EuMAR stakeholder engagement: an analysis of medically assisted reproduction (MAR) data collection practices in EU countries†.

STUDY QUESTION: What are the current national medically assisted reproduction (MAR) data collection systems across EU Member States, and how can these countries contribute to a unique, cycle-by-cycle registry for the European Monitoring of Medically Assisted Reproduction (EuMAR) project? SUMMARY ANSWER: The study identified significant variation in MAR data collection practices across Member States, with differences in data types, collection methods, and reporting requirements; the EuMAR project emerges as an opportunity to enhance data standardization and improve MAR data collection in the EU. WHAT IS KNOWN ALREADY: There is a need for new approaches in MAR data collection that include long-term and cross border follow-up. The EuMAR project intends to establish a unified, cycle-by-cycle registry of data on MAR treatments in EU countries, from which accurate cumulative outcomes can be calculated. STUDY DESIGN, SIZE, DURATION: This cross-sectional study involved a survey and interviews with stakeholders from 26 EU Member States conducted in 2023 over a period of seven months. PARTICIPANTS/MATERIALS, SETTING, METHODS: Representatives from national competent authorities and professional associations involved in MAR data collection in EU countries were invited to complete the survey and interviewed to assess current data flows, information requirements, and their interest in the EuMAR project. MAIN RESULTS AND THE ROLE OF CHANCE: Half of the participating countries reported having a national MAR registry with cycle-by-cycle data (n = 13), while 31% reported having a national registry with aggregated data (n = 8) and 19% reported having no national registry (n = 5). Of the countries with a national cycle-by-cycle registry, eight countries collect identifiable data, five countries collect pseudonymized data, and one country collects fully anonymized data. Informed consent is required in 10 countries. The main advantages that participants expected from a European registry like EuMAR were the possibility of obtaining national statistics in the absence of a national registry and improving the calculation of cumulative outcomes. LIMITATIONS, REASONS FOR CAUTION: The results of the study are based on self-reported data, which may be subject to bias, however, the validity of the collected information was verified with different means, including follow-up calls for clarifications and sharing final transcript reports. The feasibility of the proposed data flow models will be tested in a pilot study. WIDER IMPLICATIONS OF THE FINDINGS: Despite the heterogeneity of data collection practices across EU countries, the results show that stakeholders have high expectations of the benefits that the EuMAR registry can bring, namely the improvement of data consistency, cross-border comparability, and cumulative live birth rates, leading to better information for patients, health care providers and policy makers. STUDY FUNDING/COMPETING INTEREST(S): The EuMAR project was co-founded by ESHRE and the European Commission (101079865-EuMAR-EU4H-2021-PJ2). No competing interests were declared. TRIAL REGISTRATION NUMBER: N/A.

Failure to detect DNA in blastocoel fluid is associated with a higher live birth rate in both PGT-A and conventional IVF/ICSI cycles.

