Perinatal outcomes of singleton live births after preimplantation genetic testing during single frozen-thawed blastocyst transfer cycles: a propensity score-matched study.

OBJECTIVE: To determine whether singleton pregnancy achieved after preimplantation genetic testing (PGT) is associated with a higher risk of adverse perinatal outcomes than in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) singleton pregnancy. DESIGN: A retrospective cohort study. SETTING: A university-affiliated fertility center. PATIENT(S): This cohort study included singleton live births resulting from PGT (n = 232) and IVF/ICSI singleton pregnancies (n = 2,829) with single frozen-thawed blastocyst transfer. Multiple baseline covariates were used for propensity score matching, yielding 214 PGT singleton pregnancies matched to 617 IVF/ICSI singleton pregnancies. INTERVENTION(S): Trophectoderm biopsy. MAIN OUTCOME MEASURE(S): The primary outcome was gestational hypertension, and various clinical perinatal secondary outcomes related to maternal and neonatal health were measured. RESULT(S): Compared with IVF/ICSI singleton pregnancy, PGT singleton pregnancy was associated with a significantly higher risk of gestational hypertension (adjusted odds ratio, 2.58; 95% confidence interval, 1.32, 5.05). In the matched sample, the risk of gestational hypertension remained higher with PGT singleton pregnancy (odds ratio, 2.33; 95% confidence interval, 1.04, 5.22) than with IVF/ICSI singleton pregnancy. No statistical differences were noted in any other measured outcomes between the groups. CONCLUSION(S): The perinatal outcomes of PGT and IVF/ICSI singleton pregnancies were similar except for the observed potentially higher risk of gestational hypertension with PGT singleton pregnancy. However, because the data on PGT singleton pregnancies are limited, this conclusion warrants further investigation.

Time associations between U.S. birth rates and add-Ons to IVF practice between 2005-2016.

Until 2010, the National Assisted Reproductive Technology Surveillance System (NASS) report, published annually by the Center for Disease Control and Prevention (CDC), demonstrated almost constantly improving live birth rates following fresh non-donor (fnd) in vitro fertilization (IVF) cycles. Almost unnoticed by profession and public, by 2016 they, however, reached lows not seen since 1996-1997. We here attempted to understand underlying causes for this decline. This study used publicly available IVF outcome data, reported by the CDC annually under Congressional mandate, involving over 90% of U.S. IVF centers and over 95% of U.S. IVF cycles. Years 2005, 2010, 2015 and 2016 served as index years, representing respectively, 27,047, 30,425, 21,771 and 19,137 live births in fnd IVF cycles. Concomitantly, the study associated timelines for introduction of new add-ons to IVF practice with changes in outcomes of fnd IVF cycles. Median female age remained at 36.0 years during the study period and center participation was surprisingly stable, thereby confirming reasonable phenotype stability. Main outcome measures were associations of specific IVF practice changes with declines in live IVF birth rates. Time associations were observed with increased utilization of "all-freeze" cycles (embryo banking), mild ovarian stimulation protocols, preimplantation genetic testing for aneuploidy (PGT-A) and increasing utilization of elective single embryo transfer (eSET). Among all add-ons, PGT-A, likely, affected fndIVF most profoundly. Though associations cannot denote causation, they can be hypothesis-generating. Here presented time-associations are compelling, though some of observed pregnancy and live birth loss may have been compensated by increases in frozen-thawed cycles and consequential pregnancies and live births not shown here. Pregnancies in frozen-thawed cycles, however, represent additional treatment cycles, time delays and additional costs. IVF live birth rates not seen since 1996-1997, and a likely continuous downward trend in U.S. IVF outcomes, therefore, mandate a reversal of current outcome trends, whatever ultimately the causes.

Utilization of preimplantation genetic testing in the USA.

PURPOSE: To evaluate the use of preimplantation genetic testing (PGT) and live birth rates (LBR) in the USA from 2014 to 2017 and to understand how PGT is being used at a clinic and state level. METHODS: This study accessed SART data for 2014 to 2017 to determine LBR and the CDC for years 2016 and 2017 to identify PGT usage. Primary cycles included only the first embryo transfer within 1 year of an oocyte retrieval; subsequent cycles included transfers occurring after the first transfer or beyond 1 year of oocyte retrieval. RESULTS: In the SART data, the number of primary PGT cycles showed a significant monotonic annual increase from 18,805 in 2014 to 54,442 in 2017 (P = 0.042) and subsequent PGT cycles in these years increased from 2946 to 14,361 (P = 0.01). There was a significant difference in primary PGT cycle use by age, where younger women had a greater percentage of PGT treatment cycles than older women. In both PGT and non-PGT cycles, the LBR per oocyte retrieval decreased significantly from 2014 to 2017 (P<0001) and younger women had a significantly higher LBR per oocyte retrieval compared to older women (P < 0.001). The CDC data revealed that in 2016, just 53 (11.4%) clinics used PGT for more than 50% of their cycles, which increased to 99 (21.4%) clinics in 2017 (P< 0.001). CONCLUSIONS: A growing number of US clinics are offering PGT to their patients. These findings support re-evaluation of the application for PGT.

