Preimplantation genetic screening: "established" and ready for prime time. Fertil Steril. 2008;89:780-788. [PMID: 18353323 DOI: 10.1016/j.fertnstert.2008.01.072]

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

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

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

PURPOSE

To use conflict resolution analysis on the conflict between proponents and opponents of preimplantation genetic testing for aneuploidy (PGT-A), previously called preimplantation genetic screening (PGS).

METHODS

Considered in conflict analysis a case study, we reviewed the English literature based on key-word searches at www.pubmed.com and www.google.com, and interviewed professional opinion leaders and other actor-representatives. This analysis was the product of a mandated externship by L.M. at the Foundation for Reproductive Medicine (FRM), as part of the Master of Science Program in Negotiations and Conflict Resolution at Columbia University, New York, NY.

RESULTS

Initially a typical difference of opinion, conflict evolved after proponents rejected studies that failed to confirm expected benefits, and authors felt demeaned by their criticism. Becoming "destructive," the conflict evolved according to Glasl's escalation model stages. Proponents became continuous attractors. Unable to produce validations for PGT-A, proponents moved goal posts through 3 stages (PGS 1.0-PGS 3.0). Ultimately concurring that pregnancy and live birth rates are unaffected, they started claiming new benefits.

CONCLUSIONS

The FRM underwrote this study as a starting tool for a conflict resolution process. A consensus building conference of stakeholders appears as of this point to represent the most promising potential intervention. The goal of such a conference should be sustainable consensus about clinical utilization of PGS/PGT-A in IVF, based on transparent and validated criteria. A potential date for such a conference is set for 2020.

Preimplantation Genetic Testing for Breast Cancer

Breast cancer (BC), a malignant tumor characterized mainly by a lump in the breast and a change in breast shape, has plagued many women of childbearing age in Nigeria today. This has thus propelled many to find both prophylactic and curative agents to combat BC in affected persons. This article extensively reviews a method of preventing BC in the offspring of affected parents, known as preimplantation genetic testing (PGT) – an assisted reproductive technique that selects genetically unaffected embryo(s) to be transferred to the uterus of a mother upon in vitro fertilization and standard genetic analysis. The present study also seeks to present the techniques involved in PGT that have been reported to prevent the inheritance of BC, its benefits and risks, related case studies in Africa and other continents, and ethical issues surrounding the application of assisted reproduction for BC testing. To achieve these, a thorough search was conducted in reputable scientific journals of reproduction and cancer, and expert knowledge was consulted with regard to these aspects of health and reproduction. Upon reviewing this very important subject, it was confirmed that the beneficial role of assisted reproduction in the field of science and the homes of many cannot be overestimated. This review of the role of PGT in BC prevention will enlighten the understanding of many – creating awareness that with PGT, BC-affected women can have not only children, but also healthy and genetically unaffected children.

A single trophectoderm biopsy at blastocyst stage is mathematically unable to determine embryo ploidy accurately enough for clinical use

BACKGROUND

It has become increasingly apparent that the trophectoderm (TE) at blastocyst stage is much more mosaic than has been appreciated. Whether preimplantation genetic screening (PGS), utilizing a single TE biopsy (TEB), can reliably determine embryo ploidy has, therefore, increasingly been questioned in parallel.

METHODS

We for that reason here established 2 mathematical models to assess probabilities of false-negative and false-positive results of an on average 6-cell biopsy from an approximately 300-cell TE. This study was a collaborative effort between investigators at The Center for Human Reproduction in New York City and the Center for Studies in Physics and Biology and the Brivanlou Laboratory of Stem Cell Biology and Molecular Embryology, the latter two both at Rockefeller University in New York City.

RESULTS

Both models revealed that even under best case scenario, assuming even distribution of mosaicism in TE (since mosaicism is usually clonal, a highly unlikely scenario), a biopsy of at least 27 TE cells would be required to reach minimal diagnostic predictability from a single TEB.

CONCLUSIONS

As currently performed, a single TEB is, therefore, mathematically incapable of reliably determining whether an embryo can be transferred or should be discarded. Since a single TEB, as currently performed, apparently is not representative of the complete TE, this study, thus, raises additional concern about the clinical utilization of PGS.

