Premonitory symptoms (7)
With the onset of labor, there is profuse cervical secretion. Simultaneously, there is slight oozing of blood from rupture of capillary vessels of the cervix and from the raw decidual surface caused by separation of the membranes due to stretching of the lower uterine segment. Expulsion of cervical mucus plug, mixed with blood is called show.
This bloody show results as the cervix begins thinning out with the concomitant extrusion of mucus from the endocervical glands.
Patients often report the passage of blood-tinged mucus late in pregnancy.