The study was funded by a grant from Besançon and Dijon University Hospitals. The authors have no conflicts of interest to declare.

STUDY QUESTION Can time-lapse imaging systems make it possible to identify novel early non-invasive biomarkers to predict live birth? SUMMARY ANSWER From mostly high-grade embryos, out of 35 morphometric, morphologic and morphokinetic variables, only pronuclei (PN) position at time of PN juxtaposition and the absence of multinucleated blastomeres at the 2-cell stage (MNB2cell), were potentially associated with live birth. WHAT IS KNOWN ALREADY Previous studies indicate that some kinetic markers may be predictive of blastocyst development and embryonic implantation. Certain teams have suggested including some of them in decisional algorithms for embryo transfers. STUDY DESIGN, SIZE, DURATION Using a time-lapse incubator (EmbryoScope, Unisense FertiliTech), we retrospectively explored the associations between the morphometric, morphologic and morphokinetic parameters of oocytes, zygotes and embryos, and their associations with live birth. This study assessed 232 embryos from single embryo transfers after ICSI cycles performed between January 2014 and December 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS The morphometric, morphologic and morphokinetic parameters (18, 4 and 13, respectively) of oocytes, zygotes and early embryos were studied retrospectively. The associations between these parameters were examined using a Spearman’s correlation, Mann–Whitney or chi-squared test as appropriate. We examined whether these parameters were associated with outcomes in univariate and multivariate logistic regression analyses. MAIN RESULTS AND THE ROLE OF CHANCE Central PN juxtaposition was associated with a 2-fold increase in the odds of live birth (OR = 2.20; 95% CI, [1.26–3.89]; P = 0.006), while the presence of MNB2cell was associated with half the odds of live birth (OR = 0.51; 95% CI, [0.27–0.95]; P = 0.035). These two parameters were independent of embryo kinetics. The 33 remaining parameters had no significant association with the capacity of transferred embryos to develop to term. LIMITATIONS, REASONS FOR CAUTION Even though the population size was relatively small, our analyses were based on homogeneous cycles, i.e. young women whose transferred embryos were found to be high-grade according to conventional morphology evaluation. In addition, our conclusions were established from a specific, highly selected population, so other study populations, such as women in an older age bracket, may yield different results. Finally, because we assessed day 2/3 transfers, our findings cannot be generalized to embryos cultured up to the blastocyst stage. WIDER IMPLICATIONS OF THE FINDINGS It would be interesting to explore, prospectively, whether PN localisation is a relevant measure to predict embryo development when added into further algorithms and whether this parameter could be suitable for use in other IVF clinics. Further studies are needed, notably to explore the added value of timing evaluation in cohorts of embryos with low or intermediate morphology grade, as well as in other maternal populations (i.e. older women). STUDY FUNDING/COMPETING INTEREST(S) No external funding was used for this study. P. Sagot received funding from the following commercial companies: Merck Serono, Finox Biotech, Ferring, MSD France SAS, Teva Sante ́ SAS, Allergan France, Gedeon Richter France, Effik S.A., Karl Storz Endoscopie France, GE Medical Systems SCS, Laboratoires Genevrier, H.A.C. Pharma and Ipsen. All the authors confirm that none of this funding was used to support the research in this study. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the journal policies on sharing data and materials.

NCT02722252.

Objective: To study the impact of in vitro fertilization, with or without intracytoplasmic sperm injection (IVF/ICSI), frozen-embryo transfer (FET), and intrauterine insemination (IUI) on fetal growth kinetics throughout pregnancy and to compare the different modes of conception. Design: Retrospective cohort study. Setting: University. Patient(s): A total of 560 singleton pregnancies were included (96 IVF, 210 ICSI, 121 FET, and 133 IUI). Intervention(s): None. Main Outcome Measure(s): We compared crown-rump length (CRL) at the first trimester (T1: 11-13 weeks of gestation [WG] þ 6 days), estimated fetal weight (EFW) at the second (T2: 21-23 WG þ 6 days) and third (T3: 31-33 WG þ 6 days) trimesters, and birth weight (BW) z-scores with those in the reference curves (Papageorghiou for T1, and Ego M2 for T2, T3, and birth). Multivariate analyses were performed. Result(s): For T1, the CRL was longer than the reference curve whatever the assisted reproductive technique (ART). For T2, EFW was significantly greater for all groups compared with the reference curve, and for T3 only FET singletons had a greater EFW. ICSI, IVF, and IUI singletons had a significantly lower BW compared with reference curves. For all ART fetuses, growth kinetics differed from T2. Only FET fetuses maintained their significantly above-reference growth values. The proportion of fetuses for which at least one period of growth loss was observed from T2 to birth was higher after IVF, ICSI, and IUI than after FET. Conclusion(s): For the first time, we have highlighted that fetal growth kinetics differed from T2 depending on the ART protocols used. They could have an impact on trophoblastic invasiveness and might lead to long-term health effects. (Fertil Steril Ò 2018;110:1109-17. Ó2018 by American Society for Reproductive Medicine.) El resumen está disponible en Español al final del artículo.

