The value of sperm swimming speed measurements in assessing the fertility of human frozen semen

Abstract

The purpose of this study was to evaluate relationships between measured sperm velocity and in-vivo fertility, using donor semen samples from an artificial insemination (AID) programme. Seventy-one frozen semen samples were examined; measurements of sperm velocity were made immediately after thawing, upon a motile 'swim-up' fraction, and finally after 3.5 h incubation at 37 degrees C in the freezing mixture. Zona-free hamster egg penetration assays were performed upon all samples. Two groups of samples were identified; seven donors (11 samples) had failed to produce any pregnancies through AID from a range of 3 to 14 cycles tested, whilst the remaining samples (from 25 donors) had achieved at least one pregnancy each. The mean sperm velocity (+/- SEM) for the latter 'fertile' group was significantly higher than the corresponding value for the 'infertile' group; (i) after thawing, 65.9 +/- 1.8 versus 50.4 +/- 3.2 microns/s (P less than 0.001) and (ii) after 3.5 h incubation, 42.1 +/- 2.1 versus 24.7 +/- 5.7 microns/s (P less than 0.002). Using the maintenance of sperm velocity during incubation as an indicator of survival, life-table analyses were used to calculate monthly conception rates on various sub-groups of the semen samples. Poor survival (greater than 40% decline in velocity over 3.5 h) was associated with a monthly pregnancy rate of only 11.58% (362 cycles), whilst better survival (less than 40% decline) was associated with the significantly higher (P = 0.024) pregnancy rate of 16.87% (480 cycles).