In vitro fertilization plus preimplantation genetic diagnosis in patients with recurrent miscarriage: an analysis of chromosome abnormalities in human preimplantation embryos

Investigating the role of oviductal mucosa-endometrial co-culture in modulating factors relevant to embryo implantation

Background

Intrauterine adhesions (IUAs) are a significant clinical challenge, affecting reproductive health and leading to infertility or recurrent pregnancy loss. Understanding the molecular mechanisms underlying IUA prevention is crucial for developing effective treatment strategies.

Objective

To investigate the interaction between oviductal mucosal cells and endometrial cells and their effects on the expression of key molecules involved in embryo implantation, specifically leukemia inhibitory factor (LIF), avβ3, estrogen receptor (ER), and progesterone receptor (PR).

Methods

Tubal mucosa and endometrium specimens were collected from 22 patients undergoing surgical interventions. Cells were cultured alone and co-cultured at ratios of 1:1, 1:0.5, and 1:0.1. LIF, avβ3, ER, and PR expression levels were measured using real-time fluorescence quantitative polymerase chain reaction and enzyme-linked immunosorbent assay.

Results

Our results demonstrated that LIF expression was significantly augmented in co-culture conditions, particularly in the 1:1 ratio, compared to oviductal mucosa monoculture (P < 0.05). Although LIF expression was also elevated in 1:0.5 and 1:0.1 co-culture ratios, these increases were not statistically significant (P > 0.05). For avβ3, increased expression was observed in the 1:1 co-culture group (P < 0.05), but no significant differences were detected in 1:0.5 and 1:0.1 co-culture groups. ER expression showed a downward trend in co-culture, but without statistical significance (P > 0.05), and PR expression remained stable across all groups.

Conclusion

Co-culture modulates key molecules involved in embryo implantation, particularly LIF and avβ3. These findings highlight the potential roles of LIF and avβ3 in IUA prevention strategies and provide important insights for future clinical interventions. Tubal mucosal cells can not only grow in the endometrial cell microenvironment, but also the tolerance of tubal mucosal cells can be improved when they are co-cultured.

The number of prior pregnancy losses does not impact euploidy rates in young patients with idiopathic recurrent pregnancy loss

PURPOSE

Our study aimed to determine the possible factors that might impact the probability of obtaining a euploid blastocyst following intracytoplasmic sperm injection (ICSI) and preimplantation genetic testing for aneuploidy (PGT-A) procedures in idiopathic recurrent pregnancy loss (RPL) patients.

METHODS

This single-center retrospective cohort analysis included 180 oocyte retrieval cycles of 166 women under 35 years old and those diagnosed with idiopathic RPL according to American Society of Reproductive Medicine (ASRM) guidelines. Trophectoderm biopsy and next-generation sequencing (NGS) were the techniques used. Patients were stratified by the number of previous losses (Group A: 2, Group B: 3, and Group C: > 3).

RESULTS

Baseline and embryological characteristics showed no statistically significant differences. The euploidy rate per analyzed blastocyst was comparable within the groups (63.3%, 58.2%, and 58.5%; p = 0.477). Logistic regression analyses confirmed that only the trophectoderm scores of A and B increased the probability of obtaining a euploid embryo [OR: 1.82, 95% CI (1.120-2.956), p: 0.016].

CONCLUSION

It is concluded that there was no correlation between the number of previous losses and the chance of finding at least one euploid embryo in ICSI cycles of women younger than 35 years.

Pregnancy by Oocyte Donation: Reviewing Fetal-Maternal Risks and Complications

Oocyte donation (OD) has greatly improved over the last three decades, becoming a preferred practice of assisted reproductive technology (ART) for infertile women wishing for motherhood. Through OD, indeed, it has become possible to overcome the physiological limitation due to the ovarian reserve (OR) exhaustion as well as the poor gamete reliability which parallels the increasing age of women. However, despite the great scientific contribution related to the success of OD in the field of infertility, this practice seems to be associated with a higher rate of major risky events during pregnancy as recurrent miscarriage, infections and placental diseases including gestational hypertension, pre-eclampsia and post-partum hemorrhage, as well as several maternal-fetal complications due to gametes manipulation and immune system interaction. Here, we will revisit this questioned topic since a number of studies in the medical literature focus on the successful aspects of the OD procedure in terms of pregnancy rate without, however, neglecting the risks and complications potentially linked to external manipulation or heterologous implantation.

DNA repair in primordial follicle oocytes following cisplatin treatment

PURPOSE

Genotoxic chemotherapy and radiotherapy can cause DNA double stranded breaks (DSBs) in primordial follicle (PMF) oocytes, which then undergo apoptosis. The development of effective new fertility preservation agents has been hampered, in part, by a limited understanding of DNA repair in PMF oocytes. This study investigated the induction of classical DSB repair pathways in the follicles of wild type (WT) and apoptosis-deficient Puma^-/- mice in response to DSBs caused by the chemotherapy agent cisplatin.

METHODS

Adult C57BL/6 WT and Puma^-/- mice were injected i.p. with saline or cisplatin (5 mg/kg); ovaries were harvested at 8 or 24 h. Follicles were counted, and H2A histone family member (γH2AX) immunofluorescence used to demonstrate DSBs. DNA repair protein RAD51 homolog 1 (RAD51) and DNA-dependent protein kinase, catalytic subunit (DNA-PKcs) immunofluorescence were used to identify DNA repair pathways utilised.

RESULTS

Puma^-/- mice retained 100% of follicles 24 h after cisplatin treatment. Eight hours post-treatment, γH2AX immunofluorescence showed DSBs across follicular stages in Puma^-/- mice; staining returned to control levels in PMFs within 5 days, suggesting repair of PMF oocytes in this window. RAD51 immunofluorescence eight hours post-cisplatin was positive in damaged cell types in both WT and Puma^-/- mice, demonstrating induction of the homologous recombination pathway. In contrast, DNA-PKcs staining were rarely observed in PMFs, indicating non-homologous end joining plays an insignificant role.

CONCLUSION

PMF oocytes are able to conduct high-fidelity repair of DNA damage accumulated during chemotherapy. Therefore, apoptosis inhibition presents a viable strategy for fertility preservation in women undergoing treatment.

