Euploidy rates in donor egg cycles significantly differ between fertility centers.

Study question: Do external factors affect euploidy in egg donor cycles? Summary answer: The study demonstrates that during human assisted reproduction, embryonic chromosome abnormalities may be partly iatrogenic. What is known already: Chromosome abnormalities have been linked in the past to culture conditions such as temperature and Ph variations, as well as hormonal stimulation. Those reports were performed with older screening techniques (FISH), or ART methods no longer in use, and the subjects studied were not a homogeneous group. Study design, size, duration: A total of 1645 donor oocyte cycles and 13 282 blastocyst biopsies from 42 fertility clinics were included in this retrospective cohort study. Samples from donor cycles with PGS attempted between September 2011 and July 2015 were included. Participants/materials, setting, methods: PGS cycles from multiple fertility clinics referred to Reprogenetics (Livingston, NJ) that involved only oocyte donation were included in this study. Testing was performed by array comparative genomic hybridization (aCGH). Ploidy data were analyzed using Generalized Linear Mixed Models with logistic regression using a logit link function considering a number of variables that represent fixed and random effects. Main results and the role of chance: Euploidy rate was associated with the referring center and independent of almost all the parameters examined except donor age and testing technology. Average euploidy rate per center ranged from 39.5 to 82.5%. The mean expected rate of euploidy was 68.4%, but there are variations in this rate associated with the center effect. Limitations, reasons for caution: Data set does not include details of the donor selection process, donor race or ethnic origin, ovarian reserve or ovarian responsiveness. Due to the retrospective nature of the study, associations are apparent, however, causality cannot be established. Discrepancies in regard to completeness and homogeneity of data exist due to data collection from over 40 different clinics. Wider implications of the findings: This is the first study to show a strong association between center-specific ART treatment practices and the incidence of chromosome abnormality in human embryos, although the meiotic or mitotic origin of these abnormalities could not be determined using these technologies. Given the widespread applications of ART in both subfertile and fertile populations, our findings should be of interest to the medical community in general as well as the ART community in particular. Study funding/competing interest(s): No external funds were used for this study. S. Munne is a founding principle of Reprogenetics/current employee of Cooper Genomics. M Alikani's spouse is a founding principle of Reprogenetics/current consultant for Cooper Genomics. The remaining authors have no conflicts to declare.

Predicting the likelihood of live birth for elective oocyte cryopreservation: a counseling tool for physicians and patients.

Study question: Can a counseling tool be developed for women desiring elective oocyte cryopreservation to predict the likelihood of live birth based on age and number of oocytes frozen? Summary answer: Using data from ICSI cycles of a population of women with uncompromised ovarian reserve, an evidence-based counseling tool was created to guide women and their physicians regarding the number of oocytes needed to freeze for future family-building goals. What is known already: Elective oocyte cryopreservation is increasing in popularity as more women delay family building. By undertaking elective oocyte freezing at a younger age, women hope to optimize their likelihood of successful live birth(s) using their thawed oocytes at a future date. Questions often arise in clinical practice regarding the number of cryopreserved oocytes sufficient to achieve live birth(s) and whether or not additional stimulation cycles are likely to result in a meaningful increase in the likelihood of live birth. As relatively few women who have electively cryopreserved oocytes have returned to use them, available data for counseling patients wishing to undergo fertility preservation are limited. Study design, size, duration: A model was developed to determine the proportion of mature oocytes that fertilize and then form blastocysts as a function of age, using women with presumably normal ovarian reserve based on standard testing who underwent ICSI cycles in our program from January, 2011 through March, 2015 (n = 520). These included couples diagnosed exclusively with male-factor and/or tubal-factor infertility, as well as cycles utilizing egg donation. Age-specific probabilities of euploidy were estimated from 14 500 PGS embryo results from an external testing laboratory. Assuming survival of thawed oocytes at 95% for women <36 y and for egg donors, and 85% for women ≥36 y, and 60% live birth rate per transferred euploid blastocyst, probabilities of having at least one, two or three live birth(s) were calculated. Participants/materials, setting, method: First fresh male-factor and/or tubal-factor only autologous ICSI cycles (n = 466) were analyzed using Poisson regression to calculate the probability that a mature oocyte will become a blastocyst based on age. Egg donation cycles (n = 54) were analyzed and incorporated into the model separately. The proportion of blastocysts expected to be euploid was determined using PGS results of embryos analyzed via array comparative genomic hybridization. A counseling tool was developed to predict the likelihood of live birth, based on individual patient age and number of mature oocytes. Main results and the role of chance: This study provides an evidence-based model to predict the probability of a woman having at least one, two or three live birth(s) based on her age at egg retrieval and the number of mature oocytes frozen. The model is derived from a surrogate population of ICSI patients with uncompromised ovarian reserve. A user-friendly counseling tool was designed using the model to help guide physicians and patients. LIMITATIONS, REASONS FOR CAUTION: The data used to develop the prediction model are, of necessity, retrospective and not based on patients who have returned to use their cryopreserved oocytes. The assumptions used to create the model, albeit reasonable and data-driven, vary by study and will likely vary by center. Centers are therefore encouraged to consider their own blastocyst formation and thaw survival rates when counseling patients. Limitations, reasons for caution: Our model will provide a counseling resource that may help inform women desiring elective fertility preservation regarding their likelihood of live birth(s), how many cycles to undergo, and when additional cycles would bring diminishing returns. Study funding/competing interests: None. Trial registration number: Not applicable.