The origins of aneuploidy research consortium.

The presence of high levels of aneuploidy in oocytes and early embryos and their fate is of considerable scientific and clinical importance. The Origins of Aneuploidy Research Consortium (OARC) was established to promote interdisciplinary communication and collaborative research into this topic. Under the umbrella of OARC, a series of papers has now been published in this Special Issue of Prenatal Diagnosis. Recent studies have transformed the view that aneuploidy is usually attributable to meiotic non-disjunction. The molecular basis for the association between meiotic error and maternal age is becoming understood. The clinical significance of mitotic instability in the earliest cells divisions of the embryo is also becoming clearer. An error in the segregation of one or more whole chromosomes from a parent does not invariably result in a non-viable pregnancy or an abnormal outcome. Epidemiologic data allows an assessment of in utero viability, the effect of maternal age, and secondary factors that may affect aneuploidy prevalence. We advocate careful use of nomenclature and revision of educational materials to more accurately explain the complex and often nuanced mechanisms. OARC plans to hold additional workshops, promote additional publications and offer educational resources.

Diminished ovarian reserve is associated with reduced euploid rates via preimplantation genetic testing for aneuploidy independently from age: evidence for concomitant reduction in oocyte quality with quantity.

OBJECTIVE(S): To determine whether women with diminished ovarian reserve (DOR) (quantitatively) had lower rates of euploid blastocysts, as a proxy for oocyte quality. DESIGN: Retrospective cohort study. SETTING: University reproductive health clinic. PATIENT(S): A total of 1,152 women aged 19-42 years underwent 1,675 IVF cycles yielding 8,073 blastocysts for biopsy from 2010 to 2019. INTERVENTIONS(S): Preimplantation genetic testing for aneuploidy. MAIN OUTCOME MEASURE(S): Euploid rates, defined as the number of euploid blastocysts divided by the number of biopsied blastocysts per cycle. RESULT(S): A total of 225 women (20%) had DOR as infertility diagnosis per the Bologna criteria. Age was higher among the women with DOR (39.5 y vs. 37.0 y). Euploid rates were lower among women with vs. without DOR (29.0% vs. 44.9%). In generalized linear models controlling for age, women with DOR had 24% reduced odds of a biopsied blastocyst being euploid versus women without DOR. In a secondary analysis assigning DOR status to women producing the lowest quartile of age-adjusted mature oocyte yield, this relationship remained. No differences were identified in live birth rates between women with and without DOR after euploid single-embryo transfer independently from age (n = 944 transfers; 56.8% vs. 54.8%, respectively). CONCLUSION(S): Blastocysts from women with DOR are less likely to be euploid than those from women without DOR after adjustment for age. Given the concomitant reduction in euploid rates with quantity of oocytes observed in this study, quantitative ovarian reserve assessments (i.e., follicular machinery) may yield insight into relative ovarian aging.

The live birth in a woman with resistant ovary syndrome after in vitro oocyte maturation and preimplantation genetic testing for aneuploidy.

We report the pregnancy and live birth achieved after in vitro maturation (IVM) of oocytes and PGT-A in a 23-year-old patient suffering from ovarian gonadotropin resistance. A woman with resistant ovary syndrome (ROS) had secondary amenorrhea, high FSH levels (25.34 mIU/mL) and LH (29.6 mIU/mL), low estradiol levels (15.2 pg/mL), and high serum AMH levels (38.0 ng/mL), associated with an increased antral follicle count (AFC) of 45. Without gonadotropin priming and HCG trigger, ultrasound-guided transvaginal oocyte retrieval was performed. Aspiration of antral-stage follicles allowed the retrieval of 15 immature oocytes. After oocyte collection, immature oocytes were cultured in the IVM medium. Following IVM, six of them reached metaphase II stage. Resultant matured oocytes were fertilized by intracytoplasmic sperm injection (ICSI). Embryos obtained were cultured to the blastocyst stage. On day 5, three embryos reached blastocyst stage. Trophectoderm biopsy and PGT-A were performed on two better quality embryos on day 5 after fertilization. Two biopsied embryos were reported to be euploid. PGT-A was performed utilizing next-generation sequencing (NGS\MPS). One embryo was transferred in an artificial thaw cycle and resulted in a viable intrauterine pregnancy and live birth. Our experience indicates that there is no requirement for gonadotropin stimulation and use of b-hCG trigger prior to IVM in patients with ROS. The results suggest that oocytes obtained with IVM in patients with ROS are capable of meiotic and mitotic division, fertilization, and generation of euploid embryos. IVM appears to be a valuable approach in patients with ROS, allowing them to have genetically connected offspring.

