A woman’s menstrual period (period) is produced by the shedding of the lining of the uterus, which is expelled through the vagina. The uterus is located in the center of the female pelvis, in front of the bladder and behind the rectum. A woman’s endometrium is cyclical and self-limiting in nature with periodic peeling that occurs with the ovarian cycle. Normally, a woman’s menstrual cycle usually lasts about 21 to 35 days, with a duration ranging from 3 to 7 days and a bleeding volume of about 20 to 60 ml. The thickness of the endometrium varies with the level of hormones secreted by the ovaries, and when a certain thickness is reached, then the endometrium peels off and menstruation is formed. If you have a prolonged or shortened menstrual cycle, heavy or light menstrual flow, or experience discomfort during menstruation, go to the hospital for prompt medical attention, make a clear diagnosis, and deal with the cause of the problem.