Spatial and Molecular Parameters of Pre-OPU Ovarian Follicles and Their Association with Embryo Developmental Competence in Assisted Reproductive Technology

Advanced maternal age is a significant social and clinical issue associated with the natural decline in a woman’s ovarian reserve. This prospective, single-center study included women with primary infertility who presented to the Gyncentrum Clinic in Katowice and analyzed 77 ovarian follicles. The study group consisted of patients of advanced reproductive age with diminished ovarian reserve, who underwent hormonal stimulation in preparation for oocyte retrieval. Each metaphase II (MII) oocyte was fertilized in vitro and cultured individually in a time-lapse incubator. Follicular fluid obtained during oocyte retrieval was collected separately from each follicle and used for non-invasive biochemical analysis of prognostic factors using a Multiplex assay. The concentrations of interleukin 10 (IL-10), granulocyte colony-stimulating factor (G-CSF), granulocyte–macrophage colony-stimulating factor (GM-CSF), and C-type natriuretic peptide (CNP) were evaluated. The analysis showed that lower concentrations of GM-CSF and CNP were associated with an increased probability of oocyte fertilization, whereas higher levels of IL-10 and G-CSF had the greatest impact on blastocyst formation. This model was supported by continuous embryo monitoring. An eightfold increase in the likelihood of blastocyst formation was observed when early embryo cleavage occurred between 25 and 27 h after insemination. Furthermore, prolonged duration of the first cytokinesis reduced the probability of blastocyst development, while an extended cell cycle at the two-blastomere stage significantly affected further embryo development. These findings may support non-invasive embryo selection strategies.