates.

Medroxyprogesterone acetate: an alternative to GnRH-antagonist in oocyte vitrification for social fertility preservation and preimplantation genetic testing for aneuploidy

RESEARCH QUESTION

Can medroxyprogesterone acetate (MPA) be used as a pituitary suppressor instead of a gonadotrophin releasing hormone (GnRH) antagonist during ovarian stimulation in elective fertility preservation and preimplantation genetic testing for aneuploidy (PGT-A) cycles?

DESIGN

A multicentre, retrospective, observational, cohort study conducted in 11 IVIRMA centres affiliated to private universities. Of a total of 1652 cycles of social fertility preservation, 267 patients were stimulated using a progestin-primed ovarian stimulation protocol (PPOS), and 1385 patients received a GnRH antagonist. In the PGT-A cycles, 5661 treatments were analysed: 635 patients received MPA and 5026 patients received GnRH antagonist. A further 66 fertility preservation and 1299 PGT-A cycles were cancelled. All cycles took place between June 2019 and December 2021.

RESULTS

In the social fertility preservation cycles, the number of mature oocytes vitrified in MPA was similar to the number of those treated with an antagonist, a trend that was seen regardless of age (≤35 or >35 years). In the PGT-A cycles, no differences were found in number of metaphase II, two pronuclei, number of biopsied embryos (4.4 ± 3.1 versus 4.5 ± 3.1), rate of euploidy (57.9% versus 56.4%) or ongoing pregnancy rate (50.4% versus 47.1%, P = 0.119) between the group receiving MPA versus a GnRH antagonist, whereas the clinical miscarriage rate was higher in the antagonist group (10.4% versus 14.8%, P = 0.019).

CONCLUSIONS

Administration of PPOS yields similar results to GnRH antagonists in oocytes retrieved, rate of euploid embryos and clinical outcome. Hence, PPOS can be recommended for ovarian stimulation in social fertility preservation and PGT-A cycles, as it allows greater patient comfort.

Rapid and non-invasive diagnostic techniques for embryonic developmental potential: a metabolomic analysis based on Raman spectroscopy to identify the pregnancy outcomes of IVF-ET

The non-invasive and rapid assessment of the developmental potential of embryos is of great clinical importance in assisted reproductive technology (ART). In this retrospective study, we analyzed the metabolomics of 107 samples provided by volunteers and utilized Raman spectroscopy to detect the substance composition in the discarded culture medium of 53 embryos resulting in successful pregnancies and 54 embryos that did not result in pregnancy after implantation. The culture medium from D3 cleavage-stage embryos was collected after transplantation and a total of 535 (107 × 5) original Raman spectra were obtained. By combining several machine learning methods, we predicted the developmental potential of embryos, and the principal component analysis-convolutional neural network (PCA-CNN) model achieved an accuracy rate of 71.5%. Furthermore, the chemometric algorithm was used to analyze seven amino acid metabolites in the culture medium, and the data showed significant differences in tyrosine, tryptophan, and serine between the pregnancy and non-pregnancy groups. The results suggest that Raman spectroscopy, as a non-invasive and rapid molecular fingerprint detection technology, shows potential for clinical application in assisted reproduction.

PGT-A improved singleton live birth rate among all age groups of women who underwent elective single blastocyst transfer: a single-centre retrospective study

PURPOSE

This study assessed the difference in singleton live birth rate (SLBR) between preimplantation genetic testing for aneuploidy (PGT-A) and non-PGT in patients undergoing elective single frozen blastocyst transfer (eSFBT).

METHODS

This retrospective cohort study evaluated 10,701 cycles of eSFBT, including PGT-A (n = 3125) and non-PGT (n = 7576). Cycles were further stratified according to age at retrieval. The main outcome was SLBR; secondary outcomes were clinical pregnancy, conception rates, and multiple live birth rate. Confounders were adjusted using multivariable logistic regression models, and the trend test was performed using the general linear model.

RESULTS

SLBR was negatively correlated with age in the non-PGT group (p-trend < 0.001) but not in PGT-A group (p-trend = 0.974). Stratified by the age, SLBR were significantly different between two groups except for the 20-24-year-old group: PGT-A vs non-PGT group in 20-24, 25-29, 30-34, 35-39 and ≥ 40-year-old subgroups were, 53.5% vs 53.2%, 53.5% vs 48.0%, 53.5% vs 43.1%, 53.3% vs 32.5%, and 42.9% vs 17.6%, respectively. In addition, after adjusting for potential confounders, SLBR still remained significantly different in all age groups except in the youngest quartile (PGT-A vs non-PGT group, 20-24: adjusted odds ratio (aOR), 1.33, 95% CI, 0.92-1.92, p = 0.129; 25-29: aOR, 1.32, 95% CI, 1.14-1.52, p < 0.001; 30-34: aOR, 1.91, 95% CI, 1.65-2.20, p < 0.001; 35-39: aOR, 2.50, 95% CI, 1.97-3.17, p < 0.001; ≥ 40: aOR, 3.54, 95% CI, 1.66-7.55, p = 0.001).

