Abnormal uterine bleeding (AUB) includes menorrhagia (menses too heavy), metrorrhagia (bleeding in between menses) and hypermenorrhea (menses too long). Abnormal uterine bleeding may describe amenorrhea or absence of menstrual periods.

If you are between the ages of 40 and 50, you're at a higher risk for AUB. Fifty percent of patients with AUB are older than 45. Before menopause, your periods may suddenly become lighter or heavier because you are ovulating less often. If you have just begun to menstruate, you may also experience AUB.

Sometimes abnormal bleeding is caused by hormonal problems. A significant number of women with excessive menstrual bleeding fall into this category. Hormonal imbalances occur when your body produces too much or not enough of certain hormones.

Aside from hormonal problems, there are many other causes of abnormal uterine bleeding. They include:

• Certain birth control methods, such as intrauterine devices (IUDs) or birth control pills
• Infection of the uterus or cervix
• Uterine fibroids
• Blood clotting problems
• Some types of cancer, including uterine, cervical and vaginal
• Chronic medical problems, such as hypo- and hyperthyroidism, lupus and diabetes

About 20 percent of all hysterectomies are performed to stop AUB, and it's the only treatment that completely guarantees relief from the problem. However, this is a radical surgery where your uterus is removed and you will no longer be able to have children.

Some premenopausal women don't have any periods at all. Called amenorrhea, or the absence of menstruation, this condition is normal before puberty, after menopause and during your pregnancy. There are two kinds of amenorrhea: primary and secondary. Primary amenorrhea is diagnosed if you reach the age of 18 and haven't yet begun to menstruate. Secondary amenorrhea is diagnosed if you've had regular periods, but they suddenly stop.

Pain from menstrual cramps is caused by contractions of your uterus triggered by prostaglandins, hormone-like substances found in many different types of tissue.

Both medication and surgery are used to treat AUB. Typically, less invasive therapies should be considered first. Treatment depends on your age, desire to preserve fertility and the cause of the bleeding.

Premenstrual syndrome (PMS) is a term commonly used to describe a range of severe physical and psychological symptoms that some women experience seven to 10 days prior to the start of their periods and end just after. To qualify as PMS symptoms, they must be associated with the menstrual cycle, become more severe as the menstrual cycle progresses and be present for at least three consecutive menstrual cycles.

Premenstrual dysphoric disorder (PMDD) is different from the more common PMS; it's far more severe. Women who experience PMDD (about 3 to 8 percent of all women) say that it significantly interferes with lives. The most common symptoms of PMDD are heightened irritability, anxiety and mood swings. Women who have a history of major depression, postpartum depression or mood disorders are at higher risk for PMDD than other women.