The effect of follicle size and homogeneity of follicular development on the morphokinetics of human embryos

Abstract

Purpose Our aim was to investigate follicular size (large, ≥17 mm and small, <17 mm) at the time of OPU and homogeneity of follicular development (homogenous development: follicles being present in a homogenous spread of all sizes; heterogeneous: a predominance of small and large follicles) by analysing the morphokinetics of embryo development. Methods In this prospective cohort study, 2526 COCs belonging to 187 patients were cultured to day 5. Embryos were evaluated morphokinetically. Four subgroups were defined: large follicles from heterogeneous cycles (LHet) and homogenous cycles (LHom) and small follicles from heterogeneous cycles (SHet) and homogenous cycles (SHom). Results Rates of fertilization, blastocyst formation and top and good quality blastocysts were found to be significantly higher in embryos from the LHom group (p < 0.001; p < 0.001; p < 0.001). Small follicles from both homogenous and heterogeneous cycles had significantly lower blastocyst formation and top and good quality blastocyst rates (p < 0.001; p < 0.001). Embryos from SHet had significantly more direct cleavages (p = 0.011). Time to reach blastocyst was shorter in SHom than LHet and LHom (p = 0.002; p = 0.027, respectively). However, once the blastocyst stage was achieved, implantation rates were not significantly different between subgroups, the highest rate being observed in the LHom group. Multivariable analysis revealed that homogeneity of follicular development and follicular size had a significant effect on blastocyst development and quality (p = 0.049; p < 0.001, respectively). Conclusion Follicular dynamics, illustrated by follicular size and homogeneity of follicular development, influence early human embryo development. Patterns of follicular growth have an impact on embryo quality and viability which is reflected in morphokinetic variables.

Is there a correlation between follicle size and gene expression in cumulus cells and is gene expression an indicator of embryo development?

“…It was conducted in a private IVF clinic between July 2014 and September 2015 and the analysis was based on 2495 COCs belonging to 184 patients, with culture until day 5. Our previous study on follicular size and morphokinetics analysed 2526 oocytes [ 1 ]. However, in this study three patients and their 31 oocytes were excluded from the expression analysis because their CC samples did not give interpretable results due to technical issues.…”

“…The patients presented various infertility causes, all protocols were approved by the institutional review board and all patients gave their informed consent prior to their inclusion in the study. Patients were selected with inclusion criteria as similar as possible to the first part of the study [ 1 ]. Furthermore, the inclusion criteria specified good prognosis patients with at least 8 COCs in order to provide us with a sufficient number of blastocysts for statistical analyses.…”

“…In an article published in 2017 , we discussed the results of the first part of our study into the morphokinetic development of embryos in relation to follicle diameter and homogeneity of follicular development [ 1 ]. Our findings showed that embryos coming from small follicles in heterogeneous cycles had significantly higher rates of arrest or failure to reach blastocyst than embryos coming from large follicles in homogenous cycles.…”

High rates of aneuploidy, mosaicism and abnormal morphokinetic development in cases with low sperm concentration

“…The stimulation protocols have been outlined previously [14]. For ovarian stimulation, gonadotropin-releasing hormone (GnRH) analogue suppression (short or long), GnRH antagonist protocol and recombinant follicle stimulating hormone (rFSH) or a combination of rFSH and recombinant luteinizing hormone (rLH) (Luveris; Merck, Switzerland) or human menopausal gonadotropin (HMG) (HMG, Ferring, Switzerland) were used.…”

Immature oocyte incidence: Contributing factors and effects on mature sibling oocytes in intracytoplasmic sperm injection cycles

“…The rate of both MI and GV oocytes negatively impacted on the fertilization of the MII oocytes from the same cohort. In fact, increasing incidence of mature oocytes has been correlated with increasing fertilization rate (Halvaei et al, 2012;Kahraman et al, 2017). The oocyte competence depends on a multiplicity of factors; one of them is the ability to generate normal Ca 2+ oscillation response induced by sperm penetration, that develops during the final stages of oocyte growth and maturation and is essential for promoting oocyte activation and fertilization initiation; thereafter MII oocytes that did not reach fully completed cytoplasmic maturity could have impairment in the acquisition of developmental competence (Cheung et al, 2000) The fertilization of mature oocytes derived from cycles with heterogeneous follicular development can lead to abnormal early embryo development, with embryos with significantly more cleavages and lower blastocyst quality (Halvaei et al, 2012;Kahraman et al, 2017).…”