Human sperm movement assessed with the Hamilton-Thorn motility analyzer and in vitro fertilization

Summary. The relationship between sperm movement characteristics obtained by computerized analysis and the in vitro fertilization rates of human oocytes was studied. In 144 consecutive in vitro fertilization treatments a sample of prepared semen was analysed by a Hamilton-Thorn Motility Analyzer. In addition a visual estimation of sperm count and motility was made. Significant correlations with the fertilization rate were found for all visual parameters. Of the computerized measurements, the mean velocities of motile spermatozoa and the concentration of motile cells were significantly correlated. The average path velocity correlated best ( r = 0.42, P < 0.001). There was no relationship between the percentage of motile sperm showing hyperactivated movement and the fertilization rate. A forward stepwise logistic regression analysis selected the following variables of predictive value for fertilization: average path velocity, male factor infertility as indication for in vitro fertilization, motility and concentration, as measured by the Hamilton-Thorn analyzer. A logistic regression model to predict the cases with low (< 0.2) or high fertilization rates, included the average path velocity as a significant variable and classified the samples with 90% overall accuracy. In conclusion: movement characteristics of spermatozoa in culture medium, especially the average path velocity are of prognostic value in prediction of human oocyte fertilization rates.