Thorir Hardarson

Preimplantation genetic screening in women of advanced maternal age caused a decrease in clinical pregnancy rate: a randomized controlled trial

BACKGROUND Advanced maternal age (AMA) is an important parameter that negatively influences the clinical pregnancy rate in IVF, in particular owing to the increased embryo aneuploidy rate. It has thus been suggested that only transferring euploid embryos in this patient group would improve the pregnancy rate. The purpose of this study was to test whether employing preimplantation genetic screening (PGS) in AMA patients would increase the clinical pregnancy rate. METHODS We conducted a two-center, randomized controlled trial (RCT) to analyze the outcome of embryo transfers in AMA patients (>or=38 years of age) after PGS using FISH analysis for chromosomes X, Y, 13, 16, 18, 21 and 22. The PGS group was compared with a control group. The primary outcome measure was clinical pregnancy rate after 6-7 weeks of gestation per randomized patient. RESULTS The study was terminated early as an interim analysis showed a very low conditional power of superiority for the primary outcome. Of the 320 patients calculated to be included in the study, 56 and 53 patients were randomized into the PGS and control groups, respectively. The clinical pregnancy rate in the PGS group was 8.9% (95% CI, 2.9-19.6%) compared with 24.5% (95% CI, 13.8-38.3%) in the control group, giving a difference of 15.6% (95% CI, 1.8-29.4%, P = 0.039). CONCLUSIONS Although the study was terminated early, this RCT study provides evidence against the use of PGS for AMA patients when performing IVF. TRIAL REGISTRATION NUMBER ISRCTN38014610.

The Istanbul consensus workshop on embryo assessment: proceedings of an expert meeting

This paper reports the proceedings of an international consensus meeting on oocyte and embryo morphology assessment. Following background presentations about current practice, the expert panel developed a set of consensus points to define the minimum criteria for oocyte and embryo morphology assessment. It is expected that the definition of common terminology and standardization of laboratory practice related to embryo morphology assessment will result in more effective comparisons of treatment outcomes. This document is intended to be referenced as a global consensus to allow standardized reporting of the minimum dataset required for the accurate description of embryo development. This paper reports the proceedings and outcomes of an international consensus meeting on human oocyte and embryo morphology assessment. An expert panel developed a series of consensus points to define the minimum criteria for such assessments. The definition of common terminology, and standardization of laboratory practices related to these morphological assessments, will permit more effective comparisons of treatment outcomes around the world. This report is intended to be referenced as a global consensus to allow standardized reporting of the minimum descriptive criteria required for routine clinical evaluations of human embryo development in vitro.

Non-invasive metabolomic profiling of Day 2 and 5 embryo culture medium: a prospective randomized trial

BACKGROUND Near infrared (NIR) spectroscopy is a technology proposed to facilitate non-invasive screening for the most optimal human embryo for uterine transfer. It has been proposed that the NIR spectral profile of an embryos spent culture medium can be used to generate a viability score that correlates to implantation potential. As the initial proof of principle studies were all retrospective, our aim was to investigate whether NIR spectroscopy on spent embryo culture medium in an on-site, prospective setting could improve the ongoing single embryo transfer (SET) pregnancy rate after Day 2 and 5 transfers. METHODS We conducted a single-centre, double-blinded, randomized controlled trial in which the NIR group was compared with a control group. The primary outcome was the clinical pregnancy rate after 6-7 weeks of gestation per randomized patient. In the control group embryo selection was based only on traditional morphological evaluation while in the treatment group NIR spectroscopy was added to the morphological evaluation. RESULTS The study was terminated early as the analysis of the Data Safety Monitoring Board showed a very low conditional power of superiority for the primary outcome. Of the 752 patients calculated to be included in the study, 164 and 163 patients were randomized into the NIR and control groups, respectively. No significant difference in the ongoing pregnancy rate per randomized patient was found between the NIR and the control group, 34.8 versus 35.6%, (P= 0.97). The proportional difference between the study groups mean was -0.8% (95% confidence interval -11.4 to 10.2). CONCLUSIONS This study shows that adding NIR spectroscopy, in its present form, to embryo morphology does not improve the chance of a viable pregnancy when performing SET. The NIR technology appears to need further development before it can be used as an objective marker of embryo viability. CLINICAL TRIALS IDENTIFIER ISRCTN23817363.

