Asynchrony between human cumulus-corona cell complex and oocyte maturation after human menopausal gonadotropin treatment for in vitro fertilization

Abstract

One hundred seventeen oocyte-cumulus-corona cell complexes (CCCs) were obtained from 15 women undergoing in vitro fertilization after human menopausal gonadotropin/human chorionic gonadotropin follicular stimulation. In each woman, five oocyte-CCCs were left intact, and the remaining one to five oocytes were freed of their CCCs by hyaluronidase (300 IU/ml) dispersal treatment. Dispersal time for individual CCCs correlated well with their degree of mucification and was significantly shorter in 20 mature CCCs as compared with 24 intermediate CCCs (1.20 +/- 0.05 versus 2.35 +/- 0.13 minutes, respectively; P less than 0.001). Oocyte maturation at collection and after 8 hours of in vitro incubation was not related to the CCC type present at harvest. Maturation of oocytes progressed regardless of CCC type; so that after 8 hours of preincubation, 73% of the oocytes attained a polar body while 20% were still at the germinal vesicle breakdown stage and 7% at the germinal vesicle stage. Overall, the 44 denuded oocytes and 72 intact oocyte-CCCs were comparable in rate of fertilization (64% versus 68%) and subsequent cleavage (75% versus 82% of all fertilized oocytes). It is concluded that in human menopausal gonadotropin-stimulated cycles, asynchrony between individual CCC mucification and oocyte maturation may occur, and that the absence of CCC does not seem to affect in vitro fertilization and cleavage rates.