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Dysmenorrhea is pain in the lowest part of the abdomen (pelvis) during a menstrual period.

• The cause is unidentified in most women.
• Pain, usually crampy or sharp, starts a few days before a menstrual period and subsides after 2 or 3 days.
• Doctors base the diagnosis on symptoms and results of a physical examination.
• Nonsteroidal anti-inflammatory drugs or, if needed, low-dose birth control pills are used.

About three fourths of women have dysmenorrhea with no identifiable cause (primary dysmenorrhea). The rest have dysmenorrhea due to another condition (secondary dysmenorrhea).

Primary Dysmenorrhea: More than 50% of women may be affected, usually starting during adolescence. In about 5 to 15% of these women, primary dysmenorrhea is sometimes severe, interfering with daily activities and resulting in absence from school or work. Primary dysmenorrhea may become less severe with aging and after pregnancy.

In primary dysmenorrhea, the pain occurs only during menstrual cycles in which an egg is released. The pain is thought to result from prostaglandins released during menstruation. Prostaglandins are hormonelike substances that cause the uterus to contract, reduce the blood supply to the uterus, and increase the sensitivity of nerve endings in the uterus to pain. Women who have primary dysmenorrhea have higher levels of prostaglandins.

Secondary Dysmenorrhea: This type usually starts during adulthood. Common causes include the following:

Adenomyosis: Noncancerous Growth of the Uterus In adenomyosis, glandular tissue from the lining of the uterus (endometrium) grows into the muscular wall of the uterus. The uterus becomes enlarged, sometimes doubling or tripling in size. This common disorder causes symptoms in only a small percentage of women, usually those between the ages of 35 and 50. It is more common among women who have had children. The cause is unknown. Symptoms include heavy and painful periods, bleeding between periods, vague pain in the pelvic area, and a feeling of pressure on the bladder and rectum. Sometimes sexual intercourse is painful. Doctors suspect adenomyosis when they do a pelvic examination and discover that the uterus is enlarged, round, and softer than normal. Pelvic ultrasonography or magnetic resonance imaging (MRI) helps confirm the diagnosis. Sometimes when adenomyosis causes abnormal bleeding, a biopsy is done. Usually, no treatment is effective, although oral contraceptives and gonadotropin-releasing hormone analogs (such as leuprolideSome Trade Names LUPRON or goserelinSome Trade Names ZOLADEX ) may be tried. Analgesics may be taken for pain. In some women, a hysterectomy may be done.

• Endometriosis: Patches of endometrial tissue—normally occurring only in the lining of the uterus (endometrium)—appear outside the uterus.
• Fibroids: Noncancerous tumors composed of muscle and fibrous tissue grow in the uterus.
• Adenomyosis: The uterus enlarges when endometrial tissue grows into the muscular wall of the uterus.
• Pelvic congestion syndrome: Blood accumulates in the veins of the pelvis because these veins have widened and become convoluted.
• Pelvic infection: Symptoms can worsen before or during menstrual periods.
• Cervical stenosis: The passageway through the cervix (cervical canal) may be narrow at birth or may become narrow when polyps are removed or a precancerous condition (dysplasia) or cancer of the cervix is treated. In a few women, cervical stenosis causes pain during menstrual periods, as menstrual blood attempts to pass through the cervix but is partly blocked.

Symptoms

Pain occurs in the lowest part of the abdomen (pelvis) and may extend to the lower back or legs. The pain is usually crampy or sharp and comes and goes, but it may be a dull, constant ache. Usually, the pain starts 1 to 3 days before or during the menstrual period, peaks after 24 hours, and subsides after 2 or 3 days.

Other common symptoms include headache, nausea, constipation, diarrhea, and an urge to urinate frequently. Occasionally, vomiting occurs. Premenstrual irritability, nervousness, depression, and abdominal bloating may persist during part or all of the menstrual period. Sometimes the menstrual blood contains clumps of tissue.

Diagnosis

Diagnosis is based on symptoms and the results of a physical examination. To identify possible causes (such as fibroids), ultrasonography may be done. Also, doctors may examine the abdominal cavity using a viewing tube (laparoscope) inserted through a small incision just below the navel. They may examine the interior of the uterus using a similar tube (hysteroscope) inserted through the vagina and cervix. Other procedures may include magnetic resonance imaging (MRI) and removal of a tissue sample from the inside of the uterus for analysis (endometrial biopsy).

Treatment

Nonsteroidal anti-inflammatory drugs (NSAIDs) usually relieve pain effectively. NSAIDs may be more effective if started 1 or 2 days before a menstrual period begins and continued for 1 or 2 days after it begins. Nausea and vomiting usually disappear without treatment as the pain subsides. Applying heat to the lower abdomen, getting enough rest and sleep, and exercising regularly may also help relieve symptoms.

If the pain continues to interfere with daily activities, oral contraceptives that contain estrogen in a low dose plus a progestin may be prescribed to suppress the release of eggs from the ovaries (ovulation).

When dysmenorrhea results from another disorder, that disorder is treated if possible. A narrow cervical canal can be widened surgically. However, this operation usually relieves the pain only temporarily. If needed, fibroids or misplaced endometrial tissue (due to endometriosis) is surgically removed.

When other treatments are ineffective and the pain is severe, the nerves to the uterus may be cut surgically. However, this operation occasionally injures other pelvic organs, such as the ureters. Alternatively, hypnosis or acupuncture may be tried.

What Is Pelvic Congestion Syndrome? Sometimes pain that occurs before or during menstrual periods results from a problem with veins in the pelvis. The veins may widen (dilate) and become convoluted, and blood accumulates in them. The result is varicose veins in the pelvis—a disorder called pelvic congestion syndrome. Pain, sometimes debilitating, can result. Estrogen may contribute because it causes some of the veins supplying the ovaries and uterus to also dilate, so that blood can accumulate in these veins as well. Up to 15% of women of reproductive age have varicose veins in their pelvis, but not all of them have symptoms. Typically, the pain is dull and aching, but it may be sharp or throbbing. It is worse at the end of the day (after a woman has been sitting or standing a long time) and is relieved when she lies down. The pain is also worse during or after sexual intercourse. It is often accompanied by low back pain, aches in the legs, abnormal menstrual bleeding, and an occasional clear or watery vaginal discharge. Some women have fatigue, mood swings, headaches, and abdominal bloating. Doctors may suspect pelvic congestion syndrome when a woman has pelvic pain but a pelvic examination does not detect inflammation or another abnormality. Ultrasonography can help doctors confirm the diagnosis. Alternatively, the veins can be viewed with a viewing tube inserted through a small incision just below the navel in a procedure called laparoscopy. Nonsteroidal anti-inflammatory drugs (NSAIDs) usually relieve the pain.

Last full review/revision December 2008 by JoAnn V. Pinkerton, MD