Obstetric outcomes after transfer of vitrified blastocysts

BACKGROUND It has been claimed that the risks to the child resulting from vitrification as compared with the slow-freezing technique, may be higher owing to the high concentrations of potentially toxic cryoprotectants. We therefore retrospectively compared the obstetric and neonatal outcomes in a cohort of children born after transfer of vitrified blastocysts, fresh blastocysts and slow-frozen early cleavage stage embryos. METHODS All children born after transfer of vitrified blastocysts (n = 106), fresh blastocysts (n = 207) and slow-frozen early cleavage stage embryos (n = 206) during the period January 2006 to May 2008 at Fertility Center Scandinavia were included. Data on obstetric and neonatal outcomes were obtained from medical records from the antenatal and delivery clinics. RESULTS For singletons, there were no significant differences between the groups in gestational age, mortality or birth defects. After adjustment for parity and BMI, birthweight was significantly higher in singletons born after transfer of vitrified blastocysts as compared with after transfer of fresh blastocysts (median 3560 versus 3510 g, P = 0.0311). More singletons born after transfer of fresh blastocysts were small for gestational age compared with singletons born after transfer of vitrified blastocysts (12.1 versus 3.0%, P = 0.0085). A higher rate of major post-partum haemorrhage was observed in the vitrified blastocyst group as compared with the other two groups (25.0 versus 6.0 and 7.5%). CONCLUSIONS No adverse neonatal outcomes were observed in children born after transfer of vitrified, as compared with fresh blastocysts or after transfer of slow-frozen early cleavage stage embryos.

Trophectoderm morphology: an important parameter for predicting live birth after single blastocyst transfer

BACKGROUND In order to select the best blastocyst for transfer, in humans, three morphological parameters have routinely been used, i.e. degree of blastocoele expansion and appearance of both the trophectoderm (TE) and the inner cell mass (ICM). Although it has been shown that blastocysts with highest scores for all three parameters achieve highest implantation rates, their independent ability to predict pregnancy outcome remains unclear. METHOD This study is a retrospective analysis of 1117 fresh day 5 single blastocyst transfers and their live birth outcome related to each morphological parameter. RESULTS All three parameters had a significant effect on live birth however, once adjusted for known significant confounders, it was shown that TE was the only statistically significant independent predictor of live birth outcome. CONCLUSIONS This study has shown, for the first time, the predictive strength of TE grade over ICM for selecting the best blastocyst for embryo replacement. It may be that, even though ICM is important, a strong TE layer is essential at this stage of embryo development, allowing successful hatching and implantation.

Choosing the best embryo by time lapse versus standard morphology.

Within the past few years the morphological evaluation of in vitro fertilized embryos has been extended to include continuous surveillance, enabled by the introduction of time-lapse incubators developed specifically for IVF treatment. As a result time-lapse monitoring has been implemented in many clinics worldwide. The proposed benefits compared with culture in a standard incubator and fixed time-point evaluation are uninterrupted culture, a flexible workflow in the laboratory, and improved embryo selection. The latter is based on the reasonable assumption that more frequent observations will provide substantially more information on the relationship between development, timing, and embryo viability. Several retrospective studies have confirmed a relationship between time-lapse parameters and embryo viability evaluated by developmental competence, aneuploidy, and clinical pregnancy. Furthermore a much anticipated randomized study has shown improved pregnancy rates (PRs) after culture in a time-lapse incubator combined with selection using a hierarchical time-lapse selection model. At present this is the only randomized study on possible benefits of time lapse in human embryology. Strict evidence may still seem too weak to introduce time lapse in routine clinical setting. This aim of this review is therefore to perform a balanced discussion of the evidence for time-lapse monitoring.

Human blastocysts for the development of embryonic stem cells

Establishment of human embryonic stem cells (hES) from surplus human IVF embryos has been successful when both fresh and frozen-thawed cleavage stage embryos have been cultured to the blastocyst stage. This study reports the characteristics of the starting material, the blastocysts, for hES cell lines that were first derived at the University of Gothenburg, Sahlgrenska University Hospital in 1999. Twenty-two hES cell lines were derived by Cellartis AB from 114 blastocysts, giving an overall success rate of 19.3%. The blastocysts from which the hES cell lines were established were of varying morphological quality, both fresh and frozen-thawed. Two techniques of hES establishment were applied, i.e. direct application of the blastocysts on feeder cells or the standard immunosurgery method. It was further found that the efficiency by which frozen-thawed embryos gave rise to new hES cell lines was 3.7 times better than with fresh surplus embryos. These findings suggest that frozen-thawed embryos are superior to fresh surplus human embryos in hES cell establishment, which also avoids specific ethical problems associated with embryo donation in a fresh IVF cycle.

