NCT01139268.

STUDY QUESTIONTo what extent do patient- and treatment-related factors explain the variation in morphokinetic parameters proposed as embryo viability markers?SUMMARY ANSWERUp to 31% of the observed variation in timing of embryo development can be explained by embryo origin, but no single factor elicits a systematic influence.WHAT IS KNOWN ALREADYSeveral studies report that culture conditions, patient characteristics and treatment influence timing of embryo development, which have promoted the perception that each clinic must develop individual models. Most of the studies have, however, treated embryos from one patient as independent observations, and only very few studies that evaluate the influence from patient- and treatment-related factors on timing of development or time-lapse parameters as predictors of viability have controlled for confounding, which implies a high risk of overestimating the statistical significance of potential correlations.STUDY DESIGN, SIZE, DURATIONInfertile patients were prospectively recruited to a cohort study at a hospital fertility clinic from February 2011 to May 2013. Patients aged <38 years without endometriosis were eligible if ≥8 oocytes were retrieved. Patients were included only once. All embryos were monitored for 6 days in a time-lapse incubator.PARTICIPANTS/MATERIALS, SETTING, METHODSA total of 1507 embryos from 243 patients were included. The influence of fertilization method, BMI, maternal age, FSH dose and number of previous cycles on timing of t2-t5, duration of the 2- and 3-cell stage, and development of a blastocoel (tEB) and full blastocoel (tFB) was tested in multivariate, multilevel linear regression analysis. Predictive parameters for live birth were tested in a logistic regression analysis for 223 single transferred blastocysts, where time-lapse parameters were investigated along with patient and embryo characteristics.MAIN RESULTS AND THE ROLE OF CHANCEModerate intra-class correlation coefficients (0.16–0.31) were observed for all parameters except duration of the 3-cell stage, which demonstrates that embryos from one patient elicit clustering at a patient level. No single patient- and treatment-related factor was found to systematically influence the timing from cleavage to blastocyst stage, which indicates that no individual patient-related factor can be identified that separately explains the clustering throughout the entire developmental stages. The blastocyst parameters were more affected by patient-related factors than cleavage stage parameters, as tEB occurred significantly later with older age (0.29 h/year (95% confidence interval: CI 0.03; 0.56)), while both tEB and tFB occurred significantly later with increasing dose of FSH (tEB: 0.12 h/100 IU FSH (95% CI 0.01;0.24); tFB 0.14 h/100 IU FSH (95% CI 0.03;0.27)) and with more previous attempts (tEB: 1.2 h/attempt (95% CI 0.01;2.5); tFB 1.4 h/attempt (0.10;2.7)). Fertilization method affected timing of the first division, with ICSI embryos cleaving significantly faster than IVF embryos (−3.6% (95% CI −6....

The findings suggest that the causative factor for subfertility in PCOS is not related to timing of development in the pre-implantation embryo.

study question: How does tetraploidy develop in hydatidiform moles (HMs), and what is the frequency of the different origins? summary answer: Most molar pregnancies with tetraploid cells appear to be produced by somatic endoreduplications, while a minority originate from a tetraploid zygote. The frequency of zygotic tetraploidy was estimated to be 0.7%.what is known already: The parental origin of the genome in tetraploid HMs has only been evaluated in a few cases, most showing three genome sets from the father (PPPM). Estimates of the proportion of HMs that are tetraploid vary between 2 and 28%. study design, size, duration: From 1986 to 2010, unfixed samples of clinically suspected molar pregnancies were forwarded to the Danish Mole Project. For this cohort study 442 samples fulfilled the following criteria for inclusion: macroscopic appearance of HM and ≥10 vesicular chorionic villi with a diameter of ≥1 mm.participants/materials, setting, methods: Of 403 karyotyped samples, 21 cases disclosed ≥2 tetraploid metaphases.The 21 cases were scrutinized by karyotyping, flow cytometry (FC) and DNA-marker analysis.main results and the role of chance: Among 20 HMs, 3 showed the genotype PPPM: one with the sex chromosomes XXYY and two with XXXY, indicating that they originated in tetraploid zygotes. In 14 androgenetic, one likely androgenetic and two mosaics, the tetraploid cells likely developed by endoreduplications of diploid cells. One case did not fulfil the histopathological criteria for HM.limitations, reasons for caution: As an inclusion criterion was the macroscopic observation of vesicular chorionic villi, some non-molar hydropic placentas may have been included and some early moles may have been excluded.wider implications of the findings: In future, studies to determine that an HM is tetraploid and discriminate cases of mosaicism and to deduce the origin of the tetraploidy must use the techniques of karyotyping, DNA-marker analysis and FC in combination. study funding/competing interest(s): No external funding was sought to support this study. None of the authors has any conflict of interest to declare.