Percentage of motile spermatozoa at 22 hours after swim-up procedure: An indicator for intracytoplasmic sperm injection?

OBJECTIVE The decision to use in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), or split insemination (IVF-ICSI) in the first cycle is based on the number of motile sperm. Hence, total fertilization failure (TFF) often occurs during IVF cycles, despite normozoospermia. To investigate whether the cumulative motile swim-up spermatozoa percentage at 22 hours post-insemination (MSPPI) is an indicator for ICSI, we analyzed TFF, fertilization, blastocyst development, chemical pregnancy, clinical pregnancy, and live birth rates. METHODS This prospective study was performed using data obtained from 260 IVF cycles. At 22 hours after insemination, the remaining swim-up spermatozoa were observed and divided into six groups according to MSPPI (<10%, 10% to <30%, 30% to <50%, 50% to <70%, 70% to <90%, and 90% to 100%). RESULTS Regardless of the ejaculated motile sperm concentration (0.6-280×10(6)/mL motile spermatozoa), the incidence of TFF significantly increased when MSPPI was <10%, and the fertilization rate significantly decreased when MSPPI was <30%. We found that cumulative MSPPI correlated with the cumulative fertilization rate (Spearman correlation, 0.508, p<0.001). Regarding embryo development, we observed no significant differences in the rates of blastocyst development, chemical pregnancy, clinical pregnancy, or live birth among all groups. CONCLUSION Our findings suggest that MSPPI is a viable indicator for split IVF-ICSI and ICSI. Taken together, by employing the MSPPI test in advance before IVF, ICSI, or split IVF-ICSI cycles, unnecessary split IVF-ICSI and ICSI may be avoided.