Cross-validation and predictive value of near-infrared spectroscopy algorithms for day-5 blastocyst transfer

Near-infrared (NIR) spectroscopic metabolomic profiling of spent embryo-culture media has been used to calculate a viability score for individual embryos. These scores have been found to correlate to the reproductive potential of cleavage-stage embryos. In this study, 137 spent blastocyst media samples were collected after single-embryo transfer and analysed by NIR spectroscopy to generate an algorithm and calculate viability scores. To blindly validate the algorithm development process, another algorithm was trained on 47 preselected samples from clinic 1 and then used to predict the outcome of 42 samples from clinic 2. The overall pregnancy rate from the two clinical sites was 50.4%. A positive correlation (R(2)=0.82, P=0.03) was observed with the increasing viability score quintiles and their associated implantation rates. Cross-validation of an algorithm generated from NIR analysis of media samples at one clinical setting blindly was shown to predict implantation potential of blastocysts cultured at another clinic in a different culture media and culture volume. This study demonstrates that metabolomic profiling by NIR spectroscopic analysis of day-5 spent embryo-culture media can predict the implantation potential of blastocysts. Furthermore, this method may not be restricted to a specific set of culturing conditions. The successes of IVF treatment cycles are in part limited by the ability to select the best single embryo from a cohort of patient embryos for transfer back to the woman. Routine procedures of embryo selection are based on morphology, including cell number and size, and the timing of cell division. These methods are favoured because they are quick and easy to assess. Human embryos are grown in culture solutions, which are specific for their stage of development. Recent studies analysing the culture solution in which the embryo are grown, by near infrared (NIR) spectroscopic analysis, have been able to predict if an embryo will implant or not. As culture conditions often vary between IVF laboratories the questions remained if the NIR technique could be used to independently predict the implantation potential of an embryo cultured at one laboratory using an algorithm trained on embryos at a second clinic, a so-called cross-validation. The results of this study show that NIR spectroscopy can predict the ability of embryos to implant even when grown in different IVF laboratories and in two different culture solutions. This information supports the idea that NIR spectroscopy can be used globally not relying on specific culture conditions or media.

Transplantation of human embryonic stem cells onto a partially wounded human cornea in vitro

Purpose:  The aim of this study was to investigate whether cells originating from human embryonic stem cells (hESCs) could be successfully transplanted onto a partially wounded human cornea. A second aim was to study the ability of the transplanted cells to differentiate into corneal epithelial‐like cells.

Prediction of live birth in frozen–thawed single blastocyst transfer cycles by pre-freeze and post-thaw morphology

STUDY QUESTION What pre-freeze and post-thaw morphological parameters can be used to predict live birth outcomes after frozen-thawed blastocyst transfer cycles? SUMMARY ANSWER Pre-freeze blastocoele expansion and trophectoderm (TE) grade and post-thaw degree of re-expansion are the most significant predictors of live birth in frozen-thawed blastocyst transfer cycles. WHAT IS KNOWN ALREADY Currently, blastocoele re-expansion after thawing is used to indicate blastocyst cryosurvival and reproductive potential. The predictive roles of other pre-freeze and post-thaw morphological parameters are neglected. STUDY DESIGN, SIZE, DURATION This was a retrospective study of all the patients who received a frozen-thawed single blastocyst transfer (n = 1089) at our clinic between March 2008 and October 2011. PARTICIPANTS/MATERIALS, SETTING, METHODS Pre-freeze morphological parameters analyzed for all blastocysts included grade of blastocoele expansion, inner cell mass and TE. A group of blastocysts (n = 243) were also graded for post-thaw parameters: degree of blastocoele re-expansion, viability and cell contour. Univariate and multivariate generalized estimating equations (GEEs) models were used to identify the confounders that statistically significantly affected live birth outcomes and to investigate the independent effect of significant pre-freeze and post-thaw morphological parameters. Stepwise logistic regression analysis was used to select the best independent morphological predictors of live birth. Pearson correlations and linear regression analyses were performed to determine the relationship between morphological parameters and possible covariates. MAIN RESULTS AND THE ROLE OF CHANCE Multivariate GEE models estimated that the odds of live birth increased by ∼36% for each grade of expansion (P = 0.0061) and decreased by 29% for blastocysts with grade B TE compared with grade A TE (P = 0.0099). Furthermore, the odds of live birth increased by ∼39% (P = 0.0042) for each 10% increase in degree of re-expansion. Blastocoele expansion and TE grade were selected as the most significant pre-freeze morphological predictors of live birth and degree of re-expansion was selected as the best post-thaw parameter for prediction of live birth. LIMITATIONS, REASONS FOR CAUTION Blastocysts with poorer grades of morphology were not cryopreserved or transferred, limiting the ability to generalize our findings for grades of morphology not included in this study. WIDER IMPLICATIONS OF THE FINDINGS Blastocysts with higher pre-freeze grades of expansion and TE, irrespective of day of cryopreservation, should be given priority when thawing. Subsequently, re-expanding blastocysts, assessed within 2-4 h, with >60% viability should be transferred. STUDY FUNDING/COMPETING INTEREST(S) No external funding was obtained for this study. There was no competing interest. TRIAL REGISTRATION NUMBER not applicable.