CONCLUSION

PGT-A might improve SLBR among all age groups and play an increasingly important role in SLBR in older patients who underwent eSFBT.

Review of Endometrial Receptivity Array: A Personalized Approach to Embryo Transfer and Its Clinical Applications

Successful outcomes of in vitro fertilization (IVF) rely on both the formation of a chromosomally normal embryo and its implantation in a receptive endometrium. Pre-implantation genetic testing for aneuploidy (PGT-A) has been widely accepted as a tool to assess the viability of an embryo. In 2011, the endometrial receptivity array (ERA) was first published as a tool to determine when the endometrium is most receptive to an embryo, commonly referred to as the "window of implantation" (WOI). The ERA uses molecular arrays to assess proliferation and differentiation in the endometrium and screens for inflammatory markers. Unlike PGT-A, there has been dissent within the field concerning the efficacy of the ERA. Many studies that contest the success of the ERA found that it did not improve pregnancy outcomes in patients with an already-good prognosis. Alternatively, studies that utilized the ERA in patients with repeated implantation failure (RIF) and transfer of known euploid embryos demonstrated improved outcomes. This review aims to describe the ERA as a novel technique, review the various settings that the ERA may be used in, such as natural frozen embryo transfer (nFET) and hormone replacement therapy frozen embryo transfer (HRT-FET), and provide a summary of the recent clinical data for embryo transfers in patients with RIF utilizing the ERA.

Cost-effectiveness of preimplantation genetic testing for aneuploidy for women with subfertility in China: an economic evaluation using evidence from the CESE-PGS trial

BACKGROUND

There are a large number of infertile couples in China, but its treatment is notoriously expensive and not currently covered by insurance. The utility of preimplantation genetic testing for aneuploidy as an adjunct to in vitro fertilization has been debated.

OBJECTIVE

To investigate the cost-effectiveness of preimplantation genetic testing for aneuploidy (PGT-A) versus conventional technology in in vitro fertilization (IVF) from the perspective of the healthcare system in China.

METHODS

Following the exact steps in the IVF protocol, a decision tree model was developed, based on the data from the CESE-PGS trial and using cost scenarios for IVF in China. The scenarios were compared for costs per patient and cost-effectiveness. One-way sensitivity analysis and probabilistic sensitivity analysis were performed to confirm the robustness of the findings.

MAIN OUTCOME MEASURES

Costs per live birth, Costs per patient, Incremental cost-effectiveness for miscarriage prevention.

RESULTS

The average costs per live birth of PGT-A were estimated as ¥39230.71, which is about 16.8% higher than that of the conventional treatment. Threshold analysis revealed that PGT-A would need to increase the pregnancy rate of 26.24-98.24% or a cost reduction of ¥4649.29 to ¥1350.71 to achieve the same cost-effectiveness. The incremental costs per prevented miscarriage was approximately ¥45600.23. The incremental cost-effectiveness for miscarriage prevention showed that the willingness to pay would be ¥43422.60 for PGT-A to be cost-effective.

CONCLUSION

The present cost-effectiveness analysis demonstrates that embryo selection with PGT‑A is not suitable for routine applications from the perspective of healthcare providers in China, given the cumulative live birth rate and the high costs of PGT‑A.

Personalized versus standard frozen-thawed embryo transfer in IVF/ICSI cycles: a systematic review and meta-analysis

PURPOSE

To investigate whether personalized embryo transfer (pET) protocol guided by an endometrial receptivity array (ERA) can improve clinical outcomes of assisted reproduction.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane library for studies in which analytical comparisons of outcomes of pET and standard embryo transfer (sET) groups were undertaken. The references to the included studies were also manually searched. The primary outcome was clinical pregnancy rate (CPR), and the secondary outcomes were live birth rate (LBR), human chorionic gonadotropin (HCG) positivity, biochemical pregnancy rate (BPR), miscarriage rate (MR), implantation rate (IR), and ongoing pregnancy rate (OPR).

