A tale of two studies: now is no longer the best of times for preimplantation genetic testing for aneuploidy (PGT-A)

Genomic aspects in reproductive medicine

Infertility is a complex disease characterized by extreme genetic heterogeneity, compounded by various environmental factors. While there are exceptions, individual genetic and genomic variations related to infertility are typically rare, often family-specific, and may serve as susceptibility factors rather than direct causes of the disease. Consequently, identifying the cause of infertility and developing prevention and treatment strategies based on these factors remain challenging tasks, even in the modern genomic era. In this review, we first examine the genetic and genomic variations associated with infertility, and subsequently summarize the concepts and methods of preimplantation genetic testing in light of advances in genome analysis technology.

Potential Costs and Benefits of Incorporating PGT-A Across Age Groups: A Canadian Clinic Perspective

OBJECTIVE

To assess the potential costs and benefits of preimplantation genetic testing for aneuploidy (PGT-A) across age groups, considering financial costs, total euploidy rates and the potential for morphology grading to predict a euploid embryo.

METHODS

This study is a blinded retrospective chart review of patients who incorporated PGT-A as part of their in vitro fertilization (IVF) treatment cycle at a university-affiliated fertility clinic. Patients between 25-44 years of age undergoing IVF with intracytoplasmic sperm injection and PGT-A with autologous oocytes (n = 220) were included in this study. Number of blastocysts achieved, euploidy rates and PGT-A costs were compared between 3 age groups: <35 years, 35-37, and ≥38. Additionally, agreement on the top-quality embryo based on morphology assessment alone versus PGT-A selection was analyzed and further compared based on the number of blastocysts achieved.

RESULTS

A significant negative correlation between patient age and number of embryos produced, PGT-A costs, and euploidy rates (P < 0.001) was observed. Additionally, morphology alone ratings were able to predict the top-quality euploid embryo 78% of the time in the <35 age group, but only 32% of the time in the ≥38 age group (P < 0.05), with a trend toward even lower agreement when 3 or fewer blastocysts were produced.

CONCLUSION

Based on our cost analysis, it may be advantageous to incorporate PGT-A when maternal age is ≥38, given the lower financial costs associated with each cycle and the low likelihood of transferring a euploid embryo on the first attempt for this age group. Nevertheless, we acknowledge that PGT-A remains a complex decision influenced by a multitude of factors.

Preimplantation genetic testing for aneuploidy: helpful but not a first choice

PURPOSE

This retrospective cohort study aimed to assess and compare the outcomes between cumulative live birth of patients with and without PGT-A and also between prior unsuccessful IVF cycles and PGT-A cycles among patients who experienced IVF but without live birth delivery, and to clarify the effective usage of PGT-A as an in vitro fertilization (IVF) add-on.

METHODS

A total of 2113 females undergoing IVF with at least one blastocyst were reviewed. Patients in the PGT-A and non-PGT-A groups were further categorized into first-time IVF and prior unsuccessful IVF groups (previous IVF experience but without live birth delivery).

RESULTS

In the PGT-A group, there were additional oocyte retrieval cycles, fewer transfer cycles per patient, higher clinical pregnancy rates per embryo transfer, and lower miscarriage rates per clinical pregnancy as compared to the non-PGT-A group, all showing significant differences. However, the first-time IVF group with PGT-A had a significantly longer duration from the first oocyte retrieval to the first live birth delivery (LBD) and a significantly lower LBD rate per patient than the non-PGT-A group. The cumulative probability for a first LBD with PGT-A was inferior in the first-time IVF group for women < 35 years, marginally superior in the prior unsuccessful IVF group of women aged 38-40 years, and similar for other groups.

CONCLUSION

PGT-A should not be recommended to all patients; however, if the first IVF treatment failed, PGT-A may reduce the patient's burden regardless of age.

Disrupting the biological clock: Fertility benefits, egg freezing and proactive fertility management

In the last decade, the in-vitro fertilization (IVF) sector has witnessed a shift from so-called 'reactive IVF' to a new model of proactive fertility care. Whereas IVF was traditionally developed to treat people who found they were unable to conceive, the indication for IVF has broadened significantly to include a much wider group of potential patients through a new focus on proactive treatment of future (in)fertilities. This shift combines a number of new trends pertaining to preservation, prediction, private equity and platformization, all of which have gained influence in contemporary assisted reproduction. This article focuses on the emergence of company-sponsored fertility benefits, which combines each of these trends. Whereas fertility benefits - especially egg freezing insurance - have primarily been discussed in terms of women's empowerment or disenfranchisement, this article instead calls attention to the discursive, clinical and infrastructural shifts in contemporary assisted reproduction that have emerged with the rising popularity of these benefits. The analysis addresses these underdiscussed aspects of fertility benefits by focusing on the dynamics of demand; the shifts in the rationalization of intensified treatment pathways in the face of new reimbursement practices; and the online, platform-based infrastructures that are built to provide these treatments. In doing so, it analyses how this remaking of fertility towards an ethos of proactive fertility management reflects broader capitalist tailwinds.

Carrier screening and PGT for an autosomal recessive monogenic disorder: insights from virtual trials

PURPOSE

To assess the costs and benefits of carrier screening and preimplantation genetic testing (PGT) for recessive autosomal monogenic disorders for couples attempting assisted conception.

METHODS

A simulated first full cycle for women less than 35 years transferring embryos one at a time. The effect of testing on pregnancy outcomes was evaluated for different reporting scenarios. A Monte Carlo method utilising 1000 trials for 10,000 couples, testing 4, 16 and 38 genes, was used to assess the numbers likely to be at high risk and to estimate the incremental cost of screening and PGT to avoid an affected child.

RESULTS

PGT for high-risk couples: testing embryos only for the monogenic condition avoided 1 affected pregnancy for 4 cycles started. Combined with testing for chromosomal aneuploidy: ranking test results avoided 1 adverse pregnancy (affected, biochemical, clinical miscarriage) from 3 cycles started; 1 in 2 when excluding from transfer all embryos with an abnormal test result, within 1 in 25 fewer women achieving an unaffected live birth. Carrier screening for 4, 16 and 38 gene scenarios, where 1:250, 1:196 and 1:29 couples were at high risk: the incremental cost to prevent 1 affected live birth was estimated to be less than GBP 1,150,000 (US $1,587,000), < 836,642 (1,154,566) and < 137,794 (190,156), respectively, in 95% of trials.

CONCLUSIONS

Carrier screening combined with PGT, with and without testing for unrelated chromosomal abnormalities, for couples attempting assisted conception is complex but likely to be effective and also expensive.

Infertility and subsequent recurrent miscarriage: Current state of the literature and future considerations for practice and research

Background: Recurrent miscarriage (RM) and infertility are independently associated with adverse pregnancy outcomes, in addition to psychological sequelae. Experiencing pregnancy loss alongside infertility is particularly difficult. International guidance regarding RM is conflicting, and applicability to women with infertility is undetermined. The aim of this study was to: (i) establish if women/couples with a history of infertility are recognised in the literature on the investigation and management of RM, and (ii) determine if the specific needs of women/couples experiencing RM and infertility are ascertained and incorporated into clinical management strategies. Methods: We examined the wide-ranging literature to ascertain what gaps existed. Studies were retrieved through searches of PubMed and Google Scholar up to 21 January 2021 using appropriate controlled vocabulary and combinations of key words. No language or study design restrictions were applied. Results: While women/couples experiencing RM after infertility appear in studies evaluating investigations and proposed treatments, high-quality studies are lacking. Furthermore, they are largely excluded from international clinical guidance and qualitative research. Conclusions: The experiences of women/couples with RM and infertility and their specific care needs within maternity and fertility services are underexplored. It is unclear from current RM guidelines how best to manage and support this complex cohort. Women/couples with infertility and RM are underserved in the literature and in clinical guidance. Further robust studies are warranted to examine pregnancy outcomes, investigations and treatments currently used. Qualitative research is also required to identify their medical and psychological needs to better support this vulnerable group.

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.

Preimplantation genetic testing for aneuploidy: are we examining the correct outcomes?

Questions continue to be raised regarding the benefit of genetic assessment of embryos prior to transfer in IVF, specifically with regards to preimplantation genetic testing for aneuploidy (PGT-A). To evaluate and quantify these concerns, we appraised the most recent (2012-2019) randomized controlled trials on the topic. Only two of these six studies listed cumulative live birth rates per started cycle, with both eliciting a statistically non-significant result. This article describes the concern that a focus on results from the first embryo transfer compared to cumulative outcomes falsely construes PGT-A as having superior outcomes, whilst its true benefit is not confirmed, and it cannot actually improve the true pregnancy outcome of an embryo pool.

Squaring the circle of recurrent pregnancy loss (RPL)

The recent publication of a study into the contribution of embryo chromosomal abnormalities in recurrent pregnancy loss (RPL) affords the opportunity to revisit the hypothesis that women with an aneuploid pregnancy loss have a better chance of a successful pregnancy next time than women with a chromosomally normal loss. A previous miscarriage with an abnormal karyotype (unrelated to a parental chromosome rearrangement) should not be viewed as a marker of an increased likelihood of aneuploidy in a subsequent pregnancy; it is (counterintuitively) likely to be indicative of a reduced risk of clinical miscarriage (with a higher proportion of aneuploid products) and an excellent chance for the live birth of the next pregnancy. Each couple should be treated on their own merits and with appropriate investigations performed where indicated; caution should be advised regarding offering preimplantation genetic testing for aneuploidy (PGT-A).