Preimplantation Genetic Testing: ACOG Committee Opinion, Number 799

Transfer of embryos with positive PGT-M results: Genetic Counselors' perspectives and ethical considerations

Increasing numbers of fertility patients use preimplantation genetic testing for monogenic conditions (PGT-M) during in vitro fertilization (IVF). While PGT-M is primarily used to avoid implanting embryos with a monogenic condition, patients can request to transfer an embryo with the monogenic condition (positive embryo transfer), especially in cases where an IVF cycle results in no unaffected embryos. Transferring embryos with known disease-causing variants raises ethical concerns. There is limited understanding about how stakeholders in the assisted reproductive technology (ART) field approach these issues. In this study, genetic counselors were sent a survey to gather insight into their views about transferring embryos with different monogenic conditions. N = 99 genetic counselors completed the survey, 22 of whom had experience with patients requesting or deciding to transfer an embryo with a monogenic condition (positive embryo transfer experience). Most participants, including those with positive embryo transfer experience, were supportive of positive embryo transfer, regardless of the genetic condition. While participating genetic counselors were largely supportive of all patient decisions, they reported increased moral uneasiness around transferring embryos with life-limiting monogenic conditions, such as Huntington's disease. Further investigation into the experiences of genetic counselors who have experienced positive embryo transfer requests in practice can help delineate the ethical questions that ART providers face in this context and clarify how genetic counselors can contribute to establishing guidelines in the ART field.

Management strategies following implantation failure of euploid embryos

Background

Euploid blastocyst implantation failure may result from embryonic factors undetectable by preimplantation genetic testing for aneuploidy (PGT-A); however, various nonembryonic factors can also intricately interfere with implantation. This review seeks to clarify evidence-based testing and treatments for implantation failure after euploid embryo transfer.

Methods

We conducted a review of the literature on implantation failure after euploid embryo transfer or multiple embryo transfer cycles, which mainly included systematic reviews and meta-analyses.

Results

The recommended tests for implantation failure include (1) hysteroscopy, (2) endometrial CD138 immunohistochemistry and bacterial culture, (3) serum 25-hydroxyvitamin D3, and (4) thrombophilia screening. Based on diagnostic findings, the following treatments have been recommended: (1) antibiotics for chronic endometritis, (2) vitamin D replacement, (3) lifestyle modification, and (4) low-dose aspirin starting from the postimplantation period for thrombophilia. Moreover, frozen-thawed single euploid blastocyst transfer using assisted hatching and hyaluronan-enriched transfer medium may support embryo implantation.

Conclusion

To ensure a successful pregnancy in subsequent embryo transfers, simple, inexpensive, and evidence-based tests and treatments should be selected.

Challenges experienced by genetic counselors while they provided counseling about mosaic embryos

Objective

To survey genetic counselors (GCs) who have counseled about mosaic embryos regarding the challenges they faced in counseling this patient population and assess their need for more resources to support their practice.

Design

Self-administered online survey.

Setting

Academic university.

Study Population

Seventy-eight GCs primarily from the United States and Canada.

Interventions

Genetic counselors completed a quantitative survey with an embedded qualitative component. Quantitative data were analyzed by descriptive statistics. An inductive thematic analysis was performed on open-text responses.

Main Outcome Measures

Genetic counselors were asked what clinical activities relating to mosaic embryos they performed. They were then asked to rate how challenging each activity was to perform using a 5-point scale; a rating of 4 or 5 was defined as highly challenging. Open-text questions enabled GCs to describe factors that they felt contributed to these challenges.