RESULTS

Ten studies were included in the meta-analysis, including one randomized controlled trial (RCT) and nine cohort studies. We observed no significant difference in the primary outcome of CPR between the pET and sET groups in unselected patients (RR = 1.07; 95% confidence interval [CI], 0.87-1.30; P = 0.53; I2 = 89%). In terms of secondary outcomes, we likewise noted no significant differences between the groups. Further subgroup analyses indicated that the pET protocol not only significantly reduced the MR for poor-prognosis patients, but it also reduced the CPR in donor cycles, elevated the BPR for good-prognosis patients, non-preimplantation genetic testing (PGT), and programmed cycles, and decreased the proportion of women showing HCG positivity in non-PGT cycles.

CONCLUSIONS

This meta-analysis revealed that ERA appears to possess limited guidance in embryo transfer. More high-quality RCTs are therefore needed to investigate the clinical validity and feasibility of ERA in the future.

Does PGT-A affect cumulative live birth rate?

PURPOSE OF REVIEW

Preimplantation genetic testing for the purpose of aneuploidy screening (PGT-A) has increased in use over the last decade.

RECENT FINDINGS

Whether PGT-A benefits all of the patients that choose to employ it has been a concern, as recent studies have highlighted a potential decrease in cumulative live birth rate (CLBR) for younger patients undergoing embryo transfer. However, there are limitations to many of these studies and the intended benefit of PGT-A, which is to aid as a selection tool, thus increasing the live birth rate per transfer, must not be ignored.

SUMMARY

PGT-A was never intended to increase CLBR. The purpose of PGT-A is to maximize the chance at live birth per transfer while minimizing the risk of clinical miscarriage, ongoing aneuploid pregnancy and futile transfers. However, if it harms CLBR in the process that has to be taken into consideration. This review will discuss PGT-A in terms of its benefits, risks, and how it has been shown to affect the cumulative live birth rate within in-vitro fertilization cycles.

Non-Coding RNAs as Biomarkers for Embryo Quality and Pregnancy Outcomes: A Systematic Review and Meta-Analysis

Despite advances in in vitro fertilization (IVF), there is still a lack of non-invasive and reliable biomarkers for selecting embryos with the highest developmental and implantation potential. Recently, small non-coding RNAs (sncRNAs) have been identified in biological fluids, and extracellular sncRNAs are explored as diagnostic biomarkers in the prediction of IVF outcomes. To determine the predictive role of sncRNAs in embryo quality and IVF outcomes, a systematic review and meta-analysis was performed. Articles were retrieved from PubMed, EMBASE, and Web of Science from 1990 to 31 July 2022. Eighteen studies that met the selection criteria were analyzed. In total, 22 and 47 different sncRNAs were found to be dysregulated in follicular fluid (FF) and embryo spent culture medium (SCM), respectively. MiR-663b, miR-454 and miR-320a in FF and miR-20a in SCM showed consistent dysregulation in two different studies. The meta-analysis indicated the potential predictive performance of sncRNAs as non-invasive biomarkers, with a pooled area under curve (AUC) value of 0.81 (95% CI 0.78, 0.844), a sensitivity of 0.79 (95% CI 0.72, 0.85), a specificity of 0.67 (95% CI 0.52, 0.79) and a diagnostic odds ratio (DOR) of 8 (95% CI 5, 12). Significant heterogeneity was identified among studies in sensitivity (I2  =  46.11%) and specificity (I2  =  89.73%). This study demonstrates that sncRNAs may distinguish embryos with higher developmental and implantation potentials. They can be promising non-invasive biomarkers for embryo selection in ART. However, the significant heterogeneity among studies highlights the demand for prospective multicenter studies with optimized methods and adequate sample sizes in the future.

Aneuploidy screening after preimplantation genetic testing: a national survey of physician knowledge and practice

PURPOSE

To assess the knowledge of generalist OB/GYN providers on aneuploidy screening recommendations for patients who utilized preimplantation genetic testing, and to survey providers' current practice habits.

METHODS

A 12-question survey was distributed by email to OB/GYN physicians in the USA. Demographic information was also collected.

RESULTS

A total of 178 survey responses were included for analysis. Sixty-seven percent correctly identified the current ACOG recommendation to offer additional aneuploidy screening/invasive diagnostic testing regardless of PGT status, and 66% said their practice is consistent with this recommendation. Ninety-one percent of responders correctly answered that in vitro fertilization does not always include PGT and 63% of responders were able to correctly identify the 3 available types of PGT. Thirty-three percent (n = 58) were attending physicians, and 67% (n = 120) were resident physicians. Most participants (81%, n = 145) stated they have been in practice 0-9 years, and the remaining 19% (n = 33) stated they have been in practice ≥ 10 years.

CONCLUSION

Significant knowledge gaps of PGT and aneuploidy screening recommendations after PGT exist among generalist OB/GYN physicians. Efforts should be made to educate providers on the importance of offering aneuploidy screening and diagnostic testing to patients who utilized PGT to improve patient care.

