Correlates of human sperm motility assessed by laser Doppler spectroscopy

The sperm motility characteristics of 140 men (percentage motile and average velocity of all sperm in motion; percentage progressive and the average velocity of sperm swimming more than 15 microns/sec) were determined using a laser-Doppler technique and correlated with other aspects of sperm quality, including the concentration and the proportion of abnormal and dead sperm in the ejaculate. In addition, the influence of the length of the period of abstinence, the viscosity of seminal plasma and the volume of the ejaculate were also assessed. The four motility characteristics were all highly correlated with each other. The magnitude of all four parameters increased in an exponential fashion with increasing sperm number up to 400 x 10(6) per ejaculate. At higher numbers, no further improvement in motility was observed. Moreover, increasing sperm number was associated with a decline in the proportion of sperm exhibiting abnormalities in morphology but with an increase in viable sperm 30 min after ejaculation. The relative viscosity of the ejaculates had generally no influence on sperm motility. In contrast, certain of the sperm motility characteristics, including the average velocity, were significantly negatively correlated with the length of the abstinence period.