The effect of insemination/injection time on the results of IVF and ICSI

BACKGROUND: The aim of this study was to investigate whether a pre-incubati on time between oocyte retrieval and insemination or injection had any effe ct on the success rate of IVF or intracytoplasmic sperm injection (ICSI). B ased on previously published data, many laboratories retain a time interval of several hours between oocyte retrieval and insemination/injection. In o ur setting, insemination and injection times are dependent only on the labo ratory workload. METHODS: Totals of 881 IVF and 432 ICSI cycles performed b etween 1997 and 1999 were analysed retrospectively. Oocyte retrieval occurr ed 36 h after human chorionic gonadotrophin administration, and inseminatio n or injection took place 1-7 or 0.5-8 h after oocyte retrieval respectivel y. RESULTS: No statistically significant differences were found between the se time periods and outcome of IVF and ICSI with respect to fertilization r ate, embryo quality, implantation rate, abortion and ongoing pregnancy rate s, except for the abortion rate after IVF. As this finding may be due to ch ance and no differences were found in the ongoing pregnancy rates, this fin ding was considered to be of less importance. CONCLUSIONS: If laboratory co ntrol and efficiency demands early insemination or injection, it could be p erformed without reservation.