AMH independently predicts aneuploidy but not live birth per transfer in IVF PGT-A cycles

BACKGROUND

While anti-Müllerian hormone (AMH) predicts quantitative IVF outcomes such as oocyte yield, it is not certain whether AMH predicts markers of oocyte quality such as aneuploidy.

METHODS

Retrospective case-control analysis of the SART-CORS database, 2014-2016, to determine whether anti-Müllerian hormone (AMH) predicts aneuploidy and live birth in IVF cycles utilizing preimplantation genetic testing for aneuploidy (PGT-A).

RESULTS

Of 51,273 cycles utilizing PGT-A for all embryos, 10,878 cycles were included in the final analysis; of these, 2,100 cycles resulted in canceled transfer due to lack of normal embryos and 8,778 cycles resulted in primary FET. AMH levels of cycles with ≥ 1 euploid embryo were greater than those of cycles with no normal embryos, stratifying by number of embryos biopsied (1-2, 3-4, 5-6, and ≥ 7), P < 0.017 for each stratum. Adjusting for age and number of embryos biopsied, AMH was a significant independent predictor of ≥ 1 euploid embryo for all age groups: < 35 yrs (aOR 1.074; 95%CI 1.005-1.163), 35-37 years (aOR 1.085; 95%CI 1.018-1.165) and ≥ 38 years (aOR 1.055; 95%CI 1.020-1.093). In comparative model analysis, AMH was superior to age as a predictor of  ≥ 1 euploid embryo for age groups < 35 years and 35-37 years, but not  ≥ 38 years. Across all cycles, age (aOR 0.945, 95% CI 0.935-0.956) and number of embryos (aOR 1.144, 95%CI 1.127-1.162) were associated with live birth per transfer, but AMH was not (aOR 0.995, 95%CI 0.983-1.008). In the subset of cycles resulting in ≥ 1 euploid embryo for transfer, neither age nor AMH were associated with live birth.

CONCLUSIONS

Adjusting for age and number of embryos biopsied, AMH independently predicted likelihood of obtaining ≥ 1 euploid embryo for transfer in IVF PGT-A cycles. However, neither age nor AMH were predictive of live birth once a euploid embryo was identified by PGT-A for transfer. This analysis suggests a predictive role of AMH for oocyte quality (aneuploidy risk), but not live birth per transfer once a euploid embryo is identified following PGT-A.

Does embryo categorization by existing artificial intelligence, morphokinetic or morphological embryo selection models correlate with blastocyst euploidy rates?

RESEARCH QUESTION

Does embryo categorization by existing artificial intelligence (AI), morphokinetic or morphological embryo selection models correlate with blastocyst euploidy?

DESIGN

A total of 834 patients (mean maternal age 40.5 ± 3.4 years) who underwent preimplantation genetic testing for aneuploidies (PGT-A) on a total of 3573 tested blastocysts were included in this retrospective study. The cycles were stratified into five maternal age groups according to the Society for Assisted Reproductive Technology age groups (<35, 35-37, 38-40, 41-42 and >42 years). The main outcome of this study was the correlation of euploidy rates in stratified maternal age groups and an automated AI model (iDAScore® v1.0), a morphokinetic embryo selection model (KIDScore Day 5 ver 3, KS-D5) and a traditional morphological grading model (Gardner criteria), respectively.

RESULTS

Euploidy rates were significantly correlated with iDAScore (P = 0.0035 to <0.001) in all age groups, and expect for the youngest age group, with KS-D5 and Gardner criteria (all P < 0.0001). Additionally, multivariate logistic regression analysis showed that for all models, higher scores were significantly correlated with euploidy (all P < 0.0001).

CONCLUSION

These results show that existing blastocyst scoring models correlate with ploidy status. However, as these models were developed to indicate implantation potential, they cannot accurately diagnose if an embryo is euploid or aneuploid. Instead, they may be used to support the decision of how many and which blastocysts to biopsy, thus potentially reducing patient costs.

