Normal vaginal bleeding is the periodic blood that flows as a discharge from the woman's uterus. Normal (menstrual) vaginal bleeding is also called menorrhea. The process by which menorrhea occurs is called menstruation.
Normal vaginal bleeding occurs as a result of cyclic hormonal changes. The ovaries are the main source of female hormones, which control the development of female body characteristics such as the breasts, body shape, and body hair. The hormones also regulate the menstrual cycle. The ovary, or female gonad, is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs (ova) and female hormones. During each monthly menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a Fallopian tube to the uterus.