Relationship Between Sperm Motility Assessed with the Hamilton‐Thorn Motility Analyzer and Fertilization Rates In Vitro

To determine which sperm movement characteristics are related to in vitro fertilization rates, semen and swim‐up preparations used for in vitro fertilization in 108 patients were assessed using the Hamilton‐Thorn HTM‐2030 Motility Analyzer (HTMA) and other sperm tests. There were highly significant correlations between manual and HTMA results for sperm concentration (Spearman r = 0.881; P < 0.001) and the percentage of motile spermatozoa (Spearman r = 0.580; P < 0.001). The percentage of motile spermatozoa with average path velocities greater than 10 μ/s and greater than 20 μ/s, straight line and curvilinear velocity, linearity (straight line velocity vs curvilinear velocity), amplitude of lateral head displacement, and beat‐cross frequency were significantly higher in the insemination medium after selection of motile spermatozoa by the swim‐up technique than in the semen. Linearity (P < 0.01), the percentage of morphologically normal spermatozoa (P < 0.05) and straight line velocity (P < 0.05) in semen, and the percentage of motile spermatozoa with average path velocities greater than 10 μ/s in both semen (P < 0.05) and insemination medium (P < 0.05) were significantly correlated with in vitro fertilization rate when examined by a nonparametric (Spearman) test. With logistic regression analysis of all data, only the diagnoses of male infertility and tubal disease, linearity in semen, and the percentage of motile spermatozoa with average path velocities between 10 and 20 μ/s in insemination medium were significantly related to in vitro fertilization rates. All other variables were not significant. In patients with poor sperm morphology (normal < 30%), only linearity in semen and the proportion of spermatozoa with normal intact acrosomes in the insemination medium were significantly related to in vitro fertilization rates. In conclusion, objective measurement of the motility characteristics by HTMA may provide useful information for predicting in vitro fertilization rates that can be used in addition to that derived from assessment of sperm morphology and acrosomes.