STUDY QUESTION: Is the presence of DNA in the blastocoel fluid (BF) of expanded blastocysts, assessed by whole genome amplification (WGA), associated with the clinical outcome at the first transfer? SUMMARY ANSWER: At the first transfer, blastocysts with negative BF-WGA have more chance to implant and to develop to term than those with positive BF-WGA results, both in preimplantation genetic testing for aneuploidies (PGT-A) cycles (where only euploid blastocysts resulting from the chromosomal analysis of trophectoderm (TE) biopsies were transferred) and in IVF/ICSI conventional cycles. WHAT IS KNOWN ALREADY: Retrospective studies conducted in patients undergoing PGT-A have shown that the incidence of negative BF-WGA was significantly higher in TE-euploid blastocysts than in TE-aneuploid blastocysts. In addition, after the transfer of TE-euploid blastocysts, the ongoing clinical pregnancy rate was significantly higher in the group with negative BF-WGA compared with those with positive BF-WGA. STUDY DESIGN, SIZE, DURATION: A prospective cohort study including 102 consecutive PGT-A patients (Group 1) and 88 consecutive conventional IVF/ICSI patients (Group 2), was conducted between January 2019 and December 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: In both groups, BFs were collected from expanded blastocysts of high grade and processed for WGA. DNA amplification was evaluated by agarose gel electrophoresis for the presence (positive BF-WGA) or absence (negative BF-WGA) of a band. Directly after the BF retrieval, blastocysts from Group 1 underwent TE biopsy and vitrification. In Group 2, blastocysts were vitrified immediately after BF collection. In Group 1, only euploid blastocysts were considered for transfer according to the results of TE biopsies. In both groups, the selection of the blastocyst to be transferred was based on BF-WGA results giving priority, if available, to those with negative amplification. The primary outcome investigated was the live birth rate (LBR) at the first transfer. The main variable under investigation was the negative BF-WGA and results were corrected for confounders (maternal and paternal age, number of retrieved oocytes, male factor) by multiple logistic regression analysis. MAIN RESULTS AND THE ROLE OF CHANCE: In Group 1, 60 patients transferred negative BF-WGA blastocysts and 42 positive BF-WGA blastocysts, and the LBR at the first transfer was 53.3% and 26.2%, respectively (P = 0.0081). After testing for selected confounders in a multiple logistic analysis, the transfer of blastocysts with negative BF-WGA resulted in an odds ratio of (OR) 3.52 (95% CI: 1.48-8.88, P = 0.0057) compared to transfer of positive BF-WGA blastocysts. In Group 2, at the first transfer 30 deliveries resulted from blastocysts with negative BF-WGA (48.4%) and three from the transfer of positive BF-WGA blastocysts in 26 patients (11.5%; P = 0.0014). Multiple logistic analysis indicated that the transfer of blastocysts with negative BF-WGA resulted in an OR 6.89 (95% CI: 1.98-32.95, P = 0.0056) compared to transfer of positive BF-WGA blastocysts. The LBR per transfer and the cumulative LBR per patient showed the same trend. LIMITATIONS, REASONS FOR CAUTION: The study was performed in a single center. WIDER IMPLICATIONS OF THE FINDINGS: The data from this study highlight the heterogeneity of blastocysts of similar morphology, even in those classified as euploid by TE analysis. Failure to detect DNA in BFs after WGA is associated with a significantly higher LBR at the first embryo transfer as well as per transfer and per patient. The processing of the BF by WGA is an easy and cost-effective tool that could become a valuable option to offer patients the highest chances of term pregnancy in the shortest time possible. STUDY FUNDING/COMPETING INTEREST(S): The study received no funding from external sources. There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Birefringence properties of human immotile spermatozoa and ICSI outcome.

RESEARCH QUESTION: In sperm samples with complete asthenozoospermia, pregnancies are achieved by intracytoplasmic sperm injection (ICSI), but this condition has a negative impact on fertilization and embryo development owing to the difficulty of identifying viable cells for oocyte injection. Is the selection of sperm cells with head birefringence properties under polarizing light a successful strategy to identify viable spermatozoa? DESIGN: This study included 192 ICSI cycles with complete asthenozoospermia (83 ejaculated and 109 testicular samples) performed under polarized light. Two types of sperm head birefringence were distinguished: partial (presumably reacted spermatozoa) and total (presumably intact acrosome). In some sperm cells, no birefringence was present. The main outcome of the study was the cumulative live birth rate (cLBR) per ICSI cycle. RESULTS: Seventy-three deliveries resulted with 38.0% cLBR per ICSI cycle. The injection of birefringent spermatozoa led to significantly higher rates of fertilization, embryo development and implantation compared with the absence of birefringence (P < 0.001). Similarly, the resulting cLBR were 53.6% and 9.0%, respectively (P < 0.001). Spermatozoa with partial head birefringence yielded significantly higher fertilization and embryo utilization rates compared with total birefringence. The cLBR showed the same trend (62.7% and 46.7%, respectively, P = 0.048). Multiple logistic regression analysis showed the pattern of partial birefringence to be strongly associated with live birth rate. CONCLUSIONS: Immotile sperm cells with birefringence properties under polarized light have higher chances of inducing fertilization and embryo development compared with non-birefringent cells. In addition, a pattern of partial birefringence, associated with a reacted acrosome, is the strongest predictive factor for live birth delivery, both in ejaculated and testicular samples.

