Evaluation of male infertility with an in vitro cervical mucus penetration test.

The use of an in vitro bovine cervical mucus penetration test (CMPT) provides unique data for fertility assessment. Flat capillary tubes were filled, kept frozen until use, exposed to a subsample of semen for 90 minutes, and microscopically evaluated. Adequate penetration was based on results of semen specimens from donors used for artificial insemination. of 161 patients being evaluated for infertility, 37% had semen that penetrated the CMPT inadequately. Of the patients with inadequate penetration, 70% had sperm densities of greater than 21 x 10(6)/ml, and 62% had over 50% motility. Thus neither evaluation of count nor motility provided the same information as the CMPT. Human spermatozoa had a similar swimming pattern in human and bovine mucus. Spermatozoa that exhibited poor in vitro penetration of human mucus also failed to penetrate bovine mucus. Comparison of the CMPT with postcoital tests of 42 couples revealed a good correlation. When the incidence of pregnancy for individuals with adequate and inadequate penetration was compared, more individuals with a good CMPT caused a pregnancy. It appears that the CMPT, an easy office test, allows greater discrimination of sperm function than semen analysis alone and is a useful tool for the diagnosis and management of infertility.