The Impact of In vitro Oocyte Maturity on Developmental Potential of Embryos Derived from Controlled Ovarian Stimulation Cycles

One of the major subjects for improving in vitro fertilization (IVF) outcome is the quantity and quality of retrieved oocytes. In vitro maturation (IVM) provides an opportunity for using immature oocytes routinely discarded in clinics. This study aimed at evaluating the quality of embryos derived from in vivo and rescue in vitro matured oocytes. Totally, 462 immature oocytes as cases and 466 mature (MII) oocytes as controls were included for study of their developmental competence. Oocytes underwent intracytoplasmic sperm injection insemination and then denuded oocytes were microscopically assessed regarding cytoplasmic and nuclear maturity and quality. The morphological assessments showed fertilization rate of 60.9 and 61.4%, the embryo formation rate of 86.7% and 90.9% and arresting rate of 27.3% and 25.6% for the case and control oocytes, respectively. Evaluating embryo quality in the cleavage stage indicated that 63% of the embryos in the case group and 68% of the embryos in the control group were of good quality. There was no significant difference between fertility rate and arresting rate of oocytes matured in both groups, although the embryo formation rate and the quality of embryos differed significantly. Our findings suggest that IVM is a valuable and practical option for patients who had to cancel IVF treatment cycles because of severe responses or resistance to routine hormonal therapies or those with low functional ovarian reserve.