Histochemical changes in cervical mucus-secreting epithelium during the normal menstrual cycle

Recently developed specific histochemical techniques were applied to sections of human endocervix to investigate possible cyclic changes in stainable intracellular mucin glycoproteins. During the secretory phase, there is a decrease in the sialic acid/O-sulfate ester ratio, a decrease in the neutral sugar/acidic sugar ratio and increased amounts of O-sulfate ester, compared with during the proliferative phase. Endocervical epithelia from prepubertal, pregnant, and postmenopausal females also show decreased sialic acid/O-sulfate ester and neutral sugar/acidic sugar ratios, compared with during the proliferative phase. The authors conclude that proliferative phase mucin is chemically different from secretory phase mucin, and that this difference may be significant in allowing sperm penetration in the periovulatory period.