Oocyte donation: not all oocyte cryobanks are the same.

RESEARCH QUESTION: Is the efficacy of imported vitrified oocyte donation affected by the cryobank of origin? DESIGN: Longitudinal cohort study, including 249 completed oocyte warming cycles from 200 recipients (January 2016-July 2020). No severe male factor was included. Vitrified oocytes were provided by three Spanish cryobanks. Primary outcome was cumulative live birth delivery rate (CLBR) per completed oocyte warming cycle. RESULTS: After warming 1535 oocytes, 1244 survived (81.0%) and 945 fertilized (76.0%); embryo utilization rate was 65.3%. The overall CLBR per completed cycle was 47.0% but was lower in cryobank 1 (31.2%) versus cryobank 2 (56.0%, P = 0.0010) and cryobank 3 (50.8%, P = 0.0241). Multivariate logistic regression analysis identified survival of four or more oocytes as the strongest predictor for delivery (P = 0.0282). Only 202 out of 249 oocyte warming cycles had four or more survived oocytes in a proportion that was significantly lower in cryobank 1 versus cryobank 2 (70.1% versus 89.0%, P = 0.0020); comparison with cryobank 3 (81.0%) was not significant. In the 202 oocyte warming cycles, CLBR in cryobank 1 (37.0%) was lower versus cryobank 2 (58.8%, P = 0.0115) and cryobank 3 (60.8%, P = 0.0019), suggesting a reduced viability in oocytes from cryobank 1 that survived warming. CONCLUSIONS: Differences were found in the efficacy of imported vitrified oocytes in relation to the cryobank of origin. Each centre needs to evaluate the results internally when starting a collaboration with an oocyte cryobank to establish the necessary measures to maximize treatment efficacy.

IVF Lite: a smart IVF programme based on mild ovarian stimulation for good prognosis patients.

RESEARCH QUESTION: The IVF Lite programme is based on mild ovarian stimulation including up to three fresh/frozen embryo transfers within 12 months. Is it effective and safe in good prognosis patients? DESIGN: Single-centre prospective study on infertile patients at their first IVF attempt (female age ≤38 years, anti-Müllerian hormone concentrations >1.5 ng/ml and/or FSH ≤10 mIU/ml). Induction of multiple follicular growth was based on a fixed protocol consisting of clomiphene citrate (100 mg/day) from day 3 to 7 of the menstrual cycle and 150 IU of recombinant FSH on days 5, 7 and 9. In case of low follicular recruitment (fewer than four follicles), the cycle was cancelled. The IVF Lite programme was considered complete after a live birth delivery or up to three embryo transfers within 12 months. The primary outcome was the cumulative live birth rate (cLBR) per couples that completed the programme. RESULTS: A total of 369 patients completed the IVF Lite programme, with 239 live births; 132 patients delivered after one embryo transfer (35.8%), 70 after a second embryo transfer (cLBR 54.7%), and 37 after a third attempt (cLBR 64.8%). No cases of ovarian hyperstimulation syndrome or clinical complications occurred. Spontaneous dropout rate from the programme was 4.5%. The cLBR per intention to treat was 46.8%. CONCLUSIONS: The IVF Lite programme proved to be effective and safe in good prognosis patients with a good response to clomiphene citrate stimulation. It was well tolerated and implied low gonadotrophin consumption. Two-thirds of the patients achieved a live birth at the completion of the programme.

EWHETA (Eat Well for a HEalthy Third Age) Project: novel foods to improve the nutrition in the elderly people.