Preimplantation genetic testing for aneuploidies (abnormal number of chromosomes) in in vitro fertilisation

BACKGROUND

In in vitro fertilisation (IVF) with or without intracytoplasmic sperm injection (ICSI), selection of the most competent embryo(s) for transfer is based on morphological criteria. However, many women do not achieve a pregnancy even after 'good quality' embryo transfer. One of the presumed causes is that such morphologically normal embryos have an abnormal number of chromosomes (aneuploidies). Preimplantation genetic testing for aneuploidies (PGT-A), formerly known as preimplantation genetic screening (PGS), was therefore developed as an alternative method to select embryos for transfer in IVF. In PGT-A, the polar body or one or a few cells of the embryo are obtained by biopsy and tested. Only polar bodies and embryos that show a normal number of chromosomes are transferred. The first generation of PGT-A, using cleavage-stage biopsy and fluorescence in situ hybridisation (FISH) for the genetic analysis, was demonstrated to be ineffective in improving live birth rates. Since then, new PGT-A methodologies have been developed that perform the biopsy procedure at other stages of development and use different methods for genetic analysis. Whether or not PGT-A improves IVF outcomes and is beneficial to patients has remained controversial.

OBJECTIVES

To evaluate the effectiveness and safety of PGT-A in women undergoing an IVF treatment.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility (CGF) Group Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two trials registers in September 2019 and checked the references of appropriate papers.

SELECTION CRITERIA

All randomised controlled trials (RCTs) reporting data on clinical outcomes in participants undergoing IVF with PGT-A versus IVF without PGT-A were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed risk of bias, and extracted study data. The primary outcome was the cumulative live birth rate (cLBR). Secondary outcomes were live birth rate (LBR) after the first embryo transfer, miscarriage rate, ongoing pregnancy rate, clinical pregnancy rate, multiple pregnancy rate, proportion of women reaching an embryo transfer, and mean number of embryos per transfer.

MAIN RESULTS

We included 13 trials involving 2794 women. The quality of the evidence ranged from low to moderate. The main limitations were imprecision, inconsistency, and risk of publication bias. IVF with PGT-A versus IVF without PGT-A with the use of genome-wide analyses Polar body biopsy One trial used polar body biopsy with array comparative genomic hybridisation (aCGH). It is uncertain whether the addition of PGT-A by polar body biopsy increases the cLBR compared to IVF without PGT-A (odds ratio (OR) 1.05, 95% confidence interval (CI) 0.66 to 1.66, 1 RCT, N = 396, low-quality evidence). The evidence suggests that for the observed cLBR of 24% in the control group, the chance of live birth following the results of one IVF cycle with PGT-A is between 17% and 34%. It is uncertain whether the LBR after the first embryo transfer improves with PGT-A by polar body biopsy (OR 1.10, 95% CI 0.68 to 1.79, 1 RCT, N = 396, low-quality evidence). PGT-A with polar body biopsy may reduce miscarriage rate (OR 0.45, 95% CI 0.23 to 0.88, 1 RCT, N = 396, low-quality evidence). No data on ongoing pregnancy rate were available. The effect of PGT-A by polar body biopsy on improving clinical pregnancy rate is uncertain (OR 0.77, 95% CI 0.50 to 1.16, 1 RCT, N = 396, low-quality evidence). Blastocyst stage biopsy One trial used blastocyst stage biopsy with next-generation sequencing. It is uncertain whether IVF with the addition of PGT-A by blastocyst stage biopsy increases cLBR compared to IVF without PGT-A, since no data were available. It is uncertain if LBR after the first embryo transfer improves with PGT-A with blastocyst stage biopsy (OR 0.93, 95% CI 0.69 to 1.27, 1 RCT, N = 661, low-quality evidence). It is uncertain whether PGT-A with blastocyst stage biopsy reduces miscarriage rate (OR 0.89, 95% CI 0.52 to 1.54, 1 RCT, N = 661, low-quality evidence). No data on ongoing pregnancy rate or clinical pregnancy rate were available. IVF with PGT-A versus IVF without PGT-A with the use of FISH for the genetic analysis Eleven trials were included in this comparison. It is uncertain whether IVF with addition of PGT-A increases cLBR (OR 0.59, 95% CI 0.35 to 1.01, 1 RCT, N = 408, low-quality evidence). The evidence suggests that for the observed average cLBR of 29% in the control group, the chance of live birth following the results of one IVF cycle with PGT-A is between 12% and 29%. PGT-A performed with FISH probably reduces live births after the first transfer compared to the control group (OR 0.62, 95% CI 0.43 to 0.91, 10 RCTs, N = 1680, I² = 54%, moderate-quality evidence). The evidence suggests that for the observed average LBR per first transfer of 31% in the control group, the chance of live birth after the first embryo transfer with PGT-A is between 16% and 29%. There is probably little or no difference in miscarriage rate between PGT-A and the control group (OR 1.03, 95%, CI 0.75 to 1.41; 10 RCTs, N = 1680, I² = 16%; moderate-quality evidence). The addition of PGT-A may reduce ongoing pregnancy rate (OR 0.68, 95% CI 0.51 to 0.90, 5 RCTs, N = 1121, I² = 60%, low-quality evidence) and probably reduces clinical pregnancies (OR 0.60, 95% CI 0.45 to 0.81, 5 RCTs, N = 1131; I² = 0%, moderate-quality evidence).

AUTHORS' CONCLUSIONS

There is insufficient good-quality evidence of a difference in cumulative live birth rate, live birth rate after the first embryo transfer, or miscarriage rate between IVF with and IVF without PGT-A as currently performed. No data were available on ongoing pregnancy rates. The effect of PGT-A on clinical pregnancy rate is uncertain. Women need to be aware that it is uncertain whether PGT-A with the use of genome-wide analyses is an effective addition to IVF, especially in view of the invasiveness and costs involved in PGT-A. PGT-A using FISH for the genetic analysis is probably harmful. The currently available evidence is insufficient to support PGT-A in routine clinical practice.

Combination of QF-PCR and aCGH is an efficient diagnostic strategy for the detection of chromosome aberrations in recurrent miscarriage

Background

Our aim was to conduct a comprehensive genetic evaluation using the combination of QF‐PCR (quantitative fluorescence polymerase chain reaction) and aCGH (array comparative genomic hybridization) for the detection of the frequency and type of chromosome aberrations in recurrent miscarriage (RM) in the clinical setting.

Methods

This retrospective study was conducted on 73 first‐trimester products of conception (POC) between September 2014 and February 2017. The POCs were collected from 73 women with at least one previous miscarriage and analyzed for chromosomal anomalies using QF‐PCR and aCGH as part of the routine clinical evaluation.