Regulating reproductive genetic services: dealing with spiral-shaped processes and techno-scientific imaginaries.

PURPOSE: We have been inquiring into the diffusion process of reproductive genetic services (RGS) and the viability of geneticization in human reproduction. METHOD: A 2-round modified-Delphi survey was applied amongst Israeli and Spanish experts to analyze regulatory attitudes and expectations about the future applications of RGS. We argue that an explanation of RGS diffusion based on a 'technology-push' impulse should be complemented by a 'demandpull' approach, which underscores the importance of regulatory frameworks and demand-inducing policies. The diffusion of RGS is advancing in a 'spiralshaped' process where technology acts as a cause and effect simultaneously, modulating social acceptance and redefining the notions of health and responsibility along the way. RESULTS: We suggest that there is a 'grey-zone' of RGS regulations regarding four procedures: the use of germline genome modification (GGM) for severe monogenic disorders, preimplantation genetic testing (PGT) for detection of chromosomal abnormalities, PGT for multifactorial diseases, and PGT with whole-exome screening. CONCLUSIONS: Although far from the geneticization of human reproduction, our findings suggest that, since techno-scientific imaginaries tend to shape regulations and thus favor the diffusion of RGS, policymakers should pay attention to those procedures by focusing on good practices and equity while providing sound information on potential risks and expected success rates. A broad and inclusive societal debate is critical for overcoming the difficulty of drawing a clear line between medical and non-medical uses of genetic selection and engineering while searching for the right balance between allowing reproductive autonomy and protecting the public interest.

Preimplantation genetic testing for aneuploidy: A review of published blastocyst reanalysis concordance data.

Preimplantation genetic testing for aneuploidy (PGT-A) reduces miscarriage risk, increases the success of IVF, shortens time to pregnancy, and reduces multiple gestation rates without compromising outcomes. The progression of PGT-A has included common application of next-generation sequencing (NGS) from single nucleotide polymorphism microarray, quantitative real-time PCR, and array comparative hybridization platforms of analysis. Additional putative advances in PGT-A capability include classifying embryos as mosaic and predicting the presence of segmental imbalance. A critical component in the process of technical validation of these advancements involves evaluation of concordance between reanalysis results and initial testing results. While many independent studies have investigated the concordance of results obtained from the remaining embryo with the original PGT-A diagnosis, compilation and systematic analysis of published data has not been performed. Here, we review results from 26 primary research articles describing concordance in 1271 human blastocysts from 2260 pairwise comparisons. Results illustrate significantly higher discordance from PGT-A methods which utilize NGS and include prediction of mosaicism or segmental imbalance. These results suggest caution when considering new iterations PGT-A.

Third-generation sequencing: any future opportunities for PGT?

PURPOSE: To investigate use of the third-generation sequencing (TGS) Oxford Nanopore system as a new approach for preimplantation genetic testing (PGT). METHODS: Embryos with known structural variations underwent multiple displacement amplification to create fragments of DNA (average ~ 5 kb) suitable for sequencing on a nanopore. RESULTS: High-depth sequencing identified the deletion interval for the relatively large HBA1/2--SEA alpha thalassemia deletion. In addition, STRs were able to be identified in the primary sequence data for potential use in conventional PGT-M linkage confirmation. Sequencing of amplified embryo DNA carrying a translocation enabled balanced embryos to be identified and gave the precise identification of translocation breakpoints, offering the opportunity to differentiate carriers from non-carrier embryos. Low-pass sequencing gave reproducible profiles suitable for simple identification of whole-chromosome and segmental aneuploidies. CONCLUSION: TGS on the Oxford Nanopore is a possible alternative and versatile approach to PGT with potential for performing economical workups where the long read sequencing information can be used for assisting in a traditional PGT workup to design an accurate and reliable test. Additionally, application of TGS has the possibility of providing combined PGT-A/SR or in selected stand-alone PGT-M cases involving pathogenic deletions. Both of these applications offer the opportunity for simultaneous aneuploidy detection to select either balanced embryos for transfer or additional carrier identification. The low cost of the instrument offers new laboratories economical entry into onsite PGT.