Results

The challenges reported by GCs included the uncertainty of outcomes in offspring after mosaic embryo transfer, limited guidelines available to assist clinicians with counseling about mosaic embryos, and ranking mosaic embryos by suitability for transfer. The contributing factors suggested by participants included limited outcome data, limited GC involvement in pretest counseling for preimplantation genetic testing for aneuploidy (PGT-A), and perceived inconsistency in counseling practices across clinics. Genetic counselors differed in their genetic testing recommendations for pregnancies conceived after mosaic embryo transfer. Amniocentesis and postnatal assessment were recommended by 85% and 49% of GCs, respectively, and 15% recommended chorionic villus sampling and noninvasive prenatal testing. Almost all (92%) reported a need for more resources, such as standardized guidelines, more outcome data, and continuing education on PGT-A and mosaicism.

Conclusions

This study describes challenges experienced by GCs while they counseled about mosaic embryos. Our findings demonstrate a need for more outcome data on mosaic embryo pregnancies and for evidence-based clinical guidelines. The differing recommendations for prenatal genetic testing among GCs in the study warrant further research into contributing factors. We strongly recommend that pretest counseling, including a discussion regarding mosaicism, is provided to all couples considering PGT-A to reduce counseling challenges and to promote patients' informed decision-making.

Role of genetic analysis of products of conception and PGT in managing early pregnancy loss

This article considers the addition of comprehensive 24-chromosomal microarray (CMA) analysis of products of conception (POC) to a standard evaluation for recurrent pregnancy loss (RPL) to help direct treatment towards expectant management versus IVF with preimplantation genetic testing for aneuploidies (PGT-A). The review included retrospective data from 65,333 miscarriages, a prospective evaluation of 378 couples with RPL who had CMA testing of POC and the standard workup, and data from an additional 1020 couples who were evaluated for RPL but did not undergo CMA testing of POC. Aneuploidy in POC explained the pregnancy loss in 57.7% (218/378) of cases. In contrast, the full RPL evaluation recommended by the American Society for Reproductive Medicine identified a potential cause in only 42.9% (600/1398). Combining the data from the RPL evaluation and the results of genetic testing of POC provides a probable explanation for the loss in over 90% (347/378) of women. Couples with an unexplained loss after the standard evaluation with POC aneuploidy accounted for 41% of cases; PGT-A may be considered after expectant management. Conversely, PGT-A would have a limited role in those with a euploid loss and a possible explanation after the standard workup. Categorizing a pregnancy loss as an explained versus unexplained loss after the standard evaluation combined with the results of CMA testing of POC may help identify patients who would benefit from expectant management versus PGT-A.

Update on preimplantation genetic testing for aneuploidy and outcomes of embryos with mosaic results

Preimplantation genetic testing for aneuploidy (PGT-A) is used as a frequent add-on for in-vitro fertilization (IVF) to improve clinical outcomes. The purpose is to select a euploid embryo following chromosomal testing on embryo biopsies. The current practice includes comprehensive chromosome screening (CCS) technology applied on trophectoderm (TE) biopsies. Despite its widespread use, PGT-A remains a controversial topic mainly because all of the RCTs comprised only good prognosis patients with 2 or more blastocysts available; hence the results are not generalizable to all groups of patients. Furthermore, with the introduction of the highly-sensitive platforms into clinical practice (i.e. next-generation sequencing [NGS]), a result consistent with intermediate copy number surfaced and is termed "Mosaic," consistent with a mixture of euploid and aneuploid cells within the biopsy sample. The optimal disposition and management of embryos with mosaic results is still an open question, as many 'mosaics' generated healthy live births with no identifiable congenital anomalies. The present article provides a complete and comprehensive up-to-date review on PGT-A. It discusses in detail the findings of all the published RCTs on PGT-A with CCS, comments on the subject of "mosaicism" and its current management, and describes the latest technique of non-invasive PGT-A.

Indications and management of preimplantation genetic testing for monogenic conditions: a committee opinion

This statement is offered to update and expand on the prior American Society for Reproductive Medicine preimplantation genetic testing (PGT) opinion, elucidate the current clinical and technical complexities specific to PGT for monogenic conditions, assist providers in supporting patient understanding of and access to this technology, and offer considerations for the development of future clinical and laboratory guidelines on PGT for monogenic conditions.