Results

Chromosome aberrations were detected in 52/73 POCs (71.2%), of which 41 (56.2%) were identified by QF‐PCR and an additional 11 (15.1%) by aCGH. Numerical aberrations constituted 92.3% of abnormalities, with trisomies as the most common subtype (72.9%). Causative structural aberrations were found in three samples (5.8%). The frequency of chromosome aberrations was not dependent on the number of previous miscarriages, whereas it significantly increased with advanced maternal age.

Conclusion

Our results confirm that chromosome aberrations are the most common cause of RM and that QF‐PCR and aCGH combination should be included in the routine genetic analysis of POCs of couples with miscarriage.

Does anti-Mullerian hormone predict the outcome of further pregnancies in idiopathic recurrent miscarriage? A retrospective cohort study

Purpose

To evaluate whether anti-Mullerian hormone, basal follicle-stimulating hormone, luteinizing hormone, estradiol, and female age would predict future outcomes in women with idiopathic recurrent miscarriage.

Methods

One hundred and sixteen women with idiopathic recurrent miscarriage were retrospectively included. Luteal support with or without a combined treatment regimen for idiopathic recurrent miscarriage was applied in a tertiary-care center in Vienna. Occurrence and outcome of further pregnancies were analyzed.

Results

Within a median follow-up duration of 42.3 months, 94 women (81.0%) achieved one or more pregnancies. Further miscarriages occurred in 47 patients in whom only a higher number of previous miscarriages was predictive (OR 3.568, 95% CI 1.457–8.738; p = 0.005). Fifty-seven women had a live birth > 23 + 0 gestational weeks. In a multivariate analysis, age (OR 0.920, 95% CI 0.859–0.986; p = 0.019) and the number of previous miscarriages (OR 0.403, 95% CI 0.193–0.841; p = 0.016), but not AMH (OR 1.191, 95% CI 0.972–1.461; p = 0.091) were significantly predictive.

Conclusion

AMH seems of either no or only minor relevance for the prediction of further miscarriages and live birth in women with idiopathic recurrent miscarriage.

A comparison of effectiveness among frequent treatments of recurrent spontaneous abortion: A Bayesian network meta-analysis

OBJECTIVE

A comprehensive network meta-analysis was designed to clarify contradictions and offer valuable clinical guidance in the treatment of recurrent spontaneous abortion (RSA).

METHOD

The included clinical trials were selected from the relevant medical journal databases and screened. Treatments were ranked by the surface under the cumulative ranking curve. Heat plots were constructed to analyze the inconsistency between direct data and network results, and adjusted funnel plots were constructed to assess publication bias.

RESULTS

Forty-nine randomized controlled trials involving a total of 8496 RSA patients were selected. With placebo as control, corticosteroid plus low dose aspirin (LDA) plus unfractionated heparin (UFH), granulocyte colony-stimulating factor (G-CSF) alone, and LDA plus low molecular weight heparin (LMWH) all demonstrated effectiveness in increasing successful live birth rates and reducing the incidences of miscarriage. However, no treatment was demonstrably superior to placebo in terms of pregnancy success. For all 3 endpoints (live birth, abortion and success pregnancy), the adjusted funnel plots were symmetric to zero and indicated no publication bias. In terms of live birth and abortion rates, no treatment outperformed placebo in patients with antiphospholipid syndrome.

CONCLUSION

In consideration of live birth and abortion rates, corticosteroid plus LDA plus UFH appeared to be the optimum treatment strategy; G-CSF was second, followed by LDA with LMWH, LDA plus LMWH plus intravenous immunoglobulin, corticosteroid with LDA and others. Subgroup analysis demonstrated no benefit of antithrombotic therapy in patients with antiphospholipid syndrome.

Diminished ovarian reserve: is it a neglected cause in the assessment of recurrent miscarriage? A cohort study

OBJECTIVE

To study whether diminished ovarian reserve is associated with recurrent miscarriage.

DESIGN

Cross-sectional clinical study.

SETTING

Tertiary-care center.

PATIENT(S)

Women with history of recurrent miscarriage (RM; n = 71) and sequentially selected age-matched fertile women who were seeking contraception (control; n = 70).

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURES(S)

Serum levels of FSH, LH, E2, and antimüllerian hormone (AMH); FSH/LH ratio; ovarian volumes; and antral follicle count (AFC).

RESULT(S)

The levels of FSH were 8.6 ± 3.7 U/L in the RM group and 7.1 ± 3.9 U/L in the control group; this difference was statistically significant. The levels of AMH were significantly lower in the RM group than in the control group (2.9 ± 1.7 ng/mL vs. 3.6 ± 1.7 ng/mL). The percentage of women with levels of FSH ≥11 U/L was significantly higher in the RM group than in the control group (18.3% vs. 4.3%). In the RM group, the percentage of women with levels of AMH ≤1 ng/mL was significantly higher than in the control group (19.7% vs. 5.7%).

CONCLUSION(S)

Recurrent miscarriage may be associated with diminished ovarian reserve. Larger prospective randomized controlled trials are warranted to better determine the predictive potential of ovarian reserve markers in recurrent miscarriage.

Recurrent pregnancy loss: evaluation and treatment

Recurrent pregnancy loss (RPL) is a multifactorial condition. Approximately half of patients with RPL will have no explanation for their miscarriages. De novo chromosome abnormalities are common in sporadic and recurrent pregnancy loss. Testing for embryonic abnormalities can provide an explanation for the miscarriage in many cases and prognostic information. Regardless of the cause of RPL, patients should be reassured that the prognosis for live birth with an evidence-based approach is excellent for most patients. The authors review current evidence for the evaluation and treatment of RPL and explore the proposed use of newer technology for patients with RPL.

Reprogenetics: Preimplantational genetics diagnosis

Preimplantational Genetics Diagnosis (PGD) is requested by geneticists and reproductive specialists. Usually geneticists ask for PGD because one or both members of the couple have an increased genetic risk for having an affected offspring. On the other hand, reproductive specialists ask for embryo aneuploidy screening (PGS) to assures an euploid embryo transfer, with the purpose to achieve an ongoing pregnancy, although the couple have normal karyotypes. As embryonic aneuploidies are responsible for pre and post implantation abortions, it is logical to considerer that the screening of the embryonic aneuploidies prior to embryo transfer could improve the efficiency of the in vitro fertilization procedures. Nevertheless, it is still premature to affirm this until well-designed clinical trials were done, especially in women of advanced age where the rate of embryos with aneuploidies is much greater. Although the indications of PGD are similar to conventional prenatal diagnosis (PND), PGD has less ethical objections than the PND. As with the PGD/PGS results only unaffected embryos are transferred, both methods can avoid the decision to interrupt the pregnancy due to a genetic problem; this makes an important difference when compared to conventional prenatal diagnosis.

