A uterine hemorrhage is an instance of excessive blood-letting by blood vessels inside the uterus. This bleeding is usually not related to menstruation, except in the case of anovulation, and is considered abnormal and an occasion for medical emergency. The hemorrhage generally results in rapid bleeding that can cause a woman to lose so much blood that she lapses into shock. Neoplasms, pregnancy trauma, and anovulation account for the majority of abnormal bleeding cases in the uterus. Often, chronic or infectious diseases can also cause a uterine hemorrhage.

In most instances, a uterine hemorrhage can last between two days and seven days. Adolescent girls and adult women are mainly affected. A female infant or toddler, however, can suffer a uterine hemorrhage due to estrogen-related tumors, according to medical research.

Pregnancy-linked hemorrhages include postpartum bleeding and bleeding due to a miscarriage or ectopic pregnancy. During postpartum hemorrhages, uterine contractions fail to close up blood vessels in the uterus that have been torn by the detachment and expulsion of placenta. When these contractions are too slow or insufficient to halt the bleeding of the vessels, a hemorrhage results, causing some women to lose up to a quart (0.95 liters) of blood. Ectopic pregnancies and miscarriages can bring hemorrhages that are accompanied by severe cramping.

Conditions and infections like shigella and pelvic inflammatory disease can sometimes cause bleeding in the uterus. Shigella is type of food poisoning triggered by bacteria. A sexually-transmitted disease like chlamydia can also result in a uterine hemorrhage.

Neoplasms, or abnormal tissue growth, can frequently cause a uterine hemorrhage. The most common types of neoplasms include polyps, lesions, fibroids, and tumors. Often a uterine hemorrhage linked to some of these neoplasms might indicate uterine cancer. In rare cases, belated tumors can form at the site where old placenta was once attached. These tumors, formally called placental site trophoblastic tumors, and related uterine hemorrhages can occur in an older woman who has gone through menopause.

Anovulation is the circumstance of having menstruation-like bleeding that is not a true menstrual cycle. This bleeding is usually extremely heavy and recurs on a regular basis. Unlike true menstruation, this cyclical bleeding occurs without eggs being released by the fallopian tubes.

Lastly, medicines and drug prescriptions can cause uterine hemorrhaging, especially if the medicine contains hormones. Hysterectomies, ablations, and other surgical procedures might be necessary to stem the cause of uterine hemorrhages. Diagnosis of the cause of the hemorrhage is generally done through ultrasound or biopsy.