What is the term for the breakdown and loss of the uterus lining from the vagina?

The process described in the question refers specifically to menstruation, which is characterized by the shedding of the endometrial lining of the uterus when there is no implantation of a fertilized egg. During the menstrual cycle, if fertilization does not occur, hormonal changes trigger this breakdown, leading to the loss of blood, tissue, and mucus through the vagina. Menstruation typically occurs in cycles and is a key part of the reproductive system for individuals with a uterus, marking the end of one cycle and the beginning of another.

Implantation involves the embedding of a fertilized egg into the uterine lining and does not involve the loss of tissue. Ovulation is the release of an egg from the ovary, while fertilization is the union of sperm and egg. Both of these events occur earlier in the reproductive cycle and are not related to the process of shedding the uterine lining. Hence, menstruation is the correct term for the breakdown and loss of the uterus lining through the vagina.