Preimplantation genetic testing: current challenges and future prospects

Preimplantation genetic testing in the current era, a review

BACKGROUND

Preimplantation genetic testing (PGT), also referred to as preimplantation genetic diagnosis (PGD), is an advanced reproductive technology used during in vitro fertilization (IVF) cycles to identify genetic abnormalities in embryos prior to their implantation. PGT is used to screen embryos for chromosomal abnormalities, monogenic disorders, and structural rearrangements.

DEVELOPMENT OF PGT

Over the past few decades, PGT has undergone tremendous development, resulting in three primary forms: PGT-A, PGT-M, and PGT-SR. PGT-A is utilized for screening embryos for aneuploidies, PGT-M is used to detect disorders caused by a single gene, and PGT-SR is used to detect chromosomal abnormalities caused by structural rearrangements in the genome.

PURPOSE OF REVIEW

In this review, we thoroughly summarized and reviewed PGT and discussed its pros and cons down to the minutest aspects. Additionally, recent studies that highlight the advancements of PGT in the current era, including their future perspectives, were reviewed.

CONCLUSIONS

This comprehensive review aims to provide new insights into the understanding of techniques used in PGT, thereby contributing to the field of reproductive genetics.

Impact of trophectoderm biopsy for preimplantation genetic testing on obstetric and neonatal outcomes: a meta-analysis

OBJECTIVE

This study aimed to investigate whether trophectoderm biopsy for preimplantation genetic testing is associated with an increased risk of adverse obstetrical and neonatal outcomes compared with conventional in vitro fertilization or intracytoplasmic sperm injection without preimplantation genetic testing.

DATA SOURCES

Entries between January 1990 and August 2022 were searched using MEDLINE, Embase, Web of Science, the Cochrane Library, and Google Scholar.

STUDY ELIGIBILITY CRITERIA

Publications comparing the outcomes of pregnancies after preimplantation genetic testing using trophectoderm biopsy and in vitro fertilization or intracytoplasmic sperm injection were included. Only human studies with a cohort or case-control design or randomized controlled trials were eligible for inclusion.

METHODS

The study selection process was performed independently by 2 investigators. The quality of the observational studies was assessed using the Newcastle-Ottawa Scale, and the Cochrane risk-of-bias tool version 2 was used to grade the level of bias in randomized controlled trials. The pooled odds ratio and 95% confidence interval were calculated using a random-effects model when substantial heterogeneity occurred (indicated by I2 of >50% and P<.1). Otherwise, a fixed-effects model was used.

RESULTS

This meta-analysis included 13 studies involving 11,469 live births after preimplantation genetic testing treatment with trophectoderm biopsy before embryo transfer and 20,438 live births after in vitro fertilization or intracytoplasmic sperm injection only. The odds ratio of preterm delivery was higher in the trophectoderm-biopsied group than in the routine in vitro fertilization or intracytoplasmic sperm injection group (pooled odds ratio, 1.12; 95% confidence interval, 1.03-1.21); however, the difference did not exist after sensitivity analysis (odds ratio, 0.97; 95% confidence interval, 0.84-1.11). The risk of low birthweight did not increase among the biopsied pregnancies (pooled odds ratio, 1.01; 95% confidence interval, 0.85-1.20). No marked difference was observed in the risk of other obstetrical or neonatal outcomes between the biopsy and control groups. Furthermore, no difference was noted in the perinatal outcomes between trophectoderm-biopsied and nonbiopsied groups in the subgroup analyses by intracytoplasmic sperm injection, frozen-thawed transfer, or single embryo transfer.

CONCLUSION

Trophectoderm biopsy for preimplantation genetic testing treatment did not alter the risk of obstetrical or neonatal outcomes compared with conventional in vitro fertilization or intracytoplasmic sperm injection without preimplantation genetic testing. However, this study was limited by the large observational evidence base, and more randomized controlled trials are needed to further confirm these findings.

Preimplantation genetic testing: A remarkable history of pioneering, technical challenges, innovations, and ethical considerations

Preimplantation genetic testing (PGT) has emerged as a powerful companion to assisted reproduction technologies. The origins and history of PGT are reviewed here, along with descriptions of advances in molecular assays and sampling methods, their capabilities, and their applications in preventing genetic diseases and enhancing pregnancy outcomes. Additionally, the potential for increasing accuracy and genome coverage is considered, as well as some of the emerging ethical and legislative considerations related to the expanding capabilities of PGT.

Current Applications and Controversies in Preimplantation Genetic Testing for Aneuploidies (PGT-A) in In Vitro Fertilization

Preimplantation genetic testing for aneuploidy (PGT-A) has evolved over recent years, including improvements in embryo culture, biopsy, transfer, and genetic testing. The application of new comprehensive chromosome screening analysis has improved the accuracy in determining the chromosomal status of the analyzed sample, but it has brought new challenges such as the management of partial aneuploidies and mosaicisms. For the past two decades, PGT-A has been involved in a controversy regarding its efficiency in improving IVF outcomes, despite its widespread worldwide implementation. Understanding the impact of embryo aneuploidy in IVF (in vitro fertilization) should theoretically allow improving reproductive outcomes. This review of the literature aims to describe the impact of aneuploidy in human reproduction and how PGT-A was introduced to overcome this obstacle in IVF (in vitro fertilization). The article will try to analyze and summarize the evolution of the PGT-A in the recent years, and its current applications and limitations, as well as the controversy it generates. Conflicting published data could indicate the lacking value of a single biopsied sample to determine embryo chromosomal status and/or the lack of standardized methods for embryo culture and management and genetic analysis among other factors. It has to be considered that PGT-A may not be a universal test to improve the reproductive potential in IVF patients, rather each clinic should evaluate the efficacy of PGT-A in their IVF program based on their population, skills, and limitations.

A cost-effectiveness analysis of pre-pregnancy genetic screening for deafness: an empirical study in China

Objectives

This research aims to assess the effectiveness and cost-effectiveness of pre-pregnancy deafness screening policies.

Methods

Married couples from Shanghai, Beijing, and Suzhou in China were enrolled. We conducted high-throughput, pre-pregnancy genetic screenings for deafness in women and their partners. We compared the cost-effectiveness of deafness genetic screening with the status quo. The two-step screening (wife then partner) and following treatments and interventions were included in the decision tree model. We conducted a cost-effectiveness analysis based on the decrease in deaf newborns, healthy newborn births, and cost-utility analysis of pre-pregnancy deafness genetic screening separately. Cost, utility, and probability data used in the three models were collected from a survey combined with literature and expert consultants. A 5% discount rate and a series of one-way sensitivity analyses along with a Monte Carlo simulation were used to test the reliability of this research.

