Menstrual Disorders - Causes

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Dysfunctional Uterine Bleeding (DUB). DUB is a general term for abnormal uterine bleeding that usually refers to extra or excessive bleeding caused by hormonal problems. DUB usually occurs either when girls begin to menstruate or when women approach menopause, but it can occur at any time during a woman's reproductive life.

• About 90% of DUB events happen when ovulation is not occurring (anovulatory DUB). In such cases, women do not properly develop and release a mature egg. As a result, estrogen is produced continuously, causing an overgrowth of the uterus lining. The period is delayed in such cases, and when it occurs menstruation can be very heavy and prolonged.
• The other 10% of DUB cases occur in women who are ovulating (ovulatory DUB), but progesterone secretion is prolonged because estrogen levels are low. This causes irregular shedding of the uterine lining and break-through bleeding.

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Other Causes of Abnormal Uterine Bleeding. Abnormal uterine bleeding may also be related to other causes unrelated to the natural cycle or ovulation:

• Uterine Fibroids. [For more information, see In-Depth Report #73: Uterine fibroids.]
• Von Willebrand Disease and Other Bleeding Disorders. Bleeding disorders that stop blood from clotting can cause heavy menstrual bleeding. Most of these disorders have a genetic basis. Von Willebrand disease is the most common of these bleeding disorders and may be underdiagnosed in many women with unexplained menorrhagia.
• Abnormalities in the Uterus. Structural problems or other abnormalities in the uterus may cause bleeding. They include uterine polyps (small benign growths in the uterus), uterine fibroids, endometriosis, adenomyosis, and miscarriage. Infections or inflammation in the vagina or pelvic area can also cause heavy bleeding.
• Medications and Contraceptives. Certain drugs, including anticoagulants and anti-inflammatory medications, can cause heavy bleeding. Problems linked to some birth control methods, such as birth control pills or intrauterine devices (IUDs) can cause bleeding.
• Cancer. Rarely, uterine, ovarian, and cervical cancer can cause excessive bleeding
• Infection. Infection of the uterus or cervix can cause bleeding.
• Pregnancy or Miscarriage.
• Other Medical Conditions. Systemic lupus erythematosus, diabetes, pelvic inflammatory disorder, cirrhosis, and thyroid disorders can cause heavy bleeding. Women who have migraine headaches may be at increased risk for menorrhagia and endometriosis.