Prediction of post-thaw sperm motility and sperm cryosurvival rate using the pre-freeze sperm parameters

To determine the relationships between pre-freeze semen variables and cryosurvival rate and post-thaw motility and examine whether they have any predictive value for the cryosurvival rate and post-thaw sperm motility, conventional semen analysis, supravital staining for sperm viability and hypo-osmotic swelling test were performed on 50 semen samples before cryopreservation. Thawed semen samples were examined for post-thaw sperm motility and cryosurvival rate. Significant correlations were observed between post-thaw sperm motility and several pre-freeze semen variables, such as, hypo-osmotic swelling test, pre-freeze sperm motility and sperm viability. In a stepwise regression analysis, an accurate prediction of post-thaw sperm motility (R = 0.826) was obtained using a multiple regression equation incorporating 3 variables including hypo-osmotic swelling test, pre-freeze sperm motility and sperm concentration. In conclusion, a set of criteria have been identified that accurately predicts post-thaw sperm motility and which place particular emphasis on hypo-osmotic swelling test. Conventional semen analysis and hypo-osmotic swelling test are simple and effective assays for the prediction of post-thaw motility.