Bleeding from the uterus. Physiological bleeding via the vagina occurs in normal menstruation. Abnormal forms include excessive menstrual flow (hypermenorrhea, menorrhagia) or too frequent menstruation (poly-menorrhea). Non-menstrual bleeding is called metrorrhagia. Pseudo-menstrual or withdrawal bleeding may occur following estrogen therapy. Breakthrough bleeding is the term used for intermenstrual bleeding that sometimes occurs in women who take pro-gestational agents such as birth control pills or receive estrogen-progesterone replacement therapy.