PREPARATION BY DIFFERENTIAL GRADIENT CENTRIFUGATION IS BETTER THAN SWIM-UP IN SELECTING SPERM WITH NORMAL MORPHOLOGY (STRICT CRITERIA)

Objective: To evaluate two commonly used methods of sperm preparation with respect to their effects on sperm morphology (strict criteria). D esign: Auto-controlled. split sample study performed on the semen of 7 4 male partners of couples enrolled for IVF. Setting: In vitro fertili zation and andrology laboratories at a tertiary care, major teaching h ospital. Patient(s): Seventy-four male partners of couples who were sc heduled to undergo IVF. Intervention(s): Equal halves of the same seme n sample were evaluated for strict criteria sperm morphology before an d after preparation by differential gradient centrifugation using Perc oll (Pacific Andrology, Montrose, CA) and by the standard swim-up meth od. Main Outcome Measure(s): The percentage of morphologically normal sperm was assessed using strict criteria before and after the two meth ods of sperm preparation. Specific parameters studied were individual abnormalities of the head, midpiece, and tail. Result(s): Sperm prepar ation using differential gradient centrifugation with Percoll produced a significantly greater number of specimens with normal sperm morphol ogy and also showed higher absolute quantitative improvement over the swim-up method. The two methods were comparable in regard to their eff ects on specific sperm abnormalities !i.e., head, midpiece, and tail d efects). Conclusion(s): The differential gradient sperm separation met hod using Percoll is superior to the swim-up method for selecting sper m with normal morphology as assessed by strict criteria. Because sperm morphology as assessed by strict criteria is a good predictor of oocy te fertilization, this method can be recommended as the method of choi ce for assisted reproductive technology laboratories. Use of this meth od may help improve outcome by increasing fertilization rates. (C) 199 8 by American Society for Reproductive Medicine.).