Implications for Prenatal Genetic Testing in the United States After the Reversal of Roe v Wade

Prenatal genetic screening and diagnostic testing should be offered to every pregnant individual, with methods varying based on gestational age. Since Roe v Wade was overturned in June 2022, many states have implemented gestational age-based abortion restrictions. It is critical that reproductive health care professionals be aware of the interaction between the timing of genetic screening and diagnostic testing and the availability of legal abortion services in their state. We examined individual state abortion restrictions per publicly available data from The New York Times and the Guttmacher Institute and reviewed which genetic screening and diagnostic tests could be performed to provide results in time for individuals to decide whether to terminate their pregnancies legally in each state. As of December 11, 2022, 14 states have restrictions in which no diagnostic testing could be completed before gestational age-based cutoffs. Gestational age-based abortion restrictions may also influence a patient to favor chorionic villous sampling (CVS) over amniocentesis. There are two states, Florida and Arizona, where CVS would be feasible before the state's gestational age limit on abortion but amniocentesis would not. Both CVS and amniocentesis are feasible in 35 states, with legal challenges pending in 8 of the 35. Seven states specifically prohibit abortion for fetuses with genetic abnormalities. Clinicians may be placed in the suboptimal position of counseling patients with screening results alone before the gestational age-based ban in their state. There are several potential downstream consequences of gestational age-based termination restrictions for current genetic screening and testing paradigms, from adjustments to counseling options to potentially higher CVS procedure rates. Clinicians should be prepared for practice patterns to change to best serve patients in this evolving legal context.

Preimplantation genetic testing for aneuploidy: challenges in clinical practice

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

REPRODUCTIVE OPHTHALMOLOGY: The Intersection of Inherited Eye Diseases and Reproductive Technologies

PURPOSE

To propose a working framework for patients with inherited eye diseases presenting to ophthalmologists who are interested in assisted reproductive technology and preimplantation genetic testing.

METHODS

Retrospective chart review and case series of three families with inherited eye diseases who successfully underwent preimplantation genetic testing, in vitro fertilization, and birth of unaffected children.

RESULTS

Preimplantation genetic testing was performed for three families with different inherited eye diseases, which included autosomal dominant retinitis pigmentosa, autosomal recessive achromatopsia, and X-linked Goltz syndrome. Preimplantation genetic testing led to the identification of unaffected embryos, which were then selected for in vitro fertilization and resulted in the birth of unaffected children.

CONCLUSION

A close collaboration between patients, families, ophthalmologists, reproductive genetic counselors, and reproductive endocrinology and infertility specialists is the ideal model for taking care of patients interested in preimplantation genetic testing for preventing the transmission of inherited eye diseases.

Expanding insurance coverage for in vitro fertilisation with preimplantation genetic testing: putting the cart before the horse

Madison Kilbride recently argued that insurance (eg, Centers for Medicare & Medicaid Services (CMS)) should cover in vitro fertilisation with preimplantation genetic testing (IVF-PGT) services for couples at high risk of having a child affected with a genetic condition. She argues that IVF-PGT meets CMS's definition of 'medically necessary care', where such care includes 'services or supplies needed to diagnose or treat an illness, injury, condition, disease or its symptoms'. Kilbride argues that IVF-PGT satisfies this definition in two ways: as a diagnostic tool and as a treatment. Contradicting Kilbride, however, I argue that IVF-PGT provides neither diagnosis nor treatment under CMS's definition. Thus, as long as we accept CMS's definition of medically necessary care-which Kilbride does, explicitly-it follows that IVF-PGT does not count as medically necessary care. Still, there may be other reasons to conclude that IVF-Preimplantation genetic testing should be covered, and so, it would be a mistake to reject Kilbride's conclusion altogether. The problem is simply that Kilbride's argument-that the procedure should be covered because it is medically necessary per CMS's definition-is not sound. I conclude by discussing a number of other genetic services that are not currently being covered despite the fact that (unlike IVF-PGT) they do seem to satisfy CMS's definition of 'medically necessary diagnosis or treatment'. These services, I argue, should be provided under CMS before we consider expanding coverage to include elective procedures such as IVF-PGT.