Is the hypothesis of preimplantation genetic screening (PGS) still supportable? A review

The hypothesis of preimplantation genetic diagnosis (PGS) was first proposed 20 years ago, suggesting that elimination of aneuploid embryos prior to transfer will improve implantation rates of remaining embryos during in vitro fertilization (IVF), increase pregnancy and live birth rates and reduce miscarriages. The aforementioned improved outcome was based on 5 essential assumptions: (i) Most IVF cycles fail because of aneuploid embryos. (ii) Their elimination prior to embryo transfer will improve IVF outcomes. (iii) A single trophectoderm biopsy (TEB) at blastocyst stage is representative of the whole TE. (iv) TE ploidy reliably represents the inner cell mass (ICM). (v) Ploidy does not change (i.e., self-correct) downstream from blastocyst stage. We aim to offer a review of the aforementioned assumptions and challenge the general hypothesis of PGS. We reviewed 455 publications, which as of January 20, 2017 were listed in PubMed under the search phrase < preimplantation genetic screening (PGS) for aneuploidy>. The literature review was performed by both authors who agreed on the final 55 references. Various reports over the last 18 months have raised significant questions not only about the basic clinical utility of PGS but the biological underpinnings of the hypothesis, the technical ability of a single trophectoderm (TE) biopsy to accurately assess an embryo’s ploidy, and suggested that PGS actually negatively affects IVF outcomes while not affecting miscarriage rates. Moreover, due to high rates of false positive diagnoses as a consequence of high mosaicism rates in TE, PGS leads to the discarding of large numbers of normal embryos with potential for normal euploid pregnancies if transferred rather than disposed of. We found all 5 basic assumptions underlying the hypothesis of PGS to be unsupported: (i) The association of embryo aneuploidy with IVF failure has to be reevaluated in view how much more common TE mosaicism is than has until recently been appreciated. (ii) Reliable elimination of presumed aneuploid embryos prior to embryo transfer appears unrealistic. (iii) Mathematical models demonstrate that a single TEB cannot provide reliable information about the whole TE. (iv) TE does not reliably reflect the ICM. (v) Embryos, likely, still have strong innate ability to self-correct downstream from blastocyst stage, with ICM doing so better than TE. The hypothesis of PGS, therefore, no longer appears supportable. With all 5 basic assumptions underlying the hypothesis of PGS demonstrated to have been mistaken, the hypothesis of PGS, itself, appears to be discredited. Clinical use of PGS for the purpose of IVF outcome improvements should, therefore, going forward be restricted to research studies.

Accuracy of preimplantation genetic screening (PGS) is compromised by degree of mosaicism of human embryos

BACKGROUND

To preclude transfer of aneuploid embryos, current preimplantation genetic screening (PGS) usually involves one trophectoderm biopsy at blastocyst stage, assumed to represent embryo ploidy. Whether one such biopsy can correctly assess embryo ploidy has recently, however, been questioned.

METHODS

This descriptive study investigated accuracy of PGS in two ways. Part I: Two infertile couples donated 11 embryos, previously diagnosed as aneuploid and, therefore, destined to be discarded. They were dissected into 37 anonymized specimens, and sent to another national laboratory for repeat analyses to assess (i) inter-laboratory congruity and (ii) intra-embryo congruity of multiple embryo biopsies in a single laboratory. Part II: Reports on human IVF cycle outcomes after transfer of allegedly aneuploid embryos into 8 infertile patients.

RESULTS

Only 2/11 (18.2 %) embryos were identically assessed at two PGS laboratories; 4/11 (36.4 %), on repeat analysis were chromosomally normal, 2 mosaic normal/abnormal, and 5/11 (45.5 %) completely differed in reported aneuploidies. In intra-embryo analyses, 5/10 (50 %) differed between biopsy sites. Eight transfers of previously reported aneuploid embryos resulted in 5 chromosomally normal pregnancies, 4 delivered and 1 ongoing. Three patients did not conceive, though 1 among them experienced a chemical pregnancy.

