Objective The aim of this study was to evaluate the impact of vitrification on mitochondrial membrane potential (ΔΨm) in human metaphase II (MII) oocytes, and the changes of ΔΨm on thawed MII oocytes.

In this prospective cohort study, the effects of a time-lapse monitoring system on embryo quality and clinical pregnancy outcomes were assessed. A total of 608 patients undergoing in vitro fertilization between April 2013 and June 2014 at our institution were recruited for this study and group-matched into a time-lapse monitoring (TLM) (N = 304) or a standard incubator (SI) (N = 304). The patients' characteristics in the TLM and SI groups were not significantly different. The TLM group showed a significantly higher transferable embryo ratio at Day 3 (61.65% vs. 52.87%; p < 0.0010, RR =1.10 [1.02, 1.19]), a higher number of transferable embryos (4.71 ± 2.38 vs. 4.09 ± 2.35; p = 0.0053, SMD =0.26 [0.06, 0.46]) and number of good-quality embryos cryopreserved at Day 3 (2.72 ± 2.35 vs. 2.11 ± 2.33; p = 0.0056, SMD =0.26 [0.06, 0.46]). In addition, the implantation and clinical pregnancy rates were not statistically significant between the TLM and SI groups. However, the TLM group had a higher ongoing pregnancy rate (67.32% vs. 57.22%; p = 0.0410) and live birth rate (65.37% vs. 55%; p = 0.0380) compared with the SI group. The observed beneficial effects could be the result of a more stable environment provided by the TLM system.

DNA methylation have crucial roles in regulating the expression of developmental genes during mammalian pre-implantation embryonic development (PED). However, the DNA methylation dynamic pattern of long noncoding RNA (lncRNA) genes, one type of epigenetic regulators, in human PED have not yet been demonstrated. Here, we performed a comprehensive analysis of lncRNA genes in human PED based on public reduced representation bisulphite sequencing (RRBS) data. We observed that both lncRNA and protein-coding genes complete the major demethylation wave at the 2-cell stage, whereas the promoters of lncRNA genes show higher methylation level than protein-coding genes during PED. Similar methylation distribution was observed across the transcription start sites (TSS) of lncRNA and protein-coding genes, contrary to previous observations in tissues. Besides, not only the gamete-specific differentially methylated regions (G-DMRs) but also the embryonic developmental-specific DMRs (D-DMRs) showed more paternal bias, especially in promoter regions in lncRNA genes. Moreover, coding-non-coding gene co-expression network analysis of genes containing D-DMRs suggested that lncRNA genes involved in PED are associated with gene expression regulation through several means, such as mRNA splicing, translational regulation and mRNA catabolic. This firstly provides study provides the methylation profiles of lncRNA genes in human PED and improves the understanding of lncRNA genes involvement in human PED.

No abstract

To evaluate the relationship between the initial follicle stimulating hormone (FSH) dose and the number of available cleavage-stage embryos in in vitro fertilization (IVF) cycles.We included 8772 fresh IVF cycles using a GnRH antagonist protocol at the Genetic and Reproductive Institution of Chongqing, P. R. China, from January 2016 to June 2021.Univariate linear regression was used to evaluate the associations between the initial FSH dosage (≤ 150, 187.5–200, 225, 250, or 300 IU) with the number of available cleavage-stage embryos on day 3. A two-factor linear regression model was applied to calculate the threshold effect of the initial FSH dosage on the number of available cleavage-stage embryos based on a smoothing plot. The initial FSH dose was negatively correlated with the number of available cleavage-stage embryos, independent of female age, body mass index, infertility factors, duration of infertility, anti-Müllerian hormone and basal FSH levels, antral follicle count and the proportions of patients with poor ovarian response or polycystic ovarian syndrome. Using a two-factor linear regression model, we calculated the inflection point to be 200 IU of FSH. The relationship between the initial FSH dose and the number of available cleavage-stage embryos was nonlinear. The initial FSH dose was negatively associated with the number of available cleavage-stage embryos when the initial FSH dose was &gt; 200 IU. Therefore, clinicians should try to avoid unnecessarily increasing the initial FSH dose.