Society for Maternal-Fetal Medicine Consult Series #60: Management of pregnancies resulting from in vitro fertilization

The use of assisted reproductive technology has increased in the United States in the past several decades. Although most of these pregnancies are uncomplicated, in vitro fertilization is associated with an increased risk for adverse perinatal outcomes primarily caused by the increased risks of prematurity and low birthweight associated with in vitro fertilization pregnancies. This Consult discusses the management of pregnancies achieved with in vitro fertilization and provides recommendations based on the available evidence. The recommendations by the Society for Maternal-Fetal Medicine are as follows: (1) we suggest that genetic counseling be offered to all patients undergoing or who have undergone in vitro fertilization with or without intracytoplasmic sperm injection (GRADE 2C); (2) regardless of whether preimplantation genetic testing has been performed, we recommend that all patients who have achieved pregnancy with in vitro fertilization be offered the options of prenatal genetic screening and diagnostic testing via chorionic villus sampling or amniocentesis (GRADE 1C); (3) we recommend that the accuracy of first-trimester screening tests, including cell-free DNA for aneuploidy, be discussed with patients undergoing or who have undergone in vitro fertilization (GRADE 1A); (4) when multifetal pregnancies do occur, we recommend that counseling be offered regarding the option of multifetal pregnancy reduction (GRADE 1C); (5) we recommend that a detailed obstetrical ultrasound examination (CPT 76811) be performed for pregnancies achieved with in vitro fertilization and intracytoplasmic sperm injection (GRADE 1B); (6) we suggest that fetal echocardiography be offered to patients with pregnancies achieved with in vitro fertilization and intracytoplasmic sperm injection (GRADE 2C); (7) we recommend that a careful examination of the placental location, placental shape, and cord insertion site be performed at the time of the detailed fetal anatomy ultrasound, including evaluation for vasa previa (GRADE 1B); (8) although visualization of the cervix at the 18 0/7 to 22 6/7 weeks of gestation anatomy assessment with either a transabdominal or endovaginal approach is recommended, we do not recommend serial cervical length assessment as a routine practice for pregnancies achieved with in vitro fertilization (GRADE 1C); (9) we suggest that an assessment of fetal growth be performed in the third trimester for pregnancies achieved with in vitro fertilization; however, serial growth ultrasounds are not recommended for the sole indication of in vitro fertilization (GRADE 2B); (10) we do not recommend low-dose aspirin for patients with pregnancies achieved with IVF as the sole indication for preeclampsia prophylaxis; however, if 1 or more additional risk factors are present, low-dose aspirin is recommended (GRADE 1B); (11) given the increased risk for stillbirth, we suggest weekly antenatal fetal surveillance beginning by 36 0/7 weeks of gestation for pregnancies achieved with in vitro fertilization (GRADE 2C); (12) in the absence of studies focused specifically on timing of delivery for pregnancies achieved with IVF, we recommend shared decision-making between patients and healthcare providers when considering induction of labor at 39 weeks of gestation (GRADE 1C).

Revisiting selected ethical aspects of current clinical in vitro fertilization (IVF) practice