Assisted Reproductive Technology without Embryo Discarding or Freezing in Women ≥40 Years: A 5-Year Retrospective Study at a Single Center in Italy

The protocols commonly used in assisted reproductive technology (ART) consist of long-term embryo culture up to the blastocyst stage after the insemination of all mature oocytes, the freezing of all the embryos produced, and their subsequent transfer one by one. These practices, along with preimplantation genetic testing, although developed to improve the live birth rate (LBR) and reduce the risk of multiple pregnancies, are drawing attention to the possible increase in obstetric and perinatal risks, and adverse epigenetic consequences in offspring. Furthermore, ethical-legal concerns are growing regarding the increase in cryopreservation and storage of frozen embryos. In an attempt to reduce the risk associated with prolonged embryo culture and avoid embryo storage, we have chosen to inseminate a limited number of oocytes not exceeding the number of embryos to be transferred, after two days or less of culture. We retrospectively analyzed 245 ICSI cycles performed in 184 infertile couples with a female partner aged ≥40 from January 2016 to July 2021. The results showed a fertilization rate of 95.7%, a miscarriage rate of 48.9%, and a LBR of 10% with twin pregnancies of 16.7%. The cumulative LBR in our group of couples was 13%. No embryos were frozen. In conclusion, these results suggest that oocyte selection and embryo transfer at the cleaving stage constitute a practice that has a LBR comparable to that of the more commonly used protocols in older women who have reduced ovarian reserve.

PGT-A is associated with reduced cumulative live birth rate in first reported IVF stimulation cycles age ≤ 40: an analysis of 133,494 autologous cycles reported to SART CORS

PURPOSE

To evaluate the impact of preimplantation genetic testing for aneuploidy (PGT-A) on cumulative live birth rate (CLBR) in IVF cycles.

METHODS

Retrospective cohort study of the SART CORS database, comparing CLBR for patients using autologous oocytes, with or without PGT-A. The first reported autologous ovarian stimulation cycle per patient between January 1, 2014, and December 31, 2015, and all linked embryo transfer cycles between January 1, 2014, and December 31, 2016, were included in the study. Exclusion criteria were donor oocyte cycles, donor embryo cycles, gestational carrier cycles, cycles which included both a fresh embryo transfer (ET) combined with a thawed embryo previously frozen (ET plus FET), or cycles with a fresh ET after PGT-A.

RESULTS

A total of 133,494 autologous IVF cycles were analyzed. Amongst patients who had blastocysts available for either ET or PGT-A, including those without transferrable embryos, decreased CLBR was noted in the PGT-A group at all ages, except ages > 40 (p < 0.01). A subgroup analysis of only those patients who had PGT-A and a subsequent FET, excluding those without transferrable embryos, demonstrated a very high CLBR, ranging from 71.2% at age < 35 to 50.2% at age > 42. Rates of multiple gestations, preterm birth, early pregnancy loss, and low birth weight were all greater in the non-PGT-A group.

CONCLUSIONS

PGT-A was associated with decreased CLBR amongst all patients who had blastocysts available for ET or PGT-A, except those aged > 40. The negative association of PGT-A use and CLBR per cycle start was especially pronounced at age < 35.

Sperm DNA integrity does play a crucial role for embryo development after ICSI, notably when good-quality oocytes from young donors are used

Based on the inconsistent literature published thus far involving infertile patients, whether intracytoplasmic sperm injection (ICSI) allows overcoming total fertilization failure due to sperm DNA fragmentation is still unclear. Related to this, female factors, which may have a significant impact on assisted reproduction outcomes, can mask male infertility. In this scenario, evaluating ICSI outcomes following cycles using healthy donor gametes could shed light on this realm, as it would avoid the influence of (un)known confounding factors present in infertile individuals. The present work, therefore, aimed to address whether single- and double-stranded sperm DNA fragmentation leads to impaired ICSI outcomes in double gamete donation cycles. The study also compared these double-gamete donation cycles to cycles in which only sperm were donated and oocytes were obtained from infertile patients. Two cohorts were included: (a) the Donor-Donor (DD) cohort, which included 27 semen donor samples used in 49 ICSI cycles with young healthy oocyte donors; and (b) the Donor-Infertile (DI) cohort, which involved 34 semen donor samples used in 57 ICSI cycles with oocytes from patients. Single- and double-stranded sperm DNA breaks were determined with alkaline and neutral Comet assays, respectively; ICSI was conducted following standard protocols and embryos were monitored through time-lapse microscopy. In the DD cohort, the percentage of sperm with high overall DNA damage correlated with fertilization rates (Rs = - 0.666; P < 0.001) and with the percentage of blastocysts per injected oocyte (Rs = - 0.414; P = 0.040). In addition, sperm DNA damage delayed the first embryo division (Rs = 0.421; P = 0.036), and development from the 8-cell to the morula stage (Rs = 0.424; P = 0.034). In contrast, double-stranded DNA breaks had no effect in this cohort. As far as the DI cohort is concerned, while overall sperm DNA damage was not found to be correlated to fertilization or blastocyst rates, pronuclei formation following ICSI was delayed when the incidence of double-stranded DNA breaks was high (Rs = 0.485; P = 0.005). In conclusion, this study, which is the first involving double donation cycles (i.e., a donor-donor cohort), supports that sperm DNA damage has a detrimental impact on fertilization rates after ICSI, and delays embryo development. Moreover, the use of oocytes from infertile individuals is suggested to hide the male-factor effect.

