Temporary obstructive effect of human cervical mucus on spermatozoa throughout reproductive life: a scanning electron microscopic study

An investigation correlating scanning electron microscopic observations with sperm penetration tests carried out on cervical mucus samples taken throughout the menstrual cycle and pregnancy, during and after the onset of menopause, is presented. The results demonstrate that the temporary occlusion of the cervical canal by its mucous secretion can be accounted for, at the macromolecular level, by a variation in size of the glycoproteic meshes which constitute its infrastructure. Different types of experiments, some of which involve the stretching of the mucus prior to sperm penetration, have been carried out to reconstitute in vitro the various conditions of sperm orientation within the cervical canal. Conclusions are given concerning the behavior of sperm in the different kinds of cervical mucus. They strengthen the conclusion of Odeblad's theory.