Ethical considerations are central to all medicine though, likely, nowhere more essential than in the practice of reproductive endocrinology and infertility. Through in vitro fertilization (IVF), this is the only field in medicine involved in creating human life. IVF has, indeed, so far led to close to 10 million births worldwide. Yet, relating to substantial changes in clinical practice of IVF, the medical literature has remained surprisingly quiet over the last two decades. Major changes especially since 2010, however, call for an updated commentary. Three key changes deserve special notice: Starting out as a strictly medical service, IVF in recent years, in efforts to expand female reproductive lifespans in a process given the term “planned” oocyte cryopreservation, increasingly became more socially motivated. The IVF field also increasingly underwent industrialization and commoditization by outside financial interests. Finally, at least partially driven by industrialization and commoditization, so-called add-ons, the term describing mostly unvalidated tests and procedures added to IVF since 2010, have been held responsible for worldwide declines in fresh, non-donor live birthrates after IVF, to levels not seen since the mid-1990s. We here, therefore, do not offer a review of bioethical considerations regarding IVF as a fertility treatment, but attempt to point out ethical issues that arose because of major recent changes in clinical IVF practice.

Evaluation of Classic, Attenuated, and Oligopolyposis of the Colon

The goal of this review is to provide an overview of evaluating patients with adenomatous polyposis of the colon, including elements such as generating a differential diagnosis, referral considerations for genetic testing, genetic testing options, and expected outcomes from genetic testing in these individuals. In more recent years, adenomatous colonic polyposis has evolved beyond the more robustly characterized familial adenomatous polyposis (FAP) and MUTYH-associated polyposis (MAP) now encompassing more newly described genes and associated syndromes. Technological innovation, from whole-exome sequencing to multigene panel testing, has dramatically increased the amount of genotypic and phenotypic data amassed in adenomatous polyposis cohorts, which has contributed greatly to informing diagnosis and clinical management of affected individuals and their families.

Every Mother and Every Fetus Matters: A Positive Pregnant Test = Multiple Offerings of Reproductive Risk Screening for personal, family, and specific obstetrical-fetal conditions

Structured OBJECTIVE: The requirement and need for a focused 'pregnant person -centered' antenatal care process with time for informed consent and shared decision making are important for optimal antenatal care. This commentary focuses on the evidenced -based screening test options and timing as part of the overall 'pregnant person-centered' preconception and antenatal care journey.

METHODS

A structured quality improvement (QI) review (Squire 2.0) was undertaken to examine the appropriate reproductive screening process in the periods of preconception and during pregnancy.

RESULTS

First, evaluated the broader antenatal care structure which, second, enabled the directed reproductive risk screening processes to be offered within an informed consent process. Four international pre-conception and antenatal evidenced-based consensus would routinely offer specific gestational age reproductive risk screening elements: totaling 21 screening elements (preconception 3; 1st trimester 9; 2nd trimester 3; 3rd trimester 4; intrapartum 1; postpartum 1).

CONCLUSION

The best evidenced-based opportunity for comprehensive and collaborative antenatal care with appropriate screening elements requires: single national access healthcare system; expert evidenced-based guideline creation; collaborative maternity care providers based for risk assessment, triage, and management; pregnant person (women) centered care model of maternity care; clearly identified evidenced-based gestational age directed screening elements; international pre-conception and antenatal guideline consensus.

Fetal Screening for Chromosomal Abnormalities

With more and more reproductive-aged women opting to pursue genetic screening during pregnancy, health care professionals must understand the variety of testing options available as well as the advantages and limitations of each testing option. Presently, no single screening test is universally believed to be superior because the combination of the specific test and the population being tested determines the range of potential identifiable conditions as well as the positive predictive values. As a result, pre- and posttest counseling are not always straightforward and may require discussions with multiple specialists including genetic counselors, obstetricians, and pediatricians/neonatologists. The purpose of this review is to summarize the screening options currently available to pregnant women to determine their risk of having a child affected by a chromosomal disorder. Screening for chromosomal abnormalities using ultrasonography, maternal serum analytes, cell-free DNA, and preimplantation genetic testing will be discussed here. Advances in the field, including the possible future use of cell-based noninvasive prenatal screening (NIPS) as a more accurate method for genetic screening and the incorporation of screening for copy number variants (microdeletions and duplications) into traditional cell-free NIPS will also be reviewed.