CONCLUSIONS

Though populations of both study parts are too small to draw statistically adequately powered conclusions on specific degrees of inaccuracy of PGS, here presented results do raise concerns especially about false-positive diagnoses. While inter-laboratory variations may at least partially be explained by different diagnostic platforms utilized, they cannot explain observed intra-embryo variations, suggesting more frequent trophectoderm mosiaicsm than previously reported. Together with recentl published mouse studies of lineages-specific degrees of survival of aneuploid cells in early stage embryos, these results call into question the biological basis of PGS, based on the assumption that a single trophectoderm biopsy can reliably determine embryo ploidy.

Usefulness of oocyte accumulation in low ovarian response for PGS

This is an observational study of the response to ovarian stimulation and preimplantational genetic screening (PGS) cycles of 188 patients with a foreseen high aneuploid rate, undergoing two or three stimulation cycles (2SC and 3SC) and oocyte vitrification to accumulate oocytes (Accumulation group = 112 patients) compared to patients undergoing one stimulation cycle (1SC Group= 76 patients) and fresh embryo transfer, between January 2011 and July 2014. Accumulation was performed when <10 MII oocytes were retrieved. Oocytes were vitrified for later warming and IVF, when the planned number of oocytes was achieved. After PGS, euploid embryos were transferred. Comparing 2SC Group with 3SC Group, AMH, AFC, number of oocytes retrieved per pick-up and total number of biopsied embryos were significantly higher in the 2SC Group. After chromosome analysis, 18.5% of biopsied embryos were euploid and 58.9% patients reached embryo transfer. There were no differences in pregnancy rates per patient between the 1SC, 2SC and 3SC Groups (36.8%, 34.9% and 31.0%, respectively) or per embryo transfer (59.6, 56.8 and 60%, respectively). In patients with <10 MII oocytes after ovarian stimulation undergoing PGS, accumulating oocytes can render a pregnancy rate per patient and per embryo transfer comparable to those of fresh PGS cycles.

Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review

Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat". Whether PGS#2 improves IVF outcomes can, therefore, not be determined. Reassessments of data, alleged to support the efficacy of PGS#2, indeed, suggest the opposite. Like with PGS#1, the introduction of PGS#2 into unrestricted IVF practice again appears premature, and threatens to repeat the PGS#1 experience, when thousands of women experienced reductions in IVF pregnancy chances, while expecting improvements. PGS#2 is an unproven and still experimental procedure, which, until evidence suggests otherwise, should only be offered under study conditions, and with appropriate informed consents.

A review of, and commentary on, the ongoing second clinical introduction of preimplantation genetic screening (PGS) to routine IVF practice

PURPOSE

Current re-introduction of "improved" preimplantation genetic screening (PGS#2) raises the question whether PGS#2 is ready for routine clinical application.

METHODS

We assessed available evidence via review of published data for years 2005-2012, and review of currently ongoing registered clinical trials, based on searches under appropriate key words in PubMed, MEDLINE, Cochrane Database System Review and Google Scholar and http://www.ClinicalTrials.gov . In absence of prospective clinical trials, and due to limited available data, individual publications/ongoing studies are assessed.

RESULTS

PGS#2 offers significant improvements in accuracy of aneuploidy diagnosis over PGS#1. By moving embryo biopsy from day-3 after fertilization (6-8 cell stage) to trophectoderm biopsy at blastocyst stage (day 5-6), PGS#2, however, adds additional co-variables to the analysis of efficacy of the procedure, which have special relevance for women with diminished ovarian reserve (DOR), who usually produce small egg and embryo numbers. Limited published data, claiming efficacy of PGS#2, as well as ongoing clinical trials, do not consider these additional co-variables, do not analyze outcomes by intent to treat and, therefore, have to be considered biased in patient selection.

CONCLUSIONS

Here reached conclusions are based on absence of adequate data rather than affirmative outcome assessments. They, therefore, are subject to change at any future date with generation of significant new data. Premature introduction of PGS#1 caused significant damage to patients. As currently no reliable PGS#2 data are available to suggest improvements in IVF outcomes, to avoid a repeat of the PGS#1 experience, PGS#2 should be considered experimental until data show otherwise.

Lessons from elective in vitro fertilization (IVF) in, principally, non-infertile women

BACKGROUND

We here report the first investigation of exclusively elective in vitro fertilization (IVF) cycles in women with no apparent history of infertility. Since IVF outcome in women with infertility are always influenced by underlying causes of infertility, a study on non-infertile women may offer new insights.

