Clinical significance of crossed in vitro sperm-cervical mucus penetration test in infertility investigation

To evaluate the clinical significance of in vivo and in vitro testing of sperm ability to penetrate cervical mucus (CM), postcoital testing (PCT) and in vitro sperm-cervical mucus penetration testing were compared in a prospective study. Both in vivo and in vitro tests were standardized and performed after an oral course of estrogen therapy. Crossed in vitro sperm-cervical mucus penetration test, evaluated in 277 couples with CM of patients' wives and additionally with CM and semen of fertile donors, revealed that the male factor contributed to a significantly higher extent to deficient sperm-mucus interaction than the cervical factor. The overall pregnancy rate after 6 months was 23% (64/277). Whereas the outcome of PCT did not significantly predict subsequent fertility (PCT good pregnancy rate 24%/PCT poor 20%), significant differences were found for the sperm-cervical mucus penetration test with CM of patients' wives (pregnancy rate, 30.5% versus 8.5%) and for in vitro testing with donors' CM, but not for the mucus penetration test with donors' spermatozoa. Routine sperm analysis did not prove to be of prognostic value for a subsequent pregnancy. The results suggest that the in vitro sperm-cervical mucus penetration test is a good parameter of sperm function and, in particular, when performed as a cross-matching penetrability test, a valuable adjunct to PCT with regard to fertility prognosis.