Validating a Minimally Invasive Tissue Sampling (MITS) Method in Determining Cause of Death in Stillbirths and Neonates

Complete diagnostic autopsy (CDA) remains the gold standard and a valuable technique for determining cause of death. It is a source of health statistics that can be used to measure health care services’ quality, unraveling important information on disease processes, particularly in emerging and unknown diseases. It can also be a vital tool for medical education and biomedical research. However, autopsy rates have been declining globally. There is an urgent need to develop and validate alternative methods in different settings to provide reliable information on cause of death. In this study, we aimed to determine cause of death (KazCoDe) in neonates and infants using minimally invasive tissue sampling (MITS), and to compare these results with those of CDA. We conducted MITS and CDA sequentially on 24 deceased children at the Pathological Bureau of the Akimat of the city of Nur-Sultan. Clinical data of the study subjects were extracted from their clinical records. During both procedures, brain, liver and lung tissues were collected for pathological diagnosis. Fifteen (62.5%) and nine (37.5%) were stillbirths and neonates, respectively. Eight (33.3%) were females and 16 (66.7%) were males. MITS diagnosis of cause of death was concordant with CDA diagnosis in 83.3% out of the 24 cases when considering the immediate and underlying causes of death and reviewing all the clinical and laboratory test results as part of the diagnostic evaluation to arrive at a cause of death (ICD-PM). We concluded that MITS is a valuable and reliable method for cause of death diagnosis in stillbirths and neonates, which can contribute vital mortality statistics in children in the absence of CDA.

Offering preimplantation genetic testing for monogenic disorders (PGT-M) for conditions with reduced penetrance or variants of uncertain significance: Ethical insight from U.S. laboratory genetic counselors

Preimplantation genetic testing for monogenic disorders (PGT-M) was originally developed to identify embryos affected with serious childhood-onset disorders, but its use has recently broadened. Guidance on the use of PGT-M in the United States (U.S.) is currently limited, with no formal laws or guidelines established on its use. The goals of this study were to determine for which types of conditions U.S. laboratories currently do not offer PGT-M, to explore ethical considerations U.S. laboratory genetic counselors (GCs) take into consideration when deciding to accept or reject a PGT-M request, and to explore whether U.S. laboratory GCs believe PGT-M should be offered for conditions with reduced penetrance or for variants of uncertain significance (VUS). Qualitative analysis of semi-structured interviews with nine genetic counselors, from five different PGT-M laboratories, was conducted. Participants were required to be GCs working at a PGT-M laboratory in the U.S. and either actively counsel patients on PGT-M or determine a patient's eligibility for PGT-M. Two participants reported their separate laboratories have no limitations for allowable PGT-M testing, while the other seven participants representing three other laboratories reported having limitations. The main ethical consideration GCs reported considering when deciding to accept or reject a PGT-M request was patient autonomy, with a focus on the patient understanding risks of the testing. All participants reported believing PGT-M should be allowable for conditions with reduced penetrance and VUS, with all participants stating their respective laboratories allow for this currently. However, all participants reported a lack of sufficient guidelines and that having guidelines from a professional organization would be beneficial to their practice. In conclusion, lack of current guidelines in the United States has created discrepancies between PGT-M laboratories. PGT-M laboratory GCs support the use of PGT-M for conditions with reduced penetrance and VUS with informed consent. The need for guidelines is supported.