Results

Between Jan 1, 2019, and Dec 31, 2021, we recruited 6,200 females and 540 male spouses from community health service centers in Shanghai, Beijing, and Suzhou. The incremental cost-effectiveness ratio (ICER) for reducing deaf newborn births was USD 32,656 per case and USD 1,203,926 per case for increasing one healthy newborn birth. This gap exists because of the overall decrease of newborn births. From the perspective of the whole society, deafness genetic screening is not cost-effective for reducing the overall quality-adjusted life years (QALY) in the population.

Discussion

Pre-pregnancy genetic testing is effective in decreasing the occurrence of congenital deafness. It is a cost-saving measure when compared with the costs of future medical expenditure and income loss for the affected families. However, such screening and preventive avoidance of pregnancy will decrease the population size and QALY. Only post-screening ART with PGT was shown to increase the birth of healthy newborns. Focusing on key groups such as premature births or consanguineous couples may improve the societal effects of screening.

Application of the PGT-M strategy using single sperm and/or affected embryos as probands for linkage analysis in males with hereditary tumor syndromes without family history

Hereditary tumor syndromes have garnered substantial attention due to their adverse effects on both the physical and psychological health of patients, as well as the elevated risk of transmission to subsequent generations. This has prompted a growing interest in exploring preimplantation genetic testing (PGT) as a treatment option to mitigate and eliminate these impacts. Several studies have demonstrated that de novo variants have become a great cause of many hereditary tumor syndromes, which introduce certain difficulties to PGT. In the absence of adequate genetic linkage information (parents and offspring), haplotype construction seems unrealizable. In the study, researchers used single sperm or affected embryos as proband to perform single-nucleotide polymorphism linkage analysis for cases with de novo variants. For complicated variants, the strategy that sperm combined with embryo detection will increase accuracy while avoiding the limitations and potential failures of using a single detection material. The study recruited 11 couples with male de novo carriers, including 3 tumor types and 4 genes. To date, 4 couples have been clinically confirmed as pregnant and three healthy babies have been born. The results of amniocentesis or umbilical cord blood verification were consistent with the results of PGT-M. The study aims to introduce the application of the PGT-M strategy in hereditary tumor syndromes.

A novel embryo biopsy morphological analysis and genetic integrality criterion system significantly improves the outcome of preimplantation genetic testing

PURPOSE

While efforts have been made to establish blastocyst grading systems in the past decades, little research has examined the quality of biopsy specimens. This study is the first to correlate the morphology of biopsied trophectoderm (TE) cells to their quality and subsequent genetic testing results of preimplantation genetic testing (PGT), through an innovative Morphological Analysis and Genetic Integrality Criterion (MAGIC) system.

METHODS

Biopsied TE cells were first evaluated according to the MAGIC procedure, followed by whole-genome amplification (WGA) and library construction, and then sequenced using the Illumina X Ten Platform. Copy number variation (CNV) and allele drop-out (ADO) rates as well as test failure rates were compared and analyzed.

RESULTS

Our data explores the relationship between TE cell morphology and its quality and final genetic testing outcome, which is established based on the MAGIC system. MAGIC guarantees that only high- or good-quality TE cells are used for genetic testing to generate excellent data uniformity and lower ADO rates. Low-quality cells containing biopsied TE cell mass are responsible for the "background noise" of CNV analysis.

CONCLUSION

The MAGIC application has effectively decreased the false-positive mosaicism, hence to ensure the stability and veracity of detection results, to avoid misdiagnoses, and to improve accuracy, as well as to avoid re-biopsy procedures. The study also contributes to understand how the IVF laboratory and the molecular biology laboratory depend on each other to achieve good-quality PGT results, which are clinically relevant for the patients.

Does endometrial receptivity array improve reproductive outcomes in euploid embryo transfer cycles? a systematic review

Besides chromosomal normality, endometrial receptivity is an important factor in determining successful pregnancies. Endometrial receptivity array (ERA), a promising endometrial receptivity test, was speculated to improve the reproductive outcomes. However, its effectiveness is controversial in clinical practice. Therefore, we conducted this review to investigate its role in in vitro fertilization (IVF) treatment. To eliminate the interference of embryo quality, we only analyzed studies that originally reported the reproductive outcomes of patients who underwent ERA-guided euploid embryo transfer (EET). Unexpectedly, it revealed that ERA could not optimize the reproductive outcomes in EET cycles, no matter in general infertile population or in patients with a history of previous failed embryo transfers.

Cardio-Obstetrics and Heart Failure: JACC: Heart Failure State-of-the-Art Review

Heart failure and cardiomyopathy are significant contributors to pregnancy-related deaths, as maternal morbidity and mortality have been increasing over time. In this setting, the role of the multidisciplinary cardio-obstetrics team is crucial to optimizing maternal, obstetrical and fetal outcomes. Although peripartum cardiomyopathy is the most common cardiomyopathy experienced by pregnant individuals, the hemodynamic changes of pregnancy may unmask a pre-existing cardiomyopathy leading to clinical decompensation. Additionally, there are unique management considerations for women with pre-existing cardiomyopathy as well as for those women with advanced heart failure who may be on left ventricular assist device support or have undergone heart transplantation. The purpose of this review is to discuss: 1) preconception counseling; 2) risk stratification and management strategies for pregnant women extending to the postpartum "fourth trimester" with pre-existing heart failure or "pre-heart failure;" 3) the safety of heart failure medications during pregnancy and lactation; and 4) management of pregnancy for women on left ventricular assist device support or after heart transplantation.

Preimplantation genetic testing for Aicardi-Goutières syndrome induced by novel compound heterozygous mutations of TREX1: an unaffected live birth

BACKGROUND

Aicardi-Goutières syndrome (AGS) is a rare, autosomal recessive, hereditary neurodegenerative disorder. It is characterized mainly by early onset progressive encephalopathy, concomitant with an increase in interferon-α levels in the cerebrospinal fluid. Preimplantation genetic testing (PGT) is a procedure that could be used to choose unaffected embryos for transfer after analysis of biopsied cells, which prevents at-risk couples from facing the risk of pregnancy termination.

METHODS

Trio-based whole exome sequencing, karyotyping and chromosomal microarray analysis were used to determine the pathogenic mutations for the family. To block the inheritance of the disease, multiple annealing and looping-based amplification cycles was used for whole genome amplification of the biopsied trophectoderm cells. Sanger sequencing and next-generation sequencing (NGS)-based single nucleotide polymorphism (SNP) haplotyping were used to detect the state of the gene mutations. Copy number variation (CNV) analysis was also carried out to prevent embryonic chromosomal abnormalities. Prenatal diagnosis was preformed to verify the PGT outcomes.

RESULTS

A novel compound heterozygous mutation in TREX1 gene was found in the proband causing AGS. A total of 3 blastocysts formed after intracytoplasmic sperm injection were biopsied. After genetic analyses, an embryo harbored a heterozygous mutation in TREX1 and without CNV was transferred. A healthy baby was born at 38th weeks and prenatal diagnosis results confirmed the accuracy of PGT.