METHODS

We investigated 88 females without history of infertility in 109 consecutive elective IVF cycles, almost exclusively performed for purposes of preimplantation genetic screening (PGS; i.e., elective gender selection). The following questions were addressed: (i) impact of PGS on IVF pregnancy chances; (ii) impact of transfer of 1 vs. ≥2 embryos on IVF pregnancy chances; (iii) correlation of anti-Müllerian hormone (AMH) levels to embryo ploidy (iv) effect of gonadotropin dosage used in stimulation on available embryos for transfer; and (v) in form of a 1:1 case control study, compared 33 elective PGS cycles with matched control cycles without PGS, performed in couples with either prior tubal ligations and/or severe male factor infertility as indication of IVF.

RESULTS

The overall clinical pregnancy rate for the group was 36.7%; pregnancy was associated with number of euploid (P = 0.009) and number of embryos transferred (P = 0.001). Odds of pregnancy were 3.4-times higher if ≥4 euploid embryos were produced in comparison to <4 (95% CI 1.2 to 9.2; P = 0.019), and odds of pregnancy were 6.6-times higher if greater than or equal to 2 rather than <1 euploid embryos were transferred (95% CI 2.0 to 21.7; P = 0.002). Increasing AMH (P = 0.001) and gonadotropin dosage used in ovarian stimulation (P = 0.024), was, independently, associated with number of available euploid embryos. Increasing AMH, but not follicle stimulating hormone (FSH), was associated with number of embryos available for biopsy and PGS (P = 0.0001). Implantation rates were 26.4% with PGS and 9.5% without (P = 0.008). Women undergoing PGS, demonstrated 4.58-times higher odds of pregnancy than matched controls (95% CI 1.102 to 19.060, Exp 4.584, P = 0.036).

CONCLUSIONS

This study suggests that outcomes of elective IVF cycles may significantly deviate from infertility-associated cycles. Affirming proof of concept for PGS, utilizing day-3 embryo biopsy and fluorescence in-situ hybridization (FISH), both widely held responsible for earlier failures to establish such proof, suggests that the principal cause of prior failures were likely not insufficient laboratory techniques but poor patient selection for PGS. Such a conclusion questions the current reintroduction of PGS with improved techniques and technologies in absence of prior determination of suited patient populations.

Preimplantation testing: Transition from genetic to genomic diagnosis

Preimplantation genetic testing refers to the procedure to determine the genetic status of embryos formed by in vitro fertilization (IVF) prior to initiating a pregnancy. Traditional genetic methods for preimplantation genetic diagnosis (PGD) examine distinct parts of an individual genome, require the development of a custom assay for every patient family, and are time consuming and inefficient. In the last decade technologies for whole-genome amplification (WGA) from single cells have led to innovative strategies for preimplantation testing. Applications of WGA technology can lead to a universal approach that uses single-nucleotide polymorphisms (SNPs) and mutations across the entire genome for the analysis. Single-cell WGA by multiple displacement amplification has enabled a linkage approach to PGD known as “preimplantation genetic haplotyping”, as well as microarray-based techniques for preimplantation diagnosis. The use of microarrays in preimplantation diagnosis has provided genome-wide testing for gains or losses of single chromosomes (aneuploidies) or chromosomal segments. Properly designed randomized controlled trials are, however, needed to determine whether these new technologies improve IVF outcomes by increasing implantation rates and decreasing miscarriage rates. In genotype analysis of single cells, allele dropout occurs frequently at heterozygous loci. Preimplantation testing of multiple cells biopsied from blastocysts, however, can reduce allele dropout rates and increase the accuracy of genotyping, but it allows less time for PGD. Future development of fast SNP microarrays will enable a universal preimplantation testing for aneuploidies, single-gene disorders and unbalanced translocations within the time frame of an IVF cycle.

