No abstract

There are many clinicians who believe that standard sperm morphological criteria as determined by the World Health Organization (WHO) may be one of the most reliable indices of male fertility potential. Many previous studies of sperm morphology have lacked meticulous correction of all female infertility factors in forming their conclusions. Other studies may have compared morphological analysis to either the zona-free hamster oocyte penetration test or fertilization rates with in vitro fertilization/embryo transfer (IVF-ET). The former may not be a valid "gold standard" with which to compare, and the latter might not truly reflect the in vivo situation in view of the markedly different type of sperm-oocyte interaction. These data failed to find a strong correlation of abnormal sperm morphology (as determined by WHO criteria) to identify the subnormal male. When motile densities were normal (greater than 10 x 10(6)/ml), 87% of the female partners of men with normal morphology achieved pregnancies within 6 months compared to 82% with subnormal morphology. Even subnormal motile densities and morphology did not predict the subfertile male. These data strongly suggest that the normals established by WHO for morphology are inadequate to distinguish normal from subnormal. Perhaps increasing the percentage of abnormal sperm morphology to be considered subfertile might prove more useful, or perhaps using another type of morphological assessment might be more effective.

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°C. In the present study the effect of a modified rapid cryopreservation technique with reduction of exposure time to the 0 to -10°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.Keywords: ice crystal formation, cryopreservation, semen, hypoosmotic swelling test, sperm, t h a wThere have been studies suggesting very low pregnancy results following insemination of cryopreserved thawed semen specimens in the female partners of men whose sperm was frozen prior to treatment of the male partners, therapies that could destroy the intratesticular