CONCLUSIONS

In this study, we identified two novel pathogenic mutations in TREX1, which has not been previously reported. Our study extends the mutation spectrum of TREX1 gene and contributes to the molecular diagnosis as well as genetic counseling for AGS. Our results demonstrated that combining NGS-based SNP haplotyping for PGT-M with invasive prenatal diagnosis is an effective approach to block the transmission of AGS and could be applied to prevent other monogenic diseases.

Addressing ethical issues related to prenatal diagnostic procedures

BACKGROUND

For women of advanced maternal age or couples with high risk of genetic mutations, the ability to screen for embryos free of certain genetic mutations is reassuring, as it provides opportunity to address age-related decline in fertility through preimplantation genetic testing. This procedure has potential to facilitate better embryo selection, improve implantation rates with single embryo transfer and reduce miscarriage rates, among others, yet confers some risk to the embryo and additional costs of assisted reproductive technology. This raises questions whether, when and which patients should receive routine PGT-A prior to embryo transfer.

DISCUSSION

Prenatal diagnostic procedures refer to tests done when one or both genetic parents has a known genetic disorder (or has worries about the disorder) and testing is performed on them, their gametes or on the embryos to determine if the latter is likely to carry a genetic disorder. PGT is used to identify genetic defects in gametes or embryos (often created through in vitro fertilization (IVF). The procedures generate immense potential to improve health and wellbeing by preventing conception or birth of babies with undesirable traits, life-limiting conditions and even lethal conditions. However, they generate a lot of information, which often may challenge decision-making ability of healthcare providers and parents, and raise ethical challenges.

CONCLUSION

Prenatal diagnostic procedures have potential to address uncertainty and risk of having a child affected with a genetic disease. They, however, often raise own uncertainty and controversies, whose origin, manifestation and related ethical issues are presented. There is need to develop individual and couple decision support tools that incorporate patients' values and concerns in the decision-making process in order to promote more informed decisions, during counseling.

Non-invasive evaluation of embryo quality for the selection of transferable embryos in human in vitro fertilization-embryo transfer

The ultimate goal of human assisted reproductive technology is to achieve a healthy pregnancy and birth, ideally from the selection and transfer of a single competent embryo. Recently, techniques for efficiently evaluating the state and quality of preimplantation embryos using time-lapse imaging systems have been applied. Artificial intelligence programs based on deep learning technology and big data analysis of time-lapse monitoring system during in vitro culture of preimplantation embryos have also been rapidly developed. In addition, several molecular markers of the secretome have been successfully analyzed in spent embryo culture media, which could easily be obtained during in vitro embryo culture. It is also possible to analyze small amounts of cell-free nucleic acids, mitochondrial nucleic acids, miRNA, and long non-coding RNA derived from embryos using real-time polymerase chain reaction (PCR) or digital PCR, as well as next-generation sequencing. Various efforts are being made to use non-invasive evaluation of embryo quality (NiEEQ) to select the embryo with the best developmental competence. However, each NiEEQ method has some limitations that should be evaluated case by case. Therefore, an integrated analysis strategy fusing several NiEEQ methods should be urgently developed and confirmed by proper clinical trials.

Should Preimplantation Genetic Testing (PGT) Systematically Be Proposed to BRCA Pathogenic Variant Carriers?

Over the past years, BRCA genes pathogenic variants have been associated to reproductive issues. Indeed, evidence indicate that BRCA-mutated patients are not only at higher risk of developing malignancies, but may also present a reduction of the follicular stockpile. Given these characteristics, BRCA patients may be candidates to fertility preservation (FP) techniques or preimplantation genetic testing (PGT) to avoid the transmission of this inherited situation. Since the success rates of both procedures are highly related to the number of oocytes that could be recovered after ovarian stimulation, predicted by ovarian reserve tests, they are ideally performed before the diagnosis of cancer and its treatment. Despite the specific reproductive challenges related to BRCA status, no international guidelines for the application of PGT and FP in this subgroup of patients is currently available. The present article aims to review the available data regarding BRCA carriers' ovarian reserve and PGT success rates in oncologic and non-oncologic contexts, to determine the actual indication of PGT and further to improve patients' care pathway.

Clinical Utility of Medical Exome Sequencing: Expanded Carrier Screening for Patients Seeking Assisted Reproductive Technology in China

Purpose: Expanded carrier screening (ECS) is an effective method to identify at-risk couples (ARCs) and avoid birth defects. This study aimed to reveal the carrier spectrum in the Chinese population and to delineate an expanded carrier gene panel suitable in China.

Methods: Medical exome sequencing (MES), including 4,158 disease-causing genes, was offered to couples at two reproductive centers. It was initially used as a diagnostic yield for potential patients and then used for ECS. Clinical information and ECS results were retrospectively collected.

Results: A total of 2,234 couples, representing 4,468 individuals, underwent MES. In total, 254 individuals showed genetic disease symptoms, and 56 of them were diagnosed with genetic diseases by MES. Overall, 94.5% of them were carriers of at least one disease-causing variant. The most prevalent genes were GJB2 for autosomal recessive disorders and G6PD for X-linked diseases. The ARC rate was 9.80%, and couples were inclined to undergo preimplantation genetic testing when diseases were classified as “profound” or “severe.”

Conclusion: This study provided insight to establish a suitable ECS gene panel for the Chinese population. Disease severity significantly influenced reproductive decision-making. The results highlighted the importance of conducting ECS for couples before undergoing assisted reproductive technology.

Whole Genome Amplification in Preimplantation Genetic Testing in the Era of Massively Parallel Sequencing

Successful whole genome amplification (WGA) is a cornerstone of contemporary preimplantation genetic testing (PGT). Choosing the most suitable WGA technique for PGT can be particularly challenging because each WGA technique performs differently in combination with different downstream processing and detection methods. The aim of this review is to provide insight into the performance and drawbacks of DOP-PCR, MDA and MALBAC, as well as the hybrid WGA techniques most widely used in PGT. As the field of PGT is moving towards a wide adaptation of comprehensive massively parallel sequencing (MPS)-based approaches, we especially focus our review on MPS parameters and detection opportunities of WGA-amplified material, i.e., mappability of reads, uniformity of coverage and its influence on copy number variation analysis, and genomic coverage and its influence on single nucleotide variation calling. The ability of MDA-based WGA solutions to better cover the targeted genome and the ability of PCR-based solutions to provide better uniformity of coverage are highlighted. While numerous comprehensive PGT solutions exploiting different WGA types and adjusted bioinformatic pipelines to detect copy number and single nucleotide changes are available, the ones exploiting MDA appear more advantageous. The opportunity to fully analyse the targeted genome is influenced by the MPS parameters themselves rather than the solely chosen WGA.

