Effect of shortened exposure time to the critical period for ice crystal formation on subsequent post-thaw semen parameters from cryopreserved sperm.

Cryopreservation of human sperm using present methods leads to a reduced fertility potential of the specimen. In many instances this prevents the successful fertilization of the female partner from the frozen-thawed specimens of males whose semen has been cryopreserved prior to surgery, chemo-therapy, or even vasectomy. Furthermore, even though some donor specimens can be successfully used for achieving pregnancies, one needs to place the sperm intrauterine to approach the same pregnancy rates as those of fresh intracervical insemination. The main mechanism considered for sperm damage by cryopreservation is ice crystal formation. The most critical time for forming ice crystals is from 0 to -10 degrees C. In the present study the effect of a modified rapid cryopreservation technique with reduction of exposure time to the 0 to -10 degrees C temperature range was compared to standard freezing procedures on subsequent semen parameters. Though no significant differences were found on post-thaw motile densities or hypoosmotic swelling test scores, a new, equally effective, but more rapid technique for cryopreservation is reported.