Sperm counts in enzymatically liquefied cervical mucus: quantitative validation using donor cervical mucus.

The post-coital test evaluates the penetration of spermatozoa into cervical mucus; it relies on subjective measurements and therefore lacks precision. Enzymatic liquefaction of cervical mucus allows sperm concentration to be measured in post-coital test samples, but the reliability of such measurements is not known. Donor cervical mucus was used as a model to test the accuracy and sensitivity of sperm quantification in liquefied cervical mucus. Donor cervical mucus was dissolved by enzymatic treatments in the presence of known numbers of spermatozoa and the recovery of sperm cells was assessed after liquefaction of the samples. Enzymatic treatment of cervical mucus with a combination of bromelin and glycosidases resulted in reliable and fast liquefaction of the samples. The accuracy of sperm concentration measurements was 89 +/- 10% (mean +/- SD, n = 50), and the sensitivity limits were 1 x 10(6) and 0.2 x 10(6) spermatozoa/ml for quantitative concentration measurement and qualitative sperm detection respectively. This study demonstrates that liquefaction of cervical mucus by combined protease and glycosidases allows accurate and sensitive determination of sperm concentration in the sample. Therefore we believe that valuable data can be obtained for sperm concentration and total sperm counts in post-coital tests, that should help to improve the reliability of the post-coital test.