Hype or hope? Ethical and practical considerations with clinical research in women with diminished ovarian reserve

This communication suggests that investigations of treatments for women with diminished functional ovarian reserve (DOR) call for specific practical and ethical considerations, as women with DOR, because of limited remaining reproductive life spans, appropriately feel under time constraints. Another medical journal recently published an opinion piece on the use of dehydroepiandrosterone in women with DOR, raising important questions about what approaches should be taken to develop best available evidence in such patients. Their manuscript offers an excellent opportunity to consider ethical and clinical aspects of study design in clinical circumstances where patients have little to lose but face the promise of considerable gains in clinical pregnancy chances if effective treatments can be developed. This commentary concludes that, in such circumstances, common sense as well as ethical considerations support the introduction of new treatments into the clinical mainstream even in absence of prospectively randomized studies if lower levels of evidence are supportive of positive treatment effects.

PGS-FISH in reproductive medicine and perspective directions for improvement: a systematic review

INTRODUCTION

Embryo selection can be carried out via morphological criteria or by using genetic studies based on Preimplantation Genetic Screening. In the present study, we evaluate the clinical validity of Preimplantation Genetic Screening with fluorescence in situ hybridization (PGS-FISH) compared with morphological embryo criteria.

MATERIAL AND METHODS

A systematic review was made of the bibliography, with the following goals: firstly, to determine the prevalence of embryo chromosome alteration in clinical situations in which the PGS-FISH technique has been used; secondly, to calculate the statistics of diagnostic efficiency (negative Likelihood Ratio), using 2 × 2 tables, derived from PGS-FISH. The results obtained were compared with those obtained from embryo morphology. We calculated the probability of transferring at least one chromosome-normal embryo when it was selected using either morphological criteria or PGS-FISH, and considered what diagnostic performance should be expected of an embryo selection test with respect to achieving greater clinical validity than that obtained from embryo morphology.

RESULTS

After an embryo morphology selection that produced a negative result (normal morphology), the likelihood of embryo aneuploidies was found to range from a pre-test value of 65% (prevalence of embryo chromosome alteration registered in all the study groups) to a post-test value of 55% (Confidence interval: 50-61), while after PGS-FISH with a negative result (euploid), the post-test probability was 42% (Confidence interval: 35-49) (p < 0.05). The probability of transferring at least one euploid embryo was the same whether 3 embryos were selected according to morphological criteria or whether 2, selected by PGS-FISH, were transferred. Any embryo selection test, if it is to provide greater clinical validity than embryo morphology, must present a LR-value of 0.40 (Confidence interval: 0.32-0.51) in single embryo transfer, and 0.06 (CI: 0.05-0.07) in double embryo transfer.

DISCUSSION

With currently available technology, and taking into account the number of embryos to be transferred, the clinical validity of PGS-FISH, although superior to that of morphological criteria, does not appear to be clinically relevant.

Low-intensity IVF: real progress?

A recent publication in this journal strongly advocated low-intensity IVF (LI-IVF) after presenting the authors' experience with minimal ovarian stimulation (mini-IVF). The data presented failed to support their conclusions. Therefore, presented here is a critique of their manuscript and of uncontrolled clinical use of LI-IVF, in general. In the absence of properly controlled studies, all forms of LI-IVF should be considered experimental and be offered only in well-controlled research settings and with appropriate informed consent.

Dehydroepiandrosterone (DHEA) supplementation in diminished ovarian reserve (DOR)

BACKGROUND

With infertility populations in the developed world rapidly aging, treatment of diminished ovarian reserve (DOR) assumes increasing clinical importance. Dehydroepiandrosterone (DHEA) has been reported to improve pregnancy chances with DOR, and is now utilized by approximately one third of all IVF centers world-wide. Increasing DHEA utilization and publication of a first prospectively randomized trial now warrants a systematic review.

METHODS

PubMed, Cochrane and Ovid Medline were searched between 1995 and 2010 under the following strategy: [<dehydroepiandrosterone or DHEA or androgens or testosterone > and <ovarian reserve or diminished ovarian reserve or ovarian function >]. Bibliographies of relevant publications were further explored for additional relevant citations. Since only one randomized study has been published, publications, independent of evidence levels and quality assessment, were reviewed.

RESULTS

Current best available evidence suggests that DHEA improves ovarian function, increases pregnancy chances and, by reducing aneuploidy, lowers miscarriage rates. DHEA over time also appears to objectively improve ovarian reserve. Recent animal data support androgens in promoting preantral follicle growth and reduction in follicle atresia.

