O-099 The use of cumulus cells (CCs) to select spermatozoa for intracytoplasmic sperm injection improves blastocyst development and quality

Abstract Study question Is there a role for sperm selection based on the capacity to pass through cumulus oophorous column in improving the laboratory outcomes in ICSI cycles? Summary answer A higher rate of blastocyst formation and quality are obtained with the use of CCs to select spermatozoa for ICSI compared to conventional density gradients. What is known already The sperm selection for ICSI is an operator-dependent procedure based on sperm morphology and motility. ICSI bypasses all natural barriers of sperm selection, which may impact embryo development. During natural fertilization, only the spermatozoa that pass-through cumulus cells will have the chance to fertilize the egg. Spermatozoa capable of traverse COCs have better morphology, higher chromatin integrity and greater acrosomal reaction. Hyaluronic acid is an important component of these cells and plays a key role in the selection of spermatozoa with intact DNA. However, there is scarce data regarding this selection method for ICSI on the development of the embryo. Study design, size, duration This is a prospective randomized sibling oocyte pilot study (February-December 2021). A total of 996 metaphase II (MII) oocytes were randomized into two groups. In the control group (Group 0, n = 489 MII), ICSI was performed with sperm selected by conventional density gradients. In the study group (Group 1, n = 507 MII) the oocytes were microinjected with sperm selected through CCs. The main outcome was blastocyst formation rate and quality. Reproductive results were analyzed as secondary outcomes. Participants/materials, setting, methods Ninety-eight couples undergoing ICSI (private center) with ≥6 fresh own MII obtained after ovarian stimulation, embryo culture until blastocyst stage and ejaculated sperm samples were included in the study. All seminal samples were processed using density gradients and those in the study group were additionally passed through CCs (the patient's own CCs were used in all cases). Fertilization and day 5 blastocyst formation rates were assessed. Embryo quality was scored according to Gardner's criteria. Main results and the role of chance Data was similar with regards to cause of infertility, maternal age (36.47 vs 36.63 y.o.), sperm count (60.53 vs 58.25 mill/ml) and progressive motility (57.45 vs 57.50%) between group 0 vs 1, respectively. Fertilization rate was similar between groups (74.0% vs 78.7%; p = 0.419. Group 0 vs 1, respectively). However, the blastocyst format