Treating patients with "thin" endometrium - an ongoing challenge

OBJECTIVE

To review the literature regarding inadequate growth ("thin") of the endometrium and to present the hitherto published methods aimed to improve endometrial thickness and the consequent endometrial receptivity.

MATERIALS AND METHODS

A literature review was conducted for all relevant articles assessing the effect of various treatment modalities on "thin" endometrium and the consequent reproductive outcome.

RESULTS

Several treatment modalities have been offered to patients with "thin" endometrium, including hysteroscopic adhesiolysis, hormonal manipulation by estrogen and GnRH-agonist, vasoactive measures such as aspirin, vitamin E, pentoxifylline, l-arginine or sildenafil, intra-uterine infusion of growth factor such as G-CSF and the recent application of regenerative medicine. In spite of the vast diversity of treatment, most of the options accomplish only minor change in the endometrium thickness and subsequent pregnancy rate, and when they fail, patients are usually referred to surrogacy.

CONCLUSIONS

"Thin" endometrium is known to adversely affect reproductive performance. Treatment of "thin endometrium" remains a challenge and future large researches are required to further elucidate and optimal management of patients with "thin" endometrium.

Idiopathic recurrent miscarriage is caused mostly by aneuploid embryos

OBJECTIVE

To determine any beneficial effects of preimplantation genetic screening (PGS) of all chromosomes by array comparative genomic hybridization (aCGH), with either day 3 or blastocyst biopsy, for idiopathic recurrent pregnancy loss (RPL) patients compared with their expected loss rate.

DESIGN

Case series report.

SETTING

Multiple fertility centers.

PATIENT(S)

A total of 287 cycles of couples with idiopathic RPL (defined as two or more losses).

INTERVENTION(S)

PGS was done with day 3 biopsy (n = 193) or blastocyst biopsy (n = 94), followed by analysis with aCGH.

MAIN OUTCOME MEASURE(S)

Spontaneous abortion rate, euploidy rate.

RESULT(S)

A total of 2,282 embryos were analyzed, of which 35% were euploid and 60% were aneuploid. There were 181 embryo transfer cycles, of which 100 (55%) became pregnant with an implantation rate of 45% (136 sacs/299 replaced embryos) and 94 pregnancies (92%) were ongoing (past second trimester) or delivered. The miscarriage rate was found to be only 6.9% (7/102), compared with the expected rate of 33.5% in an RPL control population and 23.7% in an infertile control population.

CONCLUSION(S)

Current PGS results with aCGH indicate a significant decrease in the miscarriage rate of idiopathic RPL patients and high pregnancy rates. Furthermore, this suggests that idiopathic recurrent miscarriage is mostly caused by chromosomal abnormalities in embryos.

Expression profiles of cohesins, shugoshins and spindle assembly checkpoint genes in rhesus macaque oocytes predict their susceptibility for aneuploidy during embryonic development

High frequencies of chromosomal anomalies are reported in human and non-human primate in vitro-produced preimplantation embryos. It is unclear why certain embryos develop aneuploidies while others remain euploid. A differential susceptibility to aneuploidy is most likely a consequence of events that occur before oocyte collection. One hypothesis is that the relative transcript levels of cohesins, shugoshins and spindle assembly checkpoint genes are correlated with the occurrence of chromosomal anomalies. Transcript levels of these genes were quantified in individual oocytes that were either mature (group 1, low aneuploidy rate) or immature (group 2, high aneuploidy rate) at retrieval, utilizing TaqMan-based real-time PCR. The transcript level in each oocyte was categorized as absent, below the median or above the median in order to conduct comparisons. Statistically significant differences were observed between group 1 and group 2 for SGOL1 and BUB1. There were more oocytes with SGOL1 expression levels above the median in group 1, while oocytes lacking BUB1 were only observed in group 1. These findings suggest that higher SGOL1 levels in group 1 oocytes could better protect against a premature separation of sister chromatids than in embryos derived from group 2 oocytes. The absence of BUB1 transcripts in group 1 was frequently associated with reduced expression of either mitotic cohesins or shugoshins. We hypothesize that ablation of BUB1 could induce mitotic arrest in oocytes that fail to express a complete complement of cohesins and shugoshins, thereby reducing the number of developing aneuploid preimplantation embryos.

An in vitro model for the study of human implantation

PROBLEM

Implantation remains the rate-limiting step for the success of in vitro fertilization. Appropriate models to study the molecular aspects of human implantation are necessary in order to improve fertility.

METHODS

First trimester trophoblast cells are differentiated into blastocyst-like spheroids (BLS) by culturing them in low attachment plates. Immortalized human endometrial stromal cells and epithelial cells (ECC-1) were stably transfected with GFP or tdTomato. Co-culture experiments were monitored using Volocity imaging analysis system.

RESULTS

This method demonstrates attachment and invasion of BLS, formed by trophoblast cells, into stromal cells, but not to uterine epithelial cells.

CONCLUSION

We have developed an in vitro model of uterine implantation. The manipulation of this system allows for dual color monitoring of the cells over time. Additionally, specific compounds can be added to the culture media to test how this may affect implantation and invasion. This model is a helpful tool in understanding the complexity of human implantation.

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.

A possible mechanism of autoimmune-mediated infertility in women with endometriosis

PROBLEM

Endometriosis has been proposed to be an autoimmune disease because of the presence of a variety of autoantibodies specific for endometrial or ovarian antigens. The object of the present study is to characterize binding specificity of anti-laminin-111 autoantibodies in infertile patients with endometriosis and to investigate whether these autoantibodies affect the in vitro embryo development.

METHOD OF STUDY

An ELISA analysis using overlapping synthesized peptides that covered the entire G domain of laminin-α1 chain was performed in infertile patients with endometriosis (n = 45). Mouse blastocysts were cultured in media containing the purified IgG from one antibody-positive serum on laminin-111-coated dishes.

RESULTS

Anti-laminin-111 autoantibodies were directed to several particular biologically functional peptide sequences in laminin-α 1 chain G domain. The tested IgG significantly inhibited the extent of in vitro trophoblast outgrowth.

CONCLUSION

Anti-laminin-111 autoantibodies may have major pathogenic roles on early reproductive failure including endometriosis-associated infertility.