DISCUSSION

Improvement of oocyte/embryo quality with DHEA supplementation potentially suggests a new concept of ovarian aging, where ovarian environments, but not oocytes themselves, age. DHEA may, thus, represent a first agent beneficially affecting aging ovarian environments. Others can be expected to follow.

Dehydroepiandrosterone (DHEA) reduces embryo aneuploidy: direct evidence from preimplantation genetic screening (PGS)

BACKGROUND

Dehydroepiandrosterone (DHEA) has been reported to improve pregnancy chances in women with diminished ovarian reserve (DOR), and to reduce miscarriage rates by 50-80%. Such an effect is mathematically inconceivable without beneficial effects on embryo ploidy. This study, therefore, assesses effects of DHEA on embryo aneuploidy.

METHODS

In a 1:2, matched case control study 22 consecutive women with DOR, supplemented with DHEA, underwent preimplantation genetic screening (PGS) of embryos during in vitro fertilization (IVF) cycles. Each was matched by patient age and time period of IVF with two control IVF cycles without DHEA supplementation (n = 44). PGS was performed for chromosomes X, Y, 13, 16, 18, 21 and 22, and involved determination of numbers and percentages of aneuploid embryos.

RESULTS

DHEA supplementation to a significant degree reduced number (P = 0.029) and percentages (P < 0.001) of aneuploid embryos, adjusted for relevant covariates. Short term supplementation (4-12 weeks) resulted in greatest reduction in aneuploidy (21.6%, 95% CI -2.871-46.031).

DISCUSSION

Beneficial DHEA effects on DOR patients, at least partially, are the likely consequence of lower embryo aneuploidy. DHEA supplementation also deserves investigation in older fertile women, attempting to conceive, where a similar effect, potentially, could positively affect public health.

Misplaced obsession with prospectively randomized studies

Medical care should be based on best available evidence. While randomized controlled trials (RCT) are currently considered a gold standard of study design, they are not always available and do not represent the only study format that can lead to best available evidence. This communication argues that overvaluation of RCT and undervaluation of other study formats in establishing best available evidence hurts progress in reproductive medicine and in medicine in general.

Sex and reproduction: an evolving relationship

BACKGROUND

Although sexual activity has, until very recently, been essential to reproduction, this did not preclude the non-reproductive importance of sexual relationships and non-conceptive copulations. Technological advances, however, now allow for both sex without reproduction and reproduction without sex. This review summarizes social and ethical commentaries on the new relationship between sex and reproduction.

METHODS

For each main area discussed, a systematic search was made using (depending on the subject) PubMed, Medline, ScienceDirect, classic books, Google and/or religious websites. The search focused on publications between 1975 and 2009, although some materials from the first part of the 20th century were also utilized.

RESULTS

The classic picture of sex for reproduction and bonding between mating partners is increasingly being replaced by reproduction separate from sexual activity. Although not every advance in assisted reproduction produced, per se, a further separation from sexual intercourse, these two fundamental human activities are today increasingly carried out independently, as reproduction is possible, not only without sex, but even through the intervention of more than two partners. The possibility of reproduction with only one or even no gametes, although highly controversial and not yet feasible, is nonetheless being investigated.

CONCLUSIONS

Technological advances in the field of reproductive biology have enabled couples considered infertile to conceive and have healthy babies, causing a revolution in culture and customs. Today the independence of sex and reproduction is established and in the future human reproduction may move even further away from the sexual act, an option definitely unacceptable to some ethicists.

Single-cell DNA and FISH analysis for application to preimplantation genetic diagnosis

Preimplantation genetic testing, which includes preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS), is a form of a very early prenatal testing. The goal of this method is to avoid transfer of embryos affected with a specific genetic disease or condition. This unit describes the steps involved in amplifying DNA from a single blastomere and specific assays for detecting a variety of DNA mutations. For some assays, whole-genome amplification by primer-extension preamplification (PEP) is performed prior to analysis. Support protocols describe the biopsy of one or two blastomeres from the developing preimplantation embryo, isolation for further investigation of all blastomeres from embryos shown to have the mutant allele, and isolation of single lymphocytes or lymphoblastoid cells as models for single-cell DNA analysis. A procedure for FISH analysis on single interphase blastomeres is provided along with support protocols for probe preparation and probe validation, which is recommended as a preliminary step before performing any PGD or PGS FISH analysis.

