Motility and morphology of human spermatozoa in split ejaculates.

Sperm concentration and four motility characteristics (per cent motile spermatozoa, average velocity, average straight line approach and average speed constancy) were determined in three fractions of human split ejaculated from healthy volunteers. A semi-automatic analysis technique was used to determine sperm parameters from multiple exposure photographs (MEP). Sperm concentration and percentage motility were significantly higher in the first fraction as compared to the third fraction of split ejaculates. The average spermatozoal velocity, average speed constancy and average straight line approach were the same in all fractions. Differences in the percentage of motile spermatozoa were also found after collection of split ejaculates in culture medium. This phenomenon may have been caused by differences in sperm morphology. Significantly more normal spermatozoa were present in the first fractions of 19 split ejaculates as compared to the last fractions.