Correlation of the bovine cervical mucus penetration test with human sperm characterisitics in 1,406 ejaculates

The bovine cervical mucus penetration test (BCMPT) was performed to determine its usefulness in screening the ability of sperm to successfully penetrate mucus in vitro. Ejaculates were obtained by masturbation from patients attending an infertility clinic. Routine semen analysis was performed using a microcomputerized multiple-exposure photography system. The BCMPT was performed. Overall, the average penetration of the mucus was 38 +/- 0.46 mm. Of the 1,406 ejaculates analyzed, 244 (17%) displayed a negative result (0-20 mm), 291 (21%) a questionable result (21-30 mm), and 871 (62%) a positive result (>30 mm). A highly significant (p < .001) correlation between mucus penetration distance and sperm MD (r = 0.541), MI (r = 0.484), count (r = 0.475), motility (r = 0.448), velocity (r = 0.400) and morphology (r = 0.369) was observed. Overall, the finding of an abnormal semen parameter resulted in a 34 +/- 5% accurate prediction of a negative or questionable BCMPT (<30 mm), while a normal semen parameter resulted in a 90 +/- 4% accurate prediction of a positive BCMPT (>30 mm). Sperm MD showed the strongest positive predictive value (98%), while morphology showed the greatest negative predictive value (50%). Of the 1,406 samples, 25 +/- 2% of the samples with normal semen parameters displayed a negative BCMPT. Conversely, 6 +/- 2% of samples with abnormal parameters showed a positive BCMPT. The BCMPT successfully identifies a significant subpopulation of patients as having an inadequate penetration of mucus with otherwise normal semen characteristics.