Pregnancy outcome after preimplantation genetic screening or natural conception in couples with unexplained recurrent miscarriage: a systematic review of the best available evidence

The objective of this systematic review was to assess live birth rates and miscarriage rates after preimplantation genetic screening or natural conception for unexplained recurrent miscarriage. There were no randomized controlled trials or comparative studies found on this topic. Until data from randomized controlled trials become available, this review summarizes the best available evidence of the efficacy of preimplantation genetic screening vs. natural conception.

Preclinical validation of a microarray method for full molecular karyotyping of blastomeres in a 24-h protocol

BACKGROUND

Preimplantation genetic screening (PGS) has been used in an attempt to determine embryonic aneuploidy. Techniques that use new molecular methods to determine the karyotype of an embryo are expanding the scope of PGS.

METHODS

We introduce a new method for PGS, termed 'parental support', which leverages microarray measurements from parental DNA to 'clean' single-cell microarray measurements on embryonic cells and explicitly computes confidence in each copy number call. The method distinguishes mitotic and meiotic copy errors and determines parental source of aneuploidy.

RESULTS

Validation with 459 single cells of known karyotype indicated that per-cell false-positive and false-negative rates are roughly equivalent to the 'gold standard' metaphase karyotype. The majority of the cells were run in parallel with a clinical commercial PGS service. Computed confidences were conservative and roughly concordant with accuracy. To examine ploidy in human embryos, the method was then applied to 26 disaggregated, cryopreserved, cleavage-stage embryos for a total of 134 single blastomeres. Only 23.1% of the embryos were euploid, though 46.2% of embryos were mosaic euploid. Mosaicism affected 57.7% of the embryos. Counts of mitotic and meiotic errors were roughly equivalent. Maternal meiotic trisomy predominated over paternal trisomy, and maternal meiotic trisomies were negatively predictive of mosaic euploid embryos.

CONCLUSIONS

We have performed a major preclinical validation of a new method for PGS and found that the technology performs approximately as well as a metaphase karyotype. We also directly measured the mechanism of aneuploidy in cleavage-stage human embryos and found high rates and distinct patterns of mitotic and meiotic aneuploidy.

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.

Preimplantation genetic diagnosis (PGD) improves pregnancy outcome for translocation carriers with a history of recurrent losses

OBJECTIVE

To determine if preimplantation genetic diagnosis (PGD) for translocation carriers with three or more pregnancy losses reduces loss rates.

DESIGN

Retrospective review of data.

SETTING

Preimplantation genetic diagnosis laboratory servicing IVF groups.

PATIENT(S)

Patients (n = 192) undergoing PGD for either a reciprocal translocation or Robertsonian translocation who had three or more previous pregnancy losses.

INTERVENTION(S)

Preimplantation genetic diagnosis for translocations.

MAIN OUTCOME MEASURE(S)

Pregnancy loss rate, pregnancy success rate defined as delivery of at least one child or an ongoing pregnancy in the third trimester, and length of time to success.

RESULT(S)

Pregnancy loss rate was significantly reduced to 13% post-PGD compared with 88.5% in previous non-PGD pregnancies and to 35% to 64% from naturally conceived pregnancies as reported in the literature. Pregnancy success rate was 87%. Conception occurred after an average of 1.4 cycles or <4 months.

CONCLUSION(S)

Individuals with translocations who have experienced three or more losses benefit from PGD by realizing a significant reduction in loss rate and improvement in rate of success of pregnancy. Length of time to conceive is also dramatically reduced compared with data in the literature for similar populations not undergoing PGD.

The role of assisted reproductive technology in the management of recurrent pregnancy loss

PURPOSE OF REVIEW

Description of genetic screening of preimplantation embryos as a means of reducing miscarriages in patients with recurrent pregnancy loss.

RECENT FINDINGS

That the promise of preimplantation genetic screening (PGS) for ameliorating recurrent pregnancy loss has been fulfilled is controversial. An array of comparative studies has suggested a positive effect of PGS on implantation rate, but these have been balanced by studies showing no effect or a negative effect, highlighting the need for more rigorously designed studies and randomized controlled trials. Emerging technologies may provide more information from the embryo biopsies even as the mosaicism of the embryo and its implications for interpreting PGS data are recognized.

SUMMARY

Through the screening of embryos for abnormality in chromosome number or structure and selecting only normal embryos for transfer, PGS was envisioned and applied as a therapeutic tool for improving implantation and live birth rates from in-vitro fertilization and providing a means of attenuating pregnancy loss in recurrent pregnancy loss patients. An array of reports on the effects of PGS on embryo implantation and live birth rates has been made since its introduction, showing, variously, increases, decreases or no changes in these parameters. Various factors may influence the efficacy of PGS, including the patient population to which it is applied, technical aspects such as embryo biopsy, the genetic analysis and embryo culture environment, the current limitation of the genetic analysis (a subset of, rather than all, the 24 chromosomes) and the mosaicism of the embryo and blastocyst. Collectively, these contribute to the challenge of optimizing PGS and understanding how the screening result reflects the ultimate genetic constitution of the conceptus. Emerging cytogenetic and molecular technologies such as comparative genomic hybridization and microarray analysis may provide a broader appraisal of the embryo for a more comprehensive evaluation of developmental potential and prognosis for live birth.

Prognostic factors for preimplantation genetic screening in repeated pregnancy loss

The objective of this study was to identify specific subgroups of recurrent pregnancy loss (RPL) patients of unknown aetiology in whom the selection of chromosomally normal embryos for transfer improves reproductive outcome in preimplantation genetic screening (PGS). A total of 428 PGS cycles were included and chromosomes 13, 15, 16, 18, 21, 22, X and Y were evaluated. In RPL patients < or =37 years, a lower incidence of chromosomal abnormalities (P = 0.0004) and miscarriages (P = 0.0283) was observed, and there were significantly higher pregnancy (P < 0.0384) and implantation (P < 0.0434) rates than in patients >37 years. In the former subset, results showed: (i) significantly higher implantation rates (P = 0.0411) in couples that had experienced a previous aneuploid miscarriage; (ii) similar aneuploidy, pregnancy and implantation rates in couples suffering previous miscarriages during fertility treatments and in those with previous spontaneous pregnancies; (iii) no miscarriages after PGS in couples in whom a fluorescence in-situ hybridization assay showed the male partner's sperm to be abnormal; and (iv) lower implantation rates in couples with > or =5 previous miscarriages, associated with a lower percentage of chromosomally abnormal embryos. It is concluded that PGS is to be strongly recommended when RPL is associated with miscarriages during infertility treatments, chromosomopathy in a previous miscarriage, up to five previous miscarriages and a high incidence of chromosomal abnormalities in spermatozoa.