The role of preimplantation genetic diagnosis in diagnosing embryo aneuploidy

PURPOSE OF REVIEW

Use of preimplantation genetic diagnosis to improve in-vitro fertilization outcomes is reviewed.

RECENT FINDINGS

Many embryos produced in vitro contain chromosomal abnormalities and have little potential for forming a viable pregnancy. The most commonly used method for preimplantation genetic diagnosis involves embryo biopsy on day 3 of development, followed by fluorescence in-situ hybridization analysis of 5-12 chromosomes. However, positive results have been more common with single-cell biopsy and the analysis of nine or more chromosomes, including 15, 16, 21, and 22. Comparative genomic hybridization, array-comparative genomic hybridization, and single-nucleotide polymorphism arrays analyze all chromosomes and, although technically demanding and requiring experience for successful use, improve the selection potential of preimplantation genetic diagnosis and minimize error rates. Recent data suggest that biopsy at the blastocyst stage may allow sampling of representative genetic material without compromising embryo viability. The optimal strategy for aneuploidy screening using preimplantation genetic diagnosis seems to be blastocyst biopsy at 5 days and comprehensive chromosome analysis (comparative genomic hybridization, array-comparative genomic hybridization, single-nucleotide polymorphism array).

SUMMARY

The use of preimplantation genetic diagnosis to assist the identification and preferential transfer of healthy euploid embryos should improve implantation rates, reduce miscarriages and trisomic offspring, and ultimately lead to an increase in live birth rates.

Quantitative decision-making in preimplantation genetic (aneuploidy) screening (PGS)

PURPOSE

To analyze using hypergeometric probability statistics the impact of performing preimplantation genetic screening (PGS) on a cohort of day 3 cleavage stage embryos.

METHODS

Statistical mathematical modeling.

RESULTS

We find the benefit of performing PGS is highly dependent on the number of day 3 embryos available for biopsy. Additional hidden variables that determine the outcome of PGS are the rates of aneuploidy and mosaicism, and the probability of a chromosomally mosaic embryo to test "normal". If PGS is performed, our analysis shows that many combinations of the number of biopsiable embryos, and the rates of aneuploidy and mosaicism results in a marginal benefit from the intervention. Other combinations are detrimental if PGS is actually undertaken. Finally, increases in PGS error rates lead to a rapid loss in the ability of PGS to provide useful discriminatory information.

CONCLUSION

We set out the statistical framework to determine the limits of PGS when a specific number of day 3 preimplantation embryos are available for biopsy. In general, PGS cannot be recommended a priori for a specific clinical situation due to the statistical uncertainties associated with the different hidden variable quantitative parameters considered important to the clinical outcome.

Miscarriage rates after dehydroepiandrosterone (DHEA) supplementation in women with diminished ovarian reserve: a case control study

BACKGROUND

Dehydroepinadrosterone (DHEA) supplementation improves pregnancy chances in women with diminished ovarian reserve (DOR), by possibly reducing aneuploidy. Since a large majority of spontaneous miscarriages are associated with aneuploidy, one can speculate that DHEA supplementation may also reduce miscarriage rates.

METHODS

We retroactively compared, utilizing two independent statistical models, miscarriage rates in 73 DHEA supplemented pregnancies at two independent North American infertility centers, age-stratified, to miscarriages reported in a national U.S. in vitro fertilization (IVF) data base.

RESULTS

After DHEA supplementation the miscarriage rate at both centers was 15.1% (15.0% and 15.2%, respectively). For DHEA supplementation Mantel-Hänszel common odds ratio (and 95% confidence interval), stratified by age, was significantly lower, relative to odds of miscarriage in the general IVF control population [0.49 (0.25-0.94; p = 0.04)]. Miscarriage rates after DHEA were significantly lower at all ages but most pronounced above age 35 years.