Analysis of KRAS Mutation Status Prediction Model for Colorectal Cancer Based on Medical Imaging

This study retrospectively included some patients with colorectal cancer diagnosed by histopathology, to explore the feasibility of CT medical image texture analysis in predicting KRAS gene mutations in patients with colorectal cancer. Before any surgical procedure, all patients received an enhanced CT scan of the abdomen and pelvis, as well as genetic testing. To define patient groups, divide all patients into test and validation sets based on the order of patient enrollment. A radiologist took a look at the plain axial CT image of the tumor, as well as the portal vein CT image, at the corresponding level. The physician points the computer's cursor to the relevant area in the image, and TexRAD software programs together texture parameters based on various spatial scale factors, also known as total mean, total variance, statistical entropy, overall total average, mean total, positive mean, skewness value, kurtosis value, and general skewness. Using the same method again two weeks later, the observer and another physician measured the image of each patient again to see if the method was consistent between observers. With regard to clinical information, the KRAS gene mutation group and the wild group of participants in the test set and validation set each had values for the texture parameter. In a study of patients with colorectal cancer, the results demonstrated that CT texture parameters were correlated with the presence of the KRAS gene mutation. The best CT prediction model includes the values of the medium texture image's slope and the other CT fine texture image's value of entropy, the medium texture image's slope and kurtosis, and the medium texture image's mean and the other CT fine texture image's value of entropy. Regardless of the training set or the validation set, patients with and without KRAS gene mutations did not differ significantly in clinical characteristics. This method can be used to identify mutations in the KRAS gene in patients with colorectal cancer, making it practical to implement CT medical image texture analysis technology for that purpose.

Preimplantation Genetic Testing Prevented Intergenerational Transmission of X-Linked Alport Syndrome

BACKGROUND

Alport syndrome (AS) is a hereditary renal basement membrane disease that can lead to end-stage renal disease in young adults. It can be diagnosed by genetic analysis, being mostly caused by mutations in COL4A3, COL-4A4, and COL4A5. To date, there is no radical cure for this disease.

OBJECTIVES

The aim of this study was to avoid the transmission of AS within an affected family by selecting healthy embryos for uterine transfer. The embryos were identified by preimplantation genetic testing for monogenic disorders (PGT-M).

METHODS

We used next-generation sequencing (NGS) to identify mutations in the proband and his parents. The results of NGS were confirmed by Sanger sequencing. Targeted NGS combined with targeted single-nucleotide polymorphism haplotyping was used for the in vitro identification of COL4A5 mutations in human embryos to prevent their intergenerational transmission.

RESULTS

The c.349_359delGGACCTCAAGG and c.360_361insTGC mutations in COL4A5 were identified in a family affected by X-linked AS. Whole-genome sequencing by NGS with targeted haplotyping was performed on biopsied trophectoderm cells. A healthy baby was born after transfer of a single freeze-thawed blastocyst.

CONCLUSIONS

The use of targeted NGS for identifying diagnostic markers combined with targeted haplotyping is an easy and efficient PGT-M method for preventing intergenerational transmission of AS.

Liquid biopsy: state of reproductive medicine and beyond

Liquid biopsy is the process of sampling and analyzing body fluids, which enables non-invasive monitoring of complex biological systems in vivo. Liquid biopsy has myriad applications in health and disease as a wide variety of components, ranging from circulating cells to cell-free nucleic acid molecules, can be analyzed. Here, we review different components of liquid biopsy, survey state-of-the-art, non-invasive methods for detecting those components, demonstrate their clinical applications and discuss ethical considerations. Furthermore, we emphasize the importance of artificial intelligence in analyzing liquid biopsy data with the aim of developing ethically-responsible non-invasive technologies that can enhance individualized healthcare. While previous reviews have mainly focused on cancer, this review primarily highlights applications of liquid biopsy in reproductive medicine.

Effect of endometrial thickness changes on clinical pregnancy rates after progesterone administration in a single frozen-thawed euploid blastocyst transfer cycle using natural cycles with luteal support for PGT-SR- and PGT-M-assisted reproduction: a retrospective cohort study

BACKGROUND

To investigate whether the endometrial thickness change ratio from the progesterone administration day to the blastocyst transfer day is associated with pregnancy outcomes in a single frozen-thawed euploid blastocyst transfer cycle.

METHODS

All patients used natural cycles with luteal support for endometrial preparation and selected a single euploid blastocyst for transfer after a biopsy for preimplantation genetic testing. The endometrial thickness was measured by transvaginal ultrasound on the progesterone administration day and the transfer day, the change in endometrial thickness was measured, and the endometrial thickness change ratio was calculated. According to the change rate of endometrial thickness, the patients were divided into three groups: the endometrial thickness compaction group, endometrial thickness non-change group and endometrial thickness expansion group. Among them, the endometrial thickness non-change and expansion groups were combined into the endometrial thickness noncompaction group.

RESULTS

Ultrasound images of the endometrium in 219 frozen-thawed euploid blastocyst transfer cycles were evaluated. The clinical pregnancy rate increased with the increase in endometrial thickness change ratio, while the miscarriage rate and live birth rate were comparable among the groups. The multiple logistic regression results showed that in the fully adjusted model a higher endometrial thickness change ratio (per 10%) was associated with a higher clinical pregnancy rate (adjusted odds ratio [aOR] 1.29; 95% confidence interval [CI], 1.01-1.64; P = .040). Similarly, when the patients were divided into three groups according to the change rate of endometrial thickness, the endometrial thickness noncompaction group had a significant positive effect on the clinical pregnancy rate compared with the endometrial thickness compaction group after adjusting for all covariates.

CONCLUSIONS

In frozen-thawed euploid blastocyst transfer cycles in which the endometrium was prepared by natural cycles with luteal support, the clinical pregnancy rate was higher in cycles without endometrial compaction after progesterone administration.

Endometrial thickness changes after progesterone administration do not affect the pregnancy outcomes of frozen-thawed euploid blastocyst transfer: a retrospective cohort study

OBJECTIVE

To evaluate whether the change in endometrial thickness from progesterone administration day to transfer day is related to pregnancy outcomes in single frozen-thawed euploid blastocyst transfer cycles.

DESIGN

Observational cohort study.

SETTING

Single reproductive medical center.

PATIENT(S)

All patients were transferred with a single biopsied euploid blastocyst, and their endometrium was prepared with hormone replacement therapy (HRT).

INTERVENTION(S)

The endometrial thickness on the day of blastocyst transfer and progesterone administration was measured by transvaginal ultrasound, and the difference between them and the change ratio were calculated.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rates and live birth rates.

RESULT(S)

Endometrial ultrasound images of 508 euploid blastocyst transfer cycles using HRT were evaluated by transvaginal ultrasound. Overall, pregnancy outcomes were comparable in different groups of endometrial thickness changes. The results of multiple logistic regression showed that the clinical pregnancy rate and live birth rate did not significantly increase with the increase in endometrial thickness change ratios (per 10%) in the fully adjusted model as a continuous variable. In the adjustment model as a categorical variable, there was no statistical difference in pregnancy outcomes among the groups with changes in endometrial thickness. Interaction analysis showed that after adjusting for confounders, there was no statistically significant interaction between the endometrial thickness change ratio and pregnancy outcomes in all subgroups.