Incidence of chromosomal mosaicism in morphologically normal nonhuman primate preimplantation embryos

OBJECTIVE

To establish the exact rates of chromosomal mosaicism in morphologically normal rhesus macaque embryos by determining the chromosomal complement of all blastomeres.

DESIGN

Retrospective rhesus monkey IVF study.

SETTING

Academic laboratory and primate research center.

PATIENT(S)

Young fertile rhesus macaque females.

INTERVENTION(S)

Morphologically normal in vitro-produced rhesus macaque embryos were dissociated and cytogenetically assessed using a five-color fluorescent in situ hybridization assay developed for rhesus macaque chromosomes homologous to human chromosomes 13, 16, 18, X, and Y.

MAIN OUTCOME MEASURE(S)

The incidence and extent of chromosomal mosaicism in rhesus macaque preimplantation embryos.

RESULT(S)

Seventy-seven preimplantation embryos, displaying normal morphology and development, from 17 young rhesus macaque females were analyzed. Overall, 39 embryos (50.6%) were normal, 14 embryos (18.2%) were completely abnormal, and 24 embryos (31.2%) were mosaic. Of the 226 blastomeres analyzed in the mosaic group, 110 blastomeres (48.7%) were normal.

CONCLUSION(S)

The observed rate of mosaicism in good-quality rhesus embryos resembles previously documented frequencies in poor-quality human preimplantation embryos. A high incidence of mosaicism may limit the diagnostic accuracy of preimplantation genetic diagnosis.

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.

Chromosomal instability in rhesus macaque preimplantation embryos

OBJECTIVE

To establish a relevant animal model to systematically investigate chromosomal instability in human oocytes and preimplantation embryos.

DESIGN

Prospective rhesus monkey IVF study.

SETTING

Academic laboratory, Oregon National Primate Research Center and Caribbean Primate Research Center.

ANIMAL(S)

Young rhesus macaque females.

INTERVENTION(S)

In vitro produced entire rhesus macaque preimplantation embryos were cytogenetically assessed using a five-color fluorescent in situ hybridization assay developed for rhesus macaque chromosomes homologous to human chromosomes 13, 16, 18, X, and Y, using human bacterial artificial chromosome probes.

MAIN OUTCOME MEASURE(S)

Chromosomal abnormality rates in preimplantation embryos from young rhesus macaque females were established.

RESULT(S)

Fifty preimplantation embryos, displaying good morphology and normal development, were analyzed from 11 young rhesus macaque females. Overall, 27 embryos (54%) were normal, 11 embryos (22%) mosaic, 3 embryos (6%) chaotic, 2 embryos (4%) aneuploid, 3 embryos (6%) haploid, and 4 embryos (8%) triploid.

CONCLUSION(S)

These data indicate that in vitro produced rhesus macaque and human preimplantation embryos exhibit similar numerical chromosomal aberrations. Rhesus macaques appear to be a suitable animal model for investigating the origin of chromosomal instability observed in human preimplantation embryos.

Uterine DCs are crucial for decidua formation during embryo implantation in mice

Implantation is a key stage during pregnancy, as the fate of the embryo is often decided upon its first contact with the maternal endometrium. Around this time, DCs accumulate in the uterus; however, their role in pregnancy and, more specifically, implantation, remains unknown. We investigated the function of uterine DCs (uDCs) during implantation using a transgenic mouse model that allows conditional ablation of uDCs in a spatially and temporally regulated manner. Depletion of uDCs resulted in a severe impairment of the implantation process, leading to embryo resorption. Depletion of uDCs also caused embryo resorption in syngeneic and T cell-deficient pregnancies, which argues against a failure to establish immunological tolerance during implantation. Moreover, even in the absence of embryos, experimentally induced deciduae failed to adequately form. Implantation failure was associated with impaired decidual proliferation and differentiation. Dynamic contrast-enhanced MRI revealed perturbed angiogenesis characterized by reduced vascular expansion and attenuated maturation. We suggest therefore that uDCs directly fine-tune decidual angiogenesis by providing two critical factors, sFlt1 and TGF-beta1, that promote coordinated blood vessel maturation. Collectively, uDCs appear to govern uterine receptivity, independent of their predicted role in immunological tolerance, by regulating tissue remodeling and angiogenesis. Importantly, our results may aid in understanding the limited implantation success of embryos transferred following in vitro fertilization.

Preimplantation genetic screening does not improve delivery rate in women under the age of 36 following single-embryo transfer

BACKGROUND

Single-embryo transfer is a well-accepted strategy to avoid multiple pregnancies in an assisted reproductive technology (ART) programme. Besides the morphological quality and embryo kinetics up to the blastocyst stage, preimplantation genetic screening (PGS) of aneuploidy has been advocated as an adjuvant approach to select the embryo.

METHODS

Couples with a female partner younger than 36 were randomly assigned to undergo transfer of a single blastocyst in a cycle with or without PGS using FISH for the chromosomes X, Y, 13, 16, 18, 21, 22.

RESULTS

After the enrolment of 120 of the projected 447 patients in each group, study recruitment was terminated prematurely on the basis of futility. The observed live birth delivery rates after ART were 30.8 versus 30.8% per randomized patient, 34.6 versus 34.6% per cycle initiated, 37.8 versus 37.0% per aspirated cycle and 41.6 versus 43.5% per embryo transfer for the control versus the PGS group, respectively, with absolute between-group differences (95% CI; P value) of 0% (-11.7 to 11.7; P = 1.00), 0% (-12.7 to 12.7; P = 1.00), -0.8% (-14.2 to 12.7; P = 0.91) and 2.1% (-12.7 to 16.7; P = 0.79), respectively. Even in this younger age group, only 61% of the embryos had a normal diploid status.

CONCLUSIONS

The absence of a beneficial treatment effect in this randomized clinical trial provides no arguments in favour of PGS to improve live birth delivery rate following single-embryo transfer in women under the age 36. Clinical Trials.gov: NCT00670059.

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

The goal of preimplantation genetic diagnosis (PGD) 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-extention 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 a support protocol for probe validation that is recommended as a preliminary step before performing any PGD FISH analysis.

Preimplantation genetic screening: "established" and ready for prime time?

Unless attempts to improve pregnancy rates and/or diminish miscarriage rates through preimplantation genetic screening (PGS) are applied to only carefully selected patients, they will fail. Because specific PGS indications have remained undefined, PGS should be considered an experimental procedure.

