USE OF POSTSEPARATION SPERM PARAMETERS TO DETERMINE THE METHOD OF CHOICE FOR SPERM PREPARATION FOR ASSISTED REPRODUCTIVE TECHNOLOGY

Objective: To evaluate strict sperm morphology after preparation of semen specimens using three different sperm separation techniques, since strict morphology correlates well with IVF. Design: Semen from 30 men were analyzed before and after sperm separation using mini-Percoll gradient, direct swim-up, and SpermPrep filtration column (ZBL, Inc., Lexington, KY) methods. Setting: Assisted Reproductive Technology laboratory at Sinai Hospital of Baltimore. Main Outcome Measures: Primary end points measured were percent morphologically normal sperm and percent improvement in sperm morphology, using Kruger strict criteria. Secondary factors determined were percent motility, improvement in motility, hypoosmotic swelling, improvement in hypoosmotic swelling, and 24- and 48-hour sperm survival under simulated IVF conditions. Results: Mini-Percoll produced specimens with significantly greater normal sperm morphology, morphology improvement, motility, hypoosmotic swelling, and survival than obtained with the other two separation methods. For 25 of 30 specimens, mini-Percoll yielded the greatest number of morphologically normal, motile sperm that survived for 24 hours. In four instances, mini-Percoll was associated with an increased percentage of acrosomal abnormalities despite an overall improvement in morphology. Hypoosmotic swelling scores were lower in two subjects after mini-Percoll sperm separation and in three subjects for each of the other methods. Conclusions: Data suggest that mini-Percoll is superior to swim-up or SpermPrep for producing specimens with enhanced morphology, motility, and in vitro survival. However, no single separation technique is always superior, and methodology may induce damage to the acrosome or sperm membranes. Sperm specimens should be evaluated individually to determine the best separation method before actual ART cycles. The technique that yields the most morphologically normal, motile sperm that survive in culture should be used for ART procedures.