CONCLUSION(S)

In the euploid blastocyst transfer cycle of preparing the endometrium with HRT, the endometrial thickness change ratio after progesterone administration was not related to pregnancy outcomes.

Live birth rates after natural cycle versus hormone replacement therapy for single euploid blastocyst transfers: a retrospective cohort study

RESEARCH QUESTION

Is there any difference in live birth rate between the natural cycle and hormone replacement therapy (HRT) endometrial preparation protocols for women with regular menstrual cycles undergoing their first single vitrified-warmed euploid blastocyst transfer?

DESIGN

This was a retrospective cohort study that enrolled 722 women who underwent vitrified-warmed euploid blastocyst transfer at assisted reproductive technology (ART) centre of The First Affiliated Hospital of Zhengzhou University, from January 2013 to December 2019. Univariate and multivariate logistic regression models were used to analyse the relationship between the endometrial preparation protocols and live birth rates. Stratified analyses and sensitivity analyses were performed to ensure the reliability and stability of the results.

RESULTS

A total of 722 single vitrified-warmed euploid blastocyst transfer cycles were included. Overall, the live birth rates were 50.00% (110/220) in the natural cycle group and 47.61% (239/502) in the HRT group. Multiple logistic regression analyses showed that there was no significant association (adjusted odds ratio 0.82; 95% confidence interval 0.56-1.20; P = 0.313) between natural cycle and HRT protocols and the live birth rate. Interaction analysis showed that there was no significant difference in live birth rates between the two groups for any subgroup after adjusting for confounding factors.

CONCLUSIONS

For single vitrified-warmed euploid blastocyst transfer, natural cycle and HRT endometrial preparation protocols result in similar live birth rates among women with regular menstrual cycles. Further studies are needed into the effects of endometrial preparation protocols on pregnancy outcomes.

Effects of Gender of Reciprocal Chromosomal Translocation on Blastocyst Formation and Pregnancy Outcome in Preimplantation Genetic Testing

Objective

To determine the effect of gender of reciprocal chromosomal translocation on blastocyst formation and pregnancy outcome in preimplantation genetic testing, including different parental ages.

Methods

This was a retrospective cohort study that enrolled 1034 couples undergoing preimplantation genetic testing-structural rearrangement on account of a carrier of reciprocal chromosomal translocation from the Reproductive Medicine Center of the First Affiliated Hospital of Zhengzhou University from January 2015 to December 2019. Group A represented 528 couples in which the man was the carrier of reciprocal translocation and group B represented 506 couples in which the woman was the carrier of reciprocal translocation. All patients were divided into two groups according to their age: female age<35 and female age≥35. Furthermore, the differences in blastocyst condition and pregnancy outcome between male and female carriers in each group were further explored according to their father's age.

Results

The blastocyst formation rate of group A (55.3%) is higher than that of group B (50%) and the results were statistically significant (P<0.05). The blastocyst formation rate of group A is higher than that of group B, no matter in young maternal age or in advanced maternal age (P<0.05). The blastocyst formation rate in maternal age<35y and paternal age<30y in group A(57.1%) is higher than that of Group B(50%); Similarly, the blastocyst formation rate in maternal age≥35 and paternal age≥38y(66.7%) is higher than that of Group B(33.3%)(all P<0.05). There was no difference in fertilization rate, aeuploidy rate, clinical pregnancy rate, miscarriage rate and live birth rate between Group A and Group B.

Conclusion

When the carrier of reciprocal translocation is male, the blastocyst formation rate is higher than that of female carrier. While there is no significant difference between the two in terms of fertilization rate, aeuploidy rate, clinical pregnancy rate, miscarriage rate and live birth rate.

Variant haplophasing by long-read sequencing: a new approach to preimplantation genetic testing workups

OBJECTIVE

To apply long-read, third-generation sequencing as a part of a general workup strategy for performing structural rearrangement (PGT-SR) and monogenic disease (PGT-M) embryo testing.

DESIGN

Prospective study.

SETTING

In vitro fertilization unit.

PATIENT(S)

Couples presenting for PGT-SR (n = 15) and PGT-M (n = 2).

INTERVENTION(S)

Blastocyst biopsy with molecular testing for translocation breakpoints or mutations (targets).

MAIN OUTCOME MEASURE(S)

Detailed, parental-phased, single-nucleotide polymorphism (SNP) profiles around targets for selection of informative polymorphic markers to simplify and facilitate clinical preimplantation genetic testing (PGT) designs that enable discrimination between carrier and noncarrier embryos.

RESULT(S)

High definition of chromosome breakpoints together with closely phased polymorphic markers was achieved for all 15 couples presenting for PGT-SR. Similarly, for the two couples presenting for PGT-M, tightly linked informative markers around the mutations were also simply identified. Three couples with translocations t(1;17)(q21;p13), t(3;13)(p25;q21.2), and t(12;13)(q23;q22) proceeded with PGT-SR, requesting preferential identification of noncarrier embryos for transfer. Following selection of a set of informative SNPs linked to breakpoints, we successfully performed PGT-SR tests, resulting in ongoing pregnancies with a noncarrier fetus for all couples. Similarly, with the use of tests based on informative SNPs linked to the parental mutations, one couple proceeded with PGT-M for maple syrup urine disease, resulting in an ongoing pregnancy with a disease-free fetus.

CONCLUSION(S)

For couples contemplating clinical PGT, variant haplophasing around the target reduces the workup process by enabling rapid selection of closely linked informative markers for patient-specific test design.

Intersection of Heart Failure and Pregnancy: Beyond Peripartum Cardiomyopathy

Heart failure (HF) is a leading cause of morbidity and mortality in pregnant women in the United States. Although peripartum cardiomyopathy is the most common diagnosis for pregnant women with HF, women with preexisting cardiomyopathies and systolic dysfunction are also at risk as the hemodynamic demands of pregnancy can lead to decompensation, arrhythmia, and rarely death. The differential diagnosis of HF in pregnancy is broad and includes Takotsubo or stress cardiomyopathy, exacerbation of a preexisting cardiomyopathy, such as familial cardiomyopathy, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, or left ventricular noncompaction. This review will explore the implications of pregnancy in women with preexisting cardiomyopathies and de novo HF, risk assessment and preconception planning, decisions about contraception, the safety of HF medications and implantable cardioverter-defibrillators during pregnancy, pregnancy in women with left ventricular assist devices and following heart transplantation.

A workflow for simultaneous DNA copy number and methylome analysis of inner cell mass and trophectoderm cells from human blastocysts

OBJECTIVE

To establish a workflow for isolating single trophectoderm (TE) and inner cell mass (ICM) cells and to simultaneously evaluate these cells for copy number variation (CNV) as well as methylome development.