Preimplantation genetic testing for aneuploidy: challenges in clinical practice

Preimplantation genetic testing for aneuploidy (PGT-A) has been used widely during in vitro fertilization procedures in assisted reproductive centers throughout the world. Despite its wide use, concerns arise from the use of PGT-A technology in clinical decision-making. We address knowledge gaps in PGT-A, summarizing major challenges and current professional guidelines. First, PGT-A is a screening test and not a diagnostic test. Second, mosaicism is much higher in the blastocyst stage from PGT-A than had been recognized previously and a mosaic embryo may not accurately represent the genetic disease risk for future fetal disorders. Third, PGT-A was not validated clinically before use in patients; the best use of this technology for selected age-groups remains uncertain. Given these gaps, we believe that current professional policies relying on industry-self-regulation are insufficient. In the USA, the Food and Drug Administration may be the most appropriate agency to provide more definitive guidelines and regulations that are needed for better practice.

Aneuploidy and sex concordance rate between cell-free DNA analysis from spent culture media of preimplantation embryo and DNA from whole embryo with respect to different morphological grading

Purpose

The aneuploidy and sex concordance between cell-free DNA in spent culture media (SCM) and DNA from whole embryo with respect to different morphological grading were examined to evaluate the feasibility of non-invasive preimplantation genetic testing for aneuploidy (niPGT-A).

Methods

A total of 46 pairs of embryos and corresponding SCM were divided into two groups based on the morphological grade. DNA was extracted from 22 and 24 pairs of low- and high-grade embryos, respectively, and respective SCM followed by chromosomal analysis using next-generation sequencing. Aneuploidy study and sex determination were conducted for both groups, and concordance rates were calculated.

Results

For low-grade embryos, 63.6% (14/22) were determined as aneuploidy by whole embryo analysis, and concordance rates were 54.5% (12/22) using niPGT-A. On the contrary, for high-grade embryos 41.7% (10/24) were determined as aneuploidy by whole embryo analysis, and concordance rates were 62.5% (15/24) using niPGT-A. The concordance rates were not statistically different between the low-grade and high-grade embryo groups (p = 0.804). For sex determination, concordance rates between whole embryo and SCM were 81.8% (18/22) and 87.5% (21/24) in low- and high-grade groups, respectively.

Conclusion

Aneuploidy and sex evaluation by niPGT-A may be feasible for both morphologically low- and high-grade embryos.

An Update on Non-invasive Approaches for Genetic Testing of the Preimplantation Embryo

Preimplantation Genetic Testing (PGT) aims to reduce the chance of an affected pregnancy or improve success in an assisted reproduction cycle. Since the first established pregnancies in 1990, methodological approaches have greatly evolved, combined with significant advances in the embryological laboratory. The application of preimplantation testing has expanded, while the accuracy and reliability of monogenic and chromosomal analysis have improved. The procedure traditionally employs an invasive approach to assess the nucleic acid content of embryos. All biopsy procedures require high technical skill, and costly equipment, and may impact both the accuracy of genetic testing and embryo viability. To overcome these limitations, many researchers have focused on the analysis of cell-free DNA (cfDNA) at the preimplantation stage, sampled either from the blastocoel or embryo culture media, to determine the genetic status of the embryo non-invasively. Studies have assessed the origin of cfDNA and its application in non-invasive testing for monogenic disease and chromosomal aneuploidies. Herein, we discuss the state-of-the-art for modern non-invasive embryonic genetic material assessment in the context of PGT. The results are difficult to integrate due to numerous methodological differences between the studies, while further work is required to assess the suitability of cfDNA analysis for clinical application.

Granulocyte-macrophage colony-stimulating factor-containing medium treatment after thawing improves blastocyst-transfer outcomes in the frozen- thawed blastocyst-transfer cycle

PURPOSE

To determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium could improve embryo-transfer outcomes in frozen-thawed blastocyst transfer.

METHODS

Patients who underwent frozen-thawed blastocyst transfer (430 women, aged 30-39 years, 566 cycles) were analyzed. Frozen-thawed blastocysts were cultured in GM-CSF-containing medium or control medium for 3-5 h, followed by transfer to the uterus. The embryo-transfer outcomes in the two groups were measured and compared, and a propensity score matching (1:1) method was used to balance the differences in baseline characteristics. We analyzed 213 matched samples.