Preimplantation Genetic Testing for Aneuploidy: A Review of the Evidence

Preimplantation genetic testing for aneuploidy was developed as an invasive embryo-selection technique and is extensively used in in vitro fertilization (IVF) cycles. Around 95,000 preimplantation genetic testing cycles were carried out in the United States between 2014 and 2016, the majority of which were performed for aneuploidy. The objective of preimplantation genetic testing for aneuploidy is to select for transfer a euploid embryo, after embryo biopsy and cytogenetic analysis. The current technique consists of applying comprehensive chromosome screening on trophectoderm cells after blastocyst-stage embryo biopsy. This article reviews all the published randomized controlled trials on preimplantation genetic testing for aneuploidy with comprehensive chromosome screening and comments on the subject of embryo mosaicism detected by this technique. Most of these trials have been criticized because they only included good prognosis patients having normal ovarian reserve producing a high number of embryos available for biopsy. Preimplantation genetic testing for aneuploidy does not improve ongoing pregnancy rates per cycle started when routinely applied on the general IVF population but seems to be a good tool of embryo selection for a selected category of patients with normal ovarian reserve, yet should be only practiced by experienced IVF clinics. If no euploid embryo is available after preimplantation genetic testing for aneuploidy, a low-level mosaic embryo can be considered and prioritized for transfer after appropriate genetic counseling.

Pregnancy from mosaic embryo transfer: genetic counseling considerations

PURPOSE OF REVIEW

The transfer of mosaic embryos during an IVF procedure is becoming more common. There is limited information regarding the outcomes for such transfers, making it difficult to establish best practices for prenatal counseling of patients considering transfer of mosaic embryos. In addition, genetic counseling may be delivered by different providers in the preimplantation and pregnancy timeframes which can contribute to inconsistent information.

RECENT FINDINGS

There are many types of aneuploid results from preimplantation genetic testing for aneuploidy (PGT-A), with mosaicism being a possibility. Recent studies have reported normal prenatal diagnostic results, pregnancy and birth outcomes with mosaic embryo transfers. Reproductive and prenatal society guidelines recommend diagnostic testing in pregnancy following a mosaic result by PGT-A. Prenatal genetic counseling providers should consider the available information from the PGT-A result, emphasizing the benefits and limitations of each available prenatal test in detecting the fetal chromosome complement.

SUMMARY

While transfer of mosaic embryos can allow couples without euploid embryos to have a chance of a viable pregnancy, further studies are necessary to better guide this decision-making. In addition, better coordination between reproductive providers and prenatal providers could improve prenatal care.

Genetic testing of products of conception in recurrent pregnancy loss evaluation

Genetic testing of products of conception (POC) has been proposed as a tool to be used in the evaluation of patients with recurrent pregnancy loss (RPL). Following a complete RPL evaluation, POC results may reveal an aneuploidy and provide an explanation for the miscarriage in more than 55% of cases. When the cytogenetic result of the pregnancy loss reveals a euploid pregnancy, management should be directed towards the identification of treatable abnormalities. Furthermore, the results of POC testing might better define a subgroup of patients with unexplained RPL who may benefit from expectant management versus preimplantation genetics (aneuploid unexplained RPL) or investigational therapy (euploid unexplained RPL).

Screening for Fetal Chromosomal Abnormalities: ACOG Practice Bulletin, Number 226

Prenatal testing for chromosomal abnormalities is designed to provide an accurate assessment of a patient's risk of carrying a fetus with a chromosomal disorder. A wide variety of prenatal screening and diagnostic tests are available; each offers varying levels of information and performance, and each has relative advantages and limitations. When considering screening test characteristics, no one test is superior in all circumstances, which results in the need for nuanced, patient-centered counseling from the obstetric care professional and complex decision making by the patient. Each patient should be counseled in each pregnancy about options for testing for fetal chromosomal abnormalities. It is important that obstetric care professionals be prepared to discuss not only the risk of fetal chromosomal abnormalities but also the relative benefits and limitations of the available screening and diagnostic tests. Testing for chromosomal abnormalities should be an informed patient choice based on provision of adequate and accurate information, the patient's clinical context, accessible health care resources, values, interests, and goals. All patients should be offered both screening and diagnostic tests, and all patients have the right to accept or decline testing after counseling.The purpose of this Practice Bulletin is to provide current information regarding the available screening test options available for fetal chromosomal abnormalities and to review their benefits, performance characteristics, and limitations. For information regarding prenatal diagnostic testing for genetic disorders, refer to Practice Bulletin No. 162, Prenatal Diagnostic Testing for Genetic Disorders. For additional information regarding counseling about genetic testing and communicating test results, refer to Committee Opinion No. 693, Counseling About Genetic Testing and Communication of Genetic Test Results. For information regarding carrier screening for genetic conditions, refer to Committee Opinion No. 690, Carrier Screening in the Age of Genomic Medicine and Committee Opinion No. 691, Carrier Screening for Genetic Conditions. This Practice Bulletin has been revised to further clarify methods of screening for fetal chromosomal abnormalities, including expanded information regarding the use of cell-free DNA in all patients regardless of maternal age or baseline risk, and to add guidance related to patient counseling.