DESIGN

Experimental.

SETTING

Academic medical center.

PATIENT(S)

Donated genetically abnormal blastocysts.

INTERVENTION(S)

Single cells were isolated, followed by bisulfite conversion and sequencing to identify CNV and methylome profiles.

MAIN OUTCOME MEASURE(S)

CNV and methylation profiling.

RESULT(S)

Two embryos were dissociated, isolating 46 single cells, with 17 ICM and 12 TE cells selected for further downstream analysis. Chromosome ploidies and embryo sex were concordant with the results from conventional aneuploidy testing. In 3 of the 29 cells, additional aneuploidies were discovered, indicating possible mosaicism undetected by routine preimplantation genetic testing for aneuploidy. CpG methylation frequency was higher in ICM cells compared with TE cells (44.3% vs. 32.4%), respectively, while non-CpG methylation frequency was similar among both cell types. CpG methylation levels accurately distinguished ICM from TE cells epigenetically.

CONCLUSION(S)

We describe an effective workflow for isolating and sequencing single ICM and TE cells from human blastocysts. The use of methylation profiling can help distinguish these two cell populations better then morphologic identification alone. TE cells had significantly lower levels of DNA methylation, which may be explained in part by the fact that these cells have begun the process of differentiation and are transcriptionally more active than ICM. This approach may be used to explore the genetic complexities within human embryos, specifically among the two primary cell types seen at this stage of development.

Genetic variants of small airways and interstitial pulmonary disease in children

Genetic variants of small airways and interstitial pulmonary disease have not been comprehensively studied. This cluster of respiratory disorders usually manifests from early infancy (‘lung disease in utero’). In this study, 24 variants linked to these entities are described. The variants involved two genes associated with surfactant metabolism dysfunction (ABCA3 and CSF2RB), two with pulmonary fibrosis (MUC5B and SFTP), one with bronchiectasis (SCNN1B), and one with alpha-1-antitrypsin deficiency (SERPINA1). A nonsense variant, MUC5B:c.16861G > T, p.Glu5621*, was found in homozygous state in two siblings with severe respiratory disease from birth. One of the siblings also had heterozygous SFTPA1:c.675C > G, p.Asn225Lys, which resulted in a more severe respiratory disease. The sibling with only the homozygous MUC5B variant had lung biopsy, which showed alveolar simplification, interstitial fibrosis, intra-alveolar lipid-laden macrophages, and foci of foreign body giant cell reaction in distal airspaces. Two missense variants, MUC5B:c.14936 T > C, p.Ile4979Thr (rs201287218) and MUC5B:c.16738G > A, p.Gly5580Arg (rs776709402), were also found in compound heterozygous state in two siblings with severe respiratory disease from birth. Overall, the results emphasize the need for genetic studies for patients with complex respiratory problems. Identifying pathogenic variants, such as those presented here, assists in effective family counseling aimed at genetic prevention. In addition, results of genetic studies improve the clinical care and provide opportunities for participating in clinical trials, such as those involving molecularly-targeted therapies.

Preimplantation genetic testing for carriers of BRCA1/2 pathogenic variants

The detection of germline BRCA1/2 pathogenic variant has relevant implications for the patients and their family members. Family planning, prophylactic surgery and the possibility of preimplantation genetic testing for monogenic disorders (PGT-M) to avoid transmittance of pathogenic variants to the offspring are relevant topics in this setting. PGT-M is valuable option for BRCA carriers, but it remains a controversial and underdiscussed topic. Although the advances in PGT technologies have improved pregnancy rate, there are still several important challenges associated with its use. The purpose of this review is to report the current evidence on PGT-M for BRCA1/2 carriers, ethical concerns and controversy associated with its use, reproductive implications of BRCA pathogenic variants, underlying areas in which an educational effort would be beneficial as well as possibilities for future research efforts in the field.

Age and Serum AMH and FSH Levels as Predictors of the Number of Oocytes Retrieved from Chromosomal Translocation Carriers after Controlled Ovarian Hyperstimulation: Applicability and Limitations

We studied the impact of age and the serum anti-Müllerian hormone (AMH)/follicle-stimulating hormone (FSH) levels on the number of cumulus–oocyte complexes (COCs) retrieved from female reciprocal and Robertsonian translocation carriers after controlled ovarian hyperstimulation (COH). The number of COCs retrieved after COH was retrospectively analyzed in female translocation carriers and 46,XX partners of male translocation carriers from 100 couples. The median number of COCs varied from nine to 16 and did not differ among subgroups of women categorized by age, presence and type of a translocation. The number of COCs correlated negatively with the woman’s age in both the reciprocal and the Robertsonian translocation carriers, while in 46,XX women no correlation was detected. The number of COCs did not differ between the reciprocal and the Robertsonian translocation carriers aged either <35 or ≥35 years. In translocation carriers, the number of COCs correlated with the serum AMH level only in the younger-age subgroups; the correlation was strong positive in reciprocal and moderate positive in Robertsonian translocation carriers. The 46,XX women aged both <35 and ≥35 years showed similar moderate positive correlations. Across all subgroups, the number of COCs correlated moderately negatively with the serum FSH level only in Robertsonian translocation carriers aged <35 years. Our results suggest that chromosomal translocations per se do not increase the risk of poor oocyte retrieval outcome after COH. In translocation carriers, oocyte retrieval outcome depends to a large extent on their age. The serum AMH level strongly predicts oocyte retrieval outcomes only in young reciprocal translocation carriers, while the serum FSH level has a moderate predictive value in young Robertsonian translocation carriers.

Preimplantation Genetic Testing for a Chinese Family With X-Linked Lymphoproliferative Syndrome Type 1

Background

X-linked lymphoproliferative disease (XLP) is a rare primary immunodeficiency disorder. We performed experiments based on two strategies of preimplantation genetic testing (PGT) for a family with XLP caused by a mutation in SH2D1A (c.191G > A).

Methods

First, a single-cell polymerase chain reaction (PCR) protocol was established using single lymphocytes. A nested PCR experiment was performed with direct sequencing after whole genome amplification of single cells to assess the accuracy of the genetic diagnosis. Embryos obtained after intracytoplasmic sperm injection were biopsied on day 3 and detected using the established single-cell PCR protocol. In the second PGT cycle, targeted next generation sequencing (NGS) was performed and the single nucleotide polymorphism (SNP) markers flanking SH2D1A were selected to determine the disease-carrying haplotype phase in each embryo.

