Corpus luteum is essential for establishing and maintaining pregnancy in females. The corpus luteum secretes progesterone, which is a steroid hormone responsible for the decidualization of the endometrium (its development) and maintenance, respectively. It also produces relaxin, a hormone responsible for softening of the pubic symphysis which helps in parturition. If the egg is not fertilized, the corpus luteum stops secreting progesterone and decays (after approximately 10 days in humans). It then degenerates into a corpus albicans, which is a mass of fibrous scar tissue. The uterine lining (endometrium) is expelled through the vagina (in mammals that go through a menstrual cycle).
Menstrual cycle few days (usually 3 to 5 days, but anywhere from 2 to 7 days is considered normal). The average blood loss during menstruation is 35 milliliters with 10–80 ml considered normal. Women who experience Menorrhagia are more susceptible to iron deficiency than the average person. An enzyme called plasmin inhibits clotting in the menstrual fluid. Painful cramping in the abdomen, back, or upper thighs is common during the first few days of menstruation. Severe uterine pain during menstruation is known as dysmenorrhea, and it is most common among adolescents and younger women (affecting about 67.2% of adolescent females). When menstruation