Menstruation Phases

Menstruation lasts for a few days (usually 3 to 5 days, but anywhere from 2 to 7 days is considered normal) and involves the loss of about 30-40 millilitres of blood; many women also notice shed endometrium lining that appears as tissue mixed with the blood. An enzyme called plasmin — contained in the endometrium — inhibits the blood from clotting. Because of this blood loss, women have higher dietary requirements for iron than do males to prevent iron deficiency. Many women experience uterine cramps, also referred to as dysmenorrhea, during this time. A vast industry has grown to provide sanitary products to help women to manage their menses.

See also About your menstruation