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-incubation time between oocyte retrieval and insemination or injection had any effect on the success rate of IVF or intracytoplasmic sperm injection (ICSI). Based on previously published data, many laboratories retain a time interval of several hours between oocyte retrieval and insemination/injection. In our setting, insemination and injection times are dependent only on the laboratory workload. METHODS: Totals of 881 IVF and 432 ICSI cycles performed between 1997 and 1999 were analysed retrospectively. Oocyte retrieval occurred 36 h after human chorionic gonadotrophin administration, and insemination or injection took place 1-7 or 0.5-8 h after oocyte retrieval respectively. RESULTS: No statistically significant differences were found between these time periods and outcome of IVF and ICSI with respect to fertilization rate, embryo quality, implantation rate, abortion and ongoing pregnancy rates, except for the abortion rate after IVF. As this finding may be due to chance and no differences were found in the ongoing pregnancy rates, this finding was considered to be of less importance. CONCLUSIONS: If laboratory control and efficiency demands early insemination or injection, it could be performed without reservation.