In some cases, the cause of heavy menstrual bleeding is unknown, but a number of conditions may cause menorrhagia. Common causes include:

  • Hormone imbalance. In a normal menstrual cycle, a balance between the hormones estrogen and progesterone regulates the buildup of the lining of the uterus (endometrium), which is shed during menstruation. If a hormone imbalance occurs, the endometrium develops in excess and eventually sheds by way of heavy menstrual bleeding.
  • Dysfunction of the ovaries. If your ovaries don't release an egg (ovulate) during a menstrual cycle (anovulation), your body doesn't produce the hormone progesterone, as it would during a normal menstrual cycle. This leads to hormone imbalance and may result in menorrhagia.
  • Uterine fibroids. These noncancerous (benign) tumors of the uterus appear during your childbearing years. Uterine fibroids may cause heavier than normal or prolonged menstrual bleeding.
  • Polyps. Small, benign growths on the lining of the uterus (uterine polyps) may cause heavy or prolonged menstrual bleeding. Polyps of the uterus most commonly occur in women of reproductive age as the result of high hormone levels.
  • Adenomyosis. This condition occurs when glands from the endometrium become embedded in the uterine muscle, often causing heavy bleeding and painful menses. Adenomyosis is most likely to develop if you're a middle-aged woman who has had children.
  • Intrauterine device (IUD). Menorrhagia is a well-known side effect of using a nonhormonal intrauterine device for birth control. When an IUD is the cause of excessive menstrual bleeding, you may need to remove it.
  • Pregnancy complications. A single, heavy, late period may be due to a miscarriage. If bleeding occurs at the usual time of menstruation, however, miscarriage is unlikely to be the cause. An ectopic pregnancy — implantation of a fertilized egg within the fallopian tube instead of the uterus — also may cause menorrhagia.
  • Cancer. Rarely, uterine cancer, ovarian cancer and cervical cancer can cause excessive menstrual bleeding.
  • Inherited bleeding disorders. Some blood coagulation disorders — such as von Willebrand's disease, a condition in which an important blood-clotting factor is deficient or impaired — can cause abnormal menstrual bleeding.
  • Medications. Certain drugs, including anti-inflammatory medications and anticoagulants, can contribute to heavy or prolonged menstrual bleeding.
  • Other medical conditions. A number of other medical conditions, including pelvic inflammatory disease (PID), thyroid problems, endometriosis, and liver or kidney disease, may be associated with menorrhagia.
Jul. 02, 2014

You Are ... The Campaign for Mayo Clinic

Mayo Clinic is a not-for-profit organization. Make a difference today.