(HealthDay News) -- Unusually heavy menstrual bleeding, medically known as menorrhagia, can be caused by a variety of factors.

Here are common causes, courtesy of the University of Virginia Health System:

• Hormonal or chemical imbalances.
• Platelet disorders.
• Pelvic inflammatory disease.
• Uterine fibroids.
• An abnormal pregnancy.
• Abnormalities in the pelvis, including infections, tumors or polyps.
• Some birth control methods, including IUD.
• Liver, kidney or thyroid disease.