Cardiovascular diseases (CVD) are the leading cause of mortality. However, by treating modifiable cardiovascular risk factors and following a healthy diet as the Mediterranean diet, we have opportunity to prevent CVD. In the EWHETA (Eat Well for a HEalthy Third Age) Project, our goal has been to develop novel foods ("Mediterranean Lasagne", MLs) in versions all nutritionally complete and well balanced in terms of calories, whole carbohydrates, fibers, source of vegetable proteins, and vegetable fats. MLs can be easy prepared at home (inexpensively) and used as fresh food or can be pre-prepared and used in residences for elderly people or in health care residencies. The project has saw the alliance between nutritionists and food and sensor scientists and the active involvement of older people in tasting the novel foods to achieve the final tasty versions of the MLs. We think that the nutritional components of these novel foods and its well-accepted taste, insert in a healthy diet and life style (fundamental aspects at every age), and could contribute to improve diet in the elderly people and prevent malnutrition.

Permanence of de novo segmental aneuploidy in sequential embryo biopsies.

STUDY QUESTION: Is de novo segmental aneuploidy (SA) a biological event or an artifact that is erroneously interpreted as partial chromosome imbalance? SUMMARY ANSWER: The detection of de novo SA in sequential biopsies of preimplantation embryos supports the biological nature of SA. WHAT IS KNOWN ALREADY: Although some SAs are detected in oocytes and in blastocysts, the highest incidence is observed in cleavage-stage embryos. Based on these findings, we can postulate that the majority of cells affected by SAs are eliminated by apoptosis or that affected embryos mainly undergo developmental arrest. STUDY DESIGN, SIZE, DURATION: This retrospective study includes 342 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed between January 2014 and December 2018. Chromosome analysis was performed on 331 oocytes, 886 cleavage-stage embryos and 570 blastocysts (n = 1787). From 268 expanded blastocysts, the blastocoelic fluid (BF) was also analyzed (resulting in 2025 samples in total). In cases of SAs involving loss or gain in excess of 15 Mb, embryos were not considered for transfer and sequential biopsies were performed at following stages. This resulted in 66 sets where the initial diagnosis of SAs (4 made in polar bodies, 25 in blastomeres and 37 in trophectoderm (TE) cells) was followed up. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 2082 samples (2025 + 27 whole embryos) were processed by whole genome amplification followed by array comparative genomic hybridization. MAIN RESULTS AND THE ROLE OF CHANCE: The incidence of SAs was 6.3% in oocytes, increased to 16.6% in cleavage-stage embryos (P < 0.001) and decreased to 11.2% in blastocysts (P < 0.025 versus oocytes; P < 0.01 versus cleavage-stage embryos). The highest incidence of SAs was found in BFs (26.1%, P < 0.001). The analysis of 66 sets of sequential biopsies revealed that the initial finding was confirmed in all following samples from 39 sets (59.1% full concordance). In 12 additional sets, SAs were detected in some samples while in others the interested chromosome had full aneuploidy (18.2%). In three more sets, there was a partial concordance with the initial diagnosis in some samples, but in all TE samples the interested chromosome was clearly euploid (4.5%). In the remaining 12 sets, the initial SA was not confirmed at any stage and the corresponding chromosomes were euploid (18.2% no concordance). The pattern of concordance was not affected by the number of SAs in the original biopsy (single, double or complex) or by the absence or presence of concomitant aneuploidies for full chromosomes. LIMITATIONS, REASONS FOR CAUTION: Chromosome analyses were performed on biopsies that might not be representative of the true constitution of the embryo itself due to the occurrence of mosaicism. WIDER IMPLICATIONS OF THE FINDINGS: The permanence of SAs throughout the following stages of embryo development in more than half of the analyzed sets suggests for this dataset a very early origin of this type of chromosome imbalance, either at meiosis or at the first mitotic divisions. Since SAs remained in full concordance with the initial diagnosis until the blastocyst stage, a corrective mechanism seems not to be in place. In the remaining cases, it is likely that, as for full chromosome aneuploidy, mosaicism derived from mitotic errors could have occurred. In following cell divisions, euploid cell lines could prevail preserving the embryo chances of implantation. Due to the scarcity of data available, the transfer of embryos with SAs should be strictly followed up to establish possible clinical consequences related to this condition. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was obtained. There are no conflicts of interest.