Effect of Embryo Developmental Stage, Morphological Grading, and Ploidy Status on Live Birth Rate in Frozen Cycles of Single Blastocyst Transfer

To determine whether embryo developmental stage or morphological grading can predict live birth rate (LBR) from a single blastocyst in nonbiopsied and biopsied frozen embryo transfer (FET) cycles. This retrospective study included 1336 nonbiopsied and 360 euploid FET cycles. Blastocysts were divided according to developmental stage (day 5 [D5] and day 6 [D6]) and morphology (good quality and low quality). Nonbiopsied cycles in which D5 blastocysts were transferred were associated with a significantly higher LBR than those in the D6 group (48.5 vs. 24.3%; p < 0.001), as well as in good-quality embryo transfer cycles than that in low-quality embryo cycles (52.6 vs. 25.3%; p < 0.001). Embryos reaching good-quality blastocysts on D5 yielded significantly higher LBR than those similar quality blastocysts on D6. The same trend was seen in low-quality embryos. Concerning only D5 or D6 blastocyst transfer, the LBRs of good-quality embryos were still superior to those of low-quality embryos. In the case of euploid embryo transfers, the LBR (48.9 vs. 44.9%, p = 0.444) of D5 blastocysts did not significantly differ from that of D6 blastocysts. Good-quality embryos showed a higher LBR than low-quality embryos (51.6 vs. 40.0%, p = 0.030); the adjusted odds ratio remained insignificant after controlling for confounders (aOR 1.56; 95% CI 0.99-2.45; p = 0.056). The LBRs in the same developmental stage or morphology subgroups were not statistically significant. Embryo developmental stage and morphological grade are useful predictors of LBR in nonbiopsied FET cycles. However, no association was found in euploid transfer cycles.

Assisted conception in women of advanced maternal age

A delay in childbearing to later in life has increased the number of women of advanced maternal age (AMA) opting for assisted reproduction. Women should be made aware that there are age-related changes to fertility, including a decline in oocyte reserve and quality, in addition to an increase in the number of oocyte chromosomal aberrations. Success rates of assisted reproductive technology (ART) cycles decrease with advanced maternal age. There are different fertility options for women of AMA, including fertility preservation (oocyte or embryo freezing), in vitro fertilisation (IVF treatment) with or without preimplantation genetic screening and oocyte or embryo donation. Detailed counselling needs to be offered to these women with regard to the risks, success rates, ethical and legal implications of these fertility treatment options. Women of AMA should be screened for underlying medical conditions that could have an impact on maternal and neonatal morbidity and mortality.

Non-invasive prenatal testing in the context of IVF and PGT-A

The high incidence of chromosome aneuploidy in human gametes and embryos is a major cause of in vitro fertilization (IVF) failure and miscarriage. In order to improve live birth rates with single embryo transfer, the use of preimplantation genetic testing for aneuploidy (PGT-A) has significantly increased. PGT encompasses methods that allow embryos to be tested for inherited conditions or screened for chromosomal abnormalities. However, PGT-A is a screening method and results can never be used to definitively predict the chromosomal status of the embryo and fetus. The objective of this manuscript is to review prenatal screening and diagnostic methods available in pregnancies conceived by IVF-PGT-A.