Intermenstrual bleeding, previously known as metrorrhagia, is uterine bleeding at irregular intervals, particularly between the expected menstrual periods. It is a cause of vaginal bleeding.
In some women, menstrual spotting between periods occurs as a normal and harmless part of ovulation. Some women experience acute mid-cycle abdominal pain around the time of ovulation (sometimes referred to by the German term for this phenomenon, mittelschmerz). This may also occur at the same time as menstrual spotting. The term breakthrough bleeding or breakthrough spotting is usually used for women using hormonal contraceptives, such as IUDs or oral contraceptives, in which it refers to bleeding or spotting between any expected withdrawal bleedings, or bleeding or spotting at any time if none is expected. If spotting continues beyond the first 3-4 cycles of oral contraceptive use, a woman should have her prescription adjusted to a pill containing higher estrogen:progesterone ratio by either increasing the estrogen dose or decreasing the relative progestin dose.
Besides the aforementioned physiologic forms, metrorrhagia may also represent abnormal uterine bleeding and be a sign of an underlying disorder, such as hormone imbalance, endometriosis, uterine fibroids, uterine cancer, or vaginal cancer.
If the bleeding is repeated and heavy, it can cause significant iron-deficiency anemia.