No need for luteal phase support in IVF cycles after mild stimulation: proof-of-concept study.

This is a pilot study performed in a private IVF unit. The objective of the study was to investigate whether luteal support is required in IVF cycles after mild stimulation with clomiphene citrate and low FSH doses. The study included 15 patients with good prognosis (defined as ≤38 years old with normal ovarian reserve and normovulatory cycles, body mass index <29 kg/m2, no previous cycles, no severe endometriosis, no history of recurrent miscarriage, no endocrine/autoimmune diseases and no surgical semen extraction from the partner) undergoing IVF with mild stimulation. Patients were monitored during the luteal phase by serum progesterone and LH. The luteal support was started only when necessary. No patient needed luteal phase support because the resultant steroid environment was different from that associated with conventional stimulation techniques. The live birth rate was 40% (6/15) and the implantation rate 30% (6/20). There are several benefits to mild stimulation, including low cost, less patient distress and improved endometrial receptivity. Our study supports the concept that mild stimulation may have an additional benefit during the luteal phase, by obviating the need for luteal phase support.

Time to take human embryo culture seriously.

STUDY QUESTION: Is it important that end-users know the composition of human embryo culture media? SUMMARY ANSWER: We argue that there is as strong case for full transparency concerning the composition of embryo culture media intended for human use. WHAT IS KNOWN ALREADY: Published data suggest that the composition of embryo culture media may influence the phenotype of the offspring. STUDY DESIGN, SIZE, DURATION: A review of the literature was carried out. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data concerning the potential effects on embryo development of culture media were assessed and recommendations for users made. MAIN RESULTS AND THE ROLE OF CHANCE: The safety of ART procedures, especially with respect to the health of the offspring, is of major importance. There are reports from the literature indicating a possible effect of culture conditions, including culture media, on embryo and fetal development. Since the introduction of commercially available culture media, there has been a rapid development of different formulations, often not fully documented, disclosed or justified. There is now evidence that the environment the early embryo is exposed to can cause reprogramming of embryonic growth leading to alterations in fetal growth trajectory, birthweight, childhood growth and long-term disease including Type II diabetes and cardiovascular problems. The mechanism for this is likely to be epigenetic changes during the preimplantation period of development. In the present paper the ESHRE working group on culture media summarizes the present knowledge of potential effects on embryo development related to culture media, and makes recommendations. LIMITATIONS, REASONS FOR CAUTION: There is still a need for large prospective randomized trials to further elucidate the link between the composition of embryo culture media used and the phenotype of the offspring. We do not presently know if the phenotypic changes induced by in vitro embryo culture represent a problem for long-term health of the offspring. WIDER IMPLICATIONS OF THE FINDINGS: Published data indicate that there is a strong case for demanding full transparency concerning the compositions of and the scientific rationale behind the composition of embryo culture media. STUDY FUNDING/COMPETING INTERESTS: This work was funded by The European Society for Human Reproduction and Embryology. No competing interests to declare.

Mitochondrial DNA analysis and numerical chromosome condition in human oocytes and polar bodies.

