The effect of repeated freezing and thawing on human sperm DNA fragmentation.

Objective: To investigate the effects of repeated freezing and thawing on human sperm motility, vitality, and DNA integrity.

Design: A prospective clinical study.

Setting: Tertiary care fertility clinic.

The DNA integrity of cryopreserved spermatozoa separated for use in assisted reproductive technology is unaffected by the type of cryoprotectant used but is related to the DNA integrity of the fresh separated preparation.

Objective: To investigate and compare seven different commercially available cryoprotectant media in terms of the DNA integrity of spermatozoa recovered after cryopreservation and separation using density gradient centrifugation (DGC).

Design: A prospective clinical study.

Setting: Tertiary care fertility clinic.