Effect of caffeine on sperm penetration rate into cervical mucus in-vitro.

A system for determination of sperm penetration into cervical mucus in a glass capillary tube is described. Repeated counts are made of the number of sperm at fixed horizontal distances from the semen reservoir. The yields indices for total numbers of spermatozoa entering the mucus per unit time and the rate migration of the sperm through the mucus. It was found that the rate of entry was sensitive to changes in motility such as those induced by caffeine, and differences in cervical mucus quality. The system allowed quantitation of these differences.