The Reproductive Journey in the Genomic Era: From Preconception to Childhood.

It is estimated that around 10-15% of the population have problems achieving a pregnancy. Assisted reproduction techniques implemented and enforced by personalized genomic medicine have paved the way for millions of infertile patients to become parents. Nevertheless, having a baby is just the first challenge to overcome in the reproductive journey, the most important is to obtain a healthy baby free of any genetic condition that can be prevented. Prevention of congenital anomalies throughout the lifespan of the patient must be a global health priority. Congenital disorders can be defined as structural or functional anomalies that occur during intrauterine life and can be identified prenatally, at birth, or sometimes may only be detected later during childhood. It is considered a frequent group of disorders, affecting 3-6% of the population, and one of the leading causes of morbidity and mortality. Congenital anomalies can represent up to 30-50% of infant mortality in developed countries. Genetics plays a substantial role in the pathogenesis of congenital anomalies. This becomes especially important in some ethnic communities or populations where the incidence and levels of consanguinity are higher. The impact of genetic disorders during childhood is high, representing 20-30% of all infant deaths and 11.1% of pediatric hospital admissions. With these data, obtaining a precise genetic diagnosis is one of the main aspects of a preventive medicine approach in developed countries. The field of reproductive health has changed dramatically from traditional non-molecular visual microscope-based techniques (i.e., fluorescence in situ hybridization (FISH) or G-banding karyotype), to the latest molecular high-throughput techniques such as next-generation sequencing (NGS). Genome-wide technologies are applied along the different stages of the reproductive health lifecycle from preconception carrier screening and pre-implantation genetic testing, to prenatal and postnatal testing. The aim of this paper is to assess the new horizon opened by technologies such as next-generation sequencing (NGS), in new strategies, as a genomic precision diagnostic tool to understand the mechanisms underlying genetic conditions during the "reproductive journey".

Utilization of preimplantation genetic testing for monogenic disorders.

OBJECTIVE: To determine the rate of utilization, factors influencing the decision-making process, and patient satisfaction with preimplantation genetic diagnosis for monogenic disorders (PGT-M). DESIGN: Survey study. SETTING: Academic center. PATIENT(S): Genetically at-risk patients seen for PGT-M consultation between January 2010 and 2018. INTERVENTION(S): Electronic survey including demographics, genetic history, consultation experience, decision-making process, and satisfaction with PGT-M process. MAIN OUTCOME MEASURE(S): Rate of utilization of PGT-M, importance of decision-making factors, and satisfaction with PGT-M process. RESULT(S): Among survey respondents (n = 49), the rate of utilization of PGT-M after consultation was 89.8%. Ninety-three percent of participants decided whether to pursue PGT-M within 3 months of consultation. Factors that were considered most important to this decision-making process included information provided at consultation, accuracy of test results after PGT-M, avoidance of suffering of an affected child, and ability to avoid termination of an affected pregnancy. Key barriers to utilization included financial burden and overall complexity of the in vitro fertilization (IVF)/PGT-M process. Of those utilizing PGT-M (n = 44), 72.1% had at least one live birth or were pregnant during the study period. Satisfaction with PGT-M was high, and most couples would use IVF/PGT-M for a future pregnancy (84.1%). Participants with a live birth were more satisfied with the PGT-M process than those who had no live birth. CONCLUSION(S): Most patients seeking consultation for PGT-M were likely to pursue this technology despite financial burden and complexity of the process. Exploring factors that influence patient decision-making regarding PGT-M is important for tailoring the consultation and optimizing the overall experience.

Trophectoderm biopsy reduces the level of serum ß-human chorionic gonadotropin in early pregnancy.