To investigate the mitochondrial DNA (mtDNA) segregation in human oocytes, the level of heteroplasmy in the three products of meioses, polar bodies (PBs) and corresponding oocytes, was assessed by studying the hypervariable region I (HVRI) of the D-loop region. The DNA from 122 PBs and 51 oocytes from 16 patients was amplified by whole genome amplification (WGA). An aliquot of the WGA product was used to assess aneuploidy, and another aliquot to study mtDNA. The HVRI was amplified and sequenced with an efficiency of 75.4 and 63%, respectively, in PBs, and of 100% in oocytes. The comparison with the mtDNA sequences from blood of the individual donors showed full correspondence of polymorphisms with the matching oocytes, whilst in PBs the degree of concordance dropped to 89.6%. Haplogroups were inferred for all 16 patients. Of the 89 diagnosed PBs from the 13 patients belonging to macrohaplogroup R, 23 were euploid and 66 aneuploid. The incidence of total anomalies was significantly lower in haplogroup H (6.5%) when compared with haplogroups J and T (17.6 and 13.4% respectively; P < 0.001). In haplogroup J, hypoaneuploidy occurred more frequently than hyperaneuploidy. In the three patients belonging to haplogroup N*, 81% of PBs were aneuploid with similar rates of chromosome hypoaneuploidy and hyperaneuploidy. The presence of mtDNA base changes confined to PBs could reflect a selection mechanism against severe mtDNA mutations, while permitting a high evolution rate that could result in bioenergetic diversity. The different susceptibility to aneuploidy by some haplogroups strongly supports this hypothesis.

The educational and professional status of clinical embryology and clinical embryologists in Europe.

STUDY QUESTION: What is the recognition of clinical embryology and the current status of clinical embryologists in European countries, regarding educational levels, responsibilities and workload, and need for a formal education in assisted reproductive technology (ART)? SUMMARY ANSWER: It is striking that the profession of clinical embryology, almost 40 years after the introduction of IVF, is still not officially recognized in most European countries. WHAT IS KNOWN ALREADY: Reproductive medicine has developed into a sophisticated multidisciplinary medical branch since the birth of Louise Brown 37 years ago. The European Board & College of Obstetrics and Gynaecology (EBCOG) has recognized reproductive medicine as a subspeciality and has developed a subspeciality training for gynaecologists in collaboration with the European Society for Human Reproduction and Embryology (ESHRE). However, nothing similar exists for the field of clinical embryology or for clinical embryologists. STUDY DESIGN, SIZE, DURATION: A questionnaire about the situation in clinical embryology in the period of 2012-2013 in the respective European country was sent to ESHRE National representatives (basic scientists only) in December 2013. At this time, 28 European countries had at least one basic scientist in the ESHRE Committee of National Representatives. PARTICIPANTS/MATERIALS, SETTING, METHODS: The survey consisted of 46 numeric, dichotomous (yes/no) or descriptive questions. Answers were obtained from 27 out of 28 countries and the data were tabulated. Data about the numbers of 'ESHRE Certified Embryologists' were taken from the ESHRE Steering Committee for Embryologist Certification. MAIN RESULTS AND THE ROLE OF CHANCE: In 2012, more than 7000 laboratory staff from 1349 IVF clinics in 27 European countries performed over 700 000 fresh and frozen ART cycles. Despite this, clinical embryology is only recognized as an official profession in 3 out of 27 national health systems. In most countries clinical embryologists need to be registered under another profession, and have limited possibilities for organized education in clinical embryology. Mostly they are trained for practical work by senior colleagues. ESHRE embryologist certification so far constitutes the only internationally recognized qualification; however this cannot be considered a subspecialization. LIMITATIONS, REASONS FOR CAUTION: Data were obtained through different methods, by involving national embryologist societies and cycle registers, collecting information from centre to centre, and in some cases by individual assessment of the situation. For these reasons, the results should be interpreted with caution. WIDER IMPLICATIONS OF THE FINDINGS: This paper presents the current status of clinical embryology and clinical embryologists in Europe and is an important step towards implementation of clinical embryology as an officially recognized profession. STUDY FUNDING/COMPETING INTERESTS: None. TRIAL REGISTRATION NUMBER: No.

Objective way to support embryo transfer: a probabilistic decision.