Result

In the first PGT cycle, six embryos were biopsied. Discounting an embryo from a single failed PCR experiment, five embryos were identified, including three unaffected and two hemizygous. After PCR, one normal embryo was transferred when it was developing into an early blastocyst. Although the ultrasound images indicated a viable singleton pregnancy, the implantation was on the cesarean scar. Therefore, an artificial abortion was performed. In the haplotyping cycle, six embryos were identified to have inherited a haplotype without pathogenic mutations. After the embryo implantation process failed twice, a successful singleton pregnancy was established, and subsequently, a healthy female child was born.

Conclusion

Targeted NGS with haplotyping analysis circumvents the laborious process of multiplex PCR and is more likely to ensure diagnostic accuracy. However, when a genetic recombination occurs close to the site of mutation, confirmed identification using selected SNP markers can be challenging.

Three-dimensional digital PCR through light-sheet imaging of optically cleared emulsion

The realization of the vast potential of digital PCR (dPCR) to provide extremely accurate and sensitive measurements in the clinical setting has thus far been hindered by challenges such as assay robustness and high costs. Here we introduce a lossless and contamination-free dPCR technology, termed CLEAR-dPCR, which addresses these challenges by completing the dPCR sample preparation, PCR, and readout all in one tube. Optical clearing of the droplet dPCR emulsion was combined with emerging light-sheet fluorescence microscopy, to acquire a three-dimensional (3D) image of a half million droplets sealed in a tube in seconds. CLEAR-dPCR provides ultrahigh-throughput readout results in situ and fundamentally eliminates the possibility of either sample loss or contamination. This approach exhibits improved accuracy over existing dPCR platforms and enables a greatly increased dynamic range to be comparable to that of real-time quantitative PCR.

Pregnancy after Heart Transplantation

As post-transplant survival improves, many heart transplant (HT) recipients are of, or are surviving to, childbearing age. Solid-organ transplant recipients who become pregnant should be managed by a multidisciplinary cardio-obstetrics team, including specialists in maternal and fetal medicine, cardiology and transplant medicine, as well as anesthesia, neonatology, psychology, genetics, and social services. With careful patient selection, pregnancy after HT can been managed safely. The purpose of this comprehensive review was to summarize the current evidence and recommendations surrounding preconception counseling, medical management and surveillance, maternal outcomes, breastfeeding, and remaining gaps in knowledge.

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

OBJECTIVE

To assess whether trophectoderm biopsy has any impact on the level of serum β-human chorionic gonadotropin (β-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 β-hCG results on the 12th day after blastocysts transfers.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Serum β-hCG levels on the 12th day after warmed blastocyst transfer and perinatal outcomes of clinical pregnancy.

RESULTS

The diagnostic threshold of serum β-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 β-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 β-hCG in early pregnancies (the 12th day after embryo transfer), but no increased risk was found of adverse perinatal outcomes after trophectoderm biopsy.

Expanded carrier screening in Chinese patients seeking the help of assisted reproductive technology

Background

Expanded carrier screening (ECS) has emerged as an effective approach to identify at‐risk couples (ARCs)—before they initiate attempts at reproduction—who possess a high probability of having a child affected by severe recessive diseases. The objective of this study was to evaluate the clinical utility of ECS in Chinese patients seeking the help of assisted reproductive technology (ART).

Methods

An ECS test, which covers 201 genes implicated in 135 recessive (autosomal or X‐linked) diseases, was routinely offered to all ART patients in a single genetics and in vitro fertilization clinic. Additional options for preimplantation or prenatal genetic diagnosis were discussed and offered to all ARCs. All ECS results were aggregated and the clinical decisions of the ARCs were surveyed.

Results

A total of 2,923 ART patients, representing 1,462 couples, were screened. Overall, 46.73% of the individuals were found to be the carriers for at least 1 of the 135 diseases. Of the tested couples, 2.26% (n = 33) were identified as ARCs. As of the completion of this study, 21 (63.6%) ARCs have decided to avert an affected pregnancy with the help of preimplantation genetic testing for monogenetic conditions. The cumulative carrier rate of the 187 autosomal recessive genes in the ECS panel for the 2,836 Han Chinese individuals without a family history was estimated to be 45.91%. The estimated at‐risk couple rate indicates that the screening for only the top 31 genes with gene carrier rates >0.5% would identify more than 94% of the ARCs identified by screening all 187 genes.

Conclusion

Our study demonstrates that ESC yields a significant clinical value for ART patients in China. In addition, by estimating the yields of the ECS panel, we identify genes that are appropriate for screening the Han population.

Reproductive options for families at risk of Osteogenesis Imperfecta: a review

Background

Osteogenesis Imperfecta (OI) is a rare genetic disorder involving bone fragility. OI patients typically suffer from numerous fractures, skeletal deformities, shortness of stature and hearing loss. The disorder is characterised by genetic and clinical heterogeneity. Pathogenic variants in more than 20 different genes can lead to OI, and phenotypes can range from mild to lethal forms. As a genetic disorder which undoubtedly affects quality of life, OI significantly alters the reproductive confidence of families at risk. The current review describes a selection of the latest reproductive approaches which may be suitable for prospective parents faced with a risk of OI. The aim of the review is to alleviate suffering in relation to family planning around OI, by enabling prospective parents to make informed and independent decisions.

Main body

The current review provides a comprehensive overview of possible reproductive options for people with OI and for unaffected carriers of OI pathogenic genetic variants. The review considers reproductive options across all phases of family planning, including pre-pregnancy, fertilisation, pregnancy, and post-pregnancy. Special attention is given to the more modern techniques of assisted reproduction, such as preconception carrier screening, preimplantation genetic testing for monogenic diseases and non-invasive prenatal testing. The review outlines the methodologies of the different reproductive approaches available to OI families and highlights their advantages and disadvantages. These are presented as a decision tree, which takes into account the autosomal dominant and autosomal recessive nature of the OI variants, and the OI-related risks of people without OI.

The complex process of decision-making around OI reproductive options is also discussed from an ethical perspective.

Conclusion

The rapid development of molecular techniques has led to the availability of a wide variety of reproductive options for prospective parents faced with a risk of OI. However, such options may raise ethical concerns in terms of methodologies, choice management and good clinical practice in reproductive care, which are yet to be fully addressed.

Is cell-free DNA in spent embryo culture medium an alternative to embryo biopsy for preimplantation genetic testing? A systematic review

Preimplantation genetic testing (PGT) is increasingly used worldwide. It currently entails the use of invasive techniques, i.e. polar body, blastomere, trophectoderm biopsy or blastocentesis, to obtain embryonic DNA, with major technical limitations and ethical issues. Evidence suggests that invasive PGT can lead to genetic misdiagnosis in the case of embryo mosaicism, and, consequently, to the selection of affected embryos for implantation or to the destruction of healthy embryos. Recently, spent culture medium (SCM) has been proposed as an alternative source of embryonic DNA. An increasing number of studies have reported the detection of cell-free DNA in SCM and highlighted the diagnostic potential of non-invasive SCM-based PGT for assessing the genetic status of preimplantation human embryos obtained by IVF. The reliability of this approach for clinical applications, however, needs to be determined. In this systematic review, published evidence on non-invasive SCM-based PGT is presented, and its current benefits and limitations compared with invasive PGT. Then, ways of optimizing and standardizing procedures for non-invasive SCM-based PGT to prevent technical biases and to improve performance in future studies are discussed. Finally, clinical perspectives of non-invasive PGT are presented and its future applications in reproductive medicine highlighted.

