[SPERM SELECTION TECHNIQUES: VISUAL ASSESSMENT VERSUS THE BINDING POTENTIAL TO HYALURONIC ACID]

The human oocyte is surrounded by hyaluronic acid (HA), which acts as a natural selector. Only spermatozoa expressing HA receptors can reach and fertilize the oocyte. This study aims to compare two sperm selection techniques by correlation to fertilization rates and embryo quality.

Couples undergoing IVF-ICSI treatment due to mild male infertility were enrolled in a prospective study. According to the randomization, the sperm suspensions were put into a polyvinylpyrrolidone (PVP) droplet or an HA-containing medium droplet (Sperm Slow). In the PVP group motile spermatozoa with the best morphology were selected for injection. From the HA-containing medium those sperm demonstrating vigorous tail beating and an absence of progressive motility as well as good morphology, were selected. Primary outcome measures were fertilization rate and embryo quality.

Thirty couples were randomized to the PVP group and 24 to the slow sperm group; 353 oocytes were injected. There was no statistical difference in fertilization or cleavage rate. Furthermore, in the PVP group, the mean number of embryos was higher and the average morphology of the best embryo was superior.

Considering that the HA-based sperm selection technique is more expensive and time consuming, the current study does not support using it as a routine method.