Bhawna Bhardwaj,Subject matter expert at Edumarz
Solution- when the ovum or egg gets fertilized and the woman gets pregnant. Because the thick and soft lining of the uterus contains a lot of blood vessels that are needed for the groThe ovary of a woman releases one egg or ovum every month, therefore the uterus also prepares itself every month to receive fertilized egg or zygote. So, in this process, the lining of the uterus becomes thick and soft with lots of blood vessels in it. Preparation of the uterus is necessary because in case the egg is fertilized by a sperm, then the uterus has to keep the zygote and nourish it to develop it into a baby. If the ovum released by the ovary is not fertilized by sperm, then the uterus lining is not required. As a result, the uterine lining breaks down and comes out through the vaginal canal in the form of blood and mucus. That is why menstruation occurs.
Background-The breakdown and removal of the inner, thick, and soft lining of the uterus along with its blood vessels in the form of vaginal bleeding are called menstrual flow or menstruation.
Menstruation occurs every 28 days. The menstrual cycle is controlled by hormones.
Menstruation stops temporarily wth the development of the zygote to form a baby.