OBJECTIVE: To assess whether trophectoderm biopsy has any impact on the level of serum ß-human chorionic gonadotropin (ß-hCG) in early pregnancies. DESIGN: Retrospective cohort study. SETTING: University-affiliated reproductive medical center. PATIENT(S): Three hundred and eighty-three women undergoing 396 frozen embryo transfer (FET) cycles with preimplantation genetic testing (PGT), and 353 women undergoing 465 FET cycles with in vitro fertilization or intracytoplasmic sperm injection, all women having positive serum ß-hCG results on the 12th day after blastocysts transfers. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Serum ß-hCG levels on the 12th day after warmed blastocyst transfer and perinatal outcomes of clinical pregnancy. RESULTS: The diagnostic threshold of serum ß-hCG levels on the 12th day after FET for prediction of a live birth was 368.55 mIU/mL with an area under the curve of 0.791 (0.729∼0.853) in the biopsy group, which was lower than the 411.45 mIU/mL in the control group. The average level of serum ß-hCG in the biopsy group with clinical pregnancies was statistically significantly lower than that of the control group: 703.10 (569.63) versus 809.20 (582.00), respectively. No statistically significant differences in perinatal outcomes, including gestational age, hypertensive disorder in pregnancy, and neonatal malformation, were found between the two groups. CONCLUSION(S): Trophectoderm biopsy may reduce the level of serum ß-hCG in early pregnancies (the 12th day after embryo transfer), but no increased risk was found of adverse perinatal outcomes after trophectoderm biopsy.

Preimplantation genetic testing and chances of a healthy live birth amongst recipients of fresh donor oocytes in the United States.

PURPOSE: To evaluate if preimplantation genetic testing (PGT) improves the odds of a healthy live birth amongst recipients of fresh donor oocytes. METHODS: We performed a retrospective cohort study including in vitro fertilization cycles of women using fresh donor oocytes reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System, between 2013 and 2015. Cycles were categorized based on PGT. Primary outcome measure was a good birth outcome (GBO), defined as a singleton, term, live birth with an average birthweight. Multivariable generalized estimating equation models were fit to analyze the effect of PGT. Interaction effect between cycle type (fresh vs frozen) and PGT was tested. RESULTS: Of 28,153 included cycles, 3708 had PGT while 24,445 did not. PGT cycles were less likely to result in an embryo transfer (ET) (64 vs 94%), but were associated with increased rates of frozen ET (70 vs 41%), single ET (67 vs 44%), and blastocyst ET (87 vs 65%). There was a significant interaction between PGT and cycle type. Cycles using PGT increased the probability of a GBO 12% in frozen cycles (RR 1.12; 95% CI 1.02, 1.22; p = 0.018), but PGT was detrimental to success in fresh cycles with a 53% reduced likelihood of GBO (RR 0.47; 9% CI 0.41, 0.54; p < 0.001). CONCLUSION: PGT, as practiced during the most recently available national data in women using fresh donor oocytes, was associated with increased probability of a healthy live birth amongst frozen cycles, but was not beneficial in fresh cycles.

The dawn of the future: 30 years from the first biopsy of a human embryo. The detailed history of an ongoing revolution.

Following early studies showing no adverse effects, cleavage stage biopsy by zona drilling using acid Tyrode's solution, and removal of single blastomeres for preimplantation genetic testing (PGT) and identification of sex in couples at risk of X-linked disease, was performed by Handyside and colleagues in late 1989, and pregnancies reported in 1990. This method was later used for specific diagnosis of monogenic conditions, and a few years later also for chromosomal structural and/or numerical impairments, thereby establishing a valuable alternative option to prenatal diagnosis. This revolutionary approach in clinical embryology spread worldwide, and several other embryo biopsy strategies developed over three decades in a process that is still ongoing. The rationale of this narrative review is to outline the different biopsy approaches implemented across the years in the workflow of the IVF clinics that provided PGT: their establishment, the first clinical experiences, their downsides, evolution, improvement and standardization. The history ends with a glimpse of the future: minimally/non-invasive PGT and experimental embryo micromanipulation protocols. This grand theme review outlines a timeline of the evolution of embryo biopsy protocols, whose implementation is increasing worldwide together with the increasing application of PGT techniques in IVF. It represents a vade mecum especially for the past, present and upcoming operators and experts in this field to (re)live this history from its dawn to its most likely future.

PGT-A preimplantation genetic testing for aneuploidies and embryo selection in routine ART cycles: Time to step back?