Prognostic role of preimplantation genetic testing for aneuploidy in medically indicated fertility preservation

OBJECTIVE

To investigate the use of preimplantation genetic testing for aneuploidy (PGT-A) among patients pursuing embryo banking (EB) for medically indicated fertility preservation (FP).

DESIGN

Retrospective cohort.

SETTING

University-affiliated fertility center.

PATIENTS

All patients who underwent in vitro fertilization with or without PGT-A for medically indicated FP between January 2014 and April 2018.

INTERVENTIONS

None MAIN OUTCOME MEASURES: EB cycle characteristics, subsequent cycle pursuit/outcomes, and frozen embryo transfer (FET) outcomes.

RESULTS

A total of 58 medical EB cycles were compared; 34 cycles used PGT-A. Of the EB patients with breast cancer, 67% used PGT-A; other indications were evenly divided between PGT-A (FP/PGT-A) and no PGT-A (FP). PGT-A use increased over the study period. Groups were similar in age, days of stimulation, and days from initial FP consultation to treatment initiation. Number of oocytes (14.5 [2-63] FP vs. 17.5 [1-64] FP/PGT-A), 2PN zygotes (7 [1-38] FP vs. 9 [0-36] FP/PGT-A), and blastocysts (5.5 [0-22] FP vs. 5 [0-18] FP/PGT-A) cryopreserved were similar between groups. Equal numbers cryopreserved both oocytes and embryos (5 vs. 3). Five FP/PGT-A patients underwent a second EB cycle. Among FP/PGT-A patients, an average of 6.7 ± 5 blastocysts underwent PGT-A, with 3.5 ± 3 (48.2%) euploid embryos cryopreserved for future FET compared to an average of 7.2 ± 7 untested embryos in the FP group.

CONCLUSION

PGT-A in medical EB cycles increased over time and did not limit the use of other FP methods such as oocyte cryopreservation. In some cases, poor PGT-A results informed patients to pursue a second EB cycle. When counseling patients, the prognostic benefits of PGT-A must be weighed against the financial costs and potential for "terminal" fertility diagnosis.

Analysis of the Number of Euploid Embryos in Preimplantation Genetic Testing Cycles With Early-Follicular Phase Long-Acting Gonadotropin-Releasing Hormone Agonist Long Protocol

Studies have shown that early-follicular phase long-acting gonadotropin-releasing hormone (GnRH) agonist long protocol (EFLL), a popular controlled ovarian hyperstimulation protocol widely used in China, leads to higher rates of implantation and clinical pregnancy, as well as lower rates of spontaneous abortion and ectopic pregnancy in patients undergoing in vitro fertilization treatment. However, the impact of EFLL on euploid embryos and its underlying mechanisms remain unclear. To address these gaps of knowledge, we conducted a retrospective comparative study of 310 preimplantation genetic testing (PGT) cycles with a total of 1,541 embryos using the EFLL protocol or midluteal short-acting GnRH agonist long protocol (MLSL). Patients were matched by PGT subtype [aneuploidies (PGT-A) vs. PGT for chromosomal structural rearrangements (PGT-SR)], age (±2 years), and body mass index (±1 kg/m²). For PGT-A, there was no significant difference in the number of euploid embryos (1.80 ± 1.47 for EFLL vs. 1.84 ± 2.03 for MLSL, p > 0.05) or the rate of euploidy (44.6 vs. 36.9%, p > 0.05). For PGT-SR, the number of euploid embryos in the EFLL group was significantly higher than that in the MLSL group (1.76 ± 1.54 vs. 1.21 ± 1.24, p < 0.05). A higher euploidy rate was also observed with the EFLL protocol compared with that obtained in MLSL (31.9 vs. 25.7%), although the difference was not statistically significant (p > 0.05). Compared with the MLSL protocol, more euploid embryos were achieved when using the EFLL protocol in PGT-SR, demonstrating the value in PGT-SR. To the best of our knowledge, this study is the first one to compare embryonic outcomes between EFLL and MLSL, providing key insights into the clinical application of EFLL in PGT cycles. In the light of the limited sample size of our study, we recommend that these questions be explored using a larger prospective study.

Can preimplantation genetic diagnosis be used for monogenic endocrine diseases?

Context Preimplantation genetic diagnosis (PGD) is currently used for over 400 monogenic diseases. Some endocrine conditions that occur due to monogenic defects are either life-threatening or can cause severe morbidities; thus, PGD may be an option to avoid the occurrence of such diseases. Evidence acquisition An initial search in PubMed/Medline search was done to identify monogenic endocrine conditions using appropriate search terms. Eleven articles (1999-2018) reported 15 cases using PGD for monogenic endocrine diseases performed at major reproductive centers. Clinical and outcome data of these cases were reviewed with respect to the number of PGD cycles, successful pregnancy rates, live births and their genetic status. Evidence synthesis Fifteen couples underwent 32 PGD cycles (one to nine per couple), of which 17 resulted in a pregnancy. Seven couples underwent a single PGD cycle. Four couples had successful pregnancies each resulting in live births, one couple had an unsuccessful pregnancy, one needed medical termination of pregnancy and the outcome data were not reported in one. The remaining eight couples underwent multiple PGD cycles (two to nine per couple) and all had successful pregnancies in at least one cycle resulting in 16 live births. Of the total live births, 60% were genetically unaffected and 40% were carriers of the autosomal recessive gene mutation. Conclusions PGD may be a potential tool for preventing the inheritance of severe monogenic endocrine diseases in future generations. Currently, the use of PGD in endocrine disorders is rare but provides a promising option on a case-by-case basis, provided the optimal resources are available.

Thalassemia in the laboratory: pearls, pitfalls, and promises

Thalassemia is one of the most common hereditary disorders of the developing world, and it is associated with severe anemia and transfusion dependence. The global health burden of thalassemia has increased as a result of human mobility and migration in recent years. Depending on inherited mutations, thalassemia patients exhibit distorted hemoglobin (Hb) patterns and deviated red cell indices, both of which can be used to support identification by diagnostic tools. Diagnostic approaches vary depending on the target population and the aim of the testing. Current methods, which are based on Hb patterns, are used for first-line screening, whereas molecular testing is needed for conformation of the results and for prenatal and preimplantation genetic diagnosis. In the present paper, we review the diagnostic parameters, pitfalls, interfering factors, and methods; currently available best-practice guidelines; quality assurance and standardization of the procedures; and promising laboratory technologies for the future of thalassemia diagnosis.