Y. Hirano et al., Relationships between sperm motility characteristics assessed by the computer-aided sperm analysis (CASA) and fertilization rates in vitro, J AS REPROD, 18(4), 2001, pp. 213-218
Purpose: Some studies have suggested that computer-aided sperm analysis (CA
SA) estimates of concentration and movement characteristics of progressivel
y motile spermatozoa are related to fertilization rates in vitro. However,
it has also been suggested that the greater number of motility parameters a
ssessed by CASA does nor imply more precision in predicting fertility. This
study was carried out to investigate the relationships between the CASA es
timates and fertilization rates in vitro.
Methods: Semen quality analysis M,ns performed using CASA in 136 in vitro f
ertilization-embryo transfer (IVF-ET) cycles with at least 3 oocytes collec
ted. The CASA estimates before and after swim-up were compared between 108
cycles with fertilization rate > 50% ("good" group) and 28 cycles with fert
ilization rate less than or equal to 50% ("poor" group).
Results: Before swim-up, there were significant correlations between fertil
ization rates anti CASA estimates, including amplitude of lateral head disp
lacement (ALH) (r = .269), curvilinear velocity (VCL) (r = .297), straight
line velocity (VSL) (r = .266), and rapid sprm movement (Rapid) (r = .243).
There was also a significant correlation between the fertilization rates a
nd straightness (STR) after swim-up (r = -0.178). As for sperm movement cha
racteristics there were significant differences of ALH (p < .005), VCL (p <
.001), VSL (p < .005), and Rapid (p < .01) between "good" and "poor" group
s before swim-up. After swim-up, there were significant differences of VCL
(p < .005), average path velocity (VAP) (p < .005), and Rapid (p < .05) bet
ween the two groups.
Conclusions These results indicate that some of the CASA estimates provide
reliable estimation of the fertilizing ability of human sperm. There were s
ignificant differences of th e two sperm movement characteristics, includin
g VCL and Rapid (before and after swim-up), indicating that the total dista
nce traveled by unpin sperm movement might be important in human sperm fert
ilizing abilities.