Reinsemination of one-day-old oocytes by use of intracytoplasmic sperm injection

Objective: To evaluate the possible advantages of reinseminating oocytes by us of intracytoplasmic sperm injection (ICSI). Design: Clinical study. Setting: In vitro fertilization unit with research facilities. Patients: Fifty-seven couples who were part of our regular IVF program. Interventions: Nonfertilized oocytes from IVF cycles with no or very low fertilization were microinjected with spermatozoa approximately 25 hours after oocyte pick-up. Main Outcome Measures: Fertilization and pregnancy rates. Results: A mean fertilization rate of 46.5% was obtained when reinseminating the oocytes on day 2 using the ICSI procedure. Of 57 cycles with completely or almost completely failed fertilization, 29 patients received ET after reinsemination by ICSI. Two of these transfers resulted in pregnancies (6.9% per ET) and two healthy babies were born. Conclusion: Despite this relative success, considering both the extra work involved and the potential genetic risk, it is doubtful whether ICSI on day 2 should be recommended as a routine procedure. For training and research purposes, however, this approach can be of value.