What is Menstruation?

   Menstruation is the term applied to the periodic discharge of blood from the womb or uterus of the human female. This normal function of the body usually starts between the ages of 11 and 16 years and continues at regular intervals until the age of about 45 years. The word "menstruation" comes from the Latin word meaning "month." The usual interval between periods is 28 days although variation from 20 to 35 days must be considered within the normal limits. The flow lasts from three to five days.
   The first appearance of the discharge is one of the signs of approaching maturity. Other signs are a change in body contour and particularly in the breast structure. Accompanying behavior and emotional changes awaken in the newly-developing young woman evidence of her responsibility.
   The monthly reappearance of the flow may be accompanied in a few individuals by discomfort. There may be a feeling of fullness in the breasts or abdomen or an irregularity of the bowel function.
   Menstruation occurs after the development and discharge of the EGG or ovum. The inner cellular lining of the uterus is rejuvenated with a fresh supply of blood as part of the preparation for the reception in the Fallopian tubes of an egg properly fertilized by a male SPERM. When such fertilization does not take place, the uterus discharges these engorged cells and is ready for a new cycle. Menstruation, then, depends upon the regular development of the egg—a process called OVULATION—or its discharge.
   Periodic menstruation normally continues throughout the years of life during which conception is possible. It is intimately linked to the operation of glands which supply the internal secretions. The ovaries are both stimulated and inhibited in their activity by the PITUITARY gland which lies at the base of the brain.