Abstract

PIP: It has been known that cervical mucus can enhance or impede the passage of spermatozoa through the cervical canal. Cervical mucus consists of 2 major fractions, an insoluble gel or mucin, and an aqueous phase containing the soluble components (lipids; fatty acids; prostaglandins; trace metals; proteins; enzyme inhibitors, and immunoglobulins). Mucins are glycoproteins which are characterized by a proportion of more than 40% carbohydrates distributed along the peptide core. Ultrastructure studies of cervical mucin using transmission electron microscopy suggest either a filamentous or honeycomb-like structure. It has also been suggested that the structural integrity of cervical mucin is partly dependent on its sialic acid content, which is increased in midcycle mucin. This raises the issue concerning the type of mucus secreted by the cervical mucosa and whether the structural change of the mucin observed at midcycle is due to the transfer of sialic acid by sialyltransferase to the glycoprotein molecules by the mucin in the cervical canal. If the role of the cervical mucus in the capacitation of the spermatozoa and the mechanism of fertilization is established, it might explain some cases of infertility and cervical cancer, and may be useful in the development of alternative forms of contraception.