Removal of the cumulus oophorus from the human oocyte for in vitro fertilization.

Removal of cumulus may increase the chance of fertilization in patients with sperm antibodies, may facilitate fertilization in vitro with a small number of spermatozoa, and is necessary for microsurgical injection procedures in vitro. The aim of this study was to establish whether removal of the cumulus has any detrimental effects on the fertilization rate and embryo viability. Removal of cumulus cells from the human oocyte with bovine testicular hyaluronidase did not interfere with fertilization, early embryonic development, or pregnancy. This suggests that human spermatozoa can spontaneously undergo capacitation and fertilize oocytes in vitro in a chemically defined medium containing 10% preovulatory human serum. In three patients with low-quality semen, removal of the cumulus and the addition of hypotaurine and epinephrine apparently did not improve the motility nor the fertilizing capacity of the spermatozoa. Delayed fertilization and cleavage arrest was observed in one patient when spermatozoa obtained from the body region of the epididymis was used for insemination.