Ten-year experience with preimplantation genetic diagnosis (PGD) at the New York University School of Medicine Fertility Center

We describe our experience of over 300 cycles of preimplantation genetic diagnosis (PGD) and report clinical pregnancy rates (35%-67%) that support using this technology to screen for genetic disorders and chromosomal abnormalities. In clinical practice for over ten years, PGD offers couples the earliest form of genetic screening and may help improve ongoing pregnancy rates in poor-prognosis patients.

Preimplantation genetic diagnosis

Preimplantion genetic diagnosis (PGD) is now used for identification of gene and chromosomal defects in embryos. In this article we describe its use primarily for identification of chromosomal defects in women with recurrent abortions, repeated in vitro fertilization (IVF) failure, and advanced maternal age. In all these situations there is increase in chromosomal defects. The identification of normal embryos and the elimination of abnormal embryos are argued to be helpful in increasing implantation and pregnancy rates in these women.

PGD for aneuploidy screening: an expensive hoax?

Pre-implantation genetic diagnosis for aneuploidy screening (PGD-AS) constitutes a technique developed to improve embryo selection in patients with a poor outcome after in-vitro fertilization treatment due to an increased frequency of numerical chromosome abnormalities in the embryos. Although multiple studies have evaluated the performance of PGD-AS in different groups of patients, inconsistencies in the evidence available have not enabled definitive conclusions to be drawn. According to randomized trials, PGD-AS does not improve the outcome of women of advanced age when there is no limitation on the number of embryos to be transferred. In patients who have experienced recurrent implantation failure or recurrent miscarriage, AS only seems to provide diagnostic information, especially when aneuploid embryos alone are found. Additional evidence is needed before AS is implemented as part of routine clinical practice.

MRI analysis of angiogenesis during mouse embryo implantation

Uterine receptivity and embryo implantation depend on local induction of angiogenesis and vascular permeability. Poor uterine receptivity has been implicated in implantation failure; however, relatively little is known about the mechanism that underlies endometrial vascular hyperpermeability in implantation sites. Here we show that contrast-enhanced (CE)-MRI and fluorescence microscopy using biotin-BSA-GdDTPA allowed high-resolution detection and quantitative assessment of mouse embryo implantation sites as early as embryonic day 4.5 (E4.5), and subsequent vascular expansion at E5.5. Vessel permeability, but not blood volume, was significantly elevated in E4.5 implantation sites relative to nonimplanted uterus, showing that elevation of vascular permeability is a very early response preceding E4.5. A significantly increased blood volume was detected by MRI and fluorescence microscopy in implantation sites between E4.5 and E5.5. On the other hand, despite the increase in blood volume, implantation sites showed only a small nonsignificant further increase in vascular permeability during these 2 days, demonstrating the rapid dynamics of vascular remodeling during the early days of pregnancy. Functional imaging by MRI, as reported here, allows multiparametric measurement of angiogenesis during normal mouse implantation and would facilitate the application of MRI to evaluate involvement of the vasculature in mouse models of impaired implantation.

Current value of preimplantation genetic aneuploidy screening in IVF

Preimplantation genetic aneuploidy screening (PGS) has been performed during the last decade as a way of enhancing embryo selection in patients with an increased incidence of embryonic numerical chromosome abnormalities (advanced maternal age, recurrent miscarriage and recurrent implantation failure). It has been proposed that the replacement of euploid embryos in these patients would result in a higher implantation and pregnancy rate and a reduced miscarriage rate. Additionally, the transfer of fewer embryos could reduce the chances for multiple pregnancies in all IVF patients. Although, to date, multiple studies have addressed this issue, contradictory results have been encountered. As a result, the effectiveness of aneuploidy screening remains to be established. Moreover, child outcome studies documenting the safety of this procedure are needed. The aim of this review is to summarize the available evidence concerning the use of PGS to determine the current value of the technique.

Preimplantation genetic diagnosis significantly reduces pregnancy loss in infertile couples: a multicenter study

OBJECTIVE

The inicidence of miscarriage is correlated with maternal age. The majority of miscarriages are chromosomally abnormal. The purpose of this study was to determine in a large population of infertility patients (>2000 cycles) if preimplantation genetic diagnosis (PGD) reduced the rate of spontaneous abortions.

DESIGN

Multicenter retrospective controlled study.

SETTING

One hundred IVF centers referring samples to a reference PGD laboratory.

PATIENT(S)

Infertile women.

INTERVENTION(S)

The spontaneous abortion rate after PGD was retrospectively compared to non-PGD cycles from the 2002 American Society for Reproductive Medicine-Society for Assisted Reproduction Technology report on IVF cycles.

MAIN OUTCOME MEASURE(S)

Spontaneous abortions and trisomic offspring rates.

RESULT(S)

The study included 2,279 cycles of PGD. The pregnancy rate per retrieval was 26.7% (average age 39.6). The mean pregnancy loss for the PGD group (0.167) was significantly lower than for the general IVF group (0.215) (P<.001). After PGD, the spontaneous abortion rate was 14.1% for ages 35-40, and 22.2% for women over 40, compared to 19.4% (P=.03) and 40.6% (P<.001), respectively, in controls. The clinical error rate of PGD (1.2%) was significantly lower than expected (4.7%) (P<.001).

CONCLUSION(S)

The data suggests that PGD significantly reduces the risk of spontaneous abortions in women undergoing IVF and PGD, particularly in women over 40. In addition, PGD may also reduce the risk of trisomic offspring.

Preimplantation genetic screening for abnormal number of chromosomes (aneuploidies) in in vitro fertilisation or intracytoplasmic sperm injection

BACKGROUND

In both in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI), selection of the most competent embryo(s) for transfer is generally based on morphological criteria. However, many women fail to achieve a pregnancy after transfer of good quality embryos. One of the presumed causes is that such morphologically normal embryos show an abnormal number of chromosomes (aneuploidies). In preimplantation genetic screening (PGS), embryos are analysed for aneuploidies and only embryos that are euploid for the chromosomes tested are transferred. This technique has been suggested and used to improve pregnancy rates for the following indications: (i) advanced maternal age, (ii) repeated IVF failure, (iii) repeated miscarriage and (iv) testicular sperm extraction (TESE)-ICSI. Although PGS is used more and more often, its effectiveness is still unclear.

OBJECTIVES

To assess the effectiveness of PGS in terms of live births in women undergoing IVF or ICSI treatment.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 1, 2005), MEDLINE (1966 to present) and EMBASE (1980 to present) (searched March 2005) and reference lists of articles. We also contacted authors for providing additional data when necessary.

