Relationship between human sperm motility characteristics and sperm penetration into human cervical mucus in vitro.

A series of 100 modified Kremer tests of human sperm penetration into human cervical mucus was carried out as part of the routine investigation of couples presenting with infertility. The outcome of these tests was significantly correlated with the concentration and progressive motility of the spermatozoa in the semen sample used for the test. Other semen characteristics significantly correlated with the test result were the mean velocity of progression (VP) and the amplitude of lateral head displacement about the axis of progression (AH) of the progressive spermatozoa. Normal sperm morphology was also correlated with the outcome. Using these semen characteristics as the independent variables to predict the test outcome in a discriminant analysis (normal vs abnormal tests), 34.2% of the variance was accounted for. From the discriminant function equation 75.0% of the test results could be predicted correctly. In the 30 cases in which the semen samples used for the tests showed greater than or equal to 25 X 10(6) progressively motile spermatozoa per ml, mean VP of greater than or equal to 25 microns/sec and mean AH of greater than or equal to 7.5 microns, 83.3% had normal test results. Conversely, all 13 cases for which the semen characteristics were below these limits had abnormal test results. Therefore, both the concentration of progressively motile spermatozoa and their movement characteristics are significant factors determining the outcome of homologous tests of human sperm-cervical mucus interaction.