OBJECTIVETo investigate the influence of seasons, blood types and semen parameters on the cryosurvival rate of frozen-thawed spermatozoa from sperm donors.

METHODSWe retrospectively analyzed the influence of seasons, blood types, abstinence period, semen volume, sperm morphology, and pre-freeze sperm motility and concentration on the cryosurvival rate of frozen-thawed sperm in 4 088 semen samples from Shaanxi Human Sperm Bank.

RESULTSThe cryosurvival rate of the post-thaw sperm was correlated negatively with the progressive motility of the pre-freeze sperm (r = -0.262, P < 0.01), but positively with pre-freeze sperm concentration (r = 0.247, P < 0.01), and it was significantly higher in the 6-day abstinence group ([70.2 +/- 5.4]%) than in the other abstinence groups (P < 0.01), so was it in the normal sperm morphology rate > 20% group ([71.4 +/- 5.1]%) than in the others (P < 0.01). The survival rate of the post-thaw sperm was not correlated with seasons, blood types, and semen volume (P > 0.05).

CONCLUSIONSperm motility, concentration and morphology and the abstinence period of sperm donors may be valuable predictors of the cryosurvival rate of post-thaw sperm, but no correlation was found between the survival rate and seasons, blood types and semen volume.