A high DNA fragmentation index (DFI) when performing the sperm chromatin structural (SCSA) assay was claimed to be so specific for male subfertility that even IVF and ICSI did not result in live pregnancies. The present study was designed to corroborate or refute these findings. The SCSA test was performed on the male partner from couples failing to have a successful pregnancy despite at least 2 previous IVF attempts. In contrast to the aforementioned studies, ongoing pregnancies were found despite working with a group of recalcitrant patients. Nevertheless, a high DFI score was associated with a trend for lower ongoing pregnancy rates especially related to a high miscarriage rate. Other more recent studies seem to support our conclusions. A high DFI score should influence a patient to choose IVF as a therapeutic modality sooner, especially with ICSI.

Many centers have been disappointed with the pregnancy rate following the insemination of cryopreserved-thawed sperm, despite the maintenance of an adequate motile density. The possibility exists that damage to the sperm membrane might occur despite preservation of other semen parameters. Simple measurements of structural integrity (viability) and functional integrity (hypoosmotic swelling test) were performed on thawed specimens. In each instance, both the viability and HOS scores were less than the critical 50% level. Specimens from three different commercial centers had very poor HOS and viability scores from two of the centers, and, though the scores were generally greater than or equal to 50% from the third center, this was achieved by eliminating 11 of 12 donors. Reducing the glycerol concentration from 12 to 7% and switching from Nunc vials to plastic embryo straws did not improve the poor sperm membrane tests. The possibility exists that if modification of the cryopreservation technique leads to improved HOS and viability scores, perhaps improved pregnancy results will be realized.

Cryopreservationithawing of sperm leads to decreased motile density. Most donor programs select for cryopreservation a male with a high initial motile density and if the post-thaw semen has a motile density over 10 x 106/ml, the specimen is thought to represent a fertile specimen. Some recent data suggest that males with normal motile densities but subnormal hypo-osmotic swelling (HOS) tests may be infertile. A study was thus performed to bee if males with an adequate motile density after cryopreservation may still demonstrate membrane damage as evidenced by decreased viability and a poor HOS test. The semen species from seven men with motile densities 2 10 X 106/ml after freezethawing were evaluated for HOS changes and viability. Despite preservation of normal motile density, all 7 men had HOS scores below 50% following cryopreservation (though all were significantly above this level pre-freeze). The mean viability and HOS scores prefreezing were 70 f 9.7 and 68.5 f 9.5, and post thaw they dropped to 33.7 + 6.9 and 32.8 k 6.2. These data suggest a mechanism for impaired fertility even with adequate motile density of a thawed specimen that had been cryopreserved.