Cervical factors

The cervical canal mucus is important to human fertility since conception can only occur if sperm pass through the contents of the cervical canal to reach the ovum. The biophysical properties of the cervical mucus and their relation to sperm migration are, therefore, curcial. A variety of laboratory experimentation methods have been used in studies of cervical mucus: 1) sperm migration measurements; 2) reheological studies; 3) cell countings; 4) crystallization studies; 5) NMR: 6) EPR; and 7) photoelectron spectroscopy. Cervical mucus is the end result of complicated biosynthetic processes occurring in the epithelial cells of the cervical mucosa; this biosynthesis is regulated by many factors. Type E, characteristic for estrogenic stimuli on mucus biosynthesis, and type G, for gestagenic stimulation, are the 2 main types of cervical secretions. The 2 types always occur together, in differing proportions. For example, at normal ovulation there is a 97:3 ratio of type E to type G; at normal corpus luteum, the ratio is 10:90. The string variety of type E seems to aid in conveying sperm from the vagina while the loaf variety is inactive. The very low viscosity of the string variety intermicellar fluid permits very rapid sperm swimming. Not much is known regarding cervical mucus pathology or therapy.