Morphology of postcoital spermatozoa in the cervical secretion and its clinical significance.

Morphologic analysis of spermatozoa recovered 10 hours postcoitally from the human female genital tract and its correlation to the clinical situation have shown that (1) spermatozoa in the vagina are equivalent to those in the semen sample; (2) spermatozoa within the cervical secretion exhibit significantly better morphology than do those of the semen sample, indicating the presence of a barrier against abnormal spermatozoa at the level of the external os; (3) this barrier is significantly more effective in cases where conceptions later occur than in cases of persistent, unexplained infertility; and (4) the barrier is particularly active against spermatozoa with abnormal heads.