Objective

1. Duration Of Exposure To Polyvinylpyrrolidone(PVP): The Effects On Fertilization Rate And Embryo Development Nahid Yari1 , Sahabeh Etebary1, M. Golestan Jahromi1 , Mohammad Ali Khalili 1 1Research and clinical center for infertility, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Objective Results Recently, it has been found that exposure of sperm to PVP may cause submicroscopic changes in sperm structure and the sperm nucleus. The PVP-induced nuclear damage may have been due to breakdown of sperm membranes. Consequently, it is probable that exposure of sperm to PVP may impair embryo development. There are apparently no detailed reports regarding the specific effects of PVP on fertilization rate and embryo development . No statistically significant differences were found between the time of exposure of oocytes to hyaluronidase with blastomere number, embryo quality and fertilization rate, but there are significant differences between the time of exposure of spermatozoa with PVP and Fertilization rate (p=0.002), embryo quality (p=0.03) and blastomere numbers (p=0.001). Conclusion Method It seems different time of exposure of sperm to PVP can affect subsequent cleavage rate and embryo development, so it is suggested to decrease the time of sperm exposure to PVP as possible. In the present study, 358 oocytes from 58 cycles were evaluated. We recorded the time interval between exposure of sperm to PVP and ICSI insemination, also we recorded the time of exposure of oocytes to hyaluronidase, and then each oocyte was put it in a single droplet of G1 media. All of the procedures were performed by a single embryologist over 6 month’s period of time. Post‐ICSI rates of fertilization and blastomere number as well as embryo quality were assessed.