In vitro sperm cervical mucus penetration: studies in human and bovine cervical mucus

The objective of this study was to assess the feasibility of substituting bovine estrus cervical mucus (BCM) for human midcycle cervical mucus (MCM) for investigation of sperm cervical mucus (CM) interaction and evaluation of cervical factor in infertility. In vitro sperm cervical mucus penetration tests (ICMPT) were performed with the use of ejaculated human spermatozoa collected from fertile donors and infertile men. Tests were performed in a flat capillary tube with the use of MCM and BCM. Mean +/- standard deviation (SD) of sperm penetration in MCM was 32.3 +/- 15.5 mm and in BCM 27.3 +/- 12.1 mm after 90 minutes of migration. The difference was significant (P less than 0.001). A highly significant correlation was found between sperm penetration in MCM and BCM. The depth of sperm penetration in both human cervical mucus (HCM) and BCM was also significantly related to sperm count and motility. Positive correlation was observed between normal morphologic features and sperm migration in BCM but not in MCM. It is concluded that human sperm penetrate BCM at a slower rate than MCM, but BCM can be effectively substituted for HCM in laboratory testing of sperm penetration.