STUDY QUESTION: Is it feasible to identify factors that significantly affect the clinical outcome of IVF-ICSI cycles and use them to reliably design a predictor of implantation? SUMMARY ANSWER: The Bayesian network (BN) identified top-history embryos, female age and the insemination technique as the most relevant factors for predicting the occurrence of pregnancy (AUC, area under curve, of 0.72). In addition, it could discriminate between no implantation and single or twin implantations in a prognostic model that can be used prospectively. WHAT IS KNOWN ALREADY: The key requirement for achieving a single live birth in an IVF-ICSI cycle is the capacity to estimate embryo viability in relation to maternal receptivity. Nevertheless, the lack of a strong predictor imposes several restrictions on this strategy. STUDY DESIGN, SIZE, DURATION: Medical histories, laboratory data and clinical outcomes of all fresh transfer cycles performed at the International Institute for Reproductive Medicine of Lugano, Switzerland, in the period 2006-2008 (n = 388 cycles), were retrospectively evaluated and analyzed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients were unselected for age, sperm parameters or other infertility criteria. Before being admitted to treatment, uterine anomalies were excluded by diagnostic hysteroscopy. To evaluate the factors possibly related to embryo viability and maternal receptivity, the class variable was categorized as pregnancy versus no pregnancy and the features included: female age, number of previous cycles, insemination technique, sperm of proven fertility, the number of transferred top-history embryos, the number of transferred top-quality embryos, the number of follicles >14 mm and the level of estradiol on the day of HCG administration. To assess the classifier, the indicators of performance were computed by cross-validation. Two statistical models were used: the decision tree and the BN. MAIN RESULTS AND THE ROLE OF CHOICE: The decision tree identified the number of transferred top-history embryos, female age and the insemination technique as the features discriminating between pregnancy and no pregnancy. The model achieved an accuracy of 81.5% that was significantly higher in comparison with the trivial classifier, but the increase was so modest that the model was clinically useless for predictions of pregnancy. The BN could more reliably predict the occurrence of pregnancy with an AUC of 0.72, and confirmed the importance of top-history embryos, female age and insemination technique in determining implantation. In addition, it could discriminate between no implantation, single implantation and twin implantation with the AUC of 0.72, 0.64 and 0.83, respectively. LIMITATIONS, REASONS FOR CAUTION: The relatively small sample of the study did not permit the inclusion of more features that could also have a role in determining the clinical outcome. The design of this study was retrospective to identify the relevant features; a prospective study is now needed to verify the validity of the model. WIDER IMPLICATIONS OF THE FINDINGS: The resulting predictive model can discriminate with reasonable reliability between pregnancy and no pregnancy, and can also predict the occurrence of a single pregnancy or multiple pregnancy. This could represent an effective support for deciding how many embryos and which embryos to transfer for each couple. Due to its flexibility, the number of variables in the predictor can easily be increased to include other features that may affect implantation. STUDY FUNDING/COMPETING INTERESTS: This study was supported by a grant, CTI Medtech Project Number: 9707.1 PFLS-L, Swiss Confederation. No competing interests are declared.

When and how should new technology be introduced into the IVF laboratory?

There are many examples in assisted reproduction technology, where new technology and methods have been introduced into the clinical setting without appropriate development and evidence-based medicine to show that the procedure is safe and beneficial to the patient. Examples include preimplantation genetic screening, assisted hatching, in vitro maturation, blastocyst transfer and vitrification. Changes to culture media composition, stimulation regimes and laboratory protocols are also often established internationally without adequate validation. More recently, novel equipment that needs to be validated before it enters routine clinical use is being developed for IVF. With technologies such as producing gametes from stem cells around the corner, it is vital to ensure that the necessary research and development is conducted before bringing new techniques into clinical practice. Ideally, this should include preliminary work on animal models, such as mice/rats/rabbits/larger mammals, followed by studies on human embryos donated for research and finally well-designed RCTs with a follow up of all children born from the procedure. If such preliminary studies are not performed and published, it is possible that technology bringing no clinical benefit or leading to adverse health outcomes in the children born by these practices may be introduced. All IVF clinics need to consider the safety and efficacy of new technologies before introducing them.