SELECTION CRITERIA

Trials for all four suggested indications as mentioned above were sought. All relevant published randomised controlled trials were selected. They were eligible for inclusion if the comparison dealt with IVF/ICSI with PGS versus IVF/ICSI without PGS.

DATA COLLECTION AND ANALYSIS

Relevant data were extracted independently by two authors. All trials were screened and analysed according to predetermined quality criteria. Validity was assessed in terms of method of randomisation, completeness of follow-up, intention-to-treat analysis and presence or absence of blinding. The primary outcome measure was live birth rate per woman. Secondary outcome measures were the proportion of women reaching embryo transfer, mean number of embryos transferred per transfer, clinical pregnancy rate, multiple pregnancy rate, miscarriage rate, ongoing pregnancy rate, proportion of women reaching embryo transfer after cryopreservation and proportion of women whose child has a congenital malformation.

MAIN RESULTS

Two randomised controlled trials met our predetermined eligibility criteria. These trials used PGS for advanced maternal age. The primary outcome of live birth rate per woman was not significantly different in the PGS and control groups, though data were only available from one study. The live birth rate was 11% (21 out of 199) in the PGS group, versus 15% (29 out of 190) in the control group (OR 0.65; 95% CI 0.36 to 1.19). For a control group rate of 15%, these data suggest a live birth rate using PGS of between 4% and 17%. Ongoing pregnancy rate was provided in both studies. This was not significantly different with a combined odds ratio of 0.64 (95% CI 0.37 to 1.09). For a control group rate of 20%, this suggests an ongoing pregnancy rate using PGS of between 8% and 21%.

AUTHORS' CONCLUSIONS

To date there is insufficient data to determine whether PGS is an effective intervention in IVF/ICSI for improving live birth rates. Available data on PGS for advanced maternal age showed no difference in live birth rate and ongoing pregnancy rate. However, only two randomised trials were found, of which one included only 39 patients. For both studies comments on their methodological quality can be made. Therefore more properly conducted randomised controlled trials are needed. Until such trials have been performed PGS should not be used in routine patient care.

Preimplantation genetic diagnosis significantly improves the pregnancy outcome of translocation carriers with a history of recurrent miscarriage and unsuccessful pregnancies

Preimplantation genetic diagnosis (PGD) for translocations has been shown to significantly reduce the risk of recurrent miscarriage, but because the majority of embryos produced are unbalanced, pregnancy rate is relatively low since 20% or more cycles have no normal or balanced embryos to transfer. The purpose of this study was to evaluate whether PGD could improve pregnancy outcome in translocation carriers with a history of two or more consecutive miscarriages and no live births. PGD for translocations was offered to translocation carriers with two or more previous miscarriages (average 3.5) and no live births (0/117 pregnancies) using a combination of distal and proximal probes to the breakpoints. After PGD, only 18.3% of embryos were normal or balanced. Only 5.3% of pregnancies were lost after PGD compared with 100% before PGD (P < 0.001). The cumulative pregnancy rate was 57.6% and the cumulative ongoing pregnancy rate was 54.5% in the short period of time of 1.24 IVF cycles, or 46.3% and 43.9% respectively per cycle. In conclusion, PGD significantly reduced losses and increased the number of viable pregnancies (P < 0.001). IVF plus PGD are a faster method of conceiving a live child than natural conception, at least for translocation carriers with recurrent miscarriages and no previous live births.

Early pregnancy loss is significantly higher after day 3 single embryo transfer than after day 5 single blastocyst transfer in GnRH antagonist stimulated IVF cycles

The current study aimed to investigate whether single day-3 embryo transfer (SET) results in higher early pregnancy loss (EPL) than single blastocyst transfer (SBET). A total of 896 patients underwent 1103 IVF cycles with a gonadotrophin-releasing hormone (GnRH) antagonist protocol. In 603 cycles (D3 group) a single embryo on day 3 of the embryo culture was transferred, whereas in the remaining 500 cycles a single blastocyst was transferred on day 5 (D5 group). Multifollicular ovarian stimulation was performed with a GnRH antagonist protocol starting on day 6. SET resulted in 209 pregnancies (34.7%), compared with 221 pregnancies (44.2%) for SBET. Early pregnancy loss rate was significantly higher with SET compared with SBET (26.8% versus 17.2%, P = 0.017) and ongoing implantation rate was also significantly higher with day 5 compared with day-3 embryo transfer (OR:1.68, 95% confidence interval:1.31-2.18). Sub-optimal embryo selection for transfer on day 3, in addition to asynchronization between altered endometrium and early exposure of cleavage-stage embryos, might explain the above difference. Nevertheless, the higher implantation potential of the blastocyst questions the rationale behind performing single embryo transfer on day 3 of embryo culture in women under 36 years old.

Embryo aneuploidy screening for repeated implantation failure and unexplained recurrent miscarriage

Among other factors, chromosomal abnormalities that originate from gametogenesis and preimplantation embryonic development are thought to be one of the major contributing factors for early embryonic death and failure of pregnancy. However, so far, no non-invasive technique exists that allows the detection of the chromosomal complement of an oocyte or a developing embryo as a whole. Rather, by removing polar bodies/blastomeres, recent developments on preimplantation genetic diagnosis for aneuploidy screening (PGD-AS) have paved the way to detect and possibly eliminate the majority of chromosomally abnormal embryos, thereby increasing the chance of a healthy pregnancy. This article summarizes the origin and impact of chromosomal abnormalities on human reproduction in cases with repeated implantation failure (RIF) and unexplained recurrent miscarriage. It also discusses recent advances regarding the possible benefits of PGD-AS in such cases.

Preimplantation genetic diagnosis does not increase pregnancy rates in patients at risk for aneuploidy

OBJECTIVE

To investigate the use of preimplantation genetic diagnosis (PGD) as a method for increasing pregnancy success rates in patients at high risk for aneuploidy.

DESIGN

Literature review and discussion of current evidence.

CONCLUSION(S)

Preimplantation genetic diagnosis selects euploid embryos for transfer in assisted reproduction. Some investigators argue that it might be used to increase pregnancy rates in patient populations at high risk of aneuploidy, such as those with advanced maternal age (AMA), recurrent pregnancy loss (RPL), and recurrent IVF failure. Although analysis with PGD confirms a high rate of aneuploidy in patients with AMA, RPL, and recurrent IVF failure, its use in these patient populations has not been consistently shown, in the literature, to increase pregnancy rates. Randomized controlled trials with large patient populations, performed in programs with expertise in PGD technology, are needed before PGD can routinely be recommended as a means for increasing pregnancy rates in patients with AMA, RPL, and recurrent IVF failure.