Immunohistochemical evidence for preserved innervation of the human cervix during pregnancy.

Morphological evidence for a denervation of the human myometrium during pregnancy has previously been demonstrated. In the present study the innervation of the human cervix has been investigated in nonpregnant, early pregnant and term pregnant women. An indirect immunofluorescence method, using an antiserum to the Schwann cell specific S-100 protein, was applied to document the distribution of nerve fibers in cervical tissue biopsies. In nonpregnant, as well as in pregnant women, the cervix was by far more densely innervated than the rest of the uterus. No obvious difference in nerve density was observed between nonpregnant, early pregnant and term pregnant women, and still during labor the innervation appeared morphologically preserved. It is suggested that the segmental difference in innervation of the human uterus (corpus versus cervix) may have specific importance for myometrial and cervical contractility during pregnancy and parturition.