Five chromosome segregation in polar bodies and the corresponding oocyte.

For a comprehensive picture of the meiotic process and to follow up its products, five chromosomes were tested by fluorescent in-situ hybridization in both polar bodies (PB) and corresponding 145 oocytes. Results were obtained in 143 sets and the prediction of euploidy or aneuploidy based on PB analysis was confirmed by direct analysis in 140 oocytes (98%). Concordance for all chromosomes was found in 132 oocytes, while in the remaining eight, at least one chromosome did not reflect the prediction made by the corresponding PB. When restricting the analysis to the 132 fully concordant oocytes, 215 errors were found in PB: 58% in PB1 and 42% in PB2. Premature separation of chromatids occurred in 89% of aneuploid PB1, whereas only 11% of errors derived from bivalent non-disjunction. In 19% of meiosis-I errors, a complementary error in meiosis II compensated the error originated in the first meiotic division. In conclusion, the testing of PB predicted reliably the oocyte's chromosome condition. Although limited to five chromosomes, the follow up of meiosis by fluorescent in-situ hybridization provided a full description of chromosome allocation during the two divisions characterizing the nuclear maturation of the oocyte.

Head birefringence properties are associated with acrosome reaction, sperm motility and morphology.

Birefringence in sperm heads reflects an organized and very compacted texture, indicating nuclear and acrosomal structural normality. This study performed a direct analysis of the acrosome integrity in single spermatozoa to verify whether a pattern of total or partial head birefringence reflected the acrosome status. The morphology in fresh samples was assessed according to World Health Organization criteria while the characteristics of birefringence were evaluated by polarized light. Acrosome integrity was evaluated by fluorescein isothiocyanate Pisum sativum agglutinin that binds selectively to the acrosome content. According to the results, a reacted acrosome was present in 96% of spermatozoa with partial birefringence and only in 35% of those with totally birefringent heads. A great proportion of sperm cells with normal morphology showed total birefringence both in the presence (59%) or in the absence of motility (45%; P < 0.01), while in morphologically abnormal spermatozoa the frequency of total birefringence was comparable to that of partial birefringence irrespective of motility (26% and 27%, respectively, in motile spermatozoa; 22% and 19%, respectively, in immotile spermatozoa). These data support a strong association between partial birefringence and reacted acrosome and show that the patterns of birefringence vary depending on sperm motility and morphology.

ESHRE PGD Consortium/Embryology Special Interest Group--best practice guidelines for polar body and embryo biopsy for preimplantation genetic diagnosis/screening (PGD/PGS).

In 2005, the European Society for Human Reproduction and Embryology (ESHRE) Preimplantation Genetic Diagnosis (PGD) Consortium published a set of Guidelines for Best Practice to give information, support and guidance to potential, existing and fledgling PGD programmes (Thornhill AR, De Die-Smulders CE, Geraedts JP, Harper JC, Harton GL, Lavery SA, Moutou C, Robinson MD, Schmutzler AG, Scriven PN et al. ESHRE PGD Consortium best practice guidelines for clinical preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS). Hum Reprod 2005;20:35-48.). The subsequent years have seen the introduction of a number of new technologies as well as the evolution of current techniques. Additionally, in light of ESHRE's recent advice on how practice guidelines should be written and formulated, the Consortium believed it was timely to revise and update the PGD guidelines. Rather than one document that covers all of PGD as in the original publication, these guidelines are separated into four new documents that apply to different aspects of a PGD programme; Organization of a PGD centre, fluorescence in situ hybridization-based testing, amplification-based testing and polar body and embryo biopsy for preimplantation genetic diagnosis/screening (PGD/PGS). Here we have updated the sections that pertain to embryology (including cryopreservation) and biopsy of embryos prior to PGD or PGS. Topics covered in this guideline include uses of embryo biopsy, laboratory issues relating to biopsy, timing of biopsy, biopsy procedure and cryopreserving biopsied embryos.