Children conceived by assisted reproductive technologies (ART) have a moderate risk for a number of adverse events and conditions. The question whether this additional risk is associated with specific procedures used in ART or whether it is related to the intrinsic biological factors associated with infertility remains unresolved. One of the main hypotheses is that laboratory procedures could have an effect on the epigenome of gametes and embryos. This suspicion is linked to the fact that ART procedures occur precisely during the period when there are major changes in the organization of the epigenome. Oocyte freezing protocols are generally considered safe; however, some evidence suggests that vitrification may be associated with modifications of the epigenetic marks. In this manuscript, after describing the main changes that occur during epigenetic reprogramming, we will provide current information regarding the impact of oocyte vitrification on epigenetic regulation and the consequences on gene expression, both in animals and humans. Overall, the literature suggests that epigenetic and transcriptomic profiles are sensitive to the stress induced by oocyte vitrification, and it also underlines the need to improve our knowledge in this field.

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STUDY QUESTION Do assisted reproductive technologies (ART) and in vitro embryo culture influence the epigenetic control of imprinted genes (IGs) and transposable elements (TEs) in children? SUMMARY ANSWER Significant differences in the DNA methylation of IGs or transposon families were reported between ART and naturally conceived children, but there was no difference between culture media. WHAT IS KNOWN ALREADY There is concern that ART may play a role in increasing the incidence of adverse health outcomes in children, probably through epigenetic mechanisms. It is crucial to assess epigenetic control, especially following non-optimal in vitro culture conditions and to compare epigenetic analyses from ART-conceived and naturally conceived children. STUDY DESIGN, SIZE, DURATION This follow-up study was based on an earlier randomized study comparing in vitro fertilization outcomes following the use of two distinct culture media. We compared the epigenetic profiles of children from the initial randomized study according to the mode of conception [i.e. ART singletons compared with those of a cohort of naturally conceived singleton children (CTL)], the type of embryo culture medium used [global medium (LifeGlobal) and single step medium (Irvine Scientific)] and the mode of in vitro fertilization (i.e. IVF versus ICSI). PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 57 buccal smears were collected from 7- to 8-year-old children. The DNA methylation profiles of four differentially methylated regions (DMRs) of IGs (H19/IGF2: IG-DMR, KCNQ1OT1: TSS-DMR, SNURF: TSS-DMR, and PEG3: TSS-DMR) and two TEs (AluYa5 and LINE-1) were first assessed by pyrosequencing. We further explored IGs and TEs’ methylation changes through methylation array (Human MethylationEPIC BeadChip referred as EPIC array, Illumina). MAIN RESULTS AND THE ROLE OF CHANCE Changes in the IGs’ DNA methylation levels were found in ART children compared to controls. DNA methylation levels of H19/IGF2 DMR were significantly lower in ART children than in CTL children [52% versus 58%, P = 0.003, false discovery rate (FDR) P = 0.018] while a significantly higher methylation rate was observed for the PEG3 DMR (51% versus 48%, P = 0.007, FDR P = 0.021). However, no differences were found between the culture media. After observing these targeted modifications, analyses were performed at wider scale. Again, no differences were detected according to the culture media, but imprinted-related DMRs overlapping promoter region near the genes major for the development (MEG3, BLCAP, and DLX5) were detected between the ART and CTL children. LIMITATIONS, REASONS FOR CAUTION The sample size could seem relatively small, but the high consistency of our results was ensured by the homogeneity of the cohort from the initial randomized study, the standardized laboratory techniques and the robust statistical analyses accounting for multiple testing. WIDER IMPLICATIONS OF THE FINDINGS Although this study did not report DNA methylation differences depending on the culture medium, it sheds light on epigenetic changes that could be observed in some children conceived by ART as compared to CTL children. The clinical relevance of such differences remains largely unknown, and it is still unclear whether such changes are due to some specific ART procedures and/or to parental infertility. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by funding from the Agence Nationale pour la Recherche (‘CARE’-ANR JCJC 2017). The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER Not concerned.

Although early maternal serum beta-hCG kinetics were modified in women after severe OHSS, the outcomes of these pregnancies remained comparable to those of IVF pregnancies without OHSS. According to these data, pregnancies after severe OHSS do not require particular care compared with IVF pregnancies, but differences in beta-hCG levels and kinetics should be taken into account when interpreting these results.