RESULTS

In patients who underwent frozen-thawed blastocyst transfer with GM-CSF, the percentage of human chorionic gonadotropin-positive cases, biochemical pregnancies, clinical pregnancies, ongoing pregnancies, and live birth rates was 60.6%, 7.98%, 52.6%, 42.9%, and 40.9%, respectively, as compared with 45.1%, 3.29%, 41.8%, 31.1%, and 30.5%, respectively, for the control groups. The rates of human chorionic gonadotropin positivity (odds ratio [OR]: 1.87, 95% confidence interval: [CI]: 1.27-2.75), biochemical pregnancy (2.55, 1.04-6.29), clinical pregnancy (1.54, 1.05-2.27), ongoing pregnancy (1.64, 1.13-2.41), and live birth (1.67, 1.14-2.45) were significantly higher in the GM-CSF group than the control group. The incidence of pregnancy loss (22.3% vs. 27.0%) did not significantly differ between the groups.

CONCLUSION

The use of a GM-CSF-containing medium for blastocyst-recovery culture improved the live birth rate as a result of increased implantation rate in the frozen-thawed blastocyst-transfer cycle. The use of GM-CSF-containing medium following blastocyst thawing could be an effective choice for improving the blastocyst-transfer outcomes.

Reporting on the Value of Artificial Intelligence in Predicting the Optimal Embryo for Transfer: A Systematic Review including Data Synthesis

Artificial intelligence (AI) has been gaining support in the field of in vitro fertilization (IVF). Despite the promising existing data, AI cannot yet claim gold-standard status, which serves as the rationale for this study. This systematic review and data synthesis aims to evaluate and report on the predictive capabilities of AI-based prediction models regarding IVF outcome. The study has been registered in PROSPERO (CRD42021242097). Following a systematic search of the literature in Pubmed/Medline, Embase, and Cochrane Central Library, 18 studies were identified as eligible for inclusion. Regarding live-birth, the Area Under the Curve (AUC) of the Summary Receiver Operating Characteristics (SROC) was 0.905, while the partial AUC (pAUC) was 0.755. The Observed: Expected ratio was 1.12 (95%CI: 0.26–2.37; 95%PI: 0.02–6.54). Regarding clinical pregnancy with fetal heartbeat, the AUC of the SROC was 0.722, while the pAUC was 0.774. The O:E ratio was 0.77 (95%CI: 0.54–1.05; 95%PI: 0.21–1.62). According to this data synthesis, the majority of the AI-based prediction models are successful in accurately predicting the IVF outcome regarding live birth, clinical pregnancy, clinical pregnancy with fetal heartbeat, and ploidy status. This review attempted to compare between AI and human prediction capabilities, and although studies do not allow for a meta-analysis, this systematic review indicates that the AI-based prediction models perform rather similarly to the embryologists’ evaluations. While AI models appear marginally more effective, they still have some way to go before they can claim to significantly surpass the clinical embryologists’ predictive competence.

OUP accepted manuscript

STUDY QUESTION

Is the composition of microRNAs (miRNAs) in uterine fluid (UF) of women with recurrent implantation failure (RIF) different from that of healthy fertile women?

SUMMARY ANSWER

The composition of miRNAs in UF of women with RIF is different from that of healthy fertile women and the dysregulated miRNAs are associated with impaired endometrial receptivity and embryo implantation.

WHAT IS KNOWN ALREADY

It has previously been demonstrated that the miRNAs secreted from endometrial cells into the UF contribute to the achievement of endometrial receptivity. Endometrial miRNAs are dysregulated in women with RIF.

STUDY DESIGN, SIZE, DURATION

In this descriptive laboratory case–control study, miRNA abundancy was compared between UF collected during implantation phase from healthy fertile women (n = 17) and women with RIF (n = 34), which was defined as three failed IVF cycles with high-quality embryos.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Recruitment of study subjects and sampling of UF were performed at two university clinics in Stockholm, Sweden and Tartu, Estonia. The study participants monitored their menstrual cycles using an LH test kit. The UF samples were collected on Day LH + 7–9 by flushing with saline. Samples were processed for small RNA sequencing and mapped for miRNAs. The differential abundance of miRNAs in UF was compared between the two groups using differential expression analysis (DESeq2). Further downstream analyses, including miRNA target gene prediction (miRTarBase), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis (g:Profiler) and external validation using relevant published data, were performed on the dysregulated miRNAs. Two miRNAs were technically validated with quantitative real-time PCR (RT-PCR).