Embryo aneuploidies may be responsible for implantation failures, miscarriages and affects IVF outcomes. A variety of technologies have been implemented to individuate euploid embryos in IVF treatments, which is named preimplantation genetic testing for aneuploidies (PGT-A). According to this strategy, a better embryo selection should increase IVF results. In reality, several issues remain unaddressed including the sampling strategy, involving the test outcomes, and the frequent occurrence of embryo mosaicism, affecting the criteria for selection of supposed viable embryos and possibly posing an ethical dilemma. Safety issues are in place, including perinatal and postnatal consequences of embryo sampling and the epigenetic weaknesses from a prolonged in vitro culture, necessary for trophectoderm biopsy. On the other side, chromosome number mistakes are progressively recognized as physiologic events in the early pre-implantation embryo with many corrective mechanisms in place and their destiny in the post-implantation development is unclear. Accordingly, the increasing precision of the diagnostic tools should be used to investigate the effect of such interventions within rigorous research programs in the sake of improved clinical outcomes. Meantime the diagnosis of embryo aneuploidies in IVF cycles should be considered as a research tool and systematic implementation in clinical practice may appear unjustified.

The PGS/PGT-A controversy in IVF addressed as a formal conflict resolution analysis.

PURPOSE: To use conflict resolution analysis on the conflict between proponents and opponents of preimplantation genetic testing for aneuploidy (PGT-A), previously called preimplantation genetic screening (PGS). METHODS: Considered in conflict analysis a case study, we reviewed the English literature based on key-word searches at www.pubmed.com and www.google.com, and interviewed professional opinion leaders and other actor-representatives. This analysis was the product of a mandated externship by L.M. at the Foundation for Reproductive Medicine (FRM), as part of the Master of Science Program in Negotiations and Conflict Resolution at Columbia University, New York, NY. RESULTS: Initially a typical difference of opinion, conflict evolved after proponents rejected studies that failed to confirm expected benefits, and authors felt demeaned by their criticism. Becoming "destructive," the conflict evolved according to Glasl's escalation model stages. Proponents became continuous attractors. Unable to produce validations for PGT-A, proponents moved goal posts through 3 stages (PGS 1.0-PGS 3.0). Ultimately concurring that pregnancy and live birth rates are unaffected, they started claiming new benefits. CONCLUSIONS: The FRM underwrote this study as a starting tool for a conflict resolution process. A consensus building conference of stakeholders appears as of this point to represent the most promising potential intervention. The goal of such a conference should be sustainable consensus about clinical utilization of PGS/PGT-A in IVF, based on transparent and validated criteria. A potential date for such a conference is set for 2020.

The role of prenatal diagnosis following preimplantation genetic testing for single-gene conditions: A historical overview of evolving technologies and clinical practice.

Preimplantation genetic testing for monogenic conditions (PGT-M) has become a valued reproductive option for couples at risk of having a child with a single gene condition. In line with developments in molecular genetics, there has been an overall trend toward laboratory techniques with higher accuracy in comparison to earlier PGT-M techniques. The recommendation for confirmatory prenatal diagnostic testing has remained a standard component of PGT-M counseling, reflecting the inherent difficulties of testing the limited number of cells obtained from embryo biopsy, as well as recognition of the biological and human factors that may lead to misdiagnosis in a PGT-M cycle. Reported misdiagnosis rates are less than 1 in 200 pregnancies following PGT-M, although updated data regarding newer methods of PGT-M are required. There is limited evidence available regarding clinician and patient behavior in pregnancies resulting from PGT-M cycles. It remains essential that clinicians involved in the care of patients undergoing PGT-M provide appropriate counseling regarding the risks of misdiagnosis and the importance of confirmatory prenatal diagnosis. The nature of PGT-M test design lends itself to cell-free DNA-based noninvasive prenatal testing for monogenic conditions (NIPT-M), which is likely to become a popular method in the near future.

Noninvasive preimplantation genetic testing in assisted reproductive technology: current state and future perspectives.

Invasive genetic screening of pre-implantation embryos via biopsied trophectoderm (TE) cells has been in use for more than 20 years, while its benefits in selecting euploid embryos remain controversial. Recent advances in the ability to process embryonic cell-free DNA (cfDNA) from blastocoel fluid (BF) and spent culture media (SCM) of blastocysts in a manner similar to that of a biopsied TE sample provide a potential alternative holding great promise for obtaining cytogenetic information of the embryos without intrusive biopsy of traditional biopsy-based pre-implantation genetic testing (PGT). Several studies have reported even higher diagnostic accuracy in non-invasive PGT (ni-PGT) than conventional PGT. However, there are still several technical challenges to be overcome before ni-PGT can be accepted as a reliable genomic information source of embryo. In this review, we have summarized the emergence and current state of ni-PGT, and discussed our own perspectives on their limitations and future prospect. There is still a long way to go before truly wide clinical application of ni-PGT.