Menstruation is defined as the periodic
discharge of blood, mucus, and cellular debris
from the uterine mucosa. The average length of
menstrual cycle is 28 days with a normal range 21
to 35 days. The normal duration of bleeding is 5 to
7 days with a normal range of 3 to 7 days. The
average blood loss during menses is 35 ml with
normal range of 20 to 80 ml.
7-9
The menstrual
cycle is mainly regulated by the hypothalamus, in
which gonadotropin releasing hormone (Gn-RH) is
released in pulses to stimulate pituitary
gonadotropes to secrete follicle-stimulating