MAIN RESULTS AND THE ROLE OF CHANCE

After processing of the sequencing data, there were 15 samples in the healthy fertile group and 33 samples in the RIF group. We found 61 differentially abundant UF miRNAs (34 upregulated and 27 downregulated) in RIF compared to healthy women with a false discovery rate of <0.05 and a fold change (FC) of ≤−2 or ≥2. When analyzed with published literature, we found that several of the differentially abundant miRNAs are expressed in endometrial epithelial cells and have been reported in endometrial extracellular vesicles and in association with endometrial receptivity and RIF. Their predicted target genes were further expressed both in the trophectodermal cells of blastocyst-stage embryos and endometrial mid-secretory epithelial cells, as assessed by publicly available single-cell transcriptome-sequencing studies. Pathway analysis further revealed that 25 pathways, having key roles in endometrial receptivity and implantation, were significantly enriched. Hsa-miR-486-5p (FC −20.32; P-value = 0.004) and hsa-miR-92b-3p (FC −9.72; P-value = 0.004) were successfully technically validated with RT-PCR.

LARGE SCALE DATA

The data are available in Gene Expression Omnibus (GEO) at https://www.ncbi.nlm.nih.gov/geo/ with GEO accession number: GSE173289.

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive study with a limited number of study participants. Moreover, the identified differentially abundant miRNAs should be validated in a larger study cohort, and the predicted miRNA target genes and enriched pathways in RIF need to be confirmed and further explored in vitro.

WIDER IMPLICATIONS OF THE FINDINGS

RIF is a major challenge in the current IVF setting with no diagnostic markers nor effective treatment options at hand. For the first time, total miRNAs have been extensively mapped in receptive phase UF of both healthy women with proven fertility and women diagnosed with RIF. Our observations shed further light on the molecular mechanisms behind RIF, with possible implications in future biomarker and clinical treatment studies.

STUDY FUNDING/COMPETING INTEREST(S)

This work was financially supported by the Swedish Research Council (2017-00932), a joint grant from Region Stockholm and Karolinska Institutet (ALF Medicine 2020, FoUI-954072), Estonian Research Council (PRG1076), Horizon 2020 innovation (ERIN, EU952516) and European Commission and Enterprise Estonia (EU48695). The authors have no competing interests to declare for the current study.

Health Problems and Financial Burdens in Mislabeling IVF Failures as RIF

The Article Abstract is not Available.

The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?

Although there are large differences between horses and humans for reproductive anatomy, follicular dynamics, mono-ovulation, and embryo development kinetics until the blastocyst stage are similar. In contrast to humans, however, horses are seasonal animals and do not have a menstrual cycle. Moreover, horse implantation takes place 30 days later than in humans. In terms of artificial reproduction techniques (ART), oocytes are generally matured in vitro in horses because ovarian stimulation remains inefficient. This allows the collection of oocytes without hormonal treatments. In humans, in vivo matured oocytes are collected after ovarian stimulation. Subsequently, only intra-cytoplasmic sperm injection (ICSI) is performed in horses to produce embryos, whereas both in vitro fertilization and ICSI are applied in humans. Embryos are transferred only as blastocysts in horses. In contrast, four cells to blastocyst stage embryos are transferred in humans. Embryo and oocyte cryopreservation has been mastered in humans, but not completely in horses. Finally, both species share infertility concerns due to ageing and obesity. Thus, reciprocal knowledge could be gained through the comparative study of ART and infertility treatments both in woman and mare, even though the horse could not be used as a single model for human ART.

Molecular Drivers of Developmental Arrest in the Human Preimplantation Embryo: A Systematic Review and Critical Analysis Leading to Mapping Future Research

Developmental arrest of the preimplantation embryo is a multifactorial condition, characterized by lack of cellular division for at least 24 hours, hindering the in vitro fertilization cycle outcome. This systematic review aims to present the molecular drivers of developmental arrest, focusing on embryonic and parental factors. A systematic search in PubMed/Medline, Embase and Cochrane-Central-Database was performed in January 2021. A total of 76 studies were included. The identified embryonic factors associated with arrest included gene variations, mitochondrial DNA copy number, methylation patterns, chromosomal abnormalities, metabolic profile and morphological features. Parental factors included, gene variation, protein expression levels and infertility etiology. A valuable conclusion emerging through critical analysis indicated that genetic origins of developmental arrest analyzed from the perspective of parental infertility etiology and the embryo itself, share common ground. This is a unique and long-overdue contribution to literature that for the first time presents an all-inclusive methodological report on the molecular drivers leading to preimplantation embryos’ arrested development. The variety and heterogeneity of developmental arrest drivers, along with their inevitable intertwining relationships does not allow for prioritization on the factors playing a more definitive role in arrested development. This systematic review provides the basis for further research in the field.