DISCUSSION

Since DOR patients in the literature are reported to experience significantly higher miscarriage rates than average IVF patients, the here observed reduction in miscarriages after DHEA supplementation exceeds, however, all expectations. Miscarriage rates after DHEA not only were lower than in an average national IVF population but were comparable to rates reported in normally fertile populations. Low miscarriage rates, comparable to those of normal fertile women, are statistically impossible to achieve in DOR patients without assumption of a DHEA effect on embryo ploidy. Beyond further investigations in infertile populations, these data, therefore, also suggest the investigations of pre-conception DHEA supplementation in normal fertile populations above age 35 years.

IVF/ICSI with or without preimplantation genetic screening for aneuploidy in couples without genetic disorders: a systematic review and meta-analysis

PURPOSE

To assess the efficacy of preimplantation genetic screening to increase ongoing pregnancy rates in couples without known genetic disorders.

METHODS

Systematic review and meta-analysis of randomized controlled trials. Two reviewers independently determined study eligibility and extracted data.

RESULTS

Ten randomized trials (1,512 women) were included. The quality of evidence was moderate. Meta-analyses using a random-effects model suggest that PGS has a lower rate of ongoing pregnancies (risk ratio=0.73, 95% confidence interval 0.62-0.87) and a lower rate of live births (risk ratio=0.76, 95% confidence interval 0.64-0.91) than standard in vitro fertilization/intracytoplasmic sperm injection.

CONCLUSIONS

In women with poor prognosis or in general in vitro fertilization program, in vitro fertilization/intracytoplasmic sperm injection with preimplantation genetic screening for aneuploidy does not increase but instead was associated with lower rates of ongoing pregnancies and live births. The use of preimplantation genetic screening in daily practice does not appear to be justified.

Technology requirements for preimplantation genetic diagnosis to improve assisted reproduction outcomes

Preimplantation genetic diagnosis has been proposed as a method to improve assisted reproduction technology outcomes, but different techniques have produced conflicting results. The use of appropriate techniques may provide positive outcomes.

[Mastenbroek controversy or how much ink is spilled on preimplantation genetic screening subject]

Preimplantation genetic screening (PGS) of in vitro fertilization (IVF) embryos has been used for advanced maternal age, repeated miscarriages and repeated implantation failure indications. Several non-randomized studies have been published, showing increased implantation rates, decreased miscarriages and trisomy rates. So PGS seemed to improve prognosis for this particular population. In 2004, a prospective randomized study tempered those results, being unable to demonstrate any significant difference of live birth rate with and without PGS in case of advanced maternal age. In July 2007, another multicenter randomized double-blind trial definitely reopened the controversy, reporting that PGS did not increase but instead significantly reduced pregnancy and live birth rates after IVF in women 35 years of age or older. The debate about efficiency and usefulness of PGS is ongoing and other powered randomized studies will be needed to conclude about real PGS usefulness.

Preimplantation genetic screening for aneuploidy of embryos after in vitro fertilization in women aged at least 35 years: a prospective randomized trial

OBJECTIVE

To test the hypothesis that patients with advanced maternal age (AMA) have a higher implantation rate (IR) after embryo transfer of embryos with a normal chromosomal pattern for the chromosomes studied with preimplantation genetic screening (PGS) compared with patients who had an embryo transfer without PGS.

DESIGN

Prospective randomized controlled trial (RCT).

SETTING

Academic tertiary setting.

PATIENT(S)

Patients with AMA (> or =35 years).

INTERVENTION(S)

In an RCT, the clinical IR per embryo transferred was compared after embryo transfer on day 5 or 6 between the PGS group (analysis of chromosomes 13, 16, 18, 21, 22, X, and Y) and the Control group without PGS.

MAIN OUTCOME MEASURE(S)

No differences were observed between the PGS group and the Control group for the clinical IR (15.1%; 14.9%; rate ratio 1.01; exact confidence interval [CI], 0.25-5.27), the ongoing IR (at 12 weeks) (9.4%; 14.9%), and the live born rate per embryo transferred (9.4%; 14.9%; rate ratio 0.63; exact CI, 0.08-3.37). Fewer embryos were transferred in the PGS group (1.6 +/- 0.6) than in the Control group (2.0 +/- 0.6). A normal diploid status was observed in 30.3% of the embryos screened by PGS.

CONCLUSION(S)

In this RCT, the results did not confirm the hypothesis that PGS results in improved reproductive outcome in patients with AMA.