Answer:
Menstrual phase or Menses
Explanation:
Menses refers to the menstrual flow that consists of blood, epithelial cells shed from the uterine lining, mucus and tissue fluid. It occurs under influence of lowered levels of progesterone and estrogens in absence of fertilization. The reduced levels of progesterone and estrogens stimulate release of prostaglandins which in turn cuts off the oxygen supply to uterine lining by constriction